Which conditions must be met prior to setting up a blower door test?

To successfully conduct a blower door test, it's essential to ensure that natural gas appliances are set to pilot mode and that exhaust appliances are turned off. This precaution is critical because the blower door test measures the air tightness of a building by causing a pressure difference, which could lead to flue gas backdrafting from combustion appliances if they are operating. By setting gas appliances to pilot mode, the risk of carbon monoxide or other gases being pulled back into the living space is minimized, promoting safety during the test. Additionally, turning off exhaust appliances such as kitchen vents or bathroom fans prevents them from affecting the pressure readings, ensuring an accurate assessment of the building's air leakage.

All other options reflect important considerations but do not encompass the critical safety and technical requirements that must be met prior to initiating the blower door test. For instance, while it is beneficial for all appliances to be off and for the windows and doors to be closed to prevent external air influence, failing to control gas appliances specifically can compromise the integrity and safety of the test. Similarly, extreme temperatures might not enhance accuracy and can be a less relevant factor in the setup stage compared to appliance management.