Report on safety requirements (D2.1)

D2.1 Report on safety requirements Ref. Ares(2024)3889354 - 30/05/2024 D 2.1 Report on safety requirements DELIVERABLE TYPE Report MONTH AND DATE OF DELIVERABLE M12, 31/05/2024 WORK PACKAGE WP2 LEADER ENVI DISSEMINATION LEVEL Public AUTHORS Mattia Miglietta PROGRAMME HORIZON EUROPE GRANT AGREEMENT 101111933 START Jun.2023 DURATION 24 Months 3 Contributors NAME ORGANISATION María Panadero Gema Rodado CNH2 Marek Kruszewski Magdalena Raczyńska Żaneta Kłostowska RIGP Simon Habran TWEED Miroslava Tzekova Vasimir Radulov BH2C Peer Reviews NAME ORGANISATION Ilaria Schiavi ENVI María Panadero CNH2 Revision History The information and views set out in this report are those of the author(s) and do not necessarily reflect the official opinion of the European Union, neither the European Union Institutions and Bodies nor any person acting on their behalf. VERSION DATE REVIEWER MODIFICATIONS V1 29/05/2024 María Panadero (CNH2) MODIFICATIONS V2 30/05/2024 Ilaria Schiavi (ENVI) FINAL REVIEW 4 Index of Contents 1 Introduction .................................................................................................................................................... 9 2 Safety Approaches for Hydrogen Technologies ..................................................................................11 2.1 Generalities ...........................................................................................................................................11 2.2 Prescriptive approach for Safety of Hydrogen technologies .....................................................12 2.2.1 Technical rules for safety of hydrogen technologies in Italy: Hydrogen Refuelling stations and Hydrogen production through electrolysis ............................................................................................................. 12 2.2.1.1 Cogeneration solution for Residential application: Italian prescriptions ............................... 25 2.2.2 Regulation for safety in Bulgaria: Hydrogen Refuelling Stations ..................................................... 26 2.2.3 Safety of Hydrogen technologies: observations from French legislative framework .................. 34 2.3 Performance-based approach for Safety of Hydrogen technologies .......................................36 2.3.1 Safety for Hydrogen Distribution and Production Facilities: Performance-based Approaches from Belgium and Spain .............................................................................................................................................. 36 2.3.2 Safety for Hydrogen Distribution Facilities (HRS) and FCEVs: Performance-based Approaches from Poland and Italy ................................................................................................................................................... 42 2.3.3 Performance-based approach for HRS in Germany ............................................................................ 44 2.3.4 Evidences of safety requirements from the Performance-based point of view ........................... 47 2.3.4.1 Examples of safety approach for Hydrogen Production Facility ............................................. 47 2.3.4.2 Examples of safety approach for Hydrogen Refuelling Stations ............................................. 53 2.3.4.3 Examples of safety approach for Hydrogen Heating Systems for Residential application 56 3 Comparisons of safety approaches in HYPOP countries ...................................................................59 4 Conclusions ..................................................................................................................................................63 5 Appendix A ...................................................................................................................................................65 5.1 Italy.........................................................................................................................................................65 5.1.1 Technical rule for the installation of cogeneration units serving civil, industrial, agricultural, artisanal, commercial activities and services ........................................................................................................... 66 5.1.2 Technical rule for the design, construction, and operation of natural gas storage facilities with a density not exceeding 0.8 ........................................................................................................................................... 69 5.2 Spain ......................................................................................................................................................73 5 Index of Tables Table 1 Fire Fighters’ legislative framework for safety installation of hydrogen technologies in Italy .................................................................................................................................................................................14 Table 2 HRS components considered as dangerous by Italian technical rule .........................................18 Table 3 Safety distances for Compressors, Storage systems and Containment structure for Tube Trailers in HRS (Italy) ...........................................................................................................................................20 Table 4 Safety distances for Dispensers in HRS (Italy) ................................................................................20 Table 5 Safety distances between hydrogen and other conventional fuels (Italy) .................................22 Table 6 Correlation between operating pressures and minimum safety and protection distances for hazardous elements in a renewable hydrogen production facility (Italy) .................................................24 Table 7 Safety distances for natural gas storage system (Italy).................................................................26 Table 8 Safety distances between different elements of an integrated HRS in Bulgaria ....................30 Table 9 Other safety distances within HRS in Bulgaria ...............................................................................33 Table 10 Safety distances between H2 technologies in HRS for France .................................................34 Table 11 Categories of storage, indicators and limits for Storage Quantity in MIE APQ Regulation (Spain) .....................................................................................................................................................................40 Table 12 Location and safety distances according to MIE APQ Regulation ............................................41 Table 13 Requirements for closed area warehouses according to MIE APQ Regulation .....................41 Table 14 Requirements for open area warehouses according to MIE APQ Regulation .......................41 Table 15 Fire protection elements according to MIE APQ Regulation.....................................................41 Table 16 Examples of the compliance of the regulations for hydrogen production, storage and handling (Spain) ....................................................................................................................................................48 Table 17 International and European references for HRS in Belgium ......................................................55 Table 18 Documentation required by safety authorities and technical standards applied for electrolysers safety assessment in Bulgaria ...................................................................................................58 Table 19 Cases where cogeneration units are coupled with heat generation systems using "similar" fuels (Italy) .............................................................................................................................................................68 Table 20 Safety distances between the cogeneration unit and storage systems in Italy .....................68 Table 21 Maximum storage capacity allowed (Italy) .....................................................................................70 Table 22 Safety distances between Pipeline-tanks (high pressure) and internal buildings ..................70 Table 23 Safety distances for Tanks (medium pressure) .............................................................................71 Table 24 Safety distances for storage systems with safety degree 1 .......................................................72 Table 25 Safety distances for storage systems with safety degree 2 .......................................................72 Table 26 Safety distances for storage systems of 4th category with no safety degree .......................73 Index of Figures Figure 1 Iberdrola Hydrogen plant for ammonia production in Puertollano (Castilla-La Mancha, Spain) ......................................................................................................................................................................48 Figure 2 Layout of the HYPER project (Italy) .................................................................................................52 6 7 Partners short names ENVI Parco Scientifico Tecnologico Per L’ambiente Environment Park Torino Spa IMI Institute For Methods Innovation IME Fundacion IMDEA Energia APRE Agenzia per la Promozione della Ricerca Europea CNH2 Centro Nacional Del Hidrogeno RIGP Regionalna Izba Gospodarcza Pomorza CLUSTER TWEED Cluster Tweed BH2C Balkanski Vodoroden Klaster Abbreviations APQ Almacenamiento de Productos Quimicos BPVC Boiler and Pressure Vessel Code BRA Building Risk Assessment CGA Compressed Gas Association EIGA European Industrial Gases Association FCEV Fuel Cell Electric Vehicle FERA Fire and Explosion Risk Assessment FMECA Failure Mode, Effects & Criticality Analysis ISO International Organization for Standardization HRS Hydrogen Refuelling Stations HAZID Hazard Identification HAZOP Hazard and Operability Analysis LOPA Layers of Protection Analysis MIE Ministerio de Industria y Energia NFPA National Fire Protection Association PSV Pressure Safety Valve QRA Quantitative Risk Assessment RD Real Decreto SIL Safety Integrity Level UNE Asociación Española de Normalización 8 Executive Summary The primary aim of this report is to outline the safety requirements for hydrogen projects, detailing both prescriptive and performance-based approaches across different countries involved in the HYPOP project. This report is intended to raise public awareness and trust towards hydrogen technologies and support decision-makers in integrating hydrogen into local economies and communities. The HYPOP project focuses on stakeholder engagement through surveys, interviews, and participation in events to collect information on safety, permitting, and certification requirements for hydrogen technologies. In this deliverable the following information are shared: • General Properties of Hydrogen; • Description of the safety approaches identified for Hydrogen Technologies: Prescriptive and Performance based approach; • General description of safety requirements corresponding to both the approaches; • Examples from HYPOP stakeholders of the application of the safety approaches in different sectors like industry, mobility and residential. 9 1 Introduction HYPOP project aims to raise public awareness and trust towards hydrogen technologies and their systemic benefits. To do this, stakeholders’ engagement is a pivotal aspect that has been taken into account for this project. Work package 2 (WP2) methodology involved tools to gather information from stakeholders through surveys, interviews and participation to events (engagement activity useful also for WP1). WP2 activities are crucial to provide the basis for the final guidelines that will support decision makers in introducing hydrogen in the local communities and economies. Specifically, technical data gathered about safety, permitting and certification requirements will be used for the workshops that will involve HYPOP’s stakeholders and thus providing decision makers with valuable information coming from sharing real experiences and technical know-how. The stakeholder’s engagement methodology followed for the Deliverable 2.1 (D2.1) included the following steps: • Identification of the categories of stakeholders involved in safety issues (Technology manufacturers, early adopters and public authorities involved in the evaluation of safety); • Organization of surveys, interviews, and participation to events to engage stakeholders; • Mapping of the existing regulations on safety in each Country to highlight the main requirements and approaches; • Comparison and similarities related to safety aspects between different H2 projects in each Country. The research activity for D2.1 has covered the HYPOP countries of the partners involved in WP2 (Italy, Spain, Poland, Belgium and Bulgaria). Moreover, Frontrunner countries like Germany and France have been taken into account as well as some of the EU-13 countries. This deliverable is structured around the two main approaches to safety that emerged during the stakeholders’ engagement activity: prescriptive and performance based. The information provided exemplifies current approach to safety by the technology manufacturers, the early adopters and the authorities, and their correlation. Both approaches aim to ensure the implementation of European Regulations and Directives on safety as well as the specific requirements by National Regulations. The prescriptive approach to safety provides detailed safety requirements that must be met and which are generally produced by legislators and authorities at a central (national) level. These apply to certain categories of hydrogen installations, with the prescription of safety measures defined according to a range of possible applications. Typical requirements of a prescriptive approach may concern, for example, safety distances between different components of a system or facility, maximum working pressures and the use of specific components manufactured under certain technical standards. Detailed information on hydrogen-specific technical safety regulations, identified within HYPOP’s research, will be provided in the text, showing an example of the type and level of prescription required in this kind of regulations. Appendix A contains examples of further prescriptive technical safety rules applied in Italy to hydrogen projects and innovative end uses (e.g. the residential sector), but borrowed from traditional fuels such as natural gas. This regulatory transfer is often adopted to fill procedural gaps, as already highlighted in other studies. 