When workplace safety regulations kicked in, employers rushed to purchase Personal Protective Equipment (PPE) for their employees. But without clear guidelines on what to purchase, they’d often choose the cheapest protective apparel.
These came with a long-term consequence: inadequate protection leading to injuries on the job are costly for all parties involved.
Workplaces with significant fire hazards must provide fire-resistant clothing for their employees. This simple guide will go through how to choose the appropriate fire-resistant protective apparel.
Fire Resistant Clothing: Risk Categories
The first step to choosing FR clothing is to assess the risks present in the workplace. Chemical or gas fires, flammable liquids, molten slag, and electrical arc fires are examples of fire hazards.
The National Fire Protection Association (NFPA) cites four fire hazard risk category levels:
- Hazard Risk Category 1: Can wear 100% FR-treated cotton shirt, pants, or coveralls (single layer). Requires a minimum arc rating of 4.
- Hazard Risk Category 2: Cotton underwear plus FR-treated shirt and pants (one or two layers). Requires minimum arc rating of 8.
- Hazard Risk Category 3: Cotton underwear plus FR-treated shirt, pants, and coveralls, or cotton underwear and two FR coveralls (two or three layers). Requires minimum arc rating of 25.
- Hazard Risk Category 4: High risk. Cotton underwear plus FR shirt, pants, and multilayer flash suit (three or more layers). Minimum arc rating of 40.
Manufacturers must indicate the arc rating of their FR garments, and in most cases, you’ll find the number on the label. This will be in cal/cm2.
What’s an Arc Rating?
The term comes from the NFPA 70E (read more on FR clothing standards here) and refers to how well they protect against electrical arc discharges. All arc-rated clothing is fire-resistant, but not all fire-resistant clothing is arc-rated: certain FR fabrics have not been tested against electrical arcs.
The value, expressed in cal/cm2, is the arc thermal performance value (ATPV) or energy breakopen threshold (EBT). This is the point at which the garment will break open. Faced with an electrical arc with higher energy levels than the arc rating, there’s a much higher chance of severe burns.
If your workplace has electrical arc hazards, employees should wear FR clothing with arc ratings.
Types of Fire-Resistant Fabrics
After assessing and categorising the fire hazards present, you’ll have to select the type of FR fabric. There are two main types of flame-resistant fabrics you’ll see today:
- Treated fire-retardant fabrics
- Inherently flame-resistant fabrics
The difference between the two is in the durability and amount of protection they offer. Inherently fire-resistant materials are also more costly.
The first category can be ordinary cellulose materials like cotton or linen. These natural fabrics will ignite readily, but unlike synthetics like polyester, do not melt. When treated with a fire retardant, they offer decent protection against fire hazards common to labs. Combined with their cost efficiency, FR-treated 100% cotton lab coats are a popular choice for lab workers.
(Read more: Lab Coat Fabric — What Material Do You Need?)
Because the materials may not be inherently fire-resistant, the protection can wear off over time through repeated washing.
Inherently fire-resistant materials, on the other hand, have their protective properties built in. They resist ignition, are self-extinguishing and won’t continue to burn once the combustion source is gone, have thermal insulation to protect against heat, and won’t melt onto your skin. This protection can’t be worn away or damaged through laundering.
In some cases, the fibres even swell and become thicker when exposed to fire, increasing the protective barrier between the flames and your skin. This gives you a few more precious seconds to escape from the danger.
Types of fabric brands that are inherently fire-resistant include:
Firefighters and those in hazardous work environments typically use Nomex® clothing for their fire-resistant PPE.
Maintaining FR Clothing
When purchasing FR clothing, you’ll also need to consider how the PPE will be maintained. In most cases, employers engage specialised laundering services for the task, then conduct periodic checks to make sure the FR clothing is in good shape.
If employees wash the FR clothing themselves, employers must conduct the appropriate training to ensure that their staff understand how to properly maintain the PPE. Improper laundering will destroy the protective properties and reduce the durability of the FR apparel.
For example, most manufacturers advise against using chlorine bleach and fabric softener — even for inherently fire-resistant materials.
Even if your employees wash the garments themselves however, it’s still recommended that you check the PPE regularly to ensure they’re able to provide good protection.