ISO 9972:2006
(Main)Thermal performance of buildings — Determination of air permeability of buildings — Fan pressurization method
Thermal performance of buildings — Determination of air permeability of buildings — Fan pressurization method
ISO 9972:2006 is intended for the measurement of the air permeability of buildings or parts of buildings in the field. It specifies the use of mechanical pressurization or depressurization of a building or part of a building. It describes the measurement of the resulting air flow rates over a range of indoor-outdoor static pressure differences. ISO 9972:2006 is intended for the measurement of the air leakage of building envelopes of single-zone buildings. For the purpose of ISO 9972:2006, many multi-zone buildings can be treated as single-zone buildings by opening interior doors or by inducing equal pressures in adjacent zones. ISO 9972:2006 does not address evaluation of air permeability through individual components.
Performance thermique des bâtiments — Détermination de la perméabilité à l'air des bâtiments — Méthode de pressurisation par ventilateur
Toplotne značilnosti stavb - Ugotavljanje tesnosti obodnih konstrukcij - Metoda tlačne razlike z uporabo ventilatorja
Ta mednarodni standard je namenjen merjenju tesnosti obodnih konstrukcij ali delov obodnih konstrukcij na tem področju. Določa uporabo mehanskega ustvarjanja nadtlaka ali podtlaka obodnih konstrukcij ali delov obodnih konstrukcij. Opisuje merjenje pretoka zraka prek niza razlik v zunanjem in notranjem statičnem tlaku.
Ta mednarodni standard je namenjen merjenju puščanja zraka fasad obodnih konstrukcij pri enoconskih obodnih konstrukcijah. Za namen tega mednarodnega standarda se lahko številne večconske obodne konstrukcije obravnava kot enoconske obodne konstrukcije z odprtjem notranjih vrat ali z vzpostavitvijo enakega tlaka v sosednjih conah.
Ne obravnava vrednotenja tesnosti prek posameznih sestavnih delov.
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INTERNATIONAL ISO
STANDARD 9972
Second edition
2006-05-01
Thermal performance of buildings —
Determination of air permeability of
buildings — Fan pressurization method
Performance thermique des bâtiments — Détermination de la
perméabilité à l'air des bâtiments — Méthode de pressurisation par
ventilateur
Reference number
ISO 9972:2006(E)
©
ISO 2006
---------------------- Page: 1 ----------------------
ISO 9972:2006(E)
PDF disclaimer
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shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
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Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2006
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
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ISO 9972:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols. 1
4 Apparatus . 3
5 Measurement procedure . 4
6 Expression of results . 8
7 Test report . 12
8 Uncertainty . 13
Annex A (informative) Description of equipment used to pressurize buildings. 14
Annex B (informative) Dependence of air density on temperature, dew point and barometric
pressure. 16
Annex C (informative) Recommended procedure for estimating uncertainty in derived quantities. 17
Annex D (informative) Beaufort scale for wind force (extract) . 20
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ISO 9972:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9972 was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the
built environment, Subcommittee SC 1, Test and measurement methods.
This second edition cancels and replaces the first edition (ISO 9972:1996), which has been technically revised.
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ISO 9972:2006(E)
Introduction
The fan-pressurization method is intended to characterize the air permeability of the building envelope or parts
thereof. It can be used
a) to measure the air permeability of a building or part thereof for compliance with a design air-tightness
specification;
b) to compare the relative air permeability of several similar buildings or parts of buildings;
c) to identify the leakage sources;
d) to determine the air-leakage reduction resulting from individual retrofit measures applied incrementally to
an existing building or part of building.
The fan-pressurization method is suitable for the respective diagnostic purposes. Although the air infiltration
and exfiltration cannot be measured directly, the results of this method can also be used to estimate with
adequate precision by means of calculation both the mean infiltration through unintended leakages and the
mean air flow through intended air flow devices from outside, in relation to the pressure conditions to be
expected within the building.
This method does not measure the air-infiltration rate of a building. The results of the fan-pressurization test
can be used to estimate the air infiltration by means of calculation. Other methods are applicable when it is
desired to obtain a direct measurement of the air infiltration rate. It is better to use the fan-pressurization
method for diagnostic purposes and measure the actual infiltration rate with tracer gas methods. A single
tracer gas measurement gives limited information on the performance of ventilation and infiltration of buildings.
This method applies to measurements of air flow through the construction from outside to inside or vice versa.
It does not apply to air flow measurements from outside through the construction and from other places within
the construction back to outside.
The proper use of this International Standard requires a knowledge of the principles of air flow and pressure
measurements. Ideal conditions for the test described in this standard are small temperature differences and
low wind speeds. For tests conducted in the field, it needs to be recognized that field conditions can be less
than ideal. Nevertheless, strong winds and large indoor-outdoor temperature differences should be avoided.
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INTERNATIONAL STANDARD ISO 9972:2006(E)
Thermal performance of buildings — Determination of air
permeability of buildings — Fan pressurization method
1 Scope
This International Standard is intended for the measurement of the air permeability of buildings or parts of
buildings in the field. It specifies the use of mechanical pressurization or depressurization of a building or part
of a building. It describes the measurement of the resulting air flow rates over a range of indoor-outdoor static
pressure differences.
This International Standard is intended for the measurement of the air leakage of building envelopes of
single-zone buildings. For the purpose of this International Standard, many multi-zone buildings can be
treated as single-zone buildings by opening interior doors or by inducing equal pressures in adjacent zones.
It does not address evaluation of air permeability through individual components.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 6781, Thermal Insulation — Qualitative detection of thermal irregularities in building envelopes — Infrared
method
ISO 7345, Thermal Insulation — Physical quantities and definitions
ISO 13790:2004, Thermal performance of buildings — Calculation of energy use for space heating and
cooling
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7345 and the following apply.
3.1.1
air leakage rate
air flow rate across the building envelope
NOTE This movement includes flow through joints, cracks and porous surfaces, or a combination thereof, induced by
the air-moving equipment used in this standard (see Clause 4).
3.1.2
internal volume
deliberately heated, cooled or mechanically ventilated space within a building or part of a building subject to
the measurement, generally not including the attic space, basement space and attached structures
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ISO 9972:2006(E)
3.1.3
building envelope
boundary or barrier separating the internal volume subject to the test from the outside environment or another
part of the building
3.1.4
air change rate at reference pressure
air leakage rate per internal volume at the reference pressure difference across the building envelope
NOTE The reference pressure is usually 50 Pa.
3.1.5
air permeability
air leakage rate per envelope area at the reference pressure difference across the building envelope
NOTE The reference pressure is usually 50 Pa.
3.1.6
specific leakage rate
air leakage rate per net floor area at the reference pressure difference across the building envelope
NOTE A pressure difference of 50 Pa is the most common.
3.1.7
leakage area
area corresponding to air leakage rate at the reference pressure difference across the building envelope
NOTE A pressure difference of 10 Pa is the most common.
