AIRTIGHTNESS AND INDOOR AIR QUALITY IN
SUBSIDISED HOUSING IN SPAIN
Jessica Fe nández-Agüe a*1, Juan José Send a2, Ra ael Suá ez2, Samuel
Domínguez-Ama illo2 and Ignacio O eiza1
1 Ins i u o de Ciencias de la Cons ucción Edua do
To oja ( CSIC)
A . Se ano Gal ache, 4,
28033 Mad id, Spain
* j e nan[email p o ec ed]
2 Ins i u o Uni e si a io de A qui ec u a y Ciencias
de la Cons ucción, Uni e si y o Se ille,
A . Reina Me cedes, 2,
41012 Se ille, Spain
ABSTRACT
O e h ee million subsidised dwellings we e buil in Spain be ween 1940 and 1980. Mos o hese buildings a e
now obsole e and ail o comply wi h he mal com o and en ila ion s anda ds. A building's exis ing ene gy
pe o mance, including i s ai igh ness, should be de e mined p io o conduc ing low-ene gy e u bishmen , o
hose ac o s, pa icula ly he la e , impac he mal com o , ene gy demand and indoo ai quali y (IAQ) ai ly
hea ily.
This pape in oduces a s udy on ai igh ness and IAQ in subsidised housing buil in Spain in he a o emen ioned
40-yea pe iod. Ai igh ness and CO2 measu emen s aken in 2014-2015 in six uni s in mul i-dwelling buildings,
h ee each in Se ille and Mad id, a e desc ibed.
The esul s show ha in a building in Mad id, he numbe o ai changes pe hou a a p essu e o 50 Pa (n50) anges
om 3.2 o 8.3. The win e ime CO2 concen a ion in bed ooms is 1900 ppm and in li ing ooms 1400 ppm, wi h
peaks o 5000 ppm and 4700 ppm, espec i ely. The numbe o ai changes pe hou a 50 Pa (n50) in Se ille,
anges om 5.0 o 9.5. The win e ime CO2 concen a ion in bed ooms is 1500 ppm and in li ing ooms 800 ppm,
wi h peaks o 6000ppm and 4000 ppm, espec i ely. In he summe , howe e , when use s end o open windows
a nigh p ima ily o le in coole ai , he CO2 concen a ion alues obse ed in Se ille d op o 700 ppm and in
Mad id o 1100 ppm.
As hose alues a e much highe han ecommended in he s anda ds on good indoo ai quali y, he in e ence is
ha win e ime housing en ila ion mus no be allowed o es solely on use s’ olun a y opening o windows.
KEYWORDS
Ca bon dioxide concen a ion, in il a ion, ai igh ness, blowe doo , dwellings
1 INTRODUCTION
Gi en he impac o building en elope ai igh ness (measu ed as ai in il a ion) on ene gy
e iciency, occupan s’ he mal com o and indoo ai quali y, i has become a s anda d a ea o
esea ch in he Uni ed S a es in gene al and he Law ence Be keley Na ional Labo a o y
(LBNL) in pa icula (She man e al, 2007), and in egions o Eu ope wi h cold clima es
(Mon oya e al, 2010; Jokisalo e al; 2009, Pan, 2010). In Sou he n Eu ope, howe e , s udies
on which o base a sound analysis and in e p e a ion o he in e ac ion be ween hese ac o s a e
la gely lacking (d’Amb osio e al, 2012, Pin o e al, 2011). Spain’s Technical Building Code
(CTE, 2006), o ins ance, does no speci y he ai igh ness o be me by building en elopes,
bu only he ex- ac o y pe meabili y o he ca pen y, i.e., i espec i e o i s subsequen on-si e
assembly.
Mos o he s udies on he ela ionship be ween IAQ and ai igh ness conduc ed in he US
(P ince e al., 2006, Less e al., 2015) and o he cold clima es (Sha pe e al, 2014; Mickaël e
al, 2014; McGill e al, 2015) conclude ha esiden beha iou is ins umen al o e ec i e
en ila ion and ha mechanical en ila ion is needed o imp o e he quali y o indoo ai . The
LBNL is pionee ing esea ch on he link be ween indoo ai quali y and minimum en ila ion
a es (Tu ne e al, 2013; Tu ne e al, 2012; She man e al, 2011).
