ARC PROTECTION USING LAYERS
When ARC Flash Protective Garments are worn together in a layered combination, the combined garment set may give a total protection value that is higher than the sum of each garment when tested alone.
Arc Flash Testing Methods
There are two test methods for Arc Flash protective clothing:
- IEC61482-1-2 Commonly known as the ‘Box Test’
and - IEC61482-1-1: Commonly known as the ‘Open Arc Test’
The Box Test method gives a protective classification of either Class 1, 4KA (lower level of protection) or Class 2, 7KA (higher level of protection). This has traditionally been the popular and most recognised standard in Europe, and a default choice for certification for HAZTEC® garments.
The Open Arc test method gives an Arc Thermal Protective Value (ATPV) rating or an Energy Break Open Threshold (EBT50) rating. This is becoming increasingