Is spray foam around electrical boxes a fire hazard?

[Stephen Tashiro]

I see videos recommending to insulate around electric outlets with spray foam. Does spray foam create an additional fire hazard when used around electrical boxes? - any more of hazard than is already present due to other types of insulation that are near electric boxes?

[Erik Loza]

Isn't PU foam with FireBlock a thing? I'm sure I've seen it Lowe's.

Erik

[Frank Pratt]

That's what the box is for, to keep the hot stuff from the burnable stuff.

[Bruce King]

Fireblock was named that because the code requires a wooden block, drywall etc with sealing to stop the movement of air from one level to another. They call that fire blocking in the code. It’s a dumb name because it causes people to use it to repair fireplaces etc. It’s flammable if next to flame or heat above 240 degrees.

]When NOT to Use Spray Foam Insulation

• For areas that are too close to electrical boxes:
• For areas too close to ceiling light boxes: You should not use spray foam to insulate areas around recessed ceiling canister lights. ...
• Open-cell spray foam on your roof: ...
• For closed-cavity spaces: ...
• If you have a history of skin, respiratory, or asthma problems:

[Erik Loza]

Fireblock was named that because the code requires a wooden block, drywall etc with sealing to stop the movement of air from one level to another. They call that fire blocking in the code. It’s a dumb name because it causes people to use it to repair fireplaces etc. It’s flammable if next to flame or heat above 240 degrees.

]When NOT to Use Spray Foam Insulation

• For areas that are too close to electrical boxes:
• For areas too close to ceiling light boxes: You should not use spray foam to insulate areas around recessed ceiling canister lights. ...
• Open-cell spray foam on your roof: ...
• For closed-cavity spaces: ...
• If you have a history of skin, respiratory, or asthma problems:

Thanks, Bruce. Now I know.

Erik

[Jim Becker]

Spray Foam insulation typically fully engages electrical boxes during and after application. It's a major reason why you want to insure that your wiring is "correct" before the insulation is installed. Retrofit is difficult.

[Bill Dufour]

Firestop seal is a thing. Code requires it in all walls in schools. Schools must be inspected, by a state school building inspector, before the state issues a certificate to use it as a public school. Just meeting fire code is not the same. A local district went with lower bidder who built to code and not school code because that was all the contract said. About a million more to fire seal all the wire runs etc in every wall. retrofit cost 20-30% of original cost.
Bil lD

[Jason Roehl]

Spray foam (non-fire-seal) is fine around electrical boxes. HOWEVER, it should not make up for a poor installation. That is, electrical boxes should be flush with the finished surface of the wall.

[Jim Becker]

Firestop seal is a thing. Code requires it in all walls in schools. Schools must be inspected, by a state school building inspector, before the state issues a certificate to use it as a public school. Just meeting fire code is not the same. A local district went with lower bidder who built to code and not school code because that was all the contract said. About a million more to fire seal all the wire runs etc in every wall. retrofit cost 20-30% of original cost.
Bil lD

Firestop is technically a different product, even though it's form factor is similar to regular spray foam. It's used for sealing penetrations, particularly between floors. "Back in the day", they had to be stuffed with other firestopping materials...a can with a nozzle is a whole lot more convenient. The OP appears to be asking about normal spray foam insulation relative to electrical boxes in the wall.

[Charlie Velasquez]

I ran an additional circuit to my attached garage, coming from the top with 1/2” conduit. Outside diameter of 1/2” conduit is just shy of 3/4”. Used a 7/8” spade bit to go through the ceiling, almost a friction fit. Inspector said I had to seal it with fire stop foam. Actually had to make the hole bigger to get it into the space between the conduit and the drywall.

[Frank Pratt]

Firestopping is actually quite technical. You have to consider the fire barrier being penetrated, the size & shape of the penetration, and what is passing through the penetration. Then you have to pick a suitable tested and approved firestop assembly that may consist of a combination puddy, rock wool, metal conduit or pipe, sealant, pillows & associated hardware, etc. Just filling the gap with foam or fire caulk may not meet code. When applying for a building permit here, the types of penetrations and data sheets for approved firestop assemblies must be submitted.

[Stephen Tashiro]

The discussion is confusing because "Fireblock", "Fireseal", and "Firestop" are not (as far as I can tell) names that refer to only one particular product. For each of those names, different manufacturers make products that use the name. ( I don't know of any standard that defines a specific meaning or "block", "seal" and "stop" in product names. The use of such terminology in building codes may be standardized, but that's not my question.)

I'll try to be specific! I'm curious about spray foams that come in cans. Is there a brand of spray foam ( be it fire bloc, stop, seal, or whatever) that can be used to insulate around electric boxes and which does not create an additional fire hazard? - versus just leaving the box uninsulated?

The question of fire hazard is also somewhat ambiguous. Sealing around a box will work against fires that start in a different location by keeping air away from the fire. But my interest is how a foam helps or hurts when wires in the box overheat.

[Frank Pratt]

I'll try to be specific! I'm curious about spray foams that come in cans. Is there a brand of spray foam ( be it fire bloc, stop, seal, or whatever) that can be used to insulate around electric boxes and which does not create an additional fire hazard? - versus just leaving the box uninsulated?

The question of fire hazard is also somewhat ambiguous. Sealing around a box will work against fires that start in a different location by keeping air away from the fire. But my interest is how a foam helps or hurts when wires in the box overheat.

Your question has already been answered, and because it has, the conversation has digressed and moved on. Spray foam around an electrical box will cause no problems.

[Jim Becker]

For what you describe, simple "Great Stuff" type spray foam should be fine. If the walls are already in place and you're trying to seal infiltration, use the minimal expanding variety like would be used around windows and doors. The "fire stop/fire block" products mentioned are for specific situations, such as sealing penetrations in the stud walls between floors to prevent fire from climbing up inside the walls from areas below, etc.