3.1.8
specific leakage area
leakage area per net floor area or envelope area at the test reference pressure difference across the building
envelope
3.2 Symbols
Symbol Quantity Unit
2 2
a specific leakage area at 10 Pa m /m
10
2
A envelope area m
E
2
A floor area m
F
2
A leakage area m
L
3 n
C air flow coefficient m /(h⋅Pa )
env
3 n
C air leakage coefficient m /(h⋅Pa )
L
–1
n air change rate at 50 Pa h
50
p pressure Pa
p uncorrected barometric pressure Pa
bar
p partial vapour pressure of water Pa
v
p saturation vapour pressure of water Pa
vs
3
Q tracer gas injection rate m /h
3
q air permeability at 50 Pa m /h
50
q air permeability
a50
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ISO 9972:2006(E)
Symbol Quantity Unit
3
q air flow rate through the building envelope m /h
env
3
q air flow rate through the building envelope m /s
env,s
3
q air leakage rate at 50 Pa m /h
L50
3
q measured air flow rate m /h
m
3 2
q air permeability at 50 Pa m /(h⋅m )
p50
3
q air leakage rate at a specified reference pressure m /h
pr
difference
3
q readings of air flow rate m /h
r
3
V internal volume m
3 2
w specific leakage rate at 50 Pa m /(h⋅m )
50
∆p induced pressure difference Pa
∆p zero flow pressure difference (average) Pa
0
∆p ; ∆p zero-flow pressure difference before and after the Pa
0,1 0,2
test (air moving equipment closed)
∆p measured pressure difference Pa
m
∆p reference pressure Pa
r
Φ relative humidity –
Τ absolute temperature K
Τ external air absolute temperature K
e
Τ internal air absolute temperature K
int
3
ρ air density kg/m
3
ρ external air density kg/m
e
3
ρ internal air density kg/m
int
4 Apparatus
4.1 General
The following description of apparatus is general in nature. Any arrangement of equipment using the same
principles and capable of performing the test procedure within the allowable tolerances is permitted. Examples
of equipment configurations commonly used are indicated in Annex A.
Periodic calibration of the measurement system, used in this test method, according to manufacturer
specifications or to standardized quality insurance systems is required.
4.2 Equipment
4.2.1 Air-moving equipment
This includes any device that is capable of inducing a specific range of positive and negative pressure
differences across the building envelope or part thereof. The system shall provide a constant air flow at each
pressure difference for the period required to obtain readings of air flow rate.
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ISO 9972:2006(E)
4.2.2 Pressure-measuring device
This includes any instrument capable of measuring pressure differences with an accuracy of ± 2 Pa in the
range of 0 Pa to 100 Pa.
4.2.3 Air flow rate measuring system
This includes any device capable of measuring air flow rate within ± 7 % of the reading.
Care shall be taken if the principle underlying the measurement of volumetric flow rate is an orifice. The
reading of the air flow rate shall be corrected according to air density (see manufacturers' specifications).
4.2.4 Temperature-measuring device
This includes any instrument capable of measuring temperature to an accuracy of ± 1 K.
5 Measurement procedure
5.1 Measurement conditions
5.1.1 General
There are two methods for this measurement procedure: depressurization or pressurization of a building or
part of a building. Regardless of which method is used, the air leakage of building envelope can be measured.
The accuracy of this measurement procedure is largely dependent on the instrumentation and apparatus used
and on the ambient conditions under which the data are taken.
NOTE In general, the measurement result of the depressurization method is larger than that for the pressurization
method. However, when air-tightness in the building is high, the test results of both methods are almost equal.
5.1.2 Measured extent
The extent of the building or part of the building measured is defined as follows.
a) Normally, the part of the building measured includes all deliberately conditioned rooms.
b) In special cases, the extent of the part of the building actually to be tested can be defined in agreement
with the client.
c) If the aim of the measurement is compliance with the air-tightness specification of a building code or
standard and the measured extent is not defined in this code or by a standard, the measured extent is
defined as in a).
Individual parts of a building can be measured separately; e.g. in apartment buildings, each apartment can be
measured individually. However, interpretation of results shall consider that air leakage measured in this way
can include flow through leaks to adjacent parts of the building.
NOTE 1 It is possible that an apartment building meets air-tightness requirements, but that one or more individual
apartments do not.
NOTE 2 Good practice requires measuring pressures induced in adjoining spaces, such as the attic and basement or
adjacent apartments, since air flow into or out of these spaces can be induced by the test method.
5.1.3 Time of measurement
The measurement can take place only after the completion of the envelope of the building or part of the
building to be tested.
NOTE A preliminary air permeability measurement of the air barrier of the building under construction can allow
leakages to be repaired more easily than after the building has been completed.
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ISO 9972:2006(E)
5.1.4 Meteorological conditions
If the product of the indoor/outdoor air temperature difference, expressed in Kelvin, multiplied by the height,
expressed in metres, of the building or measured part of the building gives a result greater than 250 m⋅K, it is
unlikely that a satisfactory zero-flow pressure difference can be obtained (see 5.3.3).
If the wind speed near the ground exceeds 3 m/s or the meteorological wind speed exceeds 6 m/s or reaches
3 on the Beaufort scale, it is unlikely that a satisfactory zero-flow pressure difference can be obtained (see
5.3.3).
5.2 Preparation
5.2.1 General
This International Standard describes three types of test methods depending on the purpose. The preparation
of the building depends on the test method selected:
⎯ Method A (test of a building in use):
The condition of the building envelope should represent its condition during the season in which heating
or cooling systems are used.
⎯ Method B (test of the building envelope):
Any intentional opening in the building envelope shall be closed or sealed as specified in 5.2.2 and 5.2.3.
⎯ Method C (test of the building in use):
Automatically regulating, externally mounted air transfer devices are sealed, other openings are handled
in the same way as for method A.
5.2.2 Building components
Close all intentional exterior openings of the building or part of the building to be tested (windows, doors,
fireguard).
For the purpose of methods A and C (building in use), do not take any further measures to improve the
air-tightness of the building components (however, see also 5.2.3). For the purpose of method C, all
automatically regulating externally mounted air transfer devices are sealed. This is valid for natural supply and
exhaust systems, as well as for natural supply and mechanical exhaust systems.
For the purpose of method B (building envelope), all adjustable openings shall be closed and remaining
intentional openings shall be sealed.
The entire building or part of the building to be tested shall be configured to respond to pressurization as a
single zone.
All interconnecting doors (except for cupboards and closets, which should be closed) in the part of the building
to be tested shall be opened so that a uniform pressure is maintained within a range of less than 10 % of the
measured inside/outside pressure difference.
NOTE When testing large or complex buildings, this condition becomes increasingly important and can be verified by
selected differential pressure measurements between different rooms at the highest pressure contemplated.
Make general observations of the condition of the building. Take notes on the windows, doors, opaque walls,
roof and floor, position of adjustable openings and any sealings applied to intentional openings.
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ISO 9972:2006(E)
5.2.3 Heating, ventilation and air conditioning systems
Heating systems with indoor air intake shall be turned off. Open fireplaces shall be cleared of ashes.
Mechanical ventilation and air conditioning systems shall be turned off.
Air terminal devices of mechanical ventilation or air conditioning systems shall be sealed. Other ventilation
openings (for example, openings for natural ventilation) shall be closed for purposes of method A and sealed
for method B.
Take measures to avoid exhaust hazards from heating systems. Take into account heating sources in
adjacent apartments.
If there is an intention to estimate the infiltration/exfiltration air change rate in accordance with
ISO 13790:2004, natural system openings are kept open for the purpose of the pressurization test or their
contribution is calculated.
5.2.4 Air-moving equipment
Connect the air-moving equipment to the building envelope using a window, door, or vent opening. Ensure
that the joints between the equipment and the building are sealed to eliminate any leakage.
If the building heating, ventilation and air conditioning system is used as the air-moving equipment, arrange
the fans and dampers to allow the system to pressurize or to depressurize the building in a manner such that
the total inward or outward air flow rate can be measured (see A.4).
NOTE In an airtight building, it is possible for the door, window or vent used to pass air during the test to produce the
most leakage. It is important to be careful in such a case with regards to the selection of the position of the air-moving
equipment and/or the interpretation of the test results.
5.2.5 Pressure measuring devices
The indoor/outdoor pressure difference is usually measured at the lowest floor level of the building envelope
under consideration.
NOTE In tall buildings, it is good practice to measure the pressure difference at the top floor level of the building
envelope under consideration as well.