Many pape s ha e been published on low-ene gy e u bishmen in Spain, al hough he ocus is
p ima ily on imp o ing en elope insula ion (Dominguez e al, 2012; Cue da e al, 2014), wi h
scan a en ion in ai igh ness o i s impac on indoo ai quali y. In ligh o ha pauci y o
esea ch, his s udy analysed en elope ai igh ness in subsidised housing buil in Mad id and
Se ille in 1940-1980 and i s ela ionship o indoo ai quali y. Du ing much o ha (pos -Ci il
Wa ) pe iod, he cons uc ion indus y’s p ima y objec i e was o p o ide housing o la ge
swa hes o he popula ion in a con ex in which en i onmen al equi emen s we e simply no
en isaged. The end da e, he ea ly nine een eigh ies, ma ked he ins i u ion o he coun y’s
ea lies legisla ion limi ing ene gy demand.
Mo eo e , as mos o he housing buil in he pe iod s udied has no speci ic en ila ion sys em,
ai eplenishmen depends on he olun a y opening o windows in mild wea he . Agains ha
backd op, he p ima y aims o his s udy we e o cha ac e ise ai igh ness in a g oup o social
housing de elopmen s e ec ed in he pe iod 1940-80 and assess ai quali y a a ious le els o
ai igh ness in hese dwellings in di e en seasons o he yea .
2 METHODOLOGY
The me hodology ollowed included:
-choosing and de ining he housing uni s o he s udy sample
- aking in si u measu emen s, including blowe doo ai igh ness es s, smoke es s o loca e ai
leaks and CO2 concen a ion measu emen s o de e mine indoo ai quali y
These asks a e desc ibed in g ea e de ail below.
2.1 Case s udies
Six uni s in mul i-dwelling buildings, h ee in Se ille and h ee in Mad id, we e chosen o he
ai igh ness es s and CO2 measu emen s. The sampling c i e ion o he uni s chosen was ha
hey had o be su icien ly ep esen a i e o he a chi ec u al ypologies and cons uc ion
solu ions o açades mos commonly deployed in 1940-1980. A numbe o use p o iles we e
chosen, gi en hei e ec on use and occupancy. The buildings sampled also exhibi ed di e en
deg ees o en elope e u bishmen .
Figu e 1 shows he loca ion o he uni s in Mad id (A, B, C) and Se ille (D, E, F), while Table 1
lis s he dwelling cha ac e is ics and use p o iles.
Figu e 1: Loca ion o uni s s udied in Mad id and Se ille
Table 1: Case s udy
Case
s udy
Qua e
Yea
buil
Type o açade
Floo
a ea
(m2)
Façade
a ea
(m2)
Volume
(m3)
No.
occupan s
Use
p o ile
Ex en o
e u bish-
men
A
Mano e as
1960
1- b ick
63
36
145
2
Couple
Basic
B
Mano e as
1976
0.5- b ick+ai
chambe +pa i ion
64
69
159
3
Couple
wi h
child
Majo (ou e )
C
Hispano-
amé ica
1965
0.5- b ick+ai
chambe +pa i ion
76
45
193
4
Couple
wi h
child en
In e media e
D
Bami
1963
1- and 0.5- b ick
63
49
205
3
S u-den s
Basic
E
San Pablo
1965
0.5- b ick+ai
chambe +pa i ion
51
31
112
2
Couple
Basic
F
Diez
Mandamien os
1964
0.5- b ick+ai
chambe +pa i ion
64
47
163
4
Couple
wi h
child en
In e media e
The clea ance heigh in all he uni s anged om 2.20 o 2.50 m, excep in uni D, whe e i was
3.25 m.
Basic e u bishmen consis ed in e e yday main enance wi h no changes in he en elope o he
han epain ing; in e media e in upg ading he uni and eplacing he ca pen y; and majo in
eplacing he ca pen y and adap ing he building en elope. Majo e u bishmen in he uni in
Mad id e en in ol ed emo ing he ki chen en s wi h on-si e inspec ion du ing he wo k.
2.2 Fan p essu e ials
The blowe doo es , a echnique consolida ed among he scien i ic communi y, was conduc ed
in his s udy u he o he p ocedu e se ou in Spanish and Eu opean s anda d UNE EN
13829:2002 (UNE-EN 13829:2002). The es was pe o med in all he uni s in he sample o
de e mine building en elope ai igh ness. The indings we e subsequen ly used o asce ain i s
possible e ec on ai quali y, de ined as indoo CO2 concen a ion. Table 2 shows Pa ame e s
de ined in UNE 13829
The es consis ed in measu ing he ai low when a an was posi ioned on he ou side doo
(Figu e 2) o emo e ai ou o (dep essu ise) o o ce ai in o (p essu ise) he dwelling o a
posi i e o nega i e p essu e o a ound 50 Pa. All windows and any o he ou e doo s in he
uni we e sealed and all he inne doo s kep open du ing he es . Ou doo ai consequen ly
lowed in o he dwelling ac oss any in il a ions in he en elope. Smoke gene a o s and in a ed
he mog aphic analyse s we e used o loca e such ai leaks. En elope in il a ions we e
accu a ely loca ed by his join use o blowe doo ials and he mog aphic and smoke analyses.
