Here is a response from our PHIUS Inspector Rob Johnson:
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Good Morning Ross
I am familiar with the PHIUS + standard and they have a description of how to pressure balancing attached walls or individual zone guarded testing. I’m not sure if it is allowed in Passive or not
My experience is that it will be hard to get a townhouse to 0.6 ach but I am sure it can be done. Keep in mind now you are only testing the exterior walls, if you maintain zero pressure differential between attached walls there will be less test surface area to divide the air leakage into.
There are several ways of pressure balancing or guarding the adjacent units. I usually set up blower doors to be operated from the outside, plan your tubing runs as the meter will also be on the outside. This way you can monitor everything. Depending on the equipment you are using you can just cruse all the fans to the same pressure differential and record the flow through the fan in the test unit.
There are other ways of running this test. depending on the equipment you are using you can extend the exterior taps from the guarded units into the test unit. Then those meters will be monitoring the pressure differential between units, not interior to exterior. Those meters can then be set to auto cruse to zero. This way they will automatically operate the fan to maintain a zero pressure differential between the guarded units and the test unit. Now you can just run your regular test on the test unit, with zero pressure differential between units done for you. Easy for a one man test.
If I can help you any more just ask.
Rob
ROB JOHNSTON C.E.A., LEED® GREEN RATER, PHIUS Rater
Manager, Large Building Services
50 Fleming Drive, Unit # 6, Cambridge, ON, N1T 2B1
T | 1-800-267-6830 ext 100 C | 1-519-716-1058
F | 1-519-658-6103 E |rob@buildingknowledge.ca
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