Ensure that interior and exterior pressure drops are not influenced by the air moving equipment. The exterior
pressure tap should be protected from the effects of dynamic pressure, e.g. by fitting a T-pipe or connecting it
to a perforated box. Especially in windy conditions, it is good practice to place the exterior pressure tap some
distance away from the building, but not close to other obstacles.
The pressure tubes should not be aligned vertically. The tubing shall not be exposed to large temperature
differences (e.g. due to the sun).
5.3 Steps of the procedure
5.3.1 Preliminary check
Always check the complete building envelope at approximately the highest pressure difference used in the
test for large leaks and failings of temporarily sealed openings. If such leaks are detected, take detailed notes.
Any temporary sealings found missing or deficient, e.g. of heating, ventilation and air conditioning components,
shall be fixed at this time.
Check that water traps in plumbing systems are correctly filled or sealed.
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ISO 9972:2006(E)
5.3.2 Temperature and wind conditions
To correct the air flow rate measurement for air density (see Annex B), read the temperature inside and
outside the building before, during or after the test.
Record the wind speed or force. Determining wind force by visual assessment of trees, water, etc., in terms of
the Beaufort scale (see Table D.1) is sufficient.
5.3.3 Zero-flow pressure difference
Short-circuit the pressure-measuring device and check or adjust the zero reading.
Connect the pressure measuring device to measure inside-outside pressure difference and temporarily cover
the opening of the air moving equipment. Observe and record the average of the positive values of zero-flow
pressure difference, ∆p , over a period of at least 30 s. Observe and record the average of the negative
01+
values of zero-flow pressure difference, ∆p , over a period of at least 30 s. If either of these average values
01–
of zero-flow pressure difference is greater than 5 Pa, do not perform the test.
Observe and record the average of all values of zero-flow pressure difference, ∆p , over a period of at
01
least 30 s.
Repeat this process at the end of the test (to obtain ∆p , ∆ p and ∆ p ). If either the positive or negative
02+ 02– 02
zero-flow pressure difference reading after the test is greater than 5 Pa, the test shall be declared not valid. If
a test report is produced for such a test, this failure to meet required test conditions shall be stated in the test
report.
5.3.4 Pressure difference sequence
Uncover and turn on the air-moving equipment.
The test is carried out by taking measurements of air flow rate and indoor-outdoor pressure difference over a
range of applied pressure differences in increments of no more than approximately 10 Pa. The minimum
pressure difference shall be approximately 10 Pa or five times the zero-flow pressure difference (positive or
negative averages), whichever is greater. The highest pressure difference being tested can depend upon the
size of the building according to a) and b).
a) Single dwellings and other small buildings:
The pressure difference shall be at least 50 Pa, but it is recommended that readings are taken at
pressure differences up to 100 Pa for best accuracy of calculated results.
b) Large buildings:
Wherever possible, the pressure difference shall be the same as for single dwellings [see a)]. However,
because of the large size of many non-domestic buildings and practical limitations on the capacity of
portable air-moving equipment used to test them, it is often found that a pressure difference of 50 Pa is
not achievable. In these cases, either additional air-moving equipment should be employed (to increase
total capacity) and/or the test may be carried out up to the highest pressure difference that can be
achieved with the available air-moving equipment. In such cases, the test shall not be valid unless a
pressure difference of 25 Pa can be achieved. Where the pressure difference is between 25 Pa and
50 Pa, this shall be clearly recorded in the test report with a statement that the requirements of this
International Standard have not been fully met and an account of the reasons why.
It is recommended that two sets of measurements be made: for pressurization and depressurization. However,
it is permitted to make only one set of measurements for either pressurization or depressurization and still
comply with the requirements of this International Standard. For each test, at least five approximately equally
spaced data points between the highest and the lowest pressure differences shall be defined.
NOTE 1 It is more precise to take data at higher pressure differences than at lower differences. Therefore, it is
important to exercise special care when measurements are taken at low pressure differences.
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ISO 9972:2006(E)
NOTE 2 It is advisable to check that the condition of the building envelope have not changed during each test, for
example, that sealed openings have not become unsealed or that doors, windows or dampers have not have been forced
open by the induced pressure.
A large building shall be measured by dividing into some small parts.
6 Expression of results
6.1 Reference values
6.1.1 Internal volume
The internal volume, V, is the volume of air inside the measured building or part of building. The internal
volume is calculated by multiplying the net floor area (see 6.1.3) by the mean net ceiling height. The volume of
the furniture is not subtracted.
6.1.2 Envelope area
6.1.2.1 Total envelope area
The envelope area, A , of the building or measured part of the building is the total area of all floors, walls and
E
ceilings, bordering the internal volume subject to the test. This includes walls and floors below external ground
level.
Overall internal dimensions shall be used to calculate this area. No subtractions shall be made for the area at
junction of internal walls, floors and ceilings with exterior walls, floors and ceilings (see Figure 1).
6.1.2.2 Wall and roof envelope area
The wall and roof envelope area of the building or measured part of the building is the total area of walls and
the underside of the roof bordering the internal volume subject to the test.
This excludes the areas of floors.
NOTE In the context of this International Standard, the envelope area of a row house includes the division wall(s).
The envelope area of an apartment in a multiple story building includes the floors, walls and ceilings to adjacent
apartments.
Key
1 outside
2 overall size
3 inside
Figure 1 — Envelope area
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ISO 9972:2006(E)
6.1.3 Net floor area
The net floor area, A , is the total floor area of all floors belonging to the internal volume subject to the test. It
F
is calculated according to national regulations.
6.2 Calculation of the air leakage rate
Subtract the average zero-flow pressure difference (offset) from each of the measured pressure differences,
∆p , to obtain the induced pressure differences, ∆p, using Equation (1). Attention shall be drawn to plus or
m
minus signs.
∆∆p + p
01, 0,2
∆=p − (1)
∆p
m
2
First, convert the readings, q , of the air flow rate measuring system into measured air flow rates, q , at the
r m
temperature and pressure at the flow measuring device in accordance with manufacturer's specifications:
qq= f (2)
()
mr
Then, convert the air flow rates, q , to air flow rates, q , through the building envelope for depressurization
m env
using Equation (3).
⎛⎞
ρ ⎛⎞
T
int e
= = (3)
qq⎜⎟q
⎜⎟
env m m
⎜⎟
ρ
T
⎝⎠int
⎝⎠e
where
ρ is the internal air density, expressed in kilograms p
...
SLOVENSKI STANDARD
SIST ISO 9972:2012
01-februar-2012
7RSORWQH]QDþLOQRVWLVWDYE8JRWDYOMDQMHWHVQRVWLRERGQLKNRQVWUXNFLM0HWRGD
WODþQHUD]OLNH]XSRUDERYHQWLODWRUMD
Thermal performance of buildings - Determination of air permeability of buildings - Fan
pressurization method
Performance thermique des bâtiments - Détermination de la perméabilité à l'air des
bâtiments - Méthode de pressurisation par ventilateur
Ta slovenski standard je istoveten z: ISO 9972:2006
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation
SIST ISO 9972:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 9972:2012
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SIST ISO 9972:2012
INTERNATIONAL ISO
STANDARD 9972
Second edition
2006-05-01
Thermal performance of buildings —
Determination of air permeability of
buildings — Fan pressurization method
Performance thermique des bâtiments — Détermination de la
perméabilité à l'air des bâtiments — Méthode de pressurisation par
ventilateur
Reference number
ISO 9972:2006(E)
©
ISO 2006
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SIST ISO 9972:2012
ISO 9972:2006(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2006
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 9972:2012
ISO 9972:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols. 1
4 Apparatus . 3
5 Measurement procedure . 4
6 Expression of results . 8
7 Test report . 12
8 Uncertainty . 13
Annex A (informative) Description of equipment used to pressurize buildings. 14
Annex B (informative) Dependence of air density on temperature, dew point and barometric
pressure. 16
Annex C (informative) Recommended procedure for estimating uncertainty in derived quantities. 17
Annex D (informative) Beaufort scale for wind force (extract) . 20
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9972 was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the
built environment, Subcommittee SC 1, Test and measurement methods.
