Retrotec USACE - Manual (Page 308)

F14 ENERGY & PROCESS ASSESSMENT PROTOCOL
fl oors above and below. Refer to the ASHRAE study, Protocol for Field Testing
of Tall Buildings to Determine Envelope Air Leakage Rate 935-RP (Bahnfl eth
1998) for additional information on the fl oor-by-fl oor method of testing. It is
recommended that the whole building achieve a uniform pressure to avoid the
uncertainty inherent in the fl oor-by-fl oor method, but this protocol does not
prohibit the application of the fl oor-by-fl oor method as an option for buildings
greater than four stories in height.
Pressure gauges must be digital type and accurate to within 1 percent of
reading or 0.25 Pa, whichever is greater, and must have adjustable time averag-
ing to compensate for wind. Calibrated fans must be accurate to within 5 per-
cent of the fl ow reading. Suffi cient tubing must be available so that all gauges
used can be manifolded together and referenced to the same outdoor pres-
sure. These tubes will be connected to the negative port of all gauges. Tubing
must also be available to run from the center of each separate test zone to the
positive port of the gauge.
A minimum of four exterior pressure monitoring stations are necessary in
all situations. The pressure must be monitored across each of the four sides of
the building structure. The pressure differential readings from the four exte-
rior stations can be averaged, or the four stations can run to a common mani-
fold constructed in accordance with standard CAN/CGSB-149.10, Determina-
tion of the Airtightness of Building Envelopes by the Fan Depressurization
Method.
The pressure difference between interior zones shall be monitored to
determine whether pressure differences between interior locations are within
10 percent of the indoor-outdoor pressure difference during all tests or not. If
they are not, then adjustments to test set-up shall be made until they are within
10 percent. Interior pressure difference measurements shall be referenced to
a single interior zone that is unaffected by velocity pressure created by test
equipment. Thus, at an average 75 Pascal pressure difference across the enclo-
sure, the difference between the highest and lowest interior pressure differ-
ence measurements should be within 15 Pascals of each other. The number of
indoor pressure difference measurements required depends on the number of
interior zones separated by bottle necks that could create signifi cant pressure
drops (e.g., doorways and stairwells).
F.9.4 Pre-Test Inspection
A pre-test inspection must be performed to determine whether there is some-
thing that would prevent the test from being completed. Check local weather
forecasts for rain or strong winds before travelling to the test site. Ensure that
the test equipment has arrived at the test site on time, and that it is in oper-
able condition. The operation of the equipment is the simplest part of the test,
whereas preparing the building is the most complex, takes the most time, and
is the most likely factor to prevent the testing agency from completing the
test.