Retrotec USACE - Manual (Page 302)

F8 ENERGY & PROCESS ASSESSMENT PROTOCOL
techniques or by the erection of temporary walls. In other cases, the use of
the building HVAC or large truck mounted fans may be required to establish
useful test pressures. These special techniques will require a higher level of
experience and engineering to establish useful results. It is up to the specifi er
to establish conformance criteria and test procedures for these unique build-
ings. The Canadian General Standards Board (CGSB) standard CAN/CGSB-
149.15, “Determination of the Overall Envelope Airtightness of Buildings by
Fan Pressurization Method Using the Building’s Air Handling Systems” could
be referenced by the specifi er and used by the testing agency. However, the
importance of air tightness should not be lost on buildings with enclosures over
500,000 sq ft.
F.8.2 Air Leakage Specifi cation
The air leakage test specifi cation could be written as follows:
The test consists of measuring the fl ow rates required to establish a mini-
mum of 12 positive and 12 negative building pressures. The lowest test pres-
sure shall be 0.1 in wg (25 Pa); the highest test pressure shall be 0.3 in wg
(75 Pa); and there must be at least 0.1 in wg (25 Pa) difference between the
lowest and highest test pressures. The test pressure must be measured in a
representative location such that pressures in the extremities of the enclosure
can be shown to not exceed ±10% of the measured test pressure. At least 12
bias pressure readings must be taken across the envelope and averaged over
at least 20 seconds each before and after the fl ow rate measurements. None
of the bias pressure readings must exceed 30 percent of the minimum test
pressure when testing in both directions. Where it can be shown that it is
impossible to test in b0th directions, then the building may be tested in the
positive direction only, provided the bias pressure does not exceed 10% of the
minimum test pressure.
The mean value of the air leakage fl ow rate calculated from measured data
at 0.3 in wg (75 Pa) must not exceed the specifi ed values, e.g., 0.25 cu ft/ minute
(cfm) per square foot of envelope area (1.27 L/s*m
2 ) at standard conditions,
and the upper confi dence limit as defi ned by ASTM E-779 must not exceed
that value by more than 8% of this value (in the case of the example, 0.27 cfm
per square foot or 1.37 L/s*m
2 ). Measurements must be referenced at standard
conditions of 14.696 psi (101.325 KPa) and 68F (20°C). The envelope area is to
be supplied and/or confi rmed by the architect of record (AOR).
F.8.3 Additional Information for the Specifi er
The Testing Agency Guide provides detailed information as to exactly how
the test must be performed. The Air Leakage Test Form details the exact pro-
cedure that the testing agency followed. A completed test must consist of all
pages of the Air Leakage Test Form with required attachments plus a seventh