Figu e 2: Blowe doo posi ion du ing ai igh ness ials
Table 2: Pa ame e s de ined in UNE 13829
Pa ame e
Name
Uni
De ini ion
V50
Ai Leakage a e
a 50 Pa
m3/h
Ai low ac oss he building en elope including he low a e
h ough join s, issu es and he supe icial po ousness
n50
Ai change a e a
50 Pa
h -1
In il a ion ai low a e pe in e nal olume (V)
w50
Speci ic leakage
a ea a 50 Pa
m/h
Rela ionship be ween he a e o in il a ed ai and he usable
a ea (S).
2.3 Moni o ing en i onmen al condi ions
The en i onmen al condi ions we e moni o ed in all he uni s s udied wi h a mul i-pa ame ic
da a logge ha eco ded ambien empe a u e, ela i e humidi y and ai quali y (wi h a CO2
p obe) a 10-minu e in e als. Two such da a logge s we e posi ioned in each uni , one in he
day ime and he o he in he nigh ime li ing a ea. The logge s had USB connec i i y o
download he da a o a compu e . Thei posi ions in one o he uni s a e depic ed in Figu es 3
and 4.
Figu e 3. Plan iew o uni E, showing da a logge posi ions
Figu e 4: Da a logge ins alled in bed oom in uni E
3 ANALYSIS AND DISCUSSION OF THE RESULTS
3.1 Ai igh ness measu emen s
Table 3 gi es he blowe doo ial indings o he six uni s s udied, which a e plo ed agains
a numbe o pa ame e s in Figu e 5. No ela ionship was obse ed be ween in il a ion ai low
(V50) and any o he o he pa ame e s: açade a ea, dwelling a ea, dwelling olume o ex en o
e u bishmen .
In Mad id n50 anged om 8.9 o 3.2 and w50 om 7.9 o 21. The uni ha unde wen he mos
ex ensi e e u bishmen had he lowes in il a ion a e, due o he exhaus i e con ol conduc ed
du ing he wo ks. In Se ille, gi en he g ea e dispa i y in clea ance heigh s, w50 (which anged
om 15.4 o 20.6) was deemed o be a mo e sui able pa ame e , inasmuch as mos ai leaks
occu ed a abu men s be ween cons uc ion elemen s a he han on he con inuous a eas o he
açade. He e he alues we e simila o he uni wi h basic main enance only and he one whe e
he windows had been eplaced because wo kmanship du ing ins alla ion o he new windows
wen la gely uncon olled. Tha u he o he smoke es indings mos o he ai leaks we e
loca ed a he connec ion be ween he window and he enclosu e s ands as p oo o he
impo ance o on-si e quali y con ol.

Table 3: Blowe doo es esul s
Case
S udy
Floo a ea
(m2)
Facade a ea
(m2)
Volume
(m3)
V50
(m3/h)
n50 (m/h)
w50 (h-1)
A
63
36
145
1140
7.9
18.1
B
64
69
159
504
3.2
7.9
C
76
45
193
1594
8.3
21.0
D
63
49
205
1010
4.9
16.0
E
51
31
112
1053
9.4
20.6
F
64
47
163
988
6.1
15.4
Figu e 5: In il a ion ai low s dwelling olume, açade a ea and dwelling a ea.
3.2 Ai quali y measu emen s
Figu e 6 shows ha in a ypical win e mon h, he highes CO2 concen a ions we e eco ded in
he mos ai - igh dwelling in Mad id, wi h mean alues on he o de o 2500 ppm. In all he
o he cases s udied, he mean anged om 1100 o 1800 ppm (absolu e concen a ion in ai ).
The peak CO2 concen a ion alues, which anged om 4000 o 5000 in Mad id and om 4000
o 6000 in Se ille, we e eco ded in he bed ooms in he win e . The highes peaks we e
obse ed in he mos ai igh uni s.
The highes li ing oom concen a ions we e logged la e a nigh , wi h peaks o 3000 o 4700
in Mad id and 3000 o 4000 in Se ille.
