Determing Occupant Load for an existing 1 storey building.

[Zef Pepaj]

Hello all,

I have been tasked with letting the client know if they can remove a fire alarm system which has not been in operation for quite some time. The building is a one storey restaurant with exits leading to the outside. I have yet to go to site and measure the building floor areas.

In preparation for my site visit, I am trying to come to an understanding in what exactly to look for on site. If the building is sprinklered, the fire alarm system will remain in order to provide for the remote monitoring of the sprinkler system supervisory and alarm conditions.

I know that the threshold for requirements for a fire alarm system in a restaurant is 150 persons. As per 3.2.4.1. (2) (g) of the O.B.C.

The O.F.C. states that the occupant load shall be the lower of the occupant loads as indicated in:
-The OFC 2.7.1.4 (3) to 2.7.1.4. (7) or the occupant load for which the means of egress are provided as determined by the O.B.C.

I already understand how to determine the occupant load using the O.F.C. requirements. My issue is with figuring out the occupant load based on the O.B.C requirements.

My question is this:
Can I calculate the occupant load of an existing building under the O.B.C. by simply going to site, measuring the width of all exit door exits. Once I have the aggregate exit width, divide it by 6.11 mm per person?

My understanding is that occupant load is used (in the O.B.C.) to determine exit width and number of exits for a building when it is in the design phase (along with various other code requirements that are driven by occupant load). So if that is the methodology in determining occupant load for designing a building, can I just work backwards and divide the aggregate door width by 6.11 mm to determine the designed occupant load.

I appreciate any and all responses.

Much Regards,

 

[classicT]

Working backwards, as you have suggested, will grossly over estimate the occupant load.

I see doors every day that have calculated egress widths less then 1-ft, but are provided with multiple 3-ft doors. Your proposed method will certainly raise the occupant load to an exceedingly high number.

Instead, have you reached out to the local AHJ and requested a copy of the Certificate of Occupancy? It would be noted therein.

 

[cda]

I don’t speak Canadian but agree

Unless they do it different, normally based on square feet and use of the space

 

[Zef Pepaj]

Ok, I will simply use the number of seats for the front area, then calculate the back of house area based on usage type and building area.

Add the two up and that is my designed occupant load.

Thanks for your input!

 

[cda]

Ok, I will simply use the number of seats for the front area, then calculate the back of house area based on usage type and building area.

Add the two up and that is my designed occupant load.

Thanks for your input!

If you do a simple floor plan

Make it a link and post the link

Tell us what factor you use, we can see what numbers we come up with.

Sometimes counting seats is right way,,,, sometimes wrong way