Arkansas HVACR NewsMagazine November 2024

HVACR NewsMagazine November 2024 Tech News

Ake Blomsterberg of Princeton University fame. Ake converted the blower window to fit an exterior door. As a note, G. T. Tamura (way ahead of his time) used a blower window in Ottawa Canada in 1967 and 1968 to test houses. In 1977, a team at the National Research Council of Canada's Division of Building Research (NRC/DBR) in Saskatchewan advanced the concept to a blower door. Thank you, Mr. Tamura. At time of inception, all the calculations were made on a spreadsheet filling in the data given by a set of 3 large analog Magnehelic. Today’s technology gives most of the calculations via a DG 1000 (Minneapolis Blower Door) manometer. Retrotec offers the DM32X manometer with their blower door set up.

The readings are compared, and the building leakage is calculated. If you don’t take your time setting up the door, you will get bogus information. Once you understand the principles of operation, most operators can tell if the initial information is valid, or where the setup has failed. Most of the folks that run blower doors today were involved with the industry in 2008 or later. Most learned by way of grant funding for that era of incentives delivered by the Federal Government to the HVAC industry. Granted, we are just under two decades ago, but what was learned from the first round of implementation was groundbreaking. As monies are distributed with the next round of grants, the information provided by use of the blower door should give more information to the quality of construction today as compared with older data. So, what’s the point of all this testing discussion? The first tool we looked at was the flow hood. The flow hood validates the correct air flowing into each room. We get required air flow from our duct design generated by the load calculation. The second tool was the duct blower that validates duct is not leaking . This test ensures we are not losing or gaining loads with an efficient duct system.

The blower door is set up in a door that leads

outside the envelope. This may include a door leading to the garage. Just as the duct blower measures the differential pressures, the blower door does the same. One probe is placed outdoors out of the way of fan influence created by the door itself, and the other end is attached to Channel A on the manometer. The other probe is attached to the fan input or Channel B and then to the port on the fan itself.