Retrotec Residential Pressure & Air Leakage - Manual (Page 34)

Page 34 of 75
©Retrotec Inc. 2014
1. Pressurize or depressurize the house to 50 or -50 Pa as for a basic air leakage test.
2. Use a second gauge or manually control the fan speed so that the gauge can be used for zone
testing.
3. Close the door to the room and make sure the house pressure is still at 50 Pa.
4. Conduct a zone pressure test of the room.
5. If the room pressure is similar to the house pressure, then the room is well connected to the house.
If the room pressure is more similar to the outside pressure (there is close to a 50 Pa difference
between room and house), then the room is more connected to the outside.
4.4 Apartment air leakage
Apartments are unique in that air leakage can be from the apartment to the outdoors as in a house, but also
from one apartment to an adjacent unit, to the floor above or below, or to the hall. In order to measure leakage
in one specific direction, it is necessary to open doors to adjacent spaces to pressurize them the same as the
outdoors, or to pressurize adjacent spaces to the same test pressure to neutralize leaks in one direction.
4.5 Closed door leakage
To measure the leakage of a door in a house:
1. Set the Blower Door up over top of the existing door with the existing door closed.
2. Measure the flow when pressurized – this is due to leakage of the door and Blower Door Panel
3. Seal the door with tape
4. Measure the flow when pressurized –this is due to leakage of the Blower Door Panel
5. Subtract measurement in Step 4 from Step 2. That gives the flow due to door leakage alone.
4.6 Measure air handler flow using a blower door or duct tester as a
powered flow hood
A blower door can be the ideal tool to measure
air handler flow because it has more flow
capacity than any residential airhandler. A Duct
Tester can also be used but will not measure the
largest residential air handler flows. In California
for example, 350 CFM is required per Ton; so a 5
Ton system would need 1750 CFM of airhandler
flow. Below the capacity of most duct testers.
Using this measurement method may be the
lowest cost alternative since either a Blower Door
and/or Duct Tester may already be on site when
the system airflow must be measured, all you
must do is to connect them to the duct work with
the flexduct. Both methods will typically have
errors of less than 7% or 5 CFM whichever is
greater.
Since flow will be measured in real time, airhandler flow rate can be displayed on a Smart Device while
adjustments are made to the system; such as opening register control dampers, opening and closing interior
doors that will all affect total airhandler flow rate.
Both methods duplicate the inlet conditions to those that would be in effect at the register prior to
measurement. In the plenum matching method, the flow is going to be the same so the pressure at the register
will effectively be zero while in the second method this value is measured directly.
Figure 12 Flex attached to Blower Door