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How to Achieve 4-Hour Fire Rated Protection

Fire protection is an integral part of any building's safety protocol. Achieving a 4-hour fire rating ensures that your structure can withstand a fire for up to four hours, providing ample time for the occupants to escape and for emergency personnel to extinguish the fire. In this blog post, we're going to take an in-depth look at the process of achieving a 4-hour fire rated protection.

While many buildings have a 1- or 2-hour fire rating, 4-hour fire rated protection can easily save lives. To accomplish a four-hour rating, several elements must be considered.


Doors require a fire rating classification based on the fire rating of the wall into which they are installed. The rating is broken down by time for and typically, this includes 20 minutes, 45 minutes, 60 minutes, 90 minutes and 3 hours. The amount of time a steel door can withstand the prescribed fire exposure determines the door’s fire rating.

As doors are deemed opening protectives, the fire protection rating of the door is often less that the fire resistance rating of the wall it is installed in. 3 and 4 hour rated walls require 3 hour rated doors, and 2 hour rated walls require 90 minute rated doors. A 45-minute door is often required in a 1 hour rated corridor wall, room partition, or, sometimes, the exterior wall of a building if the fire exposure from the outside is moderate. For 3-hour fire protection, tight restrictions must be met for door size, glass size, and more. Typically, a door with a 3-hour fire protection rating is used to separate a larger building into several smaller fire areas.

Fire Protection Boards for Structural Steel

Fire protection boards are often used to protect structural steel columns and beams in a building. The boards are used to enclose the exposed faces of the members so the insulation properties of the board maintain the steel below its critical temperature. Smaller and thinner member often require multiple board layers, and if a member is required to be 4-hour fire rated, the enclosure thickness will increase. While columns may require protection on all four sides, beams often have one or more sides or faces that are protected by concrete, resulting the fire protection boards be installed only on the sides or faces of the beam not already protected by the concrete.

What is a Fire Rating?

A fire rating refers to the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be applied to a wide range of elements, from complete structures to individual fire barriers or even materials used in the construction process.

Components of a 4-Hour Fire Rated Protection

Achieving a 4-hour fire rated protection involves the use of a variety of construction elements. Below are some of the key components:
  1. Fire-rated doors and frames: These are specially designed and certified doors and frames that can resist fire and its effects for up to four hours.
  2. Fire-resistant walls and ceilings: Special materials such as fire-resistant gypsum board, masonry, or concrete are used to construct walls and ceilings that can withstand fire for extended periods.
  3. Fire-stop systems: These systems help prevent the spread of fire and smoke through penetrations in fire-resistant barriers like walls, floors, and ceilings.
  4. Fire-resistant glass: This type of glass can resist the effects of fire, including heat and smoke, for up to four hours.

Steps to Achieving a 4-Hour Fire Rated Protection

Let’s walk through the steps involved in achieving a 4-hour fire rated protection for your building:
  1. Planning: Work with an architect or engineer who understands fire safety and the requirements of a 4-hour fire rating.
  2. Material Selection: Choose materials for doors, walls, ceilings, and windows that have a 4-hour fire resistance rating. The materials should be certified by an independent testing organization.
  3. Construction: Build the structure using the chosen fire-resistant materials, adhering to the guidelines provided by the material manufacturers and the local building codes.
  4. Inspection: Have a certified professional inspect the building to ensure that all construction has been done according to the fire safety plan and that all components are installed correctly.
  5. Certification: Obtain a certification from a reputable fire safety agency, confirming that your building meets the 4-hour fire rating requirements.

Importance of Fire-Rated Protection

Fire-rated protection is crucial for a variety of reasons:
  • It allows occupants more time to evacuate in case of a fire.
  • It provides more time for firefighters to arrive and put out the fire.
  • It reduces damage to the building and its contents.
  • It can lead to lower insurance premiums due to reduced risk.

Insulating Board

To create a hollow section around an I-beam, quality insulating boards are installed with space left between the board and the beam on all sides. This fire-resistant material protects the column. In addition, the void space reduces thermal conductivity. Combined, the level of protection against a fire increases significantly.

To create 4-hour fire rated protection, things like cold-formed steel clips, gypsum board, and corner beads are included. At this level of protection, the thickness of the gypsum and the casing attachment meet tight specifications. Before the gypsum board is attached, steel clips are connected to the I-beam flanges, spaced every 4 feet from floor to ceiling. The ends of the flange clips attach to the steel to create the necessary air space.

For a building to have 4-hour fire rated protection, many other factors are involved.

As an example, glass, louvers, sidelight assemblies, door and window frames, door hardware, latching devices, hinges, and more play a critical role. Even doors in corridor walls used as an egress must have the proper smoke and draft control rating. These assemblies are thoroughly tested for both fire resistance and air leakage to ensure compliance with the current National Fire Protection Association code.