Penetrations in Fire Separations - rated ceilings

[kiwijbob]

Is there a stated maximum allowable amount of recessed ceiling lights (unprotected openings) or aggregate maximum area permitted to a rated ceiling similar to that stated in 3.1.9.4. for outlet boxes. I assume the options are to either recess the light in a type X drywall box matching the ceiling rating or install a fire rated shroud if the unit itself doesn't come with a rating? I like the clarity to the wording of 3.1.9.4 to the NBC 2015. thanks.

 

[kiwijbob]

So after much reading and conversation I understand it that metal octagonal junction boxes can be placed in a rated ceiling (forgetting about STC issues for the moment) as long as they are tightly fitted properly & firestopped. Other electrical fixtures that are recessed need to maintain the fire rating the the U/S of the assembly.

 

[steveray]

I don't know much about Canada, but yes....Typically recess fixtures need to be rated or the get a rated "hat" over them....Surface mount with boxes gat a partial pass but there may be limits as to how many...sq inches per sq foot or whatever the evil sorcery of the metric system allows up in da great white north there.....

 

[tmurray]

Are you dealing with the hockey puck lights? The issue we have had was that the electrical box allowances are based on a non-combustible box. There really isn't a good answer to this question if the assembly is designed using the component additive method in Appendix D. There are some assemblies under CAN/ULC-S101 that have some penetration allowances if the designer looks hard enough.

 

[kiwijbob]

Are you dealing with the hockey puck lights? The issue we have had was that the electrical box allowances are based on a non-combustible box. There really isn't a good answer to this question if the assembly is designed using the component additive method in Appendix D. There are some assemblies under CAN/ULC-S101 that have some penetration allowances if the designer looks hard enough.

Situation we're dealing with is bringing an existing non-ULC tested assembly up to or as close as is practically possible to NBC 2015. Owner has been instructed to remove all recessed light fixtures and replace with metal octagon boxes tightly fitted and sealed to the rated ceiling...Ceiling is now rated via the component additive method. The NBC could be clearer on this item.

 

[tmurray]

Yes, renos are always way harder.

I was dealing with a fire protection engineering firm a couple of weeks ago and they indicated their feelings about Appendix D and ceilings is that it is only good if you create a fire rated ceiling, then have another ceiling below with the lighting, HVAC, etc. penetrations in it.

Best of luck!

 

[kiwijbob]

Yes, renos are always way harder.

I was dealing with a fire protection engineering firm a couple of weeks ago and they indicated their feelings about Appendix D and ceilings is that it is only good if you create a fire rated ceiling, then have another ceiling below with the lighting, HVAC, etc. penetrations in it.

Best of luck!

thanks, yes in a new build I always drop a false ceiling for services.... much less of a headache

 

[Inspector Gadget]

Situation we're dealing with is bringing an existing non-ULC tested assembly up to or as close as is practically possible to NBC 2015. Owner has been instructed to remove all recessed light fixtures and replace with metal octagon boxes tightly fitted and sealed to the rated ceiling...Ceiling is now rated via the component additive method. The NBC could be clearer on this item.

3.1.9.1(1) is pretty clear - the exception to the fire-stop requirement is laid out in 3.1.9.1(2), aAlso, it's important to clarify if you're dealing with a membrane ceiling.