16 Annex I Activities Presidential Decree 151/2011 Hydrogen technology Italian Technical rules for fire prevention 49 A Groups for the production of auxiliary electric power with internal combustion engines and cogeneration plants of total power between 25 kW and 350 kW Fuel cells DM 13/07/2011: Technical rule for fire prevention for the installation of internal combustion engines coupled with electric generators or other operating machines and cogeneration units serving civil, industrial, agricultural, artisanal, commercial, and service activities. 49 B Groups for the production of auxiliary electric power with internal combustion engines and cogeneration plants of total power between 350 kW e 700 kW 49 C Groups for the production of auxiliary electric power with internal combustion engines and cogeneration plants of total power > 700 kW 74 A Plants for heat production fuelled by solid, liquid, or gaseous fuel with a capacity greater than 116 kW and up to 350 kW Boilers DM 08/11/2019: Technical fire prevention rule for the design, construction, and operation of heat production plants fuelled by gaseous fuels. 74 B Plants for heat production fuelled by solid, liquid, or gaseous fuel with a capacity greater than 350 kW and up to 700 kW 74 C Plants for heat production fuelled by solid, liquid, or gaseous fuel with a capacity greater than 700 kW 17 The main national regulations for fire prevention (safety) of hydrogen technologies in Italy are: 1. Decree of 23 October 2018 by the Ministry of the Interior: “Technical rule for fire prevention for the design, construction, and operation of hydrogen distribution plants for motor vehicles; 2. Decree of 7 July 2023 by the Ministry of the Interior: “Technical rule for fire prevention for identifying risk analysis methodologies and fire safety measures to be adopted for the design, construction, and operation of hydrogen production plants through electrolysis and their storage systems.” These technical rules for fire prevention are mainly applicable to the industry and mobility sector but, in absence of other regulations (technical rules) for fire prevention, their application to the residential sector cannot be excluded and can be integrated with risk assessment methodologies and the safety requirements borrowed by other technical rules for conventional fuels like natural gas. The general objectives of these technical rules are: • To reduce the causes of fire and explosion; • To limit, in the event of an accidental event, the damages to people; • To limit, in the event of an accidental event, the damages to buildings and the surrounding environment; • To allow first responders to work safely. Technical rule for Hydrogen Refuelling stations (Italy) The technical rule for fire prevention for hydrogen refuelling stations (HRS) “Decree of 23 October 2018 by the Ministry of the Interior” regulates the safety requirements that must be met for both new service stations and existing ones in case of modifications planned from the date of entry into force of the decree. Although the regulation may generally consider both gaseous and liquid fuels, it specifies prescriptions for gaseous hydrogen distribution facilities. The application of the above safety requirements to other mobility areas than road mobility, such as inland waterway and railway, should not be excluded even if not directly specified. In those cases where it is not possible to fully comply with the prescriptive requirements of the regulation, it is possible to request for a performance-based safety approach called “engineering approach to fire safety,” whose provisions are detailed in the Ministerial Decree of 9 May 2007. This technical rule opens up the possibility of constructing a HRS according to the international standard ISO 19880-1 “Gaseous Hydrogen – Fuelling stations”. Depending on the site of installation, the safety requirements can vary. A HRS is forbidden when the construction area falls: 18 a) within the homogeneous territorial zone that is fully built-up (identified as zone A in the general regulatory plan or in the building program), and within the perimeter of the built-up area in those municipalities lacking the aforementioned urban planning instruments. In both cases, the existing building density within a 200 m radius from the perimeter of the hazardous elements of the plant (Table 2) cannot be higher than 3 m³ per m²; b) in the completion and expansion zones of the urban aggregate indicated in the general regulatory plan or in the building program, where a building density higher than 3 m³ per m² is expected; c) in areas, wherever located, designated as public green spaces. However, there are some exemptions from the safety restrictions that can be granted by the territorially competent municipality. For example, if the installation site falls within the completion and expansion zones of the urban area (b), HRS powered by a pipeline system, are allowed when: • The storage system is less than 500 Nm3; • The amount of hydrogen produced on site is less than 50 Nm3/h; • There are no hydrogen bundles (even emergency ones are not allowed). The same exemptions apply if the building area of the HRS falls within areas designated as public green spaces but only when the municipal urban planning instruments already envisage the presence of fuel distributors in other green areas. In all those cases not included in the previous list, it is possible to build a HRS for road mobility. It is important to specify that the technical rule allows only trained personnel to perform hydrogen dispensing activities through the dispenser. There is an exemption only in the case of private HRS for company fleets where the facility is located within the company premises. In this case, if the employee personnel are properly trained and if the dispensing system is equipped with communication hardware and software between the vehicle and the station that ensures safe delivery, they can proceed with hydrogen dispensing in selfservice mode. According to this fire prevention technical rule, the following are considered hazardous elements (Table 2): Table 2 HRS components considered as dangerous by Italian technical rule Hazardous elements Hydrogen production units (if present) The gas hydrocarbon pressure reduction and metering cabin (only in the case of a production unit consisting of a reformer with hydrocarbons) Compressors Storage units Tube trailers, if present Dispensing units Connecting elements between hazardous elements for hydrogen transfer (piping and connections) 19 All hazardous elements, except for the dispensing unit, must be fenced with a structure not less than 1.8 meters in height and placed at a distance from other elements of the plant to allow for safe operation. In addition to fencing, the technical rule prescribes the need to create, for all elements defined as hazardous except for the dispensing unit, a solid containment structure. The containment is a structure made of reinforced concrete walls, or other non-combustible material with adequate mechanical resistance, with construction characteristics of the structures such that they only peripherally mitigate the effects of explosion and fire, including projectile debris. The containment structure can have one or two of the four sides completely open provided that such openings do not face areas open to the public. The height of the containment must be more than 1 m higher than the highest point of the hazardous elements contained therein. The technical rule recommends that, within the containment, suitable measures are adopted to prevent the formation and persistence of explosive atmospheres. The technical rule defines the design characteristics of the HRS both where there is an onsite production unit or if hydrogen is supplied through an external pipeline or tube trailers: • If the HRS includes, within its perimeter, a hydrogen production unit (via electrolysis or steam reforming of natural gas or another hydrocarbon), a specific risk assessment must be mandatorily provided, with the characteristics described in Annex I of the Ministerial Decree of 7 August 2012. Both types of hydrogen production units must be designed following international standards: ISO 16110-1 “Hydrogen generators using fuel processing technologies - Part 1: Safety (like steam methane reforming) and ISO 22734-1 “Hydrogen generators using water electrolysis - Part 1: General requirements, test protocols and safety requirements”. These hazardous elements must be placed in solid containment. • Compressors, along with any ancillary devices, must be placed in solid containments and must be designed according to the standard EN 1012-3 “Compressors and vacuum pumps - Safety requirements - Part 3: Process compressors”. Multiple safety valves must be installed at the end of the compressors. Vessels used to balance pressure variations must be installed in solid containment as well and must be characterized by a geometric volume lower than 0.4 m³; • Storage systems must be designed to operate with a variable operating pressure of up to 1,000 bars and with a storage capacity of less than 6,000 Nm³ according to the international standard ISO 19884 “Gaseous hydrogen — Cylinders and tubes for stationary storage” (this standard has been delated and a new draft is under development by ISO). Safety must also be ensured by installing a support structure for the system made of fire-resistant material R60 or similar (material capable of maintaining its mechanical integrity during 60 minutes of fire exposure), thermally actuated valves, and pressure monitoring valves. Only when the total hydrogen capacity exceeds 6,000 Nm³, the containment envisaged can be composed of several smaller, solid, wall separated containments, one for each storage tank; • Tube trailers for HRS must be designed following the ADR regulation (International Agreement on the Transport of Dangerous Goods by Road). During refuelling within 20 the HRS perimeter, the piping is considered part of the overall plant, the parking area must ensure the absence of maneuvers for the d in case of emergency, and there must be no obstacles along the trajectory from the HRS plant entrance to the unloading area. The replacement of the tube trailers should not be carried out simultaneously with the unloading of other possibly containing fuels or substances other than hydrogen. The previous hazardous elements must respect some specific safety distances. Below are the definitions of the distances indicated in the Table 3 (definitions according to D.M 30/11/83 coordinated with the modifications and integrations introduced by D.M 09/03/07): • Protection distances: the minimum value of the distances measured horizontally between the perimeter in plan of each hazardous element of an activity and the fence (where prescribed) or the boundary of the area on which the activity itself is located; • Internal safety distances: the minimum value of the distances measured horizontally between the respective perimeters in plan of the various hazardous elements; • External safety distances: the minimum value of the distances measured horizontally between the perimeter in plan of each hazardous element of an activity and the perimeter of the nearest building outside the activity itself or other public or private works or with respect to the borders of buildable areas towards which such distances must be observed Table 3 Safety distances for Compressors, Storage systems and Containment structure for Tube Trailers in HRS (Italy) Hazardous elements Protection distances Internal safety distances External safety distances Compressors 15 m \ 30 m Storage units 15 m 15 m 30 m Containment structure of the tube trailer 15 m 15 m 30 m For the compressor containment structure, the external safety distance, except for that computed from buildings for public use, can be reduced by 50% if it is proved that between the openings of the compressor containment and the buildings external to the plant, suitable continuous screening with concrete walls or other non-combustible material of adequate mechanical strength are realized, such as to ensure the containment of any fragments projected towards the external constructions. Table 4 Safety distances for Dispensers in HRS (Italy) Hazardous element Protection distance Internal safety distance External safety distance Dispensing unit 15 m 12 m 30 m 21 The external and protection distances of the dispensing unit (Table 4) can be reduced by 50% if appropriate non-combustible material barriers of adequate mechanical resistance are placed between them and the external constructions to the plant, except those for public use. Additional safety distances must be provided to separate the hazardous elements from spaces designated for auxiliary services like: • Manager's office, warehouse, toilets, workshop without the use of open flames, and washing plant: the same internal safety distances defined in the previous tables apply; • Electric power cabin: 22 m; • Manager's dwelling: external safety distance; • Dining and/or sales areas: o Up to 50 m2 of total covered area: the internal safety distances from the previous tables apply; o Up to 200 m2 of gross area accessible to the public (an additional area for services and storage not exceeding 50 m2 is also allowed): 15 m from the hydrocarbon gas reduction and measurement cabin and 22 m from the other hazardous elements of the plant; o For areas larger than those indicated above: 30 m. Furthermore, the technical rule prescribes a double