Can spray foam be used as fire blocking?

Author: Prof. Cleora Welch  |  Last update: Wednesday, December 31, 2025

Yes, the International Code Council approved a number of Dow Chemical products (mostly the Great Stuff family of foams) as an alternative fire blocking material in Type V construction (All wood framing).

Can expanding foam be used for fire stopping?

Yes, you can. Fire rated foam can expand by 40 times and can be used to seal compartment walls and floors, partitions and fire doors. Fire rated expanding foam typically offers four hours of fire resistance and is tested in accordance with EN1366-4: 2006.

What material can be used for fire blocking?

1) 2x nominal lumber 2) ¾” plywood or OSB 3) ½” Drywall or better 4) Mineral wool or Fiberglass batt “securely retained in place” in an approved manner Fiberglass batt used as fireblock must entirely fill the cavity protected and must be packed tightly around any obstruction such as a duct or pipe. R302.

Is spray foam insulation a fire retardant?

Is Spray foam insulation fire resistant? Unfortunately, all types of insulation are flammable. While spray foam insulation is not fire resistant, the material is treated with flame retardants to lower the possibility of igniting and burning when exposed to sufficient heat sources.

How to make spray foam fire-resistant?

Fire code requires a 5 or 15 minutes intumescent coating to be painted over the foam. For a coating to be considered intumescent, it must expand when exposed to heat, forming a char that insulates and protects the underlying material from fire.

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Is Great Stuff foam fireproof?

The information herein is not intended for use by non-professional designers, applicators or other persons who do not purchase or utilize this product in the normal course of their business. CAUTION: When cured, these products are combustible and will burn if exposed to open flame or sparks from high-energy sources.

Can I use fiberglass insulation for fire blocking?

Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be allowed as fireblocking in walls constructed using parallel rows of studs or staggered studs.

What is the code for fire blocking?

R302. 11 Fireblocking. In combustible construction, fire-blocking shall be provided to cut off both vertical and horizontal concealed draft openings and to form an effective fire barrier between stories, and between a top story and the roof space.

Where to use fire block foam?

Best for use where any fire rated foam is needed such as electrical, plumbing and HVAC penetrations.

What type of foam is used for fire suppression?

Firefighting foam is a foam used for fire suppression. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, thus achieving suppression of the combustion. Firefighting foam was invented by the Moldovan engineer and chemist Aleksandr Loran in 1902.

Where not to use expanding foam?

While it is hugely useful, it should not be used to solve all problems. One such example is electrical boxes. Expanding foam shouldn't be used in these locations as it could cause jams that would be expensive to repair. So avoid using it around sockets or light fixtures, or any electrical components in the property.

Can pink foam be used for fire stopping?

Whilst it can sometimes be used to effectively seal small linear gaps, for instance, pink foam has a limited tested scope of application. Therefore, we strongly advise against using it when firestopping service penetrations.

Is spray foam flammable after it dries?

Cured foam is combustible and will burn if exposed to temperatures above 240°F (116°C).

Is expanding foam fire safe?

Secondly, expanding foam is very flammable and as a result, placing it near an electrical box is hazardous and could increase the fire risk. Some foams are less hazardous once they have cured however this is not the case for all expanding foams, as some remain flammable even after curing.

How to remove fireblock foam?

So many solvents can dissolve spray foam, such as acetone, Wd40, isopropyl alcohol, lacquer thinners, etc. The most common solvent used for spray foam removal is acetone.

Can OSB be used as fire blocking?

OSB Firestop boards provide load-bearing capacity and fire resistance of building structures and are lighter and stronger than plasterboard. With the same thickness, they achieve similar fire properties as sheathing systems based on the combination of OSB and plasterboard.

What is code 3 in firefighting?

In California, the state vehicle code requires motorists to immediately pull over to the right curb whenever a Code 3 vehicle is approaching. This applies whether the emergency unit is oncoming, approaching from the rear, or in cross traffic. Most, if not all, states have similar laws.

When to use fire blocking?

states that fire blocking is required “at open- ings around vents, pipes, ducts, cables, and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion.” This means you have to seal around all those wires, pipes, and ducts that run through top plates and ...

What insulation is fireproof?

Mineral wool is noncombustible and can be used in tandem with other forms of fire-resistant insulation. Mineral wool can also refer to glass wool, rock wool, or slag wool. Glass wool in particular can withstand temperatures of up to 1,220 degrees. Mineral wool has an R-value ranging from R-2.8 to R-3.5.

Why not to use fiberglass insulation?

Fiberglass insulation is less dense than other types of insulation and does not create an airtight seal, which means air can travel freely through the insulation. This is called air leakage and it's one of the most common sources of energy loss in a house.

How fireproof is fiberglass?

Fiberglass can withstand high temperatures, with its average melting point being 540oC.. Another crucial property of fiberglass is its fire resistance. It will not catch fire and prevent fire from traveling through it, reducing the spread.

Is spray foam a fire block?

Can Great Stuff Spray Foam Insulation Be Used as a Fire-Stop System? No, a fire-stop system includes a product which has been tested under certain conditions, and performed to maintain the rating of the assembly at the point of penetration or joint.

What foam is fireproof?

Flame retardant foams are chemically treated to be slow burning or self-extinguishing when exposed to an open flame. These fabrics can be made from any material, but they must be treated with special chemicals to qualify as flame retardant.

Where not to use great stuff foam?

Do not apply Great Stuff™ foam around heaters, high heat lamps or recessed lighting fixtures, radiators, furnaces or fireplaces where it could contact heat conducting surfaces. Do not use Great Stuff™ foam inside electrical boxes or panels (applications around the outside of the boxes are permitted).

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