As professionals working in electrical, mining, or utility environments, you constantly face serious thermal hazards, chief among them being the **Arc Flash**. Choosing the right Fire-Resistant (FR) clothing is literally a matter of life and death, and understanding the labels—specifically **ATPV** and **CAT Levels**—is your first line of defence.
This guide demystifies these ratings, explains the difference between them, and shows you how to select PPE that meets the required **Australian standards** to keep you safe on the job.
What is Arc Flash and Arc Rating?
An **Arc Flash** is a sudden, explosive release of electrical energy when a high-voltage current jumps between two conductors. The resulting extreme heat (up to 20,000°C) causes catastrophic burns, which is why standard cotton or synthetic workwear is unacceptable.
The **Arc Rating** (also called **Arc Thermal Performance Value** or **ATPV**) is the key metric you need to know. It is a measurement of the thermal protection offered by the garment.
ATPV Definition: This is the maximum incident heat energy (measured in cal/cm²) that a fabric can withstand before there is a 50% probability of a second-degree burn injury occurring through the fabric. Higher numbers mean better protection.
You may also see **EbtAS** (Energy Breakopen Threshold). This is the level where the garment is likely to rupture or break open. In practice, look for the **ATPV** number as your primary safety measure.
Understanding CAT Levels (Category Rating)
While ATPV provides the specific energy protection number, **CAT Levels** (often called Hazard Risk Category or HRC) are a simplified system used to quickly classify clothing based on required minimum protection levels.
The Australian standards (aligned with international standards like NFPA 70E) typically require these minimum ratings for different risk scenarios:
- CAT 1: Minimum **4 cal/cm²** protection (General low-risk electrical work).
- CAT 2: Minimum **8 cal/cm²** protection (Higher risk, general qualified electrical work).
- CAT 3: Minimum **25 cal/cm²** protection.
- CAT 4: Minimum **40 cal/cm²** protection (Highest risk, critical operations).
Always check your site’s Hazard Assessment to determine the required CAT level before selecting your workwear. You need to match or exceed the minimum requirement to be compliant and safe.
Australian Standards: AS/NZS 4836
The primary standard governing Arc Flash protection in Australia is **AS/NZS 4836:2023**, which dictates the proper selection, use, and maintenance of protective clothing against thermal hazards from electric arcs.
When shopping for **FR clothing** in Australia, always ensure the product explicitly states compliance with relevant AS/NZS standards, confirming that the ATPV rating is legitimate and tested for local conditions.
🛒 Shop Compliant Arc Flash Clothing
Now that you understand the science behind **ATPV** and **CAT Levels**, you're ready to make an informed decision on your safety gear.
We stock only certified Fire Resistant (FR) pants, jackets, and coveralls that meet rigorous Australian safety standards for welding, construction, and electrical trades.
View Our Full Collection of Arc-Rated FR Clothing
Have questions about your specific site requirements? Our expert team is ready to help you ensure full compliance and protection.