This came up the other day and I could not find a blog post that covered it. Maybe it’s here somewhere, but with 1,455(!) published posts, it’s becoming harder to find the needle in the haystack.
I’ve had many Wordless Wednesday and Fixed-it Friday posts showing security devices that facility personnel claim to use only when the building is not occupied. Unfortunately, after a while people may tend to forget that the security bars, hooks, chains, etc. are supposed to be removed during business hours. I’ve yet to find something in a model code that says the egress requirements only apply when the building is occupied.
But there are other code requirements that are affected by whether the building is occupied or not. For example, when the model codes allow a key-operated lock to be used on the main entrance to a retail store, the lock must be unlocked when the building is occupied. So when is a building considered occupied? The answer depends on which code you’re referencing.
The word “occupied” is not defined in the IBC or the IFC. When a term is not defined in these publications, the “ordinarily accepted meaning” applies, as defined in Merriam Webster’s Collegiate Dictionary, 11th Edition. The most applicable definition of “occupied” according to Merriam Webster is “to take up (a place or extent in space)”…not very specific when you’re trying to interpret the codes based on this definition.
(1) It is open for general occupancy.
(2) It is open to the public.
(3) It is occupied by more than 10 persons.
Using the key-operated lock example, according to NFPA 101 the door would have to be unlocked when any of these criteria are met. For example, if the store is open for business but there is only one person inside, the door would have to be unlocked. Conversely, if the store was closed and there were 5 people inside doing inventory, the door could be locked, but NFPA 101 does not allow occupants to be locked beyond their control (except lockups, detention and correctional occupancies, and some types of health care units).