The terms “deferred testing” and “seasonal testing” are common throughout the building systems commissioning world. So common, in fact, that there is often very little discussion about what they mean and how they are applied. Recently, I was drawn into a discussion with someone who had a different understanding than I did, thus leading me to question my own interpretation. I requested a cursory, nonscientific literature review of nine different industry standards and guidelines and learned the following about deferred and seasonal testing.
Deferred testing (also infrequently referred to as delayed testing) appears to be universally defined as testing that cannot be effectively or conclusively performed during the construction phase acceptance period. The reasons for this include the following, all related to proper loading of the systems to demonstrate performance under near-design conditions.