February 20, 2017

Four Hour Fire Wall Construction

Protecting a building and its occupants from fire and smoke is a top priority for today’s architects and contractors. Whether the project is new construction or remodel, the overall design should reduce the spread of fire and smoke during a fire emergency. There are two primary forms of fire protection for buildings: passive and active. Passive fire protection limits the transfer of heat or smoke from one area of a building to another through fire resistant construction. Active fire protection includes automatic sprinkler systems, fire extinguishers, standpipes, etc. There are also several fire protections aimed at specific parts of a building.

  • Structural fire protection defends the essential parts of the building like the structural steel and joint systems with either an application of fireproofing material or building the structure with concrete
  • Fire protected doors and windows act as effective smoke and fire barriers
  • Firestopping materials protect the fire barriers from potential fire spread through the barrier due to mechanical, electrical, and plumbing penetrations.   

Architects, designers, and contractors use a combination of all these methods of fire protection to preserve a building’s structure and enhance the safety of its occupants.  

Passive Fire Protection Contains the Fire

During fire emergencies, passive fire protection shields those inside and defends the structure by limiting the spread of fire and smoke. Passive fire protection includes fire barriers, fire partitions, smoke barriers, horizontal assemblies, and firewalls. While passive fire protection is usually invisible to the occupants, its significance in saving lives and protecting property is clear when a fire occurs. Passive fire protection stops the spread of fire and smoke through vertical openings, like shafts. It also prevents the collapse of the building. When fire-resistive construction is properly done and maintained, a building's passive fire protection can save the building and lives.

Wall Assemblies are Essential to a Buildings Fire Protection

An important part of commercial building design is passive fire-resistant construction. The main area of attention for passive fire protection systems is the wall assemblies. According to today’s building codes, wall assemblies must be tested by industry standards to evaluate their fire resistance. Two industry standards judge the fire resistance of wall assemblies: Two industry standards judge the fire resistance of wall assemblies: the ASTM E2257 Standard Test Method for Room Fire Test of Wall and Ceiling Materials and Assemblies, and the ASTM E119, Fire Tests of Building Construction and Materials.

  • ASTM E2257 is a fire test that determines how much the wall and ceiling materials or assemblies contribute to fire growth in a space and the possibility for fire to spread beyond the area, under simulated conditions.
  • ASTM E119 (and-and ULC-S101) establishes a wall assembly’s ability to stop a fire from spreading.  Building codes assign fire ratings to fire sensitive areas in walls, partitions, floor/ceilings, and roofs. The ratings show an assembly’s relative ability to stay intact, when exposed to fire under a controlled situation, for one, two or more hours. The ASTM E-119 test involves exposing the assemblies to controlled heat until the average temperature measured on the unexposed side of the test sample increases by 250° F, the heat, flame or gases escape to the unexposed side, or the sample collapses under load. For a fire ratings of 1 hour or more, the assembly must also pass a hose stream test to mimic firefighting conditions.The hose stream test determines the ability of an assembly not to collapse during a fire.

​Additional standards include the NFPA 286: Standard Methods of Fire Tests for Evaluating Contribution of Wall and Ceiling Interior Finish to Room Fire Growth, and the NFPA 101 Life Safety Code and ASTM E84 – Surface Burning Characteristics of Building Materials.

The NFPA 286 applies specifically to the testing of material with fire and is unique to walls and ceilings.The standard determines how much the room’s different elements on the walls and ceilings contribute to the spread of fire, including the wallpaper. The NFPA 286 standard helps firefighters determine the amount of time they need to put out a fire.

The NFPA 101 is the only document that covers life safety in both new and existing structures with provisions for all types of dwellings, egress requirements, fire protection features, emergency lighting, sprinkler systems, alarms, smoke barriers, and special hazard protection.

ASTM E84 – Surface Burning Characteristics of Building Materials. The purpose of the method is to determine the relative burning behavior of the material by observing its flame spread. The test reports flame spread and smoke density.

Bautex Wall System Provides Effective Passive Fire Protection

An excellent option for passive firewall protection is Bautex Blocks. Bautex Blocks meet and exceed industry's standard for fire resistance. They have an ASTM E119 fire rating of four hours (twice the two hour requirement) and an ASTM E84 reported values for flame speed of zero and smoke development of twenty. Because the blocks meet the E84 and NFPA 286 they essentially meet the NFPA 101 code. Bautex Blocks can be used to build interior and exterior walls for commercial and residential construction. Along with excellent fire resistant capabilities, the Bautex Wall System delivers energy efficiency, sound reduction, and resistance to moisture and the wind.

Preparing for the possible outbreak of fire in a building with fire-resistant construction is a critical consideration for architects, contractors and the owners of the structure.The goal of both passive and active fire protection is to protect lives and the building. A combination of fire protection methods when building or remodeling is the best defense for protecting a structure and those inside from the spread of fire and smoke.