external safety distance from buildings intended for community uses such as schools, hospitals, offices, worship buildings, public entertainment venues, sports facilities, tourist-hotel complexes, supermarkets and shopping centers, barracks, and places where people frequently gather such as public transport stations, fairgrounds, markets, etc. The calculation of external safety distances can include the widths of roads, rivers, streams, and canals. Moreover, when the external safety distance refers to buildable areas, it is allowed to include the prescribed setback distance, in cases where local building regulations prohibit construction on the boundary. Between the hazardous elements and overhead electric lines, with voltage values greater than 1000 V AC and 1500 V DC, a distance of 45 m must be observed, measured horizontally from the overhead projection. The technical rule provides specific requirements for HRS of company fleets. Requirements are set in the case of a hydrogen production less than 50 Nm3/h. For those aspects not directly mentioned, the provisions previously indicated for the safety distances must be respected. The main differences compared to public HRS are as follows: • Hazardous elements do not necessarily have to be fenced if the company structure within which the HRS is built has a fence not lower than 1.8 meters; • If only personnel involved in refuelling are allowed, and containment structures and fences are designed according to the technical specifications mentioned before, the HRS for the company fleet can be built within the company's perimeter; 22 • The internal safety distances indicated in the previous tables must be respected, except for the distance between dispensing units which can be reduced to 6 m; • The external safety distances indicated in the previous tables must be respected without any exception. These distances apply to any other productive activity located within the company perimeter. Exceptions are also defined in the case where the refuelling station consists of different fuels. This is possible by respecting safety distances (Table 5): Table 5 Safety distances between hydrogen and other conventional fuels (Italy) Hazardous elements vs other fuels related elements Safety distances HRS vs Gasoline and diesel tanks 15 m HRS vs Liquefied petroleum gas tanks (from HRS Dispensing unit) 30 m (15 m) HRS vs liquefied petroleum gas tanks 15 m HRS vs Natural gas refuelling plant (from HRS Dispensing unit) 22 m (12m) Between the different dispensing units 12 m Technical rule for Hydrogen Production through electrolysis and related storage systems The new Italian technical rule, Ministerial Decree of July 7, 2023, from the Ministry of Interior: "Technical fire prevention rule for the identification of risk analysis methodologies and fire safety measures to be adopted for the design, construction, and operation of hydrogen production plants through electrolysis and related storage systems" is potentially applicable into different sectors even if they are not directly specified in the document. In this regulation, the risk assessment is required to provide an additional level of safety but not as a substitute or a mean for modifications of the main provisions (e.g. safety distances etc) described within the document. Anyway, its application to modify the prescription and achieve the same minimum safety is possible but a longer permitting process is needed (see Deliverable 2.2). Risk assessment is a support for the electrolysis units, the tanks aimed to store hydrogen gas, the compressors and for the areas involved in the operation of hydrogen technologies that needs to be designed according the ATEX Directive to fulfill the European requirements. The technical rule provides different ranges of allowed working pressures up to 1000 barg. For working pressures above 1000 barg or in the case of adopting storage systems different from those indicated in the technical rule, the designer must implement a risk assessment and adequate fire safety measures, also determined through the "engineering approach to fire safety" as required by the decree of the Minister of the Interior of May 9, 2007. According to the present technical rule, the following are considered hazardous elements subject to safety distances and fire prevention: 23 a) Electrolyser; b) Buffer tank; c) Compression system; d) Storage system; e) Pressure reduction and stabilization unit; f) Loading station (loading bays); g) Connecting pipes (connection elements between items a), b), c), d), e), and f) for hydrogen distribution); h) Parking area for tube trailers; i) rooms intended for auxiliary services. If the production unit is connected to tube trailers for supplying HRS or other applications, a specific area for their location must be identified. The areas where the hazardous elements are located need to be fenced, with a height of not less than 1.8 m, or otherwise made so as to make these elements inaccessible and prevent tampering. If the hydrogen technologies are within sites already equipped with their fencing, the said fencing is not necessary. Where provided, such a fence or any other measure adopted to make these elements inaccessible needs to be placed at a distance from the plant elements that allows their safe operation and maintenance. The electrolysis area must follow specific external safety distances so that the Fire Brigade vehicles can access and move without any obstacles, especially in case of emergency. Below are the minimum requirements applied to at least one entrance of the plant: • Width: 3.50 m; • Height clearance: 4 m; • Turning radius: 13 m; • Slope: not exceeding 10%; • Load capacity: at least 20 ton (8 on the front axle, 12 on the rear axle, wheelbase 4 m). For all tanks for hydrogen storage, the maximum allowed pressure is 1,000 barg, and they must be placed inside a containment structure (except for buffer tanks) with the same characteristics as for the HRS plants. For the safety of the area, when the storage has a capacity of more than 6,000 Nm3, the same containment structure needs to be divided by partition walls to mitigate effects due to incidents (each portion containing storage with a capacity of less than 6,000 Nm3). Also in this case, the materials used must be fireproof (R60 materials or similar). Compressors must be equipped with tanks capable of damping pressure fluctuations above 150 barg and with a geometric volume of less than 0.4 m3. Otherwise, if the geometric volume is greater than 0.4 m3, a risk assessment is necessary. The compressor must be contained within a reinforced concrete containment structure. The distances to be respected for the hazardous elements of the facility are (Table 6): 24 Table 6 Correlation between operating pressures and minimum safety and protection distances for hazardous elements in a renewable hydrogen production facility (Italy) Hydrogen operating pressure (barg) External safety distance Protection safety distance Internal safety distance 700 < P ≤ 1000 30 15 15 500 < P ≤ 700 25 15 15 300 < P ≤ 500 20 15 15 100 < P ≤ 300 17 12 12 50 < P ≤ 100 12 8 8 30 < P ≤ 50 8 6 6 10 < P ≤ 30 7 5 5 P ≤ 10 5 3 3 If the working pressures are higher than those indicated, the stakeholder must apply the provisions of the "Engineering approach to fire safety" as per the Ministerial Decree of May 9, 2007 (it refers to the performance-based approach). For the compressor, the external safety distance, except for the one calculated with respect to buildings intended for community use, can be reduced by 50% if between the openings of the compressor containment structure and the constructions outside the plant, suitable continuous screening with concrete walls or other incombustible material of adequate mechanical resistance is realized. In any case, such distance cannot be less than the minimum internal safety distance and the protection distance, provided for the same pressure value. Pipelines, both high and low pressure, are considered hazardous elements, and the safety distances indicated in the Table 6 apply to them, except for the internal safety distances from closely connected process elements. According to the technical rule, buildings intended for community use such as schools, hospitals, offices, places of worship, public entertainment buildings, sports facilities, tourist accommodation complexes, supermarkets and shopping centers, barracks, as well as places where people tend to gather such as public transport stations, fair areas, markets, etc., lead the external safety distances reported in the Table 6 to the double of the base value. The following internal safety distances are observed between hazardous elements and the below-mentioned buildings intended for auxiliary services: a) buildings intended for auxiliary services: safety distances as indicated in the previous Table 6; b) Electrical energy delivery cabin: 22 meters. Other relevant distances refer to power lines. Between hazardous elements and overhead power lines, with voltage values greater than 1,000 V in alternating current and 1,500 V in direct current, a distance of 45 meters from the plant projection must be observed. This fire prevention technical rule for hydrogen production plants prevents access to individuals not properly trained. 25 The described safety regulations are not conceived for the use of hydrogen technologies in residential sector. In the Appendix A, it is possible to see the safety requirements of technical rules regarding natural gas storage and cogeneration systems valid in Italy and borrowed for a hydrogen project in residential sector (see the following subsection). This is due to both a gap in the regulatory framework for the residential sector and the higher knowledge and confidence of the authorities towards conventional fuels like compressed natural gas. 2.2.1.1 Cogeneration solution for Residential application: Italian prescriptions Envi directly participated in REFLEX project (GA No779577), a European demonstrative project where a reversible solid oxide fuel cell, capable of operating both for the production of hydrogen and for the production of electricity, was installed and tested in a real environment. Specifically, it was a compact system that also integrated the hydrogen storage system and batteries. The project has been included in the prescriptive approach section as the HAZOP risk analysis regarding the safety of the technologies used for compression, storage and piping was intended only as a support instrument for the safety evaluation process of the Fire Brigade. Moreover, the technical rules applied and indicated below (described in Appendix A) are not specific to hydrogen but derive from the regulatory framework typical of the residential sector and conventional fuels such as natural gas. This more convenient choice was therefore dictated by a regulatory gap present at the time of the project where the only technical rule in Italy available was the one for HRS. In fact, the technical rule for electrolysers was only published on 7 July 2023 (less than a year before the publication of this deliverable and after the end of the REFLEX project). In this project, two European directives for safety were considered: the Seveso Directive and the ATEX Directive. The Seveso Directive did not apply because the quantities of hydrogen stored were less than 5 tons, while, due to the presence of hydrogen, there was a certain probability of forming explosive atmospheres, and therefore the ATEX Directive was considered for the classification of the aforementioned areas into zones. The technical rules chosen have been: • Decree of the Ministry of the Interior February 3, 2016, "Approval of the technical fire prevention rule for the design, construction, and operation of natural gas deposits with a density not exceeding 0.8 and of biogas deposits, even with a density above 0.8". In this case, the most relevant parameter for safety was the geometric capacity of the storage system. The installation of the hydrogen storage system thus becomes subject to the evaluation of the Fire Brigade if the geometric capacity is greater than 0.75 m3 (which corresponds to category 4). Given certain geometric and pressure characteristics, the designed hydrogen storage system fell exactly within category 4 (the less restrictive in terms of safety requirements). Despite that, in the design phase it was not possible to consider a containment structure for protection from risks of explosion. This brought the final configuration to be the stricter in 32 By № Buildings and facilities on the territory of the complex auto supply station Tanks (underground) for light fuels Above ground propanebutane tanks Underground with a volume of up to 25 m3 or equivalent to underground LPG tanks with a volume of no more than 10 m3 Bottle group for natural gas Site for a mobile platform with a gas bottle installation for natural gas Compressor for natural gas Column for charging motor vehicles (including combined vehicles) Service building 7 Equipment for filling tanks for light fuels 1.5 5 5 5 5 5 5 according to Art. 619 8 Vehicle charging station (including combined vehicles) 5 10 5 5 5 5 5 according to Art. 619, 629, 636 33 Table 9 Other safety distances within HRS in Bulgaria № order Buildings and facilities on the territory of the charging station Minimal distances, m Tanks for light fuel Equipment for filling tanks for light fuels Above ground tanks for propanebutane Under-ground tanks with volume up to 25 m3 or equivalent to underground tanks for propane – butane with volume no more than 10 m3 Filling points for propanebutane bottles Bottles for natural gas Site for a mobile platform with a gas-bottle installation for natural gas Compressor for natural gas Column for refuelling motor vehicles with light gas, propane-butane or natural gas (including the combined ones) Service building Boundaries of the property 1. Buildings/facilities where is positioned the hydrogen generator 10 10 10 5 10 5 5 5 10 10 5 2. Warehouse (metal container or bottles) for hydrogen storage under law pressure 8 8 8 8 8 8 8 8 10 15 10 3. Compressor module for hydrogen 10 10 