Life Safety

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.