This second edition cancels and replaces the first edition (ISO 9972:1996), which has been technically revised.
iv © ISO 2006 – All rights reserved
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Introduction
The fan-pressurization method is intended to characterize the air permeability of the building envelope or parts
thereof. It can be used
a) to measure the air permeability of a building or part thereof for compliance with a design air-tightness
specification;
b) to compare the relative air permeability of several similar buildings or parts of buildings;
c) to identify the leakage sources;
d) to determine the air-leakage reduction resulting from individual retrofit measures applied incrementally to
an existing building or part of building.
The fan-pressurization method is suitable for the respective diagnostic purposes. Although the air infiltration
and exfiltration cannot be measured directly, the results of this method can also be used to estimate with
adequate precision by means of calculation both the mean infiltration through unintended leakages and the
mean air flow through intended air flow devices from outside, in relation to the pressure conditions to be
expected within the building.
This method does not measure the air-infiltration rate of a building. The results of the fan-pressurization test
can be used to estimate the air infiltration by means of calculation. Other methods are applicable when it is
desired to obtain a direct measurement of the air infiltration rate. It is better to use the fan-pressurization
method for diagnostic purposes and measure the actual infiltration rate with tracer gas methods. A single
tracer gas measurement gives limited information on the performance of ventilation and infiltration of buildings.
This method applies to measurements of air flow through the construction from outside to inside or vice versa.
It does not apply to air flow measurements from outside through the construction and from other places within
the construction back to outside.
The proper use of this International Standard requires a knowledge of the principles of air flow and pressure
measurements. Ideal conditions for the test described in this standard are small temperature differences and
low wind speeds. For tests conducted in the field, it needs to be recognized that field conditions can be less
than ideal. Nevertheless, strong winds and large indoor-outdoor temperature differences should be avoided.
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INTERNATIONAL STANDARD ISO 9972:2006(E)
Thermal performance of buildings — Determination of air
permeability of buildings — Fan pressurization method
1 Scope
This International Standard is intended for the measurement of the air permeability of buildings or parts of
buildings in the field. It specifies the use of mechanical pressurization or depressurization of a building or part
of a building. It describes the measurement of the resulting air flow rates over a range of indoor-outdoor static
pressure differences.
This International Standard is intended for the measurement of the air leakage of building envelopes of
single-zone buildings. For the purpose of this International Standard, many multi-zone buildings can be
treated as single-zone buildings by opening interior doors or by inducing equal pressures in adjacent zones.
It does not address evaluation of air permeability through individual components.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 6781, Thermal Insulation — Qualitative detection of thermal irregularities in building envelopes — Infrared
method
ISO 7345, Thermal Insulation — Physical quantities and definitions
ISO 13790:2004, Thermal performance of buildings — Calculation of energy use for space heating and
cooling
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7345 and the following apply.
3.1.1
air leakage rate
air flow rate across the building envelope
NOTE This movement includes flow through joints, cracks and porous surfaces, or a combination thereof, induced by
the air-moving equipment used in this standard (see Clause 4).
3.1.2
internal volume
deliberately heated, cooled or mechanically ventilated space within a building or part of a building subject to
the measurement, generally not including the attic space, basement space and attached structures
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3.1.3
building envelope
boundary or barrier separating the internal volume subject to the test from the outside environment or another
part of the building
3.1.4
air change rate at reference pressure
air leakage rate per internal volume at the reference pressure difference across the building envelope
NOTE The reference pressure is usually 50 Pa.
3.1.5
air permeability
air leakage rate per envelope area at the reference pressure difference across the building envelope
NOTE The reference pressure is usually 50 Pa.
3.1.6
specific leakage rate
air leakage rate per net floor area at the reference pressure difference across the building envelope
NOTE A pressure difference of 50 Pa is the most common.
3.1.7
leakage area
area corresponding to air leakage rate at the reference pressure difference across the building envelope
NOTE A pressure difference of 10 Pa is the most common.
3.1.8
specific leakage area
leakage area per net floor area or envelope area at the test reference pressure difference across the building
envelope
3.2 Symbols
Symbol Quantity Unit
2 2
a specific leakage area at 10 Pa m /m
10
2
A envelope area m
E
2
A floor area m
F
2
A leakage area m
L
3 n
C air flow coefficient m /(h⋅Pa )
env
3 n
C air leakage coefficient m /(h⋅Pa )
L
–1
n air change rate at 50 Pa h
50
p pressure Pa
p uncorrected barometric pressure Pa
bar
p partial vapour pressure of water Pa
v
p saturation vapour pressure of water Pa
vs
3
Q tracer gas injection rate m /h
3
q air permeability at 50 Pa m /h
50
q air permeability
a50
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Symbol Quantity Unit
3
q air flow rate through the building envelope m /h
env
3
q air flow rate through the building envelope m /s
env,s
3
q air leakage rate at 50 Pa m /h
L50
3
q measured air flow rate m /h
m
3 2
q air permeability at 50 Pa m /(h⋅m )
p50
3
q air leakage rate at a specified reference pressure m /h
pr
difference
3
q readings of air flow rate m /h
r
3
V internal volume m
3 2
w specific leakage rate at 50 Pa m /(h⋅m )
50
∆p induced pressure difference Pa
∆p zero flow pressure difference (average) Pa
0
∆p ; ∆p zero-flow pressure difference before and after the Pa
0,1 0,2
test (air moving equipment closed)
∆p measured pressure difference Pa
m
∆p reference pressure Pa
r
Φ relative humidity –
Τ absolute temperature K
Τ external air absolute temperature K
e
Τ internal air absolute temperature K
int
3
ρ air density kg/m
3
ρ external air density kg/m
e
3
ρ internal air density kg/m
int
4 Apparatus
4.1 General
The following description of apparatus is general in nature. Any arrangement of equipment using the same
principles and capable of performing the test procedure within the allowable tolerances is permitted. Examples
of equipment configurations commonly used are indicated in Annex A.
Periodic calibration of the measurement system, used in this test method, according to manufacturer
specifications or to standardized quality insurance systems is required.
4.2 Equipment
4.2.1 Air-moving equipment
This includes any device that is capable of inducing a specific range of positive and negative pressure
differences across the building envelope or part thereof. The system shall provide a constant air flow at each
pressure difference for the period required to obtain readings of air flow rate.
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4.2.2 Pressure-measuring device
This includes any instrument capable of measuring pressure differences with an accuracy of ± 2 Pa in the
range of 0 Pa to 100 Pa.
4.2.3 Air flow rate measuring system
This includes any device capable of measuring air flow rate within ± 7 % of the reading.
Care shall be taken if the principle underlying the measurement of volumetric flow rate is an orifice. The
reading of the air flow rate shall be corrected according to air density (see manufacturers' specifications).
4.2.4 Temperature-measuring device
This includes any instrument capable of measuring temperature to an accuracy of ± 1 K.
5 Measurement procedure
5.1 Measurement conditions
5.1.1 General
There are two methods for this measurement procedure: depressurization or pressurization of a building or
part of a building. Regardless of which method is used, the air leakage of building envelope can be measured.
The accuracy of this measurement procedure is largely dependent on the instrumentation and apparatus used
and on the ambient conditions under which the data are taken.
NOTE In general, the measurement result of the depressurization method is larger than that for the pressurization
method. However, when air-tightness in the building is high, the test results of both methods are almost equal.