10 10 10 10 10 10 10 10 10 4. Warehouse/buffer metal vessel for hydrogen storage under high pressure 10 10 10 10 10 10 10 10 10 15 10 5. Systems for hydrogen pre-cooling 10 10 10 10 10 10 10 10 10 10 5 6. Column (dispenser) for refuelling vehicles with hydrogen (including the combined ones) 5 5 10 5 10 5 5 5 5 10 5 34 2.2.3 Safety of Hydrogen technologies: observations from French legislative framework In this Section some of the main elements of the French legislative framework for safety of HRS and storage systems are provided. The following description is not intended to be exhaustive but it aims to provide some terms of comparison. France has a developed HRS network which is supposed to increase further in the following years. For this reason, the experience gained is an added value for this project. Safety requirements for Hydrogen Refuelling Stations in France In France safety distances in HRS depend on the dispenser flow rate and the general approach to safety varies starting from a minimum value of hydrogen stored equal to 1 ton of hydrogen (in general, in Germany higher attention is paid through risk analysis above 5 ton). As reported by the Association France Hydrogene 2 , the safety distances between the hydrogen technologies and the facility boundaries, the ventilation devices and the storage of flammable gases vary according to the features of the HRS (e.g., the flow rate). Table 10 Safety distances between H2 technologies in HRS for France Max flow rate Distances Distances reduced 120 g/s 14 m 10 m 60 g/s 10 m 8 m 20 g/s 6 m 6 m The safety distances can be reduced in two cases: • The anti-snatch system of the distribution hose is designed to ensure an upward orientation of the gas flow by more than 45°; or • If technical means are provided and automatically ensure that the gas flow is stopped at the potential breakage point of the hose within less than 2 seconds (this is the solution most often implemented in installations). If these distances cannot be maintained, the operator must install a solid wall without openings, made of REI120 fire-resistant materials, which must be taller than the highest point of the distribution area (excluding the vent) but at least 3 meters high. 3 Moreover, HRS built in France require safety distances between hydrogen dispensers and other fuels (5 m) but in some cases authorities can allow stakeholders to install the hydrogen dispenser 2 https://s3.production.france-hydrogene.org/uploads/sites/5/2023/02/Fiche-ICPE-1416-Distributiondhydrogene.pdf 3 MultHyFuel project: https://multhyfuel.eu/progress 35 on the same island as other fuels. Instead, the allowed distance between two hydrogen dispensers is 2 meters. Safety requirements for Hydrogen storage systems in France In France there is also a Regulation that applies specifically for hydrogen storage “Arrêté Ministériel du 12 février 1998 relatif aux Prescriptions Générales (AMPG) applicables aux installations classées pour la protection de l'environnement soumises à déclaration sous la rubrique n° 4715”. According to this document, there are some prescriptions to follow for storage systems installed outdoor and indoor. These prescriptions mainly refer to safety distances that go from 8 meters (outdoor installation) to 5 meters (indoor installation) from property boundaries or any building. These distances are not needed if the building and the gaseous hydrogen storage are separated by a wall that is: • Solid without openings; • Built with non-combustible materials, with fire-resistant characteristics of 2 hours; • With a minimum height of 3 meters; • Extended from the storage by a canopy constructed with non-combustible and 1hour fire-resistant materials; • With a minimum width of 3 meters in horizontal projection. This wall must be extended on both sides and on the storage side by return walls without openings, built with non-combustible and 1-hour fire-resistant materials, with a height of 3 meters and a length of at least 2 meters. Moreover, also other flammable or combustible substances are considered and can be stored in the room or in the storage area of the installation if they are separated from the hydrogen storage systems by: • Either a distance of 8 meters; • Or a solid wall without openings with a 1-meter extension, built with fire-resistant materials with a 2-hour fire rating, rising to a height of 3 meters or to the roof unless more stringent requirements are specified by other regulations. The coexistence of Hydrogen with other flammable gases can be the base of a comparison with the two Italian technical rules for natural gas (there are not Italian H2 specific technical rules outside HRS or electrolysis facilities), described in Appendix A and linked to REFLEX project for residential sector. 36 2.3 Performance-based approach for Safety of Hydrogen technologies The performance-based approach to safety is a common practice for some countries like Germany and other North Sea Regions. In other countries, in this transition phase towards a hydrogen economy, safety authorities involved in hydrogen facility construction and operation processes are evaluating projects often designed according to the performancebased approach. This can be due to both a gap in the regulatory framework and a gap in the knowledge of safety authorities regarding this alternative fuel and its new end uses like the residential and mobility sectors. For example, this is the case of Belgium which is exploring an approach where specific safety regulations for hydrogen and hydrogen technologies are under development but not defined at the moment. New experiences about hydrogen end uses in sectors like mobility, residential and renewable hydrogen production can be made through the support of risk assessment methodologies and the application of EU legislations (pillars of the performance approach). As it will be showed along this section, the interactions with the authorities involved in the permitting processes for safety and the specific project’s features will influence the outputs of the requirements in all the countries. First of all, it is important to assess that not all the end uses sectors are analysed for all the HYPOP countries. This is due because for some countries, according to their individual national hydrogen strategies, some sectors are receiving more attention in this moment. High interest is put especially towards hydrogen mobility through the implementation of Hydrogen Refuelling stations network and FCEVs deployment on road, rail and inland waterways. In the case of hydrogen infrastructure for mobility all countries are working to provide a network capable to fulfil the requirements of the recently published Regulation on Deployment of Alternative Fuels Infrastructure (AFIR). Anyway, some evidences of projects using a performance-based approach for all the HYPOP’s topics, like industry, mobility and residential sectors, are provided in the Section 2.3.1. 2.3.1 Safety for Hydrogen Distribution and Production Facilities: Performancebased Approaches from Belgium and Spain In this Section, the performance-based approach to safety for HRS in Belgium is provided. Moreover, considerations of safety approaches for hydrogen production are described for Spain as on-site hydrogen production is a potential configuration of future HRS. Furthermore, findings about the safety approach for HRS in Spain are provided consequently. Belgium is facing this transition phase towards hydrogen economy through a cross linked approach where technical standards (more detail in D2.3), the consultation with the competent authorities and the risk assessment analysis are the pillars needed to accompany the implementation of hydrogen projects in the country as well as the to demonstrate the compliance to the minimum safety requirements asked at local and European level from the administrations. The main requirements asked by local authorities of Belgium involved at 37 different levels are the ones included in the aforementioned EU directives. Additional requirements are followed when specific project features require them. In Belgium, for the HRS that have already been built in Flanders, the existing VLAREM legislation for storage and handling of dangerous gases has been used. In cases where this legislation is not specific enough, the Dutch directive PGS35 is used to define the necessary requirements. In Wallonia, some private actors use the French Guide for the general hydrogen systems 4 . This is an example of how the performance-based approach can bring to the safety compliance of an HRS facility. To sum up, the approach is composed by the application of: - EU legislations; - local regulatory framework (not necessarily referred to hydrogen and hydrogen technologies); - guidelines and best practices (also from other surrounding countries). Moreover, stakeholder’s interviews showed that the fireman organisation (FRCSPB) needs to be consulted and it generally requires to put a significant hydrogen detector network to identify potential leakages within the facility and for the hydrogen transported. This is a complex topic as HRS is multi-component facility where different hydrogen technologies with different risks are placed together. Quantitative risk assessment is the common practice in Belgium (as in Netherlands) and the related guidelines on how to perform it for HRS but also for other applications are under development. Hydrogen production on site and its storage are indeed the main concern in HRS but in general also for other facilities for industrial and residential sectors. Several technical standards, codes and regulations are needed to ensure the safe, efficient and sustainable operation of all the installations. The outputs of the performance-based approach also depend on the authorities and the type of administrations involved in the project approval. As in Belgium also in Spain, the same project can face different interpretations depending on the region of Spain (or even the town) where it has to be located. In this Section, only references to national legislation for Spain is done. A project about hydrogen production for industrial application will be mentioned in Section 2.3.4. As a general rule, the following pieces of legislation must be taken into account for Spain when safety of hydrogen facilities must be ensured: • Low Voltage Electrical Regulations: Royal Decree 842/2002, of 2 August, which approves the Low Voltage Electrotechnical Regulations; • High Voltage Electrotechnical Regulations: Royal Decree 337/2014, of 9 May, approving the Regulation on technical conditions and safety guarantees in high voltage electrical installations and its Complementary Technical Instructions ITCRAT 01 to 23; • Pressure Equipment Regulation: Royal Decree 809/2021, of 21 September, approving the Pressure Equipment Regulation and its complementary technical instructions; 4 GUIDE POUR L’EVALUATION DE LA CONFORMITE ET LA CERTIFICATION DES SYSTEMES A HYDROGENE, 2021 written by France Hydrogen and INERIS 38 • Chemical Product Storage Regulations: Royal Decree 656/2017, of 23 June, approving the Chemical Product Storage Regulations and its Complementary Technical Instructions MIE APQ 0 to 10 (BOE 25/07/17). A focus on this Regulation will be provided as hydrogen storage is one of the main issues perceived by safety authorities (Table 11, Table 12, Table 13, Table 14); • Fire Protection Regulations: Royal Decree 2267/2004, of 3 December, approving the Fire Safety Regulations in industrial establishments and Royal Decree 513/2017, of 22 May, approving the Fire Protection Installations Regulations; • Regulation of Refrigeration Installations: Safety regulation for refrigeration installations and its ITCs approved by RD 552/2019; • Regulation of installations for the supply of gaseous fuels: Royal Decree 919/2006, of 28 July, which approves the technical regulation for the distribution and use of gaseous fuels and its complementary technical instructions ICG 01 to 11; • Major Accident Regulation: Royal Decree 840/2015, of 21 September, approving measures to control the risks inherent to major accidents involving hazardous substances. Hydrogen production, regardless of the production method, is subject to risk assessments and the general obligations established in the SEVESO Directive needs to be fulfilled if the capacity is above the minimum threshold limit of 5 ton of hydrogen stored on site. Health and safety requirements and conformity assessment procedures, as provided for in the ATEX Directive can be followed in addition to environmental assessments and other obligations. Up to now the Spanish regulatory framework has not developed specific safety requirements yet and for this reason conventional regulations coming from the industrial sector are used. Safety is a main concern when hydrogen is stored on site (as described in D2.2). In the case of a hydrogen production facility with storage on site, a list of the main documents and regulations to be applied to assess the safety of a project are reported in the Section 2.3.4. Moreover, industrial guidelines and technical standards are considered functional to the achievement of safety for the hydrogen production facility. An example is the technical guideline published by the “Bequinor Asociación Nacional de Normalizacion de Bienes de Equipo y Seguridad Industrial Guía técnica”: Seguridad del Hidrogeno” 5 where the following documents are recommended: • EIGA Doc 122/18 – Environmental impacts of Hydrogen Plants; • EIGA Doc 155 Best Available Techniques for Hydrogen Production by Steam Methane Reforming; • EIGA Doc 211/17 - Hydrogen vent systems for customer applications; • EIGA Doc 220/19 – Environmental guidelines for permitting hydrogen plants producing less than 2 Tm per day; • CGA 5.5 “Standard for Hydrogen vent systems”; • ISO 22734 – Hydrogen generators using water electrolysis – Industrial, commercial, and residential applications; 5 https://bequinor.org/wp-content/uploads/2023/04/Guia-Seguridad-H2-BEQUINOR.pdf ) 39 • UNE-ISO 16110-1 – Hydrogen generators using fuel processing technologies. Together with the hydrogen production, the storage