March 22, 2017

Why a Four-hour Fire Rating Matters

A fire raging through your property is a nightmare scenario. A blaze can start for many reasons and its effects can be devastating. That’s why building with materials that are Four-hour Fire Rated is a smart choice.

What Is the Four-hour Fire Rating?

In 1905, the National Board of Fire Underwriters (NBFU) included passive fire protection in its building code. The NBFU bestowed the designation “fireproof building” to structures that were built using non-combustible materials, including brick, stone, iron and steel. These early regulations, however, did not consider how exact materials of varying thickness actually performed when exposed to flame and extreme heat.

Today, the advantages of non-combustible concrete materials are well known. For example, concrete block will not emit noxious gases or vapors in the event of a fire and limited heat transmission maintains modest temperatures on one side of the wall even when temperatures reach 2,000 degrees F on the other. Even with concrete, however, there is variability in fire resistance that results from the composition and thickness of the material.

In order to deal with the variability within categories of building materials, architects and contractors need to rely on fire resistance ratings. To help matters, the International Building Code has instituted a time-based definition of fire resistance. Fire resistance, according to the code, is “The period of time a building element, component or assembly maintains the ability to contain a fire, continue to perform a given structural function, or both.”

How Is a Fire Rating Earned?

Wall components are usually tested using ASTM Standard E119. The testing is exceptionally rigorous and includes two phases: fire exposure and water hose testing.

The fire exposure phase measures the ability of load-bearing wall assemblies to prevent penetration by flame and super-heated gases over a period of time. As part of the testing, the wall assembly is loaded into an oven, temperature sensors are placed on both sides of it and gas flames blast away at one side of the wall.

The water hose testing provides an indication of how well the wall system will hold up under actual fire conditions, including direct fire exposure, falling debris, and high-pressure/high-volume water streams from a fire hose.

At the conclusion of the testing, the wall system receives a one-, two-, three- or four-hour rating to indicate how long it should hold up during a fire.

What Makes the Four-hour Fire Rating So Important?

There is no good news when an uncontrolled fire breaks out but wall assemblies built with four-hour fire rated materials offer some exceptional protection that can mean the difference between a devastating outcome and a tragic one.

Increased Time for Safe Egress

Evacuating from a burning building and escaping from the dangers of smoke and fire can take some time. If a fire breaks out in a multi-story building or one in which occupants with mobility impairments need to be assisted, the extra time afforded by fire-resistant materials can make all the difference.

Protection for Firefighters

Firefighters need to combat the blaze and search for any individuals who may have been left behind. Entering a building in the advanced stages of a fire comes with incredible risks, and those are increased if the wall systems of the building do not have a high fire protection rating.

Maintain the Integrity of Load-bearing Walls

Fire and smoke inhalation are the obvious dangers when we think about building fires, but collapses also pose a very real threat. The longer the load-bearing walls are able to withstand the fire, the lower the likelihood of someone being the victim of a building collapse.

Limit the Spread of the Fire

Fire can be very difficult to contain and causes the most damage when it can spread throughout a building or, worse, start a blaze in a neighboring one. Four-hour fire rated walls can contain the flame for a longer period of time, allowing firefighters greater opportunity to extinguish it before it spreads.

How Bautex Passes the Four-hour Fire Rating Test

Concrete is non-combustible but the fire rating of CMU blocks varies according to thickness and the types of aggregates used in the manufacturing process. Engineers and contractors seek to increase the fire rating of masonry walls by various means, including increasing thickness, specifying different aggregate blends, filling the inner core, and adding a plaster or wallboard finish.

Foam has very good insulating properties but, on it’s own, it is combustible.

To avoid the complications usually face with concrete and foam, Bautex Systems has developed a proprietary wall system with a four-hour fire rating. The wall system combines a cement-based mixture with a unique mix of expanded polystyrene (EPS), a product that has found increasing applications in constructional material engineering thanks to its thermal efficiency, moisture resistance, and reduced weight.  

The innovative Bautex wall system provides superior fire protection while still allowing for an efficient, single-contractor installation process.

Everyone Deserves to Be Safe

Everyone deserves the safety provided by four-hour fire rated building materials. Thankfully, with the Bautex System, providing that level of fire protection has never been simpler. Learn more here.