Insights on Drywall Construction Exposure and Prediction of Fire Resistance Performance

Insights on Drywall Construction Exposure and Prediction of Fire Resistance Performance

Insights on Drywall Construction Exposure and Prediction of Fire Resistance Performance

Fire has its importance only when it's needed and can be controlled. But when it is unwanted, it usually leaves destruction in its wake.


Since buildings came into existence, the issue of fire destroying the whole building has been a source of concern.


Luckily, since men are born with survival instincts, they surely came up with a way to tackle the problem- Gypsum!


Gypsum has been found to have great fire resistance qualities. It was discovered a long time ago and was used to protect houses in London after the great fire of 1666. All houses in Paris were protected with gypsum plaster.


The gypsum plaster was one of the first fire codes and that's what is known as the Plaster of Paris in this modern day.


Fire safety has since started to evolve and other ways to contain fire have emerged. Now, there are different fire testing standards and fire-resistant methods.


These standards and fire tests have been incorporated into building plans and now buildings can maintain their integrity during a flame spread.


This article will provide insights into how Drywall construction works especially when it's exposed to fire. Also, here, you'll learn more about fire resistance performance.


How Drywall Construction Works

When it comes to fire safety, there are two types of suppression methods: There's the passive method and the active method.


The passive suppression method works by using the materials used in the construction of the building for fire resistance.

This means that all the materials used in the construction of the building must have undergone fire tests. To ensure that they're non-combustible and can contain the fire from spreading to other parts of the building.


Active suppression is the use of external mechanical devices to reduce the spread of fire. These devices could include sprinklers that have already been installed in the building. Or fire extinguishers that have been placed in strategic places in the building.


Now, drywall construction is an efficient and cost-effective method of coalescing these passive methods into an assembly.

The materials used in the construction of the building like the ceiling, floor, and walls are called an assembly. These materials are made of passive suppression components and in these components, you'll find gypsum.


One distinctive feature of gypsum is its fire resistance characteristics. Among professionals in the construction industry, it comes highly recommended in building drywall.


The raw material used in the production of gypsum is called calcium sulfate mineral and its chemical formula is CaSO4•2H2O.

A broader study of gypsum shows that it includes calcium sulfate hemihydrate which is also known as Plaster of Paris.

As is depicted the chemical formula of gypsum, shows that about 21% of gypsum is made of water. This water is also called crystalline water.


This property makes gypsum non-combustible which means that it can't contribute to the spread of fire.


Here's a breakdown of how gypsum drywall panels are non-combustible even during fire exposure:

The process behind gypsum non-combustibility is that when a gypsum panel is exposed to fire, the heat from the fire melts the crystalline water and converts it to steam.


So, as long as there's still crystalline water in the gypsum, the other side of the panel will be unaffected.

But when there's a breach in the panel, especially when the fire is extreme, it might penetrate to the other side.


Prediction of Fire Resistance Performance

Fire resistance performance can be predicted after a specimen has passed through a fire test and these three criteria below are considered:


●     Structural adequacy

This criteria checks if the specimen can no longer bear its load (both its weight and additional load).


●     Integrity

This criteria checks if the specimen gives in to the pressure of the fire and allows the fire to pass through it.


●     Insulation

The longest an insulated specimen can last under fire is 120 minutes and that's if the fire is not more than 180°C.


If a specimen can last through fire for 120 minutes without losing its structural adequacy and integrity then that specimen qualifies as fire-resistant.


Fire-resistant materials are only predicted to be effective when certain background efforts have been made with the building. They include:


1.   Support

Not all buildings can accommodate a fire-rated system especially if there's no prior arrangement for it. Before a fire-rated system can be installed on a building, the building must have structural adequacy fit for the system.


There should be a support system like a pillar or wall across the building. This is to ensure that the fire-resistant materials can bear their weight or additional weight during a fire spread.


2.   Adjacent Structure

The standard requirement for any building installing a fire-rated system is that no building elements should run across a fire-rated wall.


Except for the structural adequacy of that building is maintained no building elements should pass through a fire-rated wall.


However, in the case materials must pass through the fire-rated wall, some measures can be put in place to ensure that the fire resistance level of the building is not reduced.

  • There should be a provision for the fire-rated ceiling to make sure that the structural members of the building are protected.
  • The structural members should also be fire protected.


3.   The direction of attack by fire

All too often, fire attacks could be from both sides of the building. And sometimes the fire attack could be from just one side.


For fire resistance measures to be effective, all the likely places of a fire attack should be included in the building plan. If it's concluded that the fire attack could be from below, the appropriate fire resistance measure will be put in place.


fire properties


4.   Fire hazard properties

Other materials that are used in the building must comply with standard fire hazard properties requirements. This is to ensure that they reduce the impact of the fire.


All USG Middle East products are ruled out as least hazardous. Like the Flexible fire-rated sealant; this product is fire-rated and is used as a sealant in fire-rated partitions.


Any product that's ruled out as Group 1(least hazardous) materials can be used as part of building materials. It makes the installed fire-rated system more effective.


5.   Combustibility

In compliance with all standard development organization fire tests, gypsum boards can be used in place of combustible materials. So long as it fits into the requirements of the material needed.


6.   Gas reticulation in fire-rated walls

Under no circumstances should any gas be situated near fire-rated walls. To accommodate gas in a building with a fire-rated system, the building must have been designed and constructed for the gas to fit in. Otherwise, gas can reduce the effective performance of a sound sure rated system.


On a final note;

Fire poses a threat to buildings and structures, and even with a fire-rated system installed, the after-effect should still be worse.


However, having a proper understanding of how gypsum drywall works and the performance of fire-resistant materials can avert extreme ruin.


Fire safety in a building goes beyond installing the fire-rated system, understanding how it works is just as important.