on site is another major concern for the safety authorities. For example, in Spain hydrogen can only be stored on areas designated for industrial use and under restrictions related to safety distances which are can result in significant barriers. As in most of the EU countries, hydrogen is considered from a legal and administrative point of view as a flammable and dangerous chemical product, so the Spanish Regulations on Chemical Product Storage (APQ) (all part from 1 to 10) are followed. These Regulations, even if not specific for hydrogen technologies and facilities, can be applied in the absence of an updated regulatory framework. For this reason, it is also likely to be applied for other new hydrogen end use sectors such as mobility and residential. Regulation MIE APQ (from 0 to 10) establishes the safety conditions for storage, loading, unloading, and transfer facilities for hazardous chemicals, as well as their complementary technical instructions: • MIE-AQP 5 directive "Gas storage in mobile pressure vessels" establishes the safety distances for hydrogen storage and sets out the technical requirements for the storage and use of mobile pressure vessels containing compressed, liquefied and dissolved gases under pressure and their mixtures; • MIE APQ-10 directive “Storage in mobile containers” sets out the technical requirements for storage, loading, unloading and transfer of hazardous chemicals in mobile vessels. According to MIE-APQ 5, five categories of storage are stablished based on the stored gases (Table 11). As a general rule, higher are the hazards associated to a fuel (gas, liquid, compressed state etc) more restrictive are the safety requirements applied. The following indicators refer to hydrogen for its flammability and the compressed state: H220 and H280 respectively (they specify the safety requirements). The values exported from the Regulation, given in Table 11, are applicable only to gases which do not present any hazard other than those indicated. In Spain, legislation regarding the design, permits, construction, and operation of HRS has not been developed yet and a regulatory gap has been observed. In the absence of a specific legal framework for hydrogen refuelling stations, competent authorities treat a potential hydrogen refuelling station as a set of independent facilities for hydrogen production, chemical storage, and refuelling activity. For this reason, MIE-AQP 5 directive "Gas storage in mobile pressure vessels" is considered also for Hydrogen Refuelling stations (HRS) and together with the technical standards are one of the main instruments at the moment to comply with the minimum safety requirements necessary to build and operate a HRS. For this type of facilities, useful standards are: • the ISO/TS 19880-1:2020 “Gaseous hydrogen - Fuelling stations - Part 1: General requirements” standard. It defines the minimum design, installation, commissioning, operation, inspection and maintenance requirements, for the safety, and, where appropriate, for the performance of public and non-public fuelling stations that dispense gaseous hydrogen to light duty road vehicles (e.g., fuel cell electric vehicles); 40 • the ISO 14687:2019 “Hydrogen fuel quality - Product specification” standard establishes the minimum quality characteristics of hydrogen fuel as distributed for utilization in vehicular and stationary applications. Without a clear set of safety requirements (including distances, permits etc) defined specifically for HRS, projects will be based on a case-by-case performance-based approach where stakeholders can take additional safety precautions as the ones determined by a risk management methodology, together with environmental impact assessments, to address potential safety risks of specific designs and applications. Table 11 Categories of storage, indicators and limits for Storage Quantity in MIE APQ Regulation (Spain) Storage Category Type of Danger Hazard indicator Storage quantity (Nm3) 1 Flammable H220 Q≤ 50 Compressed gas H280 Q≤ 200 2 Flammable H220 50 ˂ Q ≤ 175 Compressed gas H280 200 ˂ Q ≤ 1,000 3 Flammable H220 175 ˂ Q ≤ 600 Compressed gas H280 1,000 ˂ Q ≤ 2,400 4 Flammable H220 600 ˂ Q ≤ 2,000 Compressed gas H280 2,400 ˂ Q ≤ 8,000 5 Flammable H220 Q> 2,000 Compressed gas H280 Q> 8,000 41 Having done this classification, the safety distances for hydrogen storage are established consequently (Table 12, Table 13, Table 14). Other general safety elements are reported in Table 15. Table 12 Location and safety distances according to MIE APQ Regulation Storage category 1 2 3 4 5 The storage area may accommodate within it an activity other than the storage of containers provided that it does not affect the safety of the containers. Yes Yes No No No Distances (metres) between vessels of flammable gases to other gases. 6 m or separation wall Distances (metres) between vessels of flammable gases to inert gases. 3 m or separation wall Distances (metres) between vessels of flammable gases to any source of ignition or open fire. 6 m or separation wall Table 13 Requirements for closed area warehouses according to MIE APQ Regulation Storage category 1 2 3 4 5 Flammable, oxidising or inert. Distances (metres) to Public roads. – 2 (2) 3 4 6 Inhabited buildings or third parties. – 3 (2) 6 8 10 Activities with risk of fire and explosion. – 3 (2) 6 (2) 8 (2) 10 (2) Internal warehouse services. – – – 2 6 Table 14 Requirements for open area warehouses according to MIE APQ Regulation Storage category 1 2 3 4 5 Flammable, oxidising or inert. Distances (metres) to Public roads. (6) 4 (7) 6 (7) 8 (7) 10 (7) Inhabited buildings or third parties. (6) 6 (7) 8 (7) 10 (7) 15 (7) Activities with risk of fire and explosion. (6) 6 (7) 8 (7)(8) 10 (7)(8) 15 (7)(8) Internal warehouse services. – – – 2 6 Table 15 Fire protection elements according to MIE APQ Regulation Storage category 1 2 3 4 5 Fire extinguishers: minimum number/effectiveness. 2/89B 3/89B 4/89B 5/144B 5/144B (10) Fire hydrants equipped, minimum number – – – 2 (11) 48 Figure 1 Iberdrola Hydrogen plant for ammonia production in Puertollano (Castilla-La Mancha, Spain) The development of this project has led to a wider knowledge about the safety requirements in Castilla-La Mancha autonomous community. In terms of safety, the table below depicts the different documents needed for the deployment of this kind of projects in this autonomous community so as to prove the compliance of the regulations. These documents refer to certifications, inspections, and maintenance contracts, ensuring that all aspects of hydrogen production, storage, and handling comply with the highest safety standards (Table 16): Table 16 Examples of the compliance of the regulations for hydrogen production, storage and handling (Spain) Regulation Documents needed Low Voltage Electrical Regulations • Proof of payment of the corresponding fees. • Project or, where applicable, technical design report. • Certificate of works management (in the case of having submitted the project). • Installation certificate with its corresponding user information annex, in quintuplicate. • Certificate of initial inspection with favourable result qualification, from the Control Body. https://www.jccm.es/tramites/1002270 High Voltage Electrotechnical Regulations • PROJECT • FINAL WORK CERTIFICATE signed by the corresponding qualified technician • CERTIFICATE ACCREDITATING THE EXISTENCE OF A MAINTENANCE CONTRACT signed with an installation company for high voltage installations (if the owner of the installation, in the opinion of the Administration, has the necessary means and organisation to carry out his own maintenance, and assumes its execution and responsibility for it, he will be exempted from contracting it) • INSTALLATION CERTIFICATE, according to the established model, which must include at least the following: o The data referring to the main technical characteristics of the installation according to the project, documenting, where appropriate, the variations in the work carried out with respect to the project. o Technical report with a favourable result of the verifications prior to commissioning, carried out as specified in ITC-RAT 23. Where applicable, the reference of the certificate of the control body that carried out the initial inspection, with a favourable result. o Express declaration that the installation has been executed in accordance with the project, with the requirements of the Regulation on technical 49 Regulation Documents needed conditions and safety guarantees in high voltage electrical installations and its complementary technical instructions, and, when it is foreseen that the installations are to be handed over to electrical energy transmission and distribution companies, with the particular specifications approved to the electrical energy transmission and distribution company. Where applicable, it shall identify and justify the variations that have occurred in the execution of the project in relation to what was foreseen in the project. o Copy of the corresponding declarations of conformity of the components of the installation that are obliged to do so according to ITC-RAT 03. • https://www.jccm.es/tramites/1002245 Pressure Equipment Regulation • Project/sketch of principle and plan or sketch of the installation (as appropriate). • Responsible declaration of the competent technician/designer (if a project is required). • Technical direction certificate (if the installation required a project) • Declaration of responsibility of the competent technician in charge of the execution of the works/works (in the case of requiring a certificate of technical direction of work) • Installation certificate • Declarations of conformity of pressure equipment or assemblies and, where appropriate, of safety or pressure accessories. • Periodic inspection report of level C (in the case of used equipment) or level B as appropriate. • https://www.jccm.es/tramites/1002263 Chemical Product Storage Regulations • Storage project or, where appropriate, a document signed by the owner or legal representative (report). • Responsible declaration of the competent technician/designer (in the case of requiring a project). • Certification signed by the qualified technician who is the project manager (if the installation required a project). • Declaration of responsibility of the competent technician in charge of the execution of the works/works (in the case of requiring a works manager's certificate). • Certificate by the authorised inspection body (if the installation did not require a project). • Certificate of construction of the vessels issued by the manufacturer (in accordance with the provisions of article "documents" of the corresponding ITC). • Documentation accrediting the availability of insurance, guarantee or other equivalent financial guarantee covering civil liability that may arise from storage, with a minimum amount per claim as established in article 7.2 of the Regulation on the Storage of Chemical Products, approved by RD 656/2017, of 23 June. • https://www.jccm.es/tramites/1002262 Fire Protection Regulations • Responsible declaration of the competent technical designer (in the case of requiring a project). • Certificate of work management (if the installation required a project). • Declaration of the competent technician responsible for the execution of the works/works (in the case of requiring a works management certificate). • Certificate(s) of the installation(s) • Documentation accrediting that a maintenance contract has been signed with a duly authorised maintenance company that covers, at least, the maintenance of the equipment and systems subject to the Regulation on fire protection installations, approved by RD 513/2017, of 22 May. • https://www.jccm.es/tramites/1002243 50 Regulation Documents needed Regulation of Refrigeration Installations • Project (level 2 installations)/ technical report (level 1 or level 2 installations with A2L) of the installation actually executed. • Risk analysis of the installation (level 2 installations with A2L). • Certificate from the refrigeration company confirming personnel authorised to handle A2L gases (level 2 installations with A2L). • Responsible declaration of the competent technician project designer (in the case of requiring a project). • Technical certificate of work management (only for level 2 installations) (Model included in the register book). • Declaration of responsibility of the competent technician in charge of the execution of the works/works (in the case of requiring a technical/works management certificate). • Certificate of the installation, signed by an authorised refrigeration/RITE company and, when its participation is mandatory (in accordance with IF-15), by the director of the installation. (Model included in the refrigeration installation register book). • Certificate of the electrical installation, by a low voltage installer or, failing this, a report from the LV installation company. • The declarations of conformity of the pressure equipment (in accordance with R.D. 709/2015, of 24 July, and R.D. 108/2016, of 18 March) and, where appropriate, of the safety or pressure accessories. • EC declarations of conformity (in accordance with R.D. 709/2015, of 24 July), of the installation as a whole, in the case of compact equipment, and for the rest of the installations, of all the pressure equipment including the declarations of conformity of the piping when applicable. • Copy of the installation owner's civil liability insurance policy, when this is established (level 2 installations). • Maintenance contract with a refrigeration installation company (level 2 installations, when it is not a self-maintenance company). • https://www.jccm.es/tramites/1002248 Regulation of installations for the supply of gaseous fuels • Construction project of the installation • Responsible declaration of the competent technical person whis the designer and director of execution of the works/works. • Certificate of works management, including an annex • Installation certificate • Inspection certificate • Maintenance plan, either through an external contract or by own