Figu e 6: Win e ime CO2 concen a ion in ppm in bed ooms occupied by wo people in selec ed uni s
The CO2 concen a ions ound o he dwellings a e shown in Figu e 7. The alues eco ded
we e lowe in summe and sp ing han in win e and au umn. The concen a ion was
subs an ially highe in he bed ooms han in he li ing ooms in all seasons, as would be
expec ed gi en he longe pe iods o ime, a nigh especially, ha he o me we e con inually
occupied. The highes alues in he li ing oom we e obse ed in he middle hou s o he day
as well as in he hou s sho ly be o e bed ime.
Seasonal luc ua ion di e ed in Mad id and Se ille. In he o me , he a ia ion be ween win e -
au um and summe was app oxima ely 30 % in he li ing oom and 40 % in he bed oom. In
Se ille, he li ing oom win e - o-summe alues luc ua ed by 60 % and he au umn/sp ing-
o-summe concen a ions by 30 %, while he bed oom alues we e wice as high in win e as
in summe . These indings ha e o do wi h use -media ed en ila ion (by opening windows), a
mo e equen p ac ice in Se ille whe e he clima e is wa me han in Mad id.
Figu e 7: Mean CO2 concen a ion (ppm) in all ou seasons in all he uni s s udied
3.3 Rela ionship be ween ai igh ness and ai quali y
Figu e 8 shows mean CO2 concen a ion (ppm) s ai igh ness. As no ed, occupan beha iou
di e ed in Mad id and Se ille. In he o me , whe e empe a u es a e usually lowe , use s end
o open and close windows less ou inely. As a esul , en elope ai igh ness in Mad id is ela ed
mo e closely o ai eplenishmen , which is clea ly insu icien mos o he ime, unless windows
a e opened. In Se ille, whe e annual empe a u es a e mo e empe a e, windows and doo s a e
opened mo e equen ly o eplenish he ai . The ou come is a mo e andom dis ibu ion o
indoo CO2 concen a ions, which depend less on ai igh ness, o indoo eplenishmen is
obse ed o a y widely among dwellings wi h simila ai igh ness alues.
Figu e 8: Mean CO2 concen a ion (ppm) s ai igh ness in he uni s s udied
No e: The bed oom in dwelling D was occupied by only one pe son.
4 CONCLUSIONS
The V50 alues measu ed we e appa en ly un ela ed o dwelling a ea and olume, as well as o
açade a ea. Wi h one excep ion, howe e , w50 and he ex en o e u bishmen we e ound o
be ela ed. Case dwelling B (Mad id), whe e ex ensi e e u bishmen had been conduc ed, had
0500 1000 1500 2000 2500 3000
Win e , li ing
Win e , bed oom
Sp ing, li ing
Sp ing, bed oom
Summe , li ing
Summe , bed oom
Au umn, li ing
Au umn, bed oom
CO2(ppm)
F E D C B A
he lowes w50 alue, a a ound 7.9 h-1, lowe e en han equi ed by Eu opean s anda ds. Case
dwelling F (Se ille), also ex ensi ely e u bished, exhibi ed a alue o a ound 15.4 h-1, clea ly
lowe han in he dwellings in Mad id and Se ille wi h scan e u bishmen , whe e i anged
om 16 o 20.6 h-1.
The V50 alues, oge he wi h he lack o speci ic en ila ion sys ems ou side o use -dependen
opening and closing o windows, led o low n50 alues and a gene ally de icien quali y o
indoo ai wi h high CO2 concen a ions, pa icula ly in bed ooms in he win e . This was
especially appa en in housing whe e ex ensi e e u bishmen had been pe o med: dwellings
B (Mad id) and F (Se ille) exhibi ed he highes CO2 concen a ions h oughou he yea .
Concen a ion alues we e widely sca e ed, howe e , due especially (in addi ion o dwelling
use and oom occupancy) o he olun a y opening and closing o windows (pa icula ly in
Se ille), which was he sole sys em o en ila ion in he six dwellings analysed.
Use s ailed o pe cei e he de icien indoo ai quali y. Tha , in conjunc ion wi h he lack o
en ila ion sys ems in hese homes, e en in he ones wi h ex ensi e e u bishmen , ga e ise o
gene ally poo and o en unheal hy indoo en i onmen s wi h high CO2 concen a ions and he
isk o condensa ion damp, especially in he mos ai - igh dwellings. Low-ene gy
e u bishmen in housing mus , hen, aim no only o imp o e he he mal esis ance o he
building en elope and i s ai igh ness, bu also o ensu e ha en ila ion sys ems a e sui able
and e icien .
5 ACKNOWLEDGEMENTS
This s udy was unded by he Spanish Minis y o Economy and Compe i i eness unde p ojec
BIA2012-39020-C02-01. One o he au ho s bene i ed om a p e-doc o al con ac , e e ence
BES-2013-063097.
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