ASTM E779-03
(Test Method)Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
SIGNIFICANCE AND USE
Air leakage accounts for a significant portion of the thermal space conditioning load. In addition, it can affect occupant comfort and indoor air quality.
In most commercial or industrial buildings, outdoor air often is introduced by design; however, air leakage can be a significant addition to the designed outdoor airflow. In most residential buildings, indoor-outdoor air exchange is attributable primarily to air leakage through cracks and construction joints and can be induced by pressure differences due to temperature differences, wind, operation of auxiliary fans, for example, kitchen and bathroom exhausts, and the operation of combustion equipment in the building.
The fan-pressurization method is simpler than tracer gas measurements and is intended to characterize the air tightness of the building envelope. It can be used to compare the relative air tightness of several similar buildings, to identify the leakage sources and rates of leakage from different components of the same building envelope, and to determine the air leakage reduction for individual retrofit measures applied incrementally to an existing building, and to determine ventilation rates when combined with weather and leak location information.
SCOPE
1.1 This test method covers a standardized technique for measuring air-leakage rates through a building envelope under controlled pressurization and de-pressurization.
1.2 This test method is applicable to small temperature differentials and low-wind pressure conditions. For tests conducted in the field, it must be recognized that field conditions may be less than ideal. Nevertheless, strong winds and large indoor-outdoor temperature differentials should be avoided.
1.3 This test method is intended to produce a measure of air tightness of a building envelope. This test method does not measure air leakage rates under normal conditions of weather and building operation. To measure air-change rate directly, use the tracer gas dilution method (see Test Method E 741).
1.4 This test method is intended for the measurement of the airtightness of building envelopes of single-zone buildings. For the purpose of this test method, many multi-zone buildings can be treated as single-zone buildings by opening interior doors or by inducing equal pressures in adjacent zones.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Section 7.
General Information
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Standards Content (Sample)
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Designation: E779 – 03
Standard Test Method for
1
Determining Air Leakage Rate by Fan Pressurization
This standard is issued under the fixed designation E779; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 air-change rate, n—air-leakage rate in volume units/h
divided by the building space volume with identical volume
1.1 This test method covers a standardized technique for
units, normally expressed as air changes/h, ACT–.
measuring air-leakage rates through a building envelope under
3.1.2 air-leakage graph, n—the graph that shows the rela-
controlled pressurization and de-pressurization.
tionship of measured airflow rates to the corresponding mea-
1.2 This test method is applicable to small temperature
sured pressure differences, usually plotted on a log-log scale.
differentials and low-wind pressure conditions. For tests con-
3.1.3 air-leakage rate, n—the volume of air movement/unit
ducted in the field, it must be recognized that field conditions
time across the building envelope.
may be less than ideal. Nevertheless, strong winds and large
3.1.3.1 Discussion—This movement includes flow through
indoor-outdoor temperature differentials should be avoided.
joints, cracks, and porous surfaces, or a combination thereof.
1.3 Thistestmethodisintendedtoproduceameasureofair
The driving force for such an air leakage, in service can be
tightness of a building envelope. This test method does not
either mechanical pressurization and de-pressurization, natural
measure air leakage rates under normal conditions of weather
wind pressures, or air temperature differentials between the
andbuildingoperation.Tomeasureair-changeratedirectly,use
building interior and the outdoors, or a combination thereof.
the tracer gas dilution method (see Test Method E1258).
3.1.4 building envelope, n—the boundary or barrier sepa-
1.4 This test method is intended for the measurement of the
rating the interior volume of a building from the outside
airtightnessofbuildingenvelopesofsingle-zonebuildings.For
environment.
thepurposeofthistestmethod,manymulti-zonebuildingscan
3.1.4.1 Discussion—Forthepurposeofthistestmethod,the
betreatedassingle-zonebuildingsbyopeninginteriordoorsor
interior volume is the deliberately conditioned space within a
by inducing equal pressures in adjacent zones.
building, generally not including attics, basements, and at-
1.5 This standard does not purport to address all of the
tached structures, for example, garages, unless such spaces are
safety concerns, if any, associated with its use. It is the
connected to the heating and air conditioning system, such as
responsibility of the user of this standard to establish appro-
a crawl space plenum.
priate safety and health practices and determine the applica-
3.1.5 single zone, n—a space in which the pressure differ-
bility of regulatory limitations prior to use. For specific hazard
ences between any two places, differ by no more than 5% of
statements see Section 7.
the inside to outside pressure difference.
2. Referenced Documents 3.1.5.1 Discussion—A multi-room space that is intercon-
2
nected within itself with door-sized openings through any
2.1 ASTM Standards:
partitions or floors is likely to satisfy this criterion if the fan
E1258 Test Method forAirflow Calibration of Fan Pressur-
3 3 3
airflow rate is less than 3 m /s 6 3 10 ft /min).
ization Devices
3.1.6 test pressure difference, n—the measured pressure
3. Terminology
difference across the building envelope, expressed in Pascals
2
(in. of water or pounds-force/ft or in. of mercury).
3.1 Definitions of Terms Specific to This Standard:
3.2 Symbols and Units—See Table 1.
1
This test method is under the jurisdiction of ASTM Committee E06 on 4. Summary of Test Method
Performance of Buildings and is the direct responsibility of Subcommittee E06.41
4.1 This test method consists of mechanical pressurization
on Air Leakage and Ventilation.
or de-pressurization of a building and measurements of the
Current edition approved Oct. 1, 2003. Published November 2003. Originally
approved in 1981. Last previous edition approved in 1999 as E779–99. DOI:
resulting airflow rates at given indoor-outdoor static pressure
10.1520/E0779-03.
differences. From the relationship between the airflow rates
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and pressure differences, the air leakage characteristics of a
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on building envelope can be evaluated.
the ASTM w
...
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