5.1.2 Measured extent
The extent of the building or part of the building measured is defined as follows.
a) Normally, the part of the building measured includes all deliberately conditioned rooms.
b) In special cases, the extent of the part of the building actually to be tested can be defined in agreement
with the client.
c) If the aim of the measurement is compliance with the air-tightness specification of a building code or
standard and the measured extent is not defined in this code or by a standard, the measured extent is
defined as in a).
Individual parts of a building can be measured separately; e.g. in apartment buildings, each apartment can be
measured individually. However, interpretation of results shall consider that air leakage measured in this way
can include flow through leaks to adjacent parts of the building.
NOTE 1 It is possible that an apartment building meets air-tightness requirements, but that one or more individual
apartments do not.
NOTE 2 Good practice requires measuring pressures induced in adjoining spaces, such as the attic and basement or
adjacent apartments, since air flow into or out of these spaces can be induced by the test method.
5.1.3 Time of measurement
The measurement can take place only after the completion of the envelope of the building or part of the
building to be tested.
NOTE A preliminary air permeability measurement of the air barrier of the building under construction can allow
leakages to be repaired more easily than after the building has been completed.
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5.1.4 Meteorological conditions
If the product of the indoor/outdoor air temperature difference, expressed in Kelvin, multiplied by the height,
expressed in metres, of the building or measured part of the building gives a result greater than 250 m⋅K, it is
unlikely that a satisfactory zero-flow pressure difference can be obtained (see 5.3.3).
If the wind speed near the ground exceeds 3 m/s or the meteorological wind speed exceeds 6 m/s or reaches
3 on the Beaufort scale, it is unlikely that a satisfactory zero-flow pressure difference can be obtained (see
5.3.3).
5.2 Preparation
5.2.1 General
This International Standard describes three types of test methods depending on the purpose. The preparation
of the building depends on the test method selected:
⎯ Method A (test of a building in use):
The condition of the building envelope should represent its condition during the season in which heating
or cooling systems are used.
⎯ Method B (test of the building envelope):
Any intentional opening in the building envelope shall be closed or sealed as specified in 5.2.2 and 5.2.3.
⎯ Method C (test of the building in use):
Automatically regulating, externally mounted air transfer devices are sealed, other openings are handled
in the same way as for method A.
5.2.2 Building components
Close all intentional exterior openings of the building or part of the building to be tested (windows, doors,
fireguard).
For the purpose of methods A and C (building in use), do not take any further measures to improve the
air-tightness of the building components (however, see also 5.2.3). For the purpose of method C, all
automatically regulating externally mounted air transfer devices are sealed. This is valid for natural supply and
exhaust systems, as well as for natural supply and mechanical exhaust systems.
For the purpose of method B (building envelope), all adjustable openings shall be closed and remaining
intentional openings shall be sealed.
The entire building or part of the building to be tested shall be configured to respond to pressurization as a
single zone.
All interconnecting doors (except for cupboards and closets, which should be closed) in the part of the building
to be tested shall be opened so that a uniform pressure is maintained within a range of less than 10 % of the
measured inside/outside pressure difference.
NOTE When testing large or complex buildings, this condition becomes increasingly important and can be verified by
selected differential pressure measurements between different rooms at the highest pressure contemplated.
Make general observations of the condition of the building. Take notes on the windows, doors, opaque walls,
roof and floor, position of adjustable openings and any sealings applied to intentional openings.
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5.2.3 Heating, ventilation and air conditioning systems
Heating systems with indoor air intake shall be turned off. Open fireplaces shall be cleared of ashes.
Mechanical ventilation and air conditioning systems shall be turned off.
Air terminal devices of mechanical ventilation or air conditioning systems shall be sealed. Other ventilation
openings (for example, openings for natural ventilation) shall be closed for purposes of method A and sealed
for method B.
Take measures to avoid exhaust hazards from heating systems. Take into account heating sources in
adjacent apartments.
If there is an intention to estimate the infiltration/exfiltration air change rate in accordance with
ISO 13790:2004, natural system openings are kept open for the purpose of the pressurization test or their
contribution is calculated.
5.2.4 Air-moving equipment
Connect the air-moving equipment to the building envelope using a window, door, or vent opening. Ensure
that the joints between the equipment and the building are sealed to eliminate any leakage.
If the building heating, ventilation and air conditioning system is used as the air-moving equipment, arrange
the fans and dampers to allow the system to pressurize or to depressurize the building in a manner such that
the total inward or outward air flow rate can be measured (see A.4).
NOTE In an airtight building, it is possible for the door, window or vent used to pass air during the test to produce the
most leakage. It is important to be careful in such a case with regards to the selection of the position of the air-moving
equipment and/or the interpretation of the test results.
5.2.5 Pressure measuring devices
The indoor/outdoor pressure difference is usually measured at the lowest floor level of the building envelope
under consideration.
NOTE In tall buildings, it is good practice to measure the pressure difference at the top floor level of the building
envelope under consideration as well.
Ensure that interior and exterior pressure drops are not influenced by the air moving equipment. The exterior
pressure tap should be protected from the effects of dynamic pressure, e.g. by fitting a T-pipe or connecting it
to a perforated box. Especially in windy conditions, it is good practice to place the exterior pressure tap some
distance away from the building, but not close to other obstacles.
The pressure tubes should not be aligned vertically. The tubing shall not be exposed to large temperature
differences (e.g. due to the sun).
5.3 Steps of the procedure
5.3.1 Preliminary check
Always check the complete building envelope at approximately the highest pressure difference used in the
test for large leaks and failings of temporarily sealed openings. If such leaks are detected, take detailed notes.
Any temporary sealings found missing or deficient, e.g. of heating, ventilation and air conditioning components,
shall be fixed at this time.
Check that water traps in plumbing systems are correctly filled or sealed.
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5.3.2 Temperature and wind conditions
To correct the air flow rate measurement for air density (see Annex B), read the temperature inside and
outside the building before, during or after the test.
Record the wind speed or force. Determining wind force by visual assessment of trees, water, etc., in terms of
the Beaufort scale (see Table D.1) is sufficient.
5.3.3 Zero-flow pressure difference
Short-circuit the pressure-measuring device and check or adjust the zero reading.
Connect the pressure measuring device to measure inside-outside pressure difference and temporarily cover
the opening of the air moving equipment. Observe and record the average of the positive values of zero-flow
pressure difference, ∆p , over a period of at least 30 s. Observe and record the average of the negative
01+
values of zero-flow pressure difference, ∆p , over a period of at least 30 s. If either of these average values
01–
of zero-flow pressure difference is greater than 5 Pa, do not perform the test.
Observe and record the average of all values of zero-flow pressure difference, ∆p , over a period of at
01
least 30 s.
Repeat this process at the end of the test (to obtain ∆p , ∆ p and ∆ p ). If either the positive or negative
02+ 02– 02
zero-flow pressure difference reading after the test is greater than 5 Pa, the test shall be declared not valid. If
a test report is produced for such a test, this failure to meet required test conditions shall be stated in the test
report.
5.3.4 Pressure difference sequence
Uncover and turn on the air-moving equipment.
The test is carried out by taking measurements of air flow rate and indoor-outdoor pressure difference over a
range of applied pressure differences in increments of no more than approximately 10 Pa. The minimum
pressure difference shall be approximately 10 Pa or five times the zero-flow pressure difference (positive or
negative averages), whichever is greater. The highest pressure difference being tested can depend upon the
size of the building according to a) and b).
a) Single dwellings and other small buildings:
The pressure difference shall be at least 50 Pa, but it is recommended that readings are taken at
pressure differences up to 100 Pa for best accuracy of calculated results.
b) Large buildings:
Wherever possible, the pressure difference shall be the same as for single dwellings [see a)]. However,
because of the large size of many non-domestic buildings and practical limitations on the capacity of
portable air-moving equipment used to test them, it is often found that a pressure difference of 50 Pa is
not achievable. In these cases, either additional air-moving equipment should be employed (to increase
total capacity) and/or the test may be carried out up to the highest pressure difference that can be
achieved with the available air-moving equipment. In such cases, the test shall not be valid unless a
pressure difference of 25 Pa can be achieved. Where the pressure difference is between 25 Pa and
50 Pa, this shall be clearly recorded in the test report with a statement that the requirements of this
International Standard have not been fully met and an account of the reasons why.