means. • https://www.jccm.es/tramites/1002259 Major Accident Regulation • For ALL establishments to which RD 840/2015, of 21 September, is applicable (both lower and higher level establishments): Notification or its update, in accordance with the provisions of art. 7. • For HIGHER LEVEL ESTABLISHMENTS, in addition: Safety report or its update, as provided for in Art. 10. • https://www.jccm.es/tramites/1002267 Moreover, according to the guideline “Seguridad del Hidrogeno” published by Bequinor Asociación Nacional de Normalizacion de Bienes de Equipo y Seguridad Industrial” the following documents and considerations are suggested for a safety management of the production and storage systems like the included in this project: 51 • NFPA-2 – Hydrogen technologies code; • NFPA 55 – Compressed Gases and Cryogenic Fluids Code; • BPVC Section VIII -1 “Reglas para la construcción de recipientes a presión”; • UNE – EN 13445 “Recipientes a presión no sometidos a la acción de la llama”; • CGA 5.4 “STANDARD FOR HYDROGEN PIPING SYSTEMS AT USER LOCATIONS”; • CGA 5.5 “Standard for Hydrogen vent systems”; • EIGA 033/14 “HYDROGEN CYLINDERS AND TRANSPORT VESSELS”; • ISO/TR 15916:2015 “Basic considerations for the safety of hydrogen systems”. Considering the main risks associated to hydrogen production, also storage and distribution are crucial issues to be taken into account. The safety distances need to be justified by a risk analysis, whereby the distances where the effects of overpressure do not affect other installations are determined. It is recommended to simulate the overpressure waves in case of explosions or even projections should be carried out, to determine safe distances for both fixed and mobile storage of hydrogen gaseous fuels. At present, there are no specifically defined standards for fixed containers, but there are international technical standards. Regulations aforementioned like MIE APQ 5 can be considered as reference for the establishment of adequate safety distances when flammable compressed gases like hydrogen are operated in a facility. Hydrogen production and distribution facility: Italian case Connected to the previous case where a hydrogen production facility is going to be developed in Spain for ammonia production, another evidence of the performance-based approach applied in Italy as a combination of risk assessment methodologies and interactions with the safety authorities is provided. It is the case of the Production and distribution plants (HRS) for railway mobility in H2iseo Hydrogen Valley through which hydrogen is gaining more prominence in the railway sector. An interview was conducted with one of the main partners involved in the project for the hydrogen production and distribution plant in the province of Brescia. The electrolysis plant will be located next to the HRS to avoid hydrogen transport and it will be connected to a renewable electricity source through an electric pipeline crossing the city. The project has not achieved the construction phase yet, and therefore technical documentation related to safety and permitting aspects is under development. The intention of the stakeholder is to refer to the technical rule for hydrogen refuelling stations (HRS) described in detail in Section 2.2.1 applying its provisions. However, initial discussions have been started with the Provincial Fire Brigade of Brescia, bringing to a preliminary risk assessment study. It has been shared to the authorities so they can understand better the main characteristics of the project. According to the stakeholder, the design will primarily clash with the safety distances required by the technical rule of the Fire Brigade. Therefore, it is intended to apply the engineering approach to safety (the corresponding Italian performance-based approach), presenting a study on how, with certain measures, barriers can be reduced. According to the stakeholder, such an approach is not congenial in a scenario where an increasing number of future projects will be developed in parallel and will require such exemptions from regulations. 52 Another example of this performance-based approach in Italy (Figure 2) is given by a project which is still under development and called HYPER (Hydrogen valley in Mantova) 7 . Risk assessment methodologies are valuable tools for safety compliance and, in cases like these, can modify the prescriptive provisions of the regulations. Figure 2 Layout of the HYPER project (Italy) Among its different components, the project envisages an electrolysis unit, a compressor system, an innovative tube trailer (@ 500 bar) solution to reduce the environmental impact of hydrogen transport and end uses like H2 trains. For this case, the stakeholders involved in the project aims to apply the technical rule for hydrogen production through electrolysis and related storage systems (details of the technical rule in Section 2.2.1). Taking into account the safety distances required and the hazardous components of the production and distribution facility, barriers have already arisen in the design phase. The main barriers regard the need for containment structures for each of the hydrogen facility (except the HRS dispenser) and the piping, considered as hazardous component and requiring to respect safety distances. For this reason, the stakeholder intends to follow a performance-based approach (e.g., “engineering approach to safety”) in order to meet the same minimum safety requirements but reducing the distances of the technical rule. To optimise the design of the facility, a risk assessment was prepared consisting of: • HAZOP analysis to eliminate or reduce process accidental events with reference to the nitrogen reclaim system with drive lung, automatic conditioned pressurisation system and PSV and Vent exhaust in a safe area; • Statistical-historical analysis for plant optimisation for random events by means of special anti-breakage flanges and pit layout management to reduce relative areas and explosion accident events; • Domino effect mechanism evaluations of secondary accidents/scenarios that induced the displacement of piping due to interference of damage areas with cryogenic oxygen tank. The risk analysis was accompanied by the use of a software to estimate the effects and consequences of accident scenarios (“conical” model and “Unified Dispersion Model”). In addition, the risk analysis made it possible to address an issue such as the interference between hazardous elements such as 7 https://assogastecnici.federchimica.it/docs/default-source/default-library/eventi/xvii-rns/michela-capoccia-egiovanni-romano.pdf?sfvrsn=a8b10158_1 53 the loading and unloading bays and the compressor area and to propose an alternative solution by reducing the minimum internal distance between the two elements mentioned by halving it from 15 metres to 7 metres. 2.3.4.2 Examples of safety approach for Hydrogen Refuelling Stations Hydrogen refuelling station: Polish case One of the RIGP stakeholders interviewed, ORLEN, is involved in a project called "Clean Cities - Hydrogen mobility in Poland (Phase I)". It is one of the largest national projects in terms of hydrogen production volume where the company will build two publicly accessible hydrogen refuelling stations in Poznań and Katowice, as well as a mobile station in Włocławek. They will be suitable for use by all hydrogen-powered vehicles - both in the 700-bar pressure standard for cars and 350 bar for buses and heavy transport. The planned infrastructure will enable the refuelling of a total of more than 40 buses, as well as passenger cars and other hydrogen-cell-powered vehicles. As Polish regulatory framework lacks specific legislation for hydrogen and hydrogen refuelling stations, general safety considerations have been shared by the stakeholder engaged by RIGP showing the minimum safety requirements needed in the case of the planned HRS. The following list shows the different pillars for the safety of HRS in Poland (they can be taken as examples of practices to ensure safety): 1. Hydrogen Storage and Handling: • Leak Detection: Install hydrogen sensors to promptly detect any leaks; • Ventilation: Proper ventilation is essential to disperse any released hydrogen; • Emergency Shut-off Systems: Implement emergency control valves to isolate hydrogen flow during emergencies; • Excess Flow Valves (EFV): EFVs to stop hydrogen flow when it reaches a certain level. 2. Infrastructure Safety: • Hydrogen Refuelling Station (HRS): o HRS should adhere to safety standards for construction, operation, and maintenance; o Proper signage and safety instructions must be visible for users; o Emergency response plans should be in place. • Hydrogen Pipelines: o Pipelines transporting hydrogen should meet safety criteria; o Regular inspections and maintenance are crucial; o Emergency shut-off valves should be strategically placed; 3. Fire Safety: • Fire Suppression Systems: Install fire suppression systems (e.g., water mist, foam) at HRS and other hydrogen facilities; • Firefighting Training: Staff should be trained in handling hydrogen-related fires; 4. Electrical Safety: • Electrical Equipment: Use explosion-proof electrical equipment; • Electrolysers and Fuel Cells: Ensure safe electrical connections; 54 5. Hydrogen Purity and Quality: • Certification: Regulations define acceptable hydrogen purity levels for different applications (e.g., fuel cells, industrial processes); • Quality Control: Ensuring consistent quality through monitoring and testing; 6. Emergency Response Plans: • Incident Preparedness: HRS and other facilities should have emergency plans for leaks, fires, or other accidents; • Coordination: Collaboration between industry stakeholders, emergency services, and local authorities; 7. Public Awareness and Education: • Educate the public about hydrogen safety; • Promote awareness of safe practices. Together with the minimum safety requirements for a proper construction and installation and the regulations and directives listed, Polish and International Standards have been followed as well (more evidences of the international technical standards for HRS are reported in D2.3). Hydrogen refuelling station: Belgian case Performance-based approach is also based on the application of requirements from the EU framework as showed in the following table. Regarding safety requirements for hydrogen projects construction and operation in Belgium, the following experience has been analysed and shared by Tweed as a result of its stakeholder’s engagement activity. An experience about a new hydrogen refuelling station for practical training on hydrogen cars is reported here as a proof of the requirements for safety compliance, where permitting approval is a crosslinked topic as well. Moreover, this case can provide another example of the performance-based approach about Hydrogen refuelling station deployment. Technifutur is a technical training center in Belgium, it is dedicated to automobile and motorcycle mechanics and is located next to the Spa Francorchamps circuit (Campus Automobile Spa Francorchamps). Practical training on electric cars but also on hydrogen cars is carried out on this site. In order to improve these trainings, the installation of a hydrogen refuelling station has been studied. The study has been carried out by the strategy consultancy company HINICIO. One of the outputs of this study (only the public information has been shared) brought to the following list of directives, technical standards and regulations for HRS (Table 17). 55 Table 17 International and European references for HRS in Belgium Type of regulation Scope Reference Subject Description Directive Europe 2014/94/EU Alternative fuel infrastructure directive (AFID) Common directive to deploy alternative fuel infrastructure Standards International ISO/TS 19880-1 General requirements for refuelling station Technical specifications for public and private refuelling stations Europe EN 17127 General requirements for refuelling station European transposition of ISO/TS 19880-1 International ISO 14687-2 + ISO 19880-8 Quality conformity and Hydrogen purity Quality specification for hydrogen use for mobility Europe EN 17268 Hydrogen purity European transposition of ISO 14687-2 and ISO 19880-8 International ISO 17268 Recharging connectors Standards for the design, the security and the operations of refuelling connectors Sector standards International SAE J2601-1 SAE J2601-2 SAE J2601-3 SAE J2601-4 Refuelling protocols for: Light vehicles Hight vehicles Forklift Slow refuelling Security and performance limits for refuelling stations (350 bar and 700 bar) International SAE J2799 Communication between vehicle and refuelling station Description of infrared communication between the vehicle and the refuelling station (350 bar and 700 bar). This communication system must also correspond to the SAE J2601 standard. Together with the European and International legislation, also the regional safety requirements for this HRS study in Belgium have been shared. The following considerations have been obtained through the interactions with the competent regional authority. The DGO3 (General Operational Directorate for Agriculture, Natural Resources and Environment) is the competent authority at regional level to issue an environmental permit necessary for the construction of the hydrogen station. A specific interview with the competent staff of the DGO3 made it possible to specify the operating conditions to be taken into account for the installation of a hydrogen refuelling station on the Francorchamps Automotive Campus: • Hydrogen does not yet have sectoral conditions and is therefore subject to specific conditions within the framework of the environmental permit; • The hydrogen station studied does not imply SEVESO classification. The storage quantities for a station corresponding to the specifications are well below the SEVESO thresholds; • The safety distances to be respected from buildings, the neighborhood and parking lots must be greater than the thermal radiation in the event of an explosion (risk of fire propagation); 56 • This distance in the case of a non-SEVESO classified site is