Retrotec Blower Door - Manual (Page 34)

Page 34 of 87
©Retrotec Inc. 2015
4. Conduct a Test
4.1 Observe house to avoid problems during testing
4.1.1. Ashes and other materials can blow into house
Depressurizing a house causes air to be sucked in from openings. This can be especially troublesome in a fireplace.
If proper care isn't taken to cover exposed, loose ashes, prior to beginning a test, the air flowing in through the
chimney can blow ashes out of the fireplace.
Likewise, other loose household materials can be moved around by airflow, especially if the materials are located
close to a major leak or the fan itself. It's very easy to blow loose papers, and other small objects around a house if
due care isn't taken to secure them before beginning testing.
4.1.2. Doors can slam shut
If a door suddenly shuts while using a Door Fan, the sudden change in pressure can be enough to damage an
enclosure or pop the fan out of the panel. Be sure to secure doors in the correct position, prior to starting the fan.
If a door shuts during testing, and it goes unnoticed, the accuracy of the test will be affected, because not all of the
building will be included in the test, as the area behind the closed door is treated as unconditioned space.
4.2 Select a Location
The first step in any test is to select a doorway, and install the Door Panel.
An exterior doorway in a large open room is best. Avoid doorways that have walls, stairs, or other obstructions
nearby. These will restrict airflow, and can lead to inaccurate results.
If the exterior doorway opens to an enclosed porch, garage or other area, open doors or windows to ensure the
enclosed area is open to the outside.
4.3 Where to place the exterior Pressure pickup tube
The exterior pressure reference for the differential pressure measurement across the door panel is provided by the
red tube. The exterior pickup location must be chosen to minimize the influence of wind, sun and atmospheric
pressure on the differential measurement, or measurements must be taken to allow correction for these influences.
Each standard defines what is expected in terms of the exterior reference pressure measurement. Use Table 2 to
determine where best to locate your red tube depending on the standard procedure you are following.
Table 2: Locations for Exterior Reference Pressure Pickup as required by the various Standard Procedures
Exterior pressure pick-up locations from Standards
ASTM
1 tube across the middle of each façade (NOT at corners of the building)
Manifold and average all pressure readings using a manifold (averaged ver 10s)
If > 3 stories, measured at more than 1 height
ATTMA
Measured at the lowest floor level of the building
Located "some distance away" from the building envelope, out of the way of fan airflow and sheltered from
wind
CGSB
Calm conditions - 1 pressure measurement outside the building is ok
Windy - min of 4 measurements on each façade, manifold