It is recommended that two sets of measurements be made: for pressurization and depressurization. However,
it is permitted to make only one set of measurements for either pressurization or depressurization and still
comply with the requirements of this International Standard. For each test, at least five approximately equally
spaced data points between the highest and the lowest pressure differences shall be defined.
NOTE 1 It is more precise to take data at higher pressure differences than at lower differences. Therefore, it is
important to exercise special care when measurements are taken at low pressure differences.
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NOTE 2 It is advisable to check that the condition of the building envelope have not changed during each test, for
example, that sealed openings have not become unsealed or that doors, windows or dampers have not have been forced
open by the induced pressure.
A large building shall be measured by dividing into some small parts.
6 Expression of results
6.1 Reference values
6.1.1 Internal volume
The internal volume, V, is the volume of air inside the measured building or part of building. The internal
volume is calculated by multiplying the net floor area (see 6.1.3) by the mean net ceiling height. The volume of
the furniture is not subtracted.
6.1.2 Envelope area
6.1.2.1 Total envelope area
The envelope area, A , of the building or measured part of the building is the total area of all floors, walls and
E
ceilings, bordering the internal volume subject to the test. This includes walls and floors below external ground
level.
Overall internal dimensions shall be used to calculate this area. No subtractions shall be made for the area at
junction of internal walls, floors and ceilings with exterior walls, floors and ceilings (see Figure 1).
6.1.2.2 Wall and roof envelope area
The wall and roof envelope area of the building or measured part of the building is the total area of walls and
the underside of the roof bordering the internal volume subject to the test.
This excludes the areas of floors.
NOTE In the context of this International Standard, the envelope area of a row house includes the division wall(s).
The envelope area of an apartment in a multiple story building includes the floors, walls and ceilings to adjacent
apartments.
Key
1 outside
2 overall size
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Performance thermique des bâtiments -- Détermination de la perméabilité à l'air des bâtiments -- Méthode de pressurisation par ventilateurThermal performance of buildings -- Determination of air permeability of buildings -- Fan pressurization method91.120.10Toplotna izolacija stavbThermal insulationICS:Ta slovenski standard je istoveten z:ISO 9972:2006oSIST ISO 9972:2010en01-junij-2010oSIST ISO 9972:2010SLOVENSKI
STANDARD
oSIST ISO 9972:2010
Reference numberISO 9972:2006(E)© ISO 2006
INTERNATIONAL STANDARD ISO9972Second edition2006-05-01Thermal performance of buildings — Determination of air permeability of buildings — Fan pressurization method Performance thermique des bâtiments — Détermination de la perméabilité à l'air des bâtiments — Méthode de pressurisation par ventilateur
oSIST ISO 9972:2010
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ii © ISO 2006 – All rights reserved
oSIST ISO 9972:2010
ISO 9972:2006(E) © ISO 2006 – All rights reserved iiiContents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms, definitions and symbols.1 4 Apparatus.3 5 Measurement procedure.4 6 Expression of results.8 7 Test report.12 8 Uncertainty.13 Annex A (informative)
Description of equipment used to pressurize buildings.14 Annex B (informative)
Dependence of air density on temperature, dew point and barometric pressure.16 Annex C (informative)
Recommended procedure for estimating uncertainty in derived quantities.17 Annex D (informative)
Beaufort scale for wind force (extract).20
oSIST ISO 9972:2010
ISO 9972:2006(E) iv © ISO 2006 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 9972 was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the built environment, Subcommittee SC 1, Test and measurement methods. This second edition cancels and replaces the first edition (ISO 9972:1996), which has been technically revised. oSIST ISO 9972:2010
ISO 9972:2006(E) © ISO 2006 – All rights reserved vIntroduction The fan-pressurization method is intended to characterize the air permeability of the building envelope or parts thereof. It can be used a) to measure the air permeability of a building or part thereof for compliance with a design air-tightness specification; b) to compare the relative air permeability of several similar buildings or parts of buildings; c) to identify the leakage sources; d) to determine the air-leakage reduction resulting from individual retrofit measures applied incrementally to an existing building or part of building. The fan-pressurization method is suitable for the respective diagnostic purposes. Although the air infiltration and exfiltration cannot be measured directly, the results of this method can also be used to estimate with adequate precision by means of calculation both the mean infiltration through unintended leakages and the mean air flow through intended air flow devices from outside, in relation to the pressure conditions to be expected within the building. This method does not measure the air-infiltration rate of a building. The results of the fan-pressurization test can be used to estimate the air infiltration by means of calculation. Other methods are applicable when it is desired to obtain a direct measurement of the air infiltration rate. It is better to use the fan-pressurization method for diagnostic purposes and measure the actual infiltration rate with tracer gas methods. A single tracer gas measurement gives limited information on the performance of ventilation and infiltration of buildings. This method applies to measurements of air flow through the construction from outside to inside or vice versa. It does not apply to air flow measurements from outside through the construction and from other places within the construction back to outside. The proper use of this International Standard requires a knowledge of the principles of air flow and pressure measurements. Ideal conditions for the test described in this standard are small temperature differences and low wind speeds. For tests conducted in the field, it needs to be recognized that field conditions can be less than ideal. Nevertheless, strong winds and large indoor-outdoor temperature differences should be avoided. oSIST ISO 9972:2010
oSIST ISO 9972:2010
INTERNATIONAL STANDARD ISO 9972:2006(E) © ISO 2006 – All rights reserved 1Thermal performance of buildings — Determination of air permeability of buildings — Fan pressurization method 1 Scope This International Standard is intended for the measurement of the air permeability of buildings or parts of buildings in the field. It specifies the use of mechanical pressurization or depressurization of a building or part of a building. It describes the measurement of the resulting air flow rates over a range of indoor-outdoor static pressure differences. This International Standard is intended for the measurement of the air leakage of building envelopes of single-zone buildings. For the purpose of this International Standard, many multi-zone buildings can be treated as single-zone buildings by opening interior doors or by inducing equal pressures in adjacent zones. It does not address evaluation of air permeability through individual components. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6781, Thermal Insulation — Qualitative detection of thermal irregularities in building envelopes — Infrared method ISO 7345, Thermal Insulation — Physical quantities and definitions ISO 13790:2004, Thermal performance of buildings — Calculation of energy use for space heating and cooling 3 Terms, definitions and symbols 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 7345 and the following apply. 3.1.1 air leakage rate air flow rate across the building envelope NOTE This movement includes flow through joints, cracks and porous surfaces, or a combination thereof, induced by the air-moving equipment used in this standard (see Clause 4). 3.1.2 internal volume deliberately heated, cooled or mechanically ventilated space within a building or part of a building subject to the measurement, generally not including the attic space, basement space and attached structures oSIST ISO 9972:2010