calculated by the DGO3 using a simulation tool in the case of the environmental permit application. An exception can be made so that this is done upstream of the request; • The DGO3 can also issue operating conditions to prevent possible “domino effects”. In the case of this specific project, there is no equipment deemed dangerous around site. Therefore, the station should not be subject to any particular operating conditions. Hydrogen refuelling station: Italian case If the use of regulations, directives and technical standards is an effective way to achieve safety requirements, also communication and interaction with safety authorities is part of the performance-based approach. An example of how this interaction has been fruitful to overcome barriers and ensure a fast deployment is the case of the first HRS built and operated in Bolzano (Italy). This case study was considered relevant as it refers to the first and, currently, only operating HRS for road mobility of both light and heavy FCEV. To date, thanks to funds from the Italian National Recovery and Resilience Plan (PNRR), about 47 refuelling stations have been approved for funding and are expected to be built by 2026. Although the applied fire prevention technical rule has been replaced by the current Ministerial Decree of October 18, 2018 (more detail in Section 2.3), this case study was considered as evidence of interactions with the Bolzano Fire Brigade (fire safety authority of the competent province). When the project was evaluated (2014), the fire prevention technical rule in force allowed hydrogen dispensing up to 350 bar, but since the HRS could be modified to fuel passenger transport vehicles, amendment was requested to the Fire Brigade by the stakeholders involved. The technical documentation submitted to the Fire Brigade included a risk assessment demonstrating the safety of a 700 bar plant and a detailed ATEX evaluation of the surrounding area. The discussion with the Fire Brigade then allowed for a second amendment regarding the possibility of self-service refuelling for both bus drivers and motorists. This was made possible by providing an analysis of incidents that occurred in similar facilities operating at 700 bars in other countries and in analogy with the Austrian regulation that governs the possibility of performing self-service refuelling after having conducted a test of at least 6 months on the facility. The stakeholder also shared the experience of co-designing an intervention plan that involved the Institute for Technological Innovations Bolzano (which manages the facility) and the Provincial Fire Brigade of Bolzano. This approach showed the effects of constant interactions between project owners and safety authorities. 2.3.4.3 Examples of safety approach for Hydrogen Heating Systems for Residential application In this subsection, two evidences of hydrogen and hydrogen technologies use in residential sector will be represented. Information have been gathered thanks the support of BH2C and RIGP that shared us the results of the interviews had with their stakeholders. The performance-based approach showed in these projects can be the base for comparisons with the project for cogeneration described in the Prescriptive approach section. 57 Hydrogen heating system: Polish case In the case of Polish project, the company SES Hydrogen Energy has completed functional tests of a prototype of a 0.5 MW hydrogen-oxygen boiler and has simulated the work on a real installation. The innovative technology is going through the certification process but it is intended to be used to heat apartments in the housing estate in Śrem with hydrogen. The planned hydrogen boiler plant will be part of a diversified heating system supplying heat to 195 apartments under construction at the Srem TBS housing estate. It will serve to provide central heating and central water for the buildings. The entire system envisages the installation of a hydrogen boiler room based on the combustion of hydrogen and oxygen, as well as a heating system including ground-based brine-to-water heat pumps. The focal point of the boiler plant will be a hydrogenoxygen boiler with gas preparation systems. In addition, the infrastructure will include: a hydrogen and oxygen generation module using electrolysers, an electrolysis water preparation system, a hydrogen and oxygen storage module, and power and control systems for technological processes and heat exchange. The stakeholders involved are SES Hydrogen Energy and the Śrem Social Housing Society (TBS), the Municipality of Śrem and Con-Project. In Poland, safety regulations for hydrogen heating systems are essential to ensure the safe implementation of this technology. Technical supervision of equipment for handling, transporting, and storing hydrogen, fire protection, occupational health and safety, and emergency services are present because in this transition phase the existing regulations in Poland can apply broadly to gaseous and hazardous fuels including hydrogen. Anyway, while specific safety requirements for hydrogen heating systems are not explicitly outlined in the available framework, it is essential to adhere to general safety practices (similar safety practices and considerations are present in the previous section for HRS in Poland): • Hydrogen Leak Detection: Install sensors to detect any hydrogen leaks promptly; • Ventilation: Ensure proper ventilation in areas where hydrogen is used or stored; • Emergency Shut-off Systems: Implement emergency control valves to isolate hydrogen flow during emergencies; • Excess Flow Valves: Fit excess flow valves (EFV) to stop hydrogen flow when it reaches a certain level. Hydrogen heating system: Bulgarian case Another evidence of the performance-based approach in the residential sector comes from Bulgaria where one of the stakeholders interviewed by BH2C partner brought its experience in a similar case. A project for the construction of a facility for green hydrogen production for the heating needs of Otets Paisii Primary School, Lozen, Sofia City has been developed. This project is under development but it will represent the first public building in Southeast Europe to use on-site production of renewable hydrogen for its heating needs. Main goal of this demonstrative project is to analyse, design and install a green hydrogen production system connected to a hydrogen boiler to optimize 64 In this transition phase towards a hydrogen economy, prescriptive hydrogen regulations rules are not necessarily the best solutions because, a too prescriptive approach to safety can hinder the development of projects where innovative technologies or new end uses like the ones involving renewable hydrogen are deployed. Anyway, prescriptive approach can become more aligned to the technical needs of this new fuel and new end uses once more experienced is acquired in the following years. On the second hand, a performance approach based on industry guidelines and regulations commonly followed may not be enough to fulfill safety requirements asked by authorities at different levels and in different countries. Despite that, during this transition phase the performance-based can be the best compromise as it can ensure minimum safety requirements by means of the sector knowledge of stakeholders on conventional fuels even if this does not fully prevent hydrogen projects and technologies from obstacles. Risk assessment methodologies, technical standards, technical reports and manufacturers guidelines can be valuable tools to achieve minimum requirements of safety authority and at the same time to provide a scientific approach that can facilitate the deployment of the innovative hydrogen projects and its related technologies. Finally, case by case analysis is needed, both for prescriptive and performance-based approach in order to meet safety and public health requirements associated to the project and environment characteristics. 65 5 Appendix A 5.1 Italy For the residential sector, hydrogen can be used to produce thermal energy, as in the case of heat generators through the combustion process of hydrogen blended with natural gas or through generators capable of producing both electrical and thermal energy (the latter with lower thermal efficiencies depending on the technology used) through fuel cells. In Italy, the use of hydrogen in residential contexts goes through a series of specific fire prevention technical rules. Within the parameters of natural gas quality defined by the Ministerial Decree of May 18, 2018, "Technical rule on the chemical-physical characteristics and the presence of other components in the combustible gas", a first precautionary limit value for the injection of hydrogen into the networks was introduced: ≤ 2% by volume. Among the normative references of the Ministerial Decree of May 18, 2018, "Technical rule on the chemical-physical characteristics and the presence of other components in the combustible gas", there are the following technical rules: • Ministerial Decree of April 16, 2008, Technical rule for the design, construction, testing, operation, and supervision of the works and systems of distribution and direct lines of natural gas with a density not exceeding 0.8; • Ministerial Decree of April 17, 2008, Technical rule for the design, construction, testing, operation, and supervision of the works and plants for the transport of natural gas with a density not exceeding 0.8; • Ministerial Decree of February 3, 2016, Approval of the fire prevention technical rule for the design, construction, and operation of natural gas storage facilities with a density not exceeding 0.8; • Decree of December 22, 2000, "Identification of the National Gas Pipeline Network pursuant to art. 9 of legislative decree May 23, 2000, n. 164 and subsequent amendments and integrations". The following sections provide a detailed analysis of the main safety requirements from two technical rules for conventional fuels that have been applied in hydrogen projects like REFLEX where reversible fuel cells and hydrogen storage systems were used in a residential field: • Cogeneration systems were regulated by a fire prevention technical rule of the Fire Brigade, Ministerial Decree of July 13, 2011, "Fire prevention technical rule for the installation of internal combustion engines coupled to an electric generator or another operating machine and cogeneration units serving civil, industrial, agricultural, artisanal, commercial activities and services." • Fire prevention technical rule for the design, construction, and operation of natural gas storage facilities with a density not exceeding 0.8 and of biogas storage facilities, even if with a density exceeding 0.8, published in the Decree of the Ministry of the Interior on February 3, 2016. 66 5.1.1 Technical rule for the installation of cogeneration units serving civil, industrial, agricultural, artisanal, commercial activities and services The technical rule for the safe installation of cogeneration units and/or groups provides common provisions for all the various cases reported in the document within Title I, while the other Titles are more specific: • Total power up to 25 kW (not subject to fire brigade control): Title IV; • Total power between 25 kW and 50 kW: Title I and Title III; • Total power between 50 kW and 10,000 kW: Title I and Title II. The provisions of the Fire Prevention Technical Rule apply to both fixed and mobile installations and also for installations with a total power of less than 25 kW, which, however, from an authorization standpoint, are not subject to fire brigade control. When the productive activity exceeds a total power of 10,000 kW or concerns installations included, for example, in industrial production processes, fire-fighting systems, stations and power plants, this technical rule offers only useful reference criteria which are not mandatory provisions. Given the chemical-physical characteristics of hydrogen, the common safety provisions reported in the Fire Prevention Technical Rule referring to gaseous fuels with a density lower than 0.8 and to liquid fuels with a flash point lower than 55 °C were considered. In the case of gaseous hydrogen, the ratio between its density (0.084 kg/m3) and the density of air (1.22 kg/m3) is less than 0.8, and therefore only some of the provisions reported along the decree apply. The same goes for liquid hydrogen which falls among the liquid fuels with a flash point lower than 55 °C. Relevant safety aspects for the design of a hydrogen cogeneration systems, which are important within the common provisions, involve: • incorporated tanks; • service tanks; • storage tanks. and their respective fuel supply systems for all three mentioned types. A parameter to consider for distinguishing the different provisions of the technical rule is the geometric capacity of the tanks. For liquid fuels with a flash point lower than 55 °C like liquid hydrogen, each cogeneration unit and/or group can have both incorporated and service tanks, even divided into multiple compartments or several single tanks provided that the total capacity does not exceed 120 dm3. The technical rule specifies that the overall geometric capacity is to be understood as the sum of both incorporated tanks and service tanks possibly present to fuel the units and/or cogeneration groups but only if these are installed inside the same room where the units and/or cogeneration groups are located. The supply of the incorporated or service tank, not fuelled from the storage tank and with a total capacity of less than 120 dm3, is allowed with portable containers of the type approved according to current regulations. 