When is mechanical equipment failure most critical during testing?

The most critical time for mechanical equipment failure during testing is when the building is at baseline conditions. At this point, the testing apparatus is functioning under typical operational parameters without any additional external influences, and any mechanical failure could significantly impact the accuracy and reliability of the test results. A failure in the mechanical equipment during this critical moment can lead to erroneous readings or a complete inability to perform the test, resulting in a misunderstanding of the building’s airtightness.

During baseline conditions, the established air pressure and environmental factors are controlled, making it easier to detect leaks and other issues. If the equipment fails at this time, it may not be possible to capture the necessary data to evaluate the building's envelope performance accurately, thus potentially compromising the integrity of the testing process and making follow-up actions difficult.

In contrast, mechanical equipment failure during other phases, such as when air pressure is being lowered or during comparisons with previous tests, might not be as critical since testing at those times can often be adjusted or repeated without the same immediate implications for the overall results.