While fire safety is always important, it is never more so than when large groups of people are in one place. You might be surprised to learn that certain rooms or buildings are limited regarding how many people they can safely hold. It isn’t just down to the size of the room or building, either.
Today, we will explain the concept behind occupancy load, how it is calculated, and why it is important to monitor occupancy load for the sake of fire safety.
Occupancy Load| Big Room, Lots of People, Right?
Not necessarily.
Think about the reasons why occupancy, the number of people permitted in a place at one time, might be limited?
Want a hint?
It’s all about how quickly people can escape if a fire breaks out. The occupancy load of a building is based on two things:
- The total number of people
- The intended use for that space
The intended use? Yep, that’s super important. Consider the following scenario.
There are two rooms equal in area. One is entirely empty, and the other is used as a ‘jungle gym’. Which do you think would be the easiest to escape from in an emergency? You’ll likely find that the latter has a lower occupancy load to deal with exactly this kind of situation.
Does occupancy load have any bearing on anything else?
Absolutely. It also dictates how many exits are required out of a particular space, as well as the required size of those exits.
How is Occupancy Load Calculated?
The good news is that you can easily get to grips with the concept of occupancy load by referencing a handy factsheet produced by the NFPA.
Here’s how occupancy load is calculated:
- The total floor space of the area under review is measured.
- The ‘footprint’ of any furniture, fixtures, or interior cubicles and rooms is subtracted, leaving you with a ‘usable floor area’.
- This usable area is divided by something called an occupant load factor.
- The result of the calculation in step #3 is the number of people permitted in the room or space, otherwise known as the load occupancy.
Wait, what is the “occupant load factor”?
Good question!
Remember above when we talked about the intended use for a given space? An occupancy load factor refers to how much space (in square feet) a single person will need depending on the intended purpose of the room.
Or, to put it in even simpler terms…
The minimum floor area that is required by each occupant.
Want a few examples of occupant load factors?
Ok, here goes. According to table 7.3.1 of NFPA 101: Life Safety Code, here’s a decent range to give you an idea of how much space is assigned to each person based on the intended use:
- Casinos – 11ft²/person
- Exercise studios – 15ft²/person
- Small meeting rooms – 15ft²/person
- Street floor sales areas – 30ft²/person
- Warehouses and storage – 300ft²/person
Notice the difference? Let’s try plugging in a few numbers to see how that changes the occupancy load. Don’t worry. We’ll keep the math simple.
Let’s say we have a room that is 300ft². And we are trying to decide what the occupancy load is. We haven’t decided what we are going to do with the room yet. We might want it to be a sales area or decide to make it into a storeroom.
Remember, the rooms occupancy load is the total number of people permitted in a single space. It is derived by dividing the floor space by the occupant load factor.
So, for a sales area, it will be 300ft²/30… This is an occupancy load factor of 10. Not bad. That means at any given time, you can have 10 people in that space.
However…
For a storage area, it will be 300ft²/300… this equals an occupancy load factor of 1! If that sounds restrictive, it gets worse. If you were using it for storage, the usable floor area might not be 300ft² as there would be boxes, racks, and other units inside.
Look at the above again. Same area, but quite a difference when you look at the rules! Now, do you see why it is important?
What About Areas with Multiple Uses?
This is an easy one!
The rules state that the most limiting factor is to be used permanently. The reason for this is undoubtedly to stop those with fewer scruples from saying a building was a salesroom, when in fact, it was a storage unit!
Why is Occupancy Load So Important?
It’s important to monitor occupancy load for the sake of fire safety for several reasons. Let’s take a look at why it is so important.
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Egress
Above all, this is the overwhelming reason why you must consistently monitor and adhere to the regulated occupancy load.
It is literally about saving people’s lives.
There are numerous examples of fires where lives were lost because they were overcrowded. The Station Nightclub fire is listed on the NFPA website as one of the deadliest in history.
If there are fewer people, it is much easier to make your escape from a fire. The beauty of the occupancy load calculation is that it only allows for usable floor space. Anything that would block a person’s escape is taken into account.
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Regulatory Compliance
The occupancy load also dictates the number of fire exits needed and how big they must be. This may be specified in the building’s regulations. However, it is always important to check.
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Insurance
If you exceed the occupancy load, you could find that it invalidates any insurance you have for the building. Squeezing a few more people could prove to be extremely expensive in more ways than one!
Conclusion
If the above sounds like hard work, or you aren’t sure about your occupancy load, perhaps it is time to speak to the professionals? Fraker Fire can offer expert guidance on all things related to fire protection.
They can even offer fire safety consultations. They are experts in installing fire protection systems and can provide expert guidance on exactly the right type of fire protection equipment to suit your home or business. Why not give them a call?