Firestopping: Materials, Codes, and Requirements

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Firestopping is an important step in bringing your structure up to code and protecting it from fire damage—but it comes with many special considerations.

Down below, we’ll go over what firestopping is, how to avoid the most common firestop code violations, how firestopping differs from other forms of fire protection, and more.

What is firestopping?

Firestopping is the use of fire-resistant seals at points of penetration in a fire-rated construction to prevent the spread of fire and smoke. Firestopping seals gaps created in walls, floors, or ceilings by penetrants like pipes, ductwork, and cables that can give fire and hot gasses free access to other areas of a structure.

This also applies to membrane penetrations, which do not pierce all the way through the construction. For example, an unsealed electrical box can lower the fire rating it provides by exposing the wall’s interior to fire.

In the case of things like cables, conduits, and non-metallic piping, firestop products can also protect these materials from fire damage in addition to filling gaps.

Common firestop materials include silicones, rubbers, mineral wool, and cementitious mortars. Each of these materials has different features and chemical qualities, so be sure to research your firestopping products carefully.

What materials require firestopping to be IBC and NFPA compliant?

According to the International Building Code (IBC) and National Fire Protection Association (NFPA) Life Safety Code, the following structural features require firestopping:

IBC:

• Penetrations in walls and horizontal assemblies, including penetrating ducts
• Protective sleeves (e.g., around cables), inside and out
• Membrane penetrations in walls and horizontal assemblies, such as electrical/utility boxes
• Joints, including joints in smoke barriers and joints between curtain walls and slab edge systems

NFPA:

• Penetrations in walls and horizontal assemblies
• Sleeves, inside and out
• Pipe coverings
• Membrane penetrations, including outlet boxes
• Penetrations in smoke partitions
• Joints, including curtain wall/slab edge joints

You can find all the relevant firestopping codes in the most recent editions of the IBC 101 and NFPA 101.

The most common firestop code violations

Here are some of the most common firestop code violations you should look out for:

• Inappropriate firestop material: Inappropriate fasteners or packing material can compromise the security of a seal, and some firestopping products may experience undesired chemical reactions with certain penetrant materials.
• Untested product substitutions: Similarly, substituting products may also lead to firestop system failure because the substitutions have not been tested alongside the other products in the system.
• Improper tooling: Tooling creates an airtight seal between the penetrant and the substrate, so a lack of or improper tooling will compromise that seal.
• Improper firestopping for dissimilar materials: Use of dissimilar materials in the same penetration requires special attention to their qualities. For example, if one material will melt or combust under high heat but the other will not, then you will need a product that can protect one while sealing the other.
• Improper firestopping at joints: Failing to correctly firestop head-of-wall or bottom-of-wall joints, or joints between non-rated exterior walls and floor slab edges is another common code violation.
• Too-large cast-in-place devices: Penetrations through concrete require appropriately sized cast-in-place devices to adhere to code.
• Failure to adapt to unusual environments: Failure to research appropriate firestop products to adapt to an area’s humidity, exposure to water or chemicals, degree of vibration, and other environmental factors will cause firestop systems to fail.

You can avoid many of these firestop code violations simply by choosing the right firestop product and following the manufacturer’s instructions for application.

What firestopping maintenance is required by building owners?

The International Fire Code requires building owners to conduct maintenance on the following structures:

• Fire-resistance-rated construction, including structural members, horizontal assemblies, interior and exterior joints, exterior and fire walls, fire barriers and partitions, and shaft enclosures
• Smoke barriers and smoke partitions
• Membrane and through penetrations
• Any materials, devices, or systems used to firestop or repair penetrations or gaps in fire-resistance-rated construction and any construction installed to resist smoke transfer

Additionally, building owners must maintain an inventory of their fire-resistance-rated construction and construction designed to resist the movement of smoke. Building owners must also conduct and maintain records of annual visual inspections and repairs.

What’s the difference between fireblocking and firestopping?

Like firestopping, fireblocking prevents the movement of fire and smoke throughout a structure. However, fireblocking is not limited to sealing penetrations and is exclusively intended for concealed spaces.

Concealed spaces are areas in a structure that are not visible and are inaccessible or difficult for firefighters to reach. Some examples include vertical chases that allow pipes to run up the length of a building, or gaps in the joist or truss hidden by floors or ceilings.

Fire can easily grow and spread in concealed spaces without occupants’ knowledge. That makes fireblocking just as important as firestopping for keeping a structure safe from damage.

It’s also important to note that though some fireblocking products, like insulating foam, work similarly to firestopping products, they are not interchangeable. Fireblocking products are not tested as part of a firestop system and will not provide the same level of fire and smoke resistance as firestop products.

What’s the difference between firestopping and fireproofing?

Fireproofing is a broader term meaning the process of protecting your structure from fire by providing fire resistance. Fireproofing products provide a structure with a certain fire-resistance rating and slow the spread of fire.

Firestopping is a complementary practice to fireproofing. By filling in the extra spaces in a structure to further prevent the spread of fire and gasses, firestopping increases the effectiveness of fireproofing systems.