Retrotec Residential Pressure & Air Leakage - Manual (Page 19)

Page 19 of 75
Suspended ceilings using T-bars and acoustical tiles may not be able to withstand the 50 Pa of negative pressure
created during a multi-reading (point) test. The same is true for the plastic light diffusers under some
fluorescent lamps. If the tile ceiling or lights are installed under an older plaster or sheetrock ceiling which has
many penetrations through it, remove a tile or light diffuser leading into this cavity before starting the test.
If the suspended ceiling is the thermal envelope (such as in the typical commercial building that has insulation
batts on the ceiling), removing a tile may give a very erroneous reading. Perform a single reading test at a lower
pressure and don't increase the pressure without keeping an eye on the ceiling. A pressurization test isn't
recommended as the tiles may lift up and give erroneous readings.
2.4.2. Fragile Decorations
Ask the homeowner to move any fragile decorations, bric-a-brac, papers etc..., which may get disturbed by the
Blower Door airflow. If this is not possible, pick another doorway, or do the entire test under negative pressure
only.
2.4.3. Flying Floors
Under negative pressure, a one-piece vinyl floor may rise up if it is over a leaky crawlspace. It is rare, but will
significantly affect test results. Testing under positive pressure will prevent this.
2.4.4. Airstreams
Watch out for doors that may slam shut from the pressure changes during a test. In a smaller, tighter home, a
sudden increase in negative pressure (from the door shutting) can spike the house pressure, and pull the whole
Blower Door out of the doorway. This is highly embarrassing for the tester, and potentially damaging to the
homeowner’s floors.
2.4.5. Energy Efficient New Homes
Testing new energy efficient homes for a utility sponsored program, or for a builder who is building energy
efficient homes, may require a different house preparation than what is described. For example, the Canadian
R-2000 program specifies that furnace, water heater, wood stove and fireplace flues may be sealed for the test.
Some intentional ventilation openings such as air-to-air heat exchanger intakes and exhausts may be sealed as
well. The objective is to measure the tightness of the building envelope itself, independent of any mechanical
systems and intentional openings. Contact the local program administrators for current requirements. Note
that extra time is generally needed if openings are to be sealed off.
2.4.6. Plumbing Traps
In many homes, especially newly built ones, considerable amounts of air can flow in through the drainage
system (if there is no water in the traps). This should be stopped in new construction by filling the traps with
water. Use antifreeze if the home is unheated and if freezing is possible after the testing is complete.
2.5 Return the House to Pre-Test Condition.
Ensure that the building is returned to its original condition before leaving. This includes turning the thermostat
and water heater temperature controls to their original setting. Always check to see that furnace, water heater
and gas fireplace pilot lights have not been blown out during the test; re-light them if necessary. Remove any
temporary seals from fireplaces or other openings sealed during the test. Occupants may not be aware of what
was turned off or sealed for the test.
2.6 Site Conditions affect tests so need to be recorded
2.6.1. Estimate the Wind Speed