67 Concerning storage tanks for liquid fuel with a flash point lower than 55°C, these cannot be placed within rooms or on terraces. The installation of such tanks is governed by the regulations of the decree of the Minister of the Interior July 31, 1934, published in the Official Gazette September 28, 1934, no. 228. For all types of installation, a risk assessment related to explosive atmospheres in accordance with current regulations is needed. The installations of groups and/or cogeneration units, with a total nominal power of up to 25 kW, are carried out by the installer according to the prescriptions provided by the manufacturer of the group and/or cogeneration unit, reported in the instruction manual for use and based on good technical standards. For such installations, it is the installer, once the installation is completed, who attests under his own responsibility that the group and/or cogeneration unit is installed according to the rules of the art. Considering all the valid provisions in general for tanks and fuelling from gaseous and liquid fuels, the technical rule also defines the characteristics for the safe construction of rooms containing different types of groups and/or cogeneration units with different nominal powers. All these three types of installation can envisage three types of installation locations: • outdoors; • in external rooms; • in rooms included in the volume of a building. The technical rule provides a set of common provisions that generally apply to groups and/or cogeneration units with a total nominal power greater than 50 kW and up to 10,000 kW. These provisions are mainly related to the construction of the room containing the cogeneration group and any heat production system connected to it. Specific limits related to the total power of the cogeneration groups and the maximum allowable geometric capacity of the various tanks also change depending on the function of the buildings in which they are installed. These limits are generally reduced in the presence of activities with high people attendance or with specific functions for the community. In general, in the same room, multiple groups and/or cogeneration units with different fuels can be placed as long as the total installed nominal power does not exceed 8,000 kW. Instead, groups and/or cogeneration units fuelled with liquid fuel having a flash point lower than 55°C, such as liquid hydrogen, can coexist in the same room only with groups and/or cogeneration units fuelled with the same type of fuel. Similar constraints also apply in the case of integrating cogeneration groups and/or units with heat generation systems (subject to the technical rule Ministerial Decree of November 8, 2019). Groups and/or cogeneration units with heat production systems are allowed in the same room provided that they are fuelled by the same type of fuel. Furthermore, the coexistence in the same room of one or more groups and/or one or more cogeneration units with heat production systems fuelled with the fuels reported in the following Table 19 is also permitted: 68 Table 19 Cases where cogeneration units are coupled with heat generation systems using "similar" fuels (Italy) Thermal unit / Group or cogeneration unit Liquids with a flash point lower than 55°C Liquids with a flash point equal or higher than 55 °C Gas with a relative density to air greater than 0.8 Gas with a relative density to air lower than 0,8 Solid fuels Liquids with a flash point lower than 55°C Yes Yes No No No Liquids with a flash point equal or higher than 55 °C Yes Yes Yes Yes Yes Gas with a relative density to air greater than 0.8 No Yes Yes No No Gas with a relative density to air lower than 0,8 No Yes No Yes No In reference to scenarios where cogeneration units are coupled with heat generation systems using "similar" fuels, there are additional common conditions to comply with: • The sum of the total thermal power of the cogeneration units and the capacity of the heat production plants does not exceed 10,000 kW; • Any incorporated or service tanks of the cogeneration units altogether do not exceed 120 dm3; • The cogeneration units do not perform safety functions; • The cogeneration units are equipped with a metal enclosure; • The lateral distances between the cogeneration units and the heat production plants must not be less than 0.6 m; • For the aspects like access, communication, fire resistance and ventilation, the fire safety measures provided by the current fire prevention standards of the heat production plants, applicable according to the type of fuel used, must be applied if more restrictive than the ones indicated in the cogeneration unit technical rule. Given the previous common provisions for outdoor installations there are a series of safety distances to be respected between the cogeneration unit and storage systems. These distances can be reduced (Table 20) in case of interposition of an adequate protective structure made of incombustible material and of dimensions sufficient to protect the entirety of the storage system. The cogeneration units must be surrounded by an area not less than 3 m deep and free of materials or vegetation that may constitute a fire hazard. Table 20 Safety distances between the cogeneration unit and storage systems in Italy Total nominal power Distance Reduced distance Up to 2.500 kW 3 m 3 m Up to 5.000 kW 4 m Up to 7.500 kW 5 m 4 m Up to 10.000 kW 6 m 5 m 69 The provisions described so far are an example of what is required for cogeneration units with a total nominal power between 50 kW and 10,000 kW. Then, the fire prevention technical rule provides specific construction-related guidelines for cogeneration groups and/or units with a total nominal power greater than 25 kW and not exceeding 50 kW, while most of the provisions related to geometric capacity and total nominal power mentioned are similar to those described previously. 5.1.2 Technical rule for the design, construction, and operation of natural gas storage facilities with a density not exceeding 0.8 Another technical rule for fire prevention has been applied in REFLEX project. The project needed the installation of a hydrogen storage system missing of the corresponding technical rule. Provisions of the Fire Prevention Technical Rule for the design, construction, and operation of natural gas storage facilities with a density not exceeding 0.8 and biogas storage facilities, even with a density exceeding 0.8, published in the Decree of the Ministry of Interior on February 3, 2016, has been taken into account for the approval of safety of the hydrogen storage systems. The decree contemplates fire prevention measures for storages not subject to Fire Brigade control. These measures must be adopted under the responsibility of the activity owner and the designer. Generally, for storage systems, safety aspects can find reference in the Seveso Directive, ATEX Directive, and PED directive, as well as the fire prevention technical rules of the fire brigade. The technical rule mentions different types of storage systems: • storage in fixed tank; • storage in mobile containers. Fixed storage safety requirements For storage in fixed tanks, the technical rule defines the maximum operating pressures allowed, different according to the type of storage: • for pressostatic accumulators: 0.05 bar (0.005 MPa); • for gasometers: 0.5 bar (0.05 MPa); • for tanks: 30 bar (3 MPa) for the geometric volume of a single tank over 50 m3 and 50 bar (5 MPa) for the geometric volume of a single tank equal to or less than 50 m3; • for pipeline-tanks: the maximum pressures provided for pipelines, up to a maximum of 120 bar if buried (12 MPa); pipeline-tanks possibly above ground are assimilated to medium-pressure tanks (Pmax operation = 50 bar). Each of these types of storage is also classified respectively as: • low; • medium; • high. 70 The technical rule then provides a further classification of storages in fixed tanks based on the global storage capacity, intended as the sum of the individual storage capacities and measured in m3 as follows: C = V x P/Po where: V = geometric volume of the tanks or pipeline-tanks, expressed in m3; P = maximum absolute pressure, expressed in bar; Po = absolute barometric pressure, expressed in bar and conventionally assumed to be equal to 1 bar. For gasometers and pressostatic accumulators, the maximum geometric volume is assumed. For maximum absolute pressure, it means the maximum operating pressure as declared by the operator. Table 21 Maximum storage capacity allowed (Italy) Category Maximum storage capacity (m3) 1st over 120,000 2nd over 20,000 and up to 120,000 3rd over 1,000 m3 and up to 20,000 4th up to 1,000 The technical rule considers hazardous elements of a storage with fixed tanks: a) containers intended to contain gas (pipeline-tanks, tanks, gasometers, pressostatic accumulators, digesters); b) compression stations and decompression cabins; c) any other element presenting a danger of explosion or fire under normal operating conditions, including the transfer point, components, and fixed pipelines with an operating pressure exceeding 5.0 bar (0.5 MPa). For all elements referred to in points b) and c), with operating pressures lower than 5.0 bar (0.5 MPa), the provisions of the DM April 16, 2008 "Technical rule for the design, construction, testing, operation, and supervision of natural gas distribution systems and direct lines with a density not exceeding 0.8" must be respected. Storage systems can be installed in areas compatible with urban planning instruments. The installing area of the storage must be delimited by a specific fence, at least 1.80 m of height, placed at a distance from the hazardous elements not lower than the protection distance set for the elements themselves and indicated in the tables below. The fire prevention technical rule provides a set of general provisions for assessing safety distances in the case of storages in fixed tanks. Table 22 Safety distances between Pipeline-tanks (high pressure) and internal buildings Maximum operating pressure [bar] 24 < P ≤ 60 12 < P ≤ 24 P ≤ 12 Distance (m) 10 7 5 71 For operating pressures above 60 bar, distances must be increased proportionally to a maximum of double. Additional distances to be respected: o Protection distance: 10 m (reduced by 50% if referring to storages consisting of 4th category underground pipeline-tanks); o Internal safety distance: 15 m (reduced by 50% if referring to storages consisting of 4th category underground pipeline-tanks); o External safety distance: 20 m, (reduced by 50% if referring to storages consisting of 4th category underground pipeline-tanks). Table 23 Safety distances for Tanks (medium pressure) Tanks with individual storage capacity Internal building Protection distance Internal safety distance External safety distance 1st cat. 2nd cat. 3rd cat. 4th cat. Up to 5.000 m3 15 m 10 m 12 m 45 m 40 m 35 m 30 m Over 5.000 m3 and up to 10.000 m3 20 m 50 m 45 m 40 m \ Over 10.000 m3 30 m 60 m 50 m 45 m \ For all types of fixed storages, unless specific exceptions are reported in the technical rule, the external safety distance must be increased by 50% if the buildings to be protected are used for activities: o with the presence of the public, with a crowd exceeding 100 units; o intended for communities, included in Annex I to the DPR 1 August 2011 n. 151; o characterized by the detention and use of flammable, inflammable, or explosive products, included in category C of the said decree. Mobile storage safety requirements The fire prevention technical rule also specifies safety requirements for storage in mobile systems. Hazardous elements are: • Buildings, structures, and areas designated for the storage of storage containers; • Containment structures, where present, or the area designated for the parking of vehicles used for the transportation of natural gas; • Natural gas compression plants and decompression cabins; • Any other element that presents a risk of explosion or fire under normal operating conditions. In general, the same provisions described for storage in fixed systems apply. 72 For mobile storage, the possible capacity ranges are: • 1st category: more than 10,000 m3; • 2nd category: more than 5,000 up to 10,000 m3; • 3rd category: more than 850 m3 up to 5,000 m3; • 4th category: more than 75 up to 850 m3. Depending on the construction characteristics of the storage buildings, the mobile storage and the containment structures designated for the parking of vehicles used for gas transportation can have two different degrees of safety: • 1st degree of safety: if the construction characteristics of the structures ensure containment, both laterally and upwards, of fragments or other materials projected in case of an explosion; • 2nd degree of safety: if the construction characteristics of the structures ensure containment, only laterally, of fragments or other materials projected in case of an explosion. 4th category storages can be made outdoors or under a canopy even without containment elements. Fences to be used for the pertinent area of the storage follow the same provisions described for fixed storage systems. The safety distances required between the storage systems and the other hazardous elements or buildings are reported in the following tables. Protection, internal and external safety distances are defined as in the Section 2.2.1 regarding the Italian technical rules for HRS and electrolysis plants. Table 24 Safety distances for storage systems with safety degree 1 Storage capacity Protection distance Internal safety distance External safety distance 4th category 5 m \ 10 m 3rd category 5 m \ 20 m 2nd category 5 m \ 25 m 1st category 5 m \ 30 m Table 25 Safety distances for storage systems with safety degree 2 Storage capacity Protection distance Internal safety distance External safety distance 4th category 5 m 7,5 m 15 m 3rd category 10 m 10 m 20 m 2nd category 10 m 15 m 25 m 1st category 10 m 15 m 30 m 73 Table 26 Safety distances for storage systems of 4th category with no safety degree Storage capacity Protection distance Internal safety distance External safety distance 4th category 20 m 20 m 30 m 5.2 Spain In Spain, a concentration of 5% hydrogen for injection in the grid is allowed if it comes from non-conventional sources according to protocol PD-01 "Measurement, quality, and odorization of gas", which provides the limits on the composition of gases that are allowed in the gas network. This protocol is established by the System Technical Management Regulations (Normas de Gestión Técnica del Sistema or NGTS), which articulates the operation of the gas system.