ISO 9972:2006(E) 2 © ISO 2006 – All rights reserved 3.1.3 building envelope boundary or barrier separating the internal volume subject to the test from the outside environment or another part of the building 3.1.4 air change rate at reference pressure air leakage rate per internal volume at the reference pressure difference across the building envelope NOTE The reference pressure is usually 50 Pa. 3.1.5 air permeability air leakage rate per envelope area at the reference pressure difference across the building envelope NOTE The reference pressure is usually 50 Pa. 3.1.6 specific leakage rate air leakage rate per net floor area at the reference pressure difference across the building envelope NOTE A pressure difference of 50 Pa is the most common. 3.1.7 leakage area area corresponding to air leakage rate at the reference pressure difference across the building envelope NOTE A pressure difference of 10 Pa is the most common. 3.1.8 specific leakage area leakage area per net floor area or envelope area at the test reference pressure difference across the building envelope 3.2 Symbols Symbol Quantity Unit a10 specific leakage area at 10 Pa m2/m2 AE envelope area m2 AF floor area m2 AL leakage area m2 Cenv air flow coefficient m3/(h⋅Pan) CL air leakage coefficient m3/(h⋅Pan) n50 air change rate at 50 Pa h–1 p pressure Pa pbar uncorrected barometric pressure Pa pv partial vapour pressure of water Pa pvs saturation vapour pressure of water Pa Q tracer gas injection rate m3/h q50 air permeability at 50 Pa m3/h qa50 air permeability
oSIST ISO 9972:2010
ISO 9972:2006(E) © ISO 2006 – All rights reserved 3Symbol Quantity Unit qenv air flow rate through the building envelope m3/h qenv,s air flow rate through the building envelope m3/s qL50 air leakage rate at 50 Pa m3/h qm measured air flow rate m3/h qp50 air permeability at 50 Pa m3/(h⋅m2) qpr air leakage rate at a specified reference pressure difference m3/h qr readings of air flow rate m3/h V internal volume m3 w50 specific leakage rate at 50 Pa m3/(h⋅m2) ∆p induced pressure difference Pa ∆p0 zero flow pressure difference (average) Pa ∆p0,1; ∆p0,2 zero-flow pressure difference before and after the test (air moving equipment closed) Pa ∆pm measured pressure difference Pa ∆pr reference pressure Pa Φ relative humidity – Τ=absolute temperature K Τe=external air absolute temperature K Τint=internal air absolute temperature K ρ air density kg/m3 ρe=external air density kg/m3 ρint=internal air density kg/m3 4 Apparatus 4.1 General The following description of apparatus is general in nature. Any arrangement of equipment using the same principles and capable of performing the test procedure within the allowable tolerances is permitted. Examples of equipment configurations commonly used are indicated in Annex A. Periodic calibration of the measurement system, used in this test method, according to manufacturer specifications or to standardized quality insurance systems is required. 4.2 Equipment 4.2.1 Air-moving equipment This includes any device that is capable of inducing a specific range of positive and negative pressure differences across the building envelope or part thereof. The system shall provide a constant air flow at each pressure difference for the period required to obtain readings of air flow rate. oSIST ISO 9972:2010
ISO 9972:2006(E) 4 © ISO 2006 – All rights reserved 4.2.2 Pressure-measuring device This includes any instrument capable of measuring pressure differences with an accuracy of ± 2 Pa in the range of 0 Pa to 100 Pa. 4.2.3 Air flow rate measuring system This includes any device capable of measuring air flow rate within ± 7 % of the reading. Care shall be taken if the principle underlying the measurement of volumetric flow rate is an orifice. The reading of the air flow rate shall be corrected according to air density (see manufacturers' specifications). 4.2.4 Temperature-measuring device This includes any instrument capable of measuring temperature to an accuracy of ± 1 K. 5 Measurement procedure 5.1 Measurement conditions 5.1.1 General There are two methods for this measurement procedure: depressurization or pressurization of a building or part of a building. Regardless of which method is used, the air leakage of building envelope can be measured. The accuracy of this measurement procedure is largely dependent on the instrumentation and apparatus used and on the ambient conditions under which the data are taken. NOTE In general, the measurement result of the depressurization method is larger than that for the pressurization method. However, when air-tightness in the building is high, the test results of both methods are almost equal. 5.1.2 Measured extent The extent of the building or part of the building measured is defined as follows. a) Normally, the part of the building measured includes all deliberately conditioned rooms. b) In special cases, the extent of the part of the building actually to be tested can be defined in agreement with the client. c) If the aim of the measurement is compliance with the air-tightness specification of a building code or standard and the measured extent is not defined in this code or by a standard, the measured extent is defined as in a). Individual parts of a building can be measured separately; e.g. in apartment buildings, each apartment can be measured individually. However, interpretation of results shall consider that air leakage measured in this way can include flow through leaks to adjacent parts of the building. NOTE 1 It is possible that an apartment building meets air-tightness requirements, but that one or more individual apartments do not. NOTE 2 Good practice requires measuring pressures induced in adjoining spaces, such as the attic and basement or adjacent apartments, since air flow into or out of these spaces can be induced by the test method. 5.1.3 Time of measurement The measurement can take place only after the completion of the envelope of the building or part of the building to be tested. NOTE A preliminary air permeability measurement of the air barrier of the building under construction can allow leakages to be repaired more easily than after the building has been completed. oSIST ISO 9972:2010
ISO 9972:2006(E) © ISO 2006 – All rights reserved 55.1.4 Meteorological conditions If the product of the indoor/outdoor air temperature difference, expressed in Kelvin, multiplied by the height, expressed in metres, of the building or measured part of the building gives a result greater than 250 m⋅K, it is unlikely that a satisfactory zero-flow pressure difference can be obtained (see 5.3.3). If the wind speed near the ground exceeds 3 m/s or the meteorological wind speed exceeds 6 m/s or reaches 3 on the Beaufort scale, it is unlikely that a satisfactory zero-flow pressure difference can be obtained (see 5.3.3). 5.2 Preparation 5.2.1 General This International Standard describes three types of test methods depending on the purpose. The preparation of the building depends on the test method selected: ⎯ Method A (test of a building in use): The condition of the building envelope should represent its condition during the season in which heating or cooling systems are used. ⎯ Method B (test of the building envelope): Any intentional opening in the building envelope shall be closed or sealed as specified in 5.2.2 and 5.2.3. ⎯ Method C (test of the building in use): Automatically regulating, externally mounted air transfer devices are sealed, other openings are handled in the same way as for method A. 5.2.2 Building components Close all intentional exterior openings of the building or part of the building to be tested (windows, doors, fireguard). For the purpose of methods A and C (building in use), do not take any further measures to improve the air-tightness of the building components (however, see also 5.2.3). For the purpose of method C, all automatically regulating externally mounted air transfer devices are sealed. This is valid for natural supply and exhaust systems, as well as for natural supply and mechanical exhaust systems. For the purpose of method B (building envelope), all adjustable openings shall be closed and remaining intentional openings shall be sealed. The entire building or part of the building to be tested shall be configured to respond to pressurization as a single zone. All interconnecting doors (except for cupboards and closets, which should be closed) in the part of the building to be tested shall be opened so that a uniform pressure is maintained within a range of less than 10 % of the measured inside/outside pressure difference. NOTE When testing large or complex buildings, this condition becomes increasingly important and can be verified by selected differential pressure measurements between different rooms at the highest pressure contemplated. Make general observations of the condition of the building. Take notes on the windows, doors, opaque walls, roof and floor, position of adjustable openings and any sealings applied to intentional openings. oSIST ISO 9972:2010
ISO 9972:2006(E) 6 © ISO 2006 – All rights reserved 5.2.3 Heating, ventilation and air conditioning systems Heating systems with indoor air intake shall be turned off. Open fireplaces shall be cleared of ashes. Mechanical ventilation and air conditioning systems shall be turned off. Air terminal devices of mechanical ventilation or air conditioning systems shall be sealed. Other ventilation openings (for example, openings for natural ventilation) shall be closed for purposes of method A and sealed for method B. Take measures to avoid exhaust hazards from heating systems. Take into account heating sources in adjacent apartments. If there is an intention to estimate the infiltration/exfiltration air change rate in accordance with ISO 13790:2004, natural system openings are kept open for the purpose of the pressurization test or their contribution is calculated. 5.2.4 Air-moving equipment Connect the air-moving equipment to the building envelope using a window, door, or vent opening. Ensure that the joints between the equipment and the building are sealed to eliminate any leakage. If the building heating, ventilation and air conditioning system is used as the air-moving equipment, arrange the fans and dampers to allow the system to pressurize or to depressurize the building in a manner such that the total inward or outward air flow rate can be measured (see A.4). NOTE In an airtight building, it is possible for the door, window or vent used to pass air during the test to produce the most leakage. It is important to be careful in such a case with regards to the selection of the position of the air-moving equipment and/or the interpretation of the test results. 5.2.5 Pressure measuring devices The indoor/outdoor pressure difference is usually measured at the lowest floor level of the building envelope under consideration. NOTE In tall buildings, it is good practice to measure the pressure difference at the top floor level of the building envelope under consideration as well. Ensure that interior and exterior pressure drops are not influenced by the air moving equipment. The exterior pressure tap should be protected from the effects of dynamic pressure, e.g. by fitting a T-pipe or connecting it to a perforated box. Especially in windy conditions, it is good practice to place the exterior pressure tap some distance away from the building, but not close to other obstacles. The pressure tubes should not be aligned vertically. The tubing shall not be exposed to large temperature differences (e.g. due to the sun). 5.3 Steps of the procedure 5.3.1 Preliminary check Always check the complete building envelope at approximately the highest pressure difference used in the test for large leaks and failings of temporarily sealed openings. If such leaks are detected, take detailed notes. Any temporary sealings found missing or deficient, e.g. of heating, ventilation and air conditioning components, shall be fixed at this time. Check that water traps in plumbing systems are correctly filled or sealed. oSIST ISO 9972:2010
ISO 9972:2006(E) © ISO 2006 – All rights reserved 75.3.2 Temperature and wind conditions To correct the air flow rate measurement for air density (see Annex B), read the temperature inside and outside the building before, during or after the test. Record the wind speed or force. Determining wind force by visual assessment of trees, water, etc., in terms of the Beaufort scale (see Table D.1) is sufficient. 5.3.3 Zero-flow pressure difference Short-circuit the pressure-measuring device and check or adjust the zero reading. Connect the pressure measuring device to measure inside-outside pressure difference and temporarily cover the opening of the air moving equipment. Observe and record the average of the positive values of zero-flow pressure difference, ∆p01+, over a period of at least 30 s. Observe and record the average of the negative values of zero-flow pressure difference, ∆p01–, over a period of at least 30 s. If either of these average values of zero-flow pressure difference is greater than 5 Pa, do not perform the test. Observe and record the average of all values of zero-flow pressure difference, ∆p01, over a period of at least 30 s. Repeat this process at the end of the test (to obtain ∆p02+, ∆ p02– and ∆ p02). If either the positive or negative zero-flow pressure difference reading after the test is greater than 5 Pa, the test shall be declared not valid. If a test report is produced for such a test, this failure to meet required test conditions shall be stated in the test report. 5.3.4 Pressure difference sequence Uncover and turn on the air-moving equipment. The test is carried out by taking measurements of air flow rate and indoor-outdoor pressure difference over a range of applied pressure differences in increments of no more than approximately 10 Pa. The minimum pressure difference shall be approximately 10 Pa or five times the zero-flow pressure difference (positive or negative averages), whichever is greater. The highest pressure difference being tested can depend upon the size of the building according to a) and b). a) Single dwellings and other small buildings: The pressure difference shall be at least 50 Pa, but it is recommended that readings are taken at pressure differences up to 100 Pa for best accuracy of calculated results. b) Large buildings: Wherever possible, the pressure difference shall be the same as for single dwellings [see a)]. However, because of the large size of many non-domestic buildings and practical limitations on the capacity of portable air-moving equipment used to test them, it is often found that a pressure difference of 50 Pa is not achievable. In these cases, either additional air-moving equipment should be employed (to increase total capacity) and/or the test may be carried out up to the highest pressure difference that can be achieved with the available air-moving equipment. In such cases, the test shall not be valid unless a pressure difference of 25 Pa can be achieved. Where the pressure difference is between 25 Pa and 50 Pa, this shall be clearly recorded in the test report with a statement that the requirements of this International Standard have not been fully met and an account of the reasons why. It is recommended that two sets of measurements be made: for pressurization and depressurization. However, it is permitted to make only one set of measurements for either pressurization or depressurization and still comply with the requirements of this International Standard. For each test, at least five approximately equally spaced data points between the highest and the lowest pressure differences shall be defined. NOTE 1 It is more precise to take data at higher pressure differences than at lower differences. Therefore, it is important to exercise special care when measurements are taken at low pressure differences. oSIST ISO 9972:2010
ISO 9972:2006(E) 8 © ISO 2006 – All rights reserved NOTE 2 It is advisable to check that the condition of the building envelope have not changed during each test, for example, that sealed openings have not become unsealed or that doors, windows or dampers have not have been forced open by the induced pressure. A large building shall be measured by dividing into some small parts. 6 Expression of results 6.1 Reference values 6.1.1 Internal volume The internal volume, V, is the volume of air inside the measured building or part of building. The internal volume is calculated by multiplying the net floor area (see 6.1.3) by the mean net ceiling height. The volume of the furniture is not subtracted. 6.1.2 Envelope area 6.1.2.1 Total envelope area The envelope area, AE, of the building or measured part of the building is the total area of all floors, walls and ceilings, bordering the internal volume subject to the test. This includes walls and floors below external ground level. Overall internal dimensions shall be used to calculate this area. No subtractions shall be made for the area at junction of internal walls, floors and ceilings with exterior walls, floors and ceilings (see Figure 1). 6.1.2.2 Wall and roof envelope area The wall and roof envelope area of the building or measured part of the building is the total area of walls and the underside of the roof bordering the internal volume subject to the test. This excludes the areas of floors. NOTE In the context of this International Standard, the envelope area of a row house includes the division wall(s). The envelope area of an apartment in a multiple story building includes the floors, walls and ceilings to adjacent apartments.
Key 1 outside 2 overall size 3 inside Figure 1 — Envelope area oSIST ISO 9972:2010
ISO 9972:2006(E) © ISO 2006 – All rights reserved 96.1.3 Net floor area The net floor area, AF, is the total floor area of all floors belonging to the internal volume subject to the test. It is calculated according to national regulations. 6.2 Calculation of the air leakage rate Subtract the average zero-flow pressure difference (offset) from each of the measured pressure differences, ∆pm, to obtain the induced pressure differences, ∆p, using Equation (1). Attention shall be drawn to plus or minus signs. 0102m2,,pppp+∆∆∆=−∆ (1) First, convert the readings, qr, of the air flow rate measuring system into measured air flow rates, qm, at the temperature and pressure at the flow measuring device in accordance with manufacturer's specifications: ()mrfqq= (2) Then, convert the air flow rates, qm, to air flow rates, qenv, through the building envelope for depressurization using Equation (3).
=
inteenvmminteTqqqTρρ⎛⎞⎛⎞=⎜⎟⎜⎟⎜⎟⎝⎠⎝⎠ (3) where ρint is the internal air density, expressed in kilograms per cubic metre; ρe is the external air density, expressed in kilograms per cubic metre; intT is the internal air absolute temperature, expressed in kelvins; eT is the external air absolute temperature, expressed in kelvins. Convert the measured air flow rate, qm, to air flow rate through the building envelope, qenv, for pressurisation using Equation (4).
=
eintenvmmeintTqqqTρρ⎛⎞⎛⎞=⎜⎟⎜⎟⎜⎟⎝⎠⎝⎠ (4) Plot the air flow rate through the building en
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