There are two categories or kinds of FR “Inherent” and “Treated”. These terms always confuse people when they buy fire resistant coverall for their workplace. The first question that comes into their mind is about the quality of these FR. Which one is better for them to use?
This question is not an easy one to answer because both fire-resistant have their pros and cons. To answer the questions, we should understand the origin and the meaning of these two terms.
Inherent FR is a type of FR that does not contain any additional fire-retardant chemistry. The actual structure of the inherent FR is non-flammable. It can extinguish the fire from the fabric when the source of ignition does not remain anymore.
It is the type of FR that makers treat with fire-retardant chemistry in its engineering. They treat the fabric with chemicals during manufacturing to make it non-flammable.
Engineering of FR
You can achieve the properties of FR by following these steps;
The Molecular Level:
At this level, you initiate the process of making the FR by using synthetic derivatives. For example, Kevlar, Nomex, Kermel, etc.
The Fiber Level:
Before the initiation of extrusion, manufacturers add the fire retardant chemicals. For example, FR Modacrylics, FR Rayons.
The Fabric Level:
At this level, they use chemical and mechanical processes. The manufacturers divulge FR characteristics into flammable fabrics.
For example 88/12, FR Cotton.
History of Inherent and Treated FR
In earlier times, around about 30 years ago, these two terms were the name of resilience. These terms embraced at that time is evidence of the durability of FR technology. Before 1987 the inherent FR was more reliable than the treated one.
All the natural flammable materials like cotton were treated with fire-retardant chemicals. These treated garments tend to lose their FR treatment after a few washes. So the inherent FR like aramids were considered as the appropriate one for the workplace.
After 1987, there are a lot of substantial changes in the field of technology. Technology is also making advancements towards making the best FR. This progress is removing the line between these two separate terms. Nowadays, the best FR fabrics are a mixture of multiple fibers.
It is a complex blend of fibers and often contains all levels of engineering. For example, one of FR contains 35% Aramid (molecular level) and 65% FR cotton (fiber level). This blend causes confusion for people. Apparently, this FR fabric is a combination of both inherent and treated.
Pros and Cons of Inherent and Treated FR
To make it easy for the customers to choose the FR, we should discuss the pros and cons of both.
Pros of Inherent FR
- It scores higher in Thermal Protective Performance (TPP) than treated
- It is more duarable
- It does not ignite at normal O2 concentration
- FR properties of the clothes will never diminish
Cons of Inherent FR
- It is costly
- Less comfortable than treated FR
Pros of Treated FR
- It extinguishes the fire if you remove the source of heat
- Treated FR is more comfortable than inherent FR
- It is relatively cheap in comparison to inherent
Cons of Treated FR
- Treated FR may lose quality with time
- No apparent way to tell if it loses the fire-resistant capabilities
The evolution in FR technology is making the fabric more durable and reliable. The quality which previous ones lack. Both inherent or treated comes with pros and cons. The important points while buying FR clothes should be comfort and protection.
The FR are usually heavy, and workers wear them because it is necessary. So the manufacturers should try to make lightweight FR without compromising durability