8 Jan 2024

Fire-rated wall assemblies form an important integral component of a fire safety system when it comes to protecting people in the workplace, commercial, or residential buildings.

In this article, they will go into some detail regarding firewalls and the other components of the passive fire system, and why it is essential to contact a fireproofing contractor for inspecting and maintaining them.

What is the purpose of a firewall?

Fire-rated wall assemblies are employed to impede the spread of fire in a building or structure. It is clear that if the fire can manage to move beyond, around, or through the wall, a firewall in isolation would be ineffective in halting the blaze. The firewall and the elements it is linked to must work together to form a fire-rated system.

The passive fire protection system of a building typically comprises firewalls. These walls are designed to impede or retard the progress of a fire. Active fire devices, such as fire sprinklers and extinguishers, are intended to directly battle the flames.

What are the components of these items?

For exterior exposure to fire, there are required exterior faces, such as fiber cement siding, stucco

A fire-rated wall assembly is a prescriptive list of materials used and the configuration of such materials. These materials include fire-retardant-treated lumber and/or plywood, Type X gypsum board, fire-stopping collars and pillows, intumescent paint, caulk, and in some designs, fasteners. 

For exterior exposure to fire, there are required exterior faces, such as fiber cement siding, stucco, or brick.

Fire Rating Evaluation

To measure the effectiveness of a fire-rated product, the Fire (FR) rating is used. This rating is composed of three different elements: Fire test results, including fire resistance ratings, enable code officials to compare materials and systems against code requirements to determine compliance.

A fire-resistance rating is one of many tools used by designers to assess relative fire risk. The Fire Rating (FR) for buildings of various types is stipulated in the NFPA Code, of which the International Building Code (IBC) is a component.

The NFPA relies on the IBC, NFPA 101 or the fire code enforced by the local authority having jurisdiction for building construction and compartmentation, fire alarm and smoke detection systems, and fire suppression systems.

Regular examination and upkeep of firewalls necessary

Any alterations or breaches need to be fixed or replaced with methods approved by the FR of the wall

It is essential to inspect and maintain the firewall every year. Any alterations or breaches need to be fixed or replaced with methods approved by the FR of the wall.

Also, any openings made for pipes, electrical conduits, ducts, wires, and air transfer openings must be sealed according to the specified regulations. Architects, engineers, and specifiers should pay close attention to maximizing space while maintaining the cost-effectiveness of the building’s construction and design in the building and code environment.

The use of pre-designed fire-resistance-rated assemblies is permitted by building codes in case designers meet the structure’s fire demands. A one- or two-hour rating is provided for a certain combination of materials, as determined by testing the specific assembly design. For less well-known materials, a different procedure is used to calculate the fire resistance based on the materials used.

ASTM E119 Fire Test Methods

Floor/ceiling systems and wall assemblies are the most common fire-rated assemblies. They are rated for fire exposure to one side or both sides, depending on the application. A third-party laboratory such as Underwriters Laboratories (UL) certifies that the designs comply with the required standard. Each design is evaluated under ASTM E119 Fire Test Methods for Building Construction Materials to ensure it meets the required standard.

One and two-hour ratings are used to describe how long the assembly will maintain its structural capabilities when exposed to fire. Each assembly is loaded to 100 percent of its design load before being exposed to flames to determine its endurance performance.

Each Fire-rated wall design offers a diagram for the configuration of the materials needed to achieve the specified fire-resistance rating. This includes spacing of framing members and minimum dimensions for insulation, gypsum board or boards, and exterior facings. Fire retardant makers each have developed and tested assemblies utilizing lumber and plywood treated with their formulations. The most common assemblies they offer are one- and two-hour rated bearing walls.

Commercial and industrial facilities

A two-hour fire-rated wall is a wall that has been designed to withstand fire for at least two hours. It may be constructed of bricks, concrete, or other fire-resistant materials. Commercial and industrial facilities, as well as some residential areas, may benefit from these walls. The wall may have coatings or treatments to prevent it from catching on fire, in addition to its basic construction. 

A two-hour fire-rated wall plays an important role in protecting buildings and people from fire. To ensure that a two-hour fire-rated wall is effective, it must be installed correctly. Installing a two-hour fire-rated wall is not a do-it-yourself project; it must be handled by a certified contractor.