How does a construction site account for everyone in an evacuation?

The gap that kills is always the same gap

Visitors and new inductions. The people who arrived this morning, who are not on yesterday’s printed list, who do not know where the assembly point is, and who are least equipped to find it in a hurry.

A printed roster describes yesterday. An evacuation is about today, and specifically about the people who are least like yesterday.

One number, across twenty subcontractors

The question is “how many of whose workers are on site, right now”. Siloed per-subcontractor attendance gives you twenty correct answers and no usable one.

And at an assembly point, twenty correct answers is the same as none — because the only thing anybody needs to know is whether the number at the gate matches the number in front of them, and nobody can add up twenty lists while a building is on fire.

The counting has to be somebody’s job

OSHA suggests roughly one trained evacuation warden per twenty employees. That ratio is a planning guideline rather than a penalty-backed rule, and the number matters less than the principle underneath it: every person on site must be counted BY a specific someone, and that someone must know who they were counting.

A headcount that comes out right by luck is indistinguishable from one that comes out right by design — right up until the day it does not, which is the only day it was ever going to matter.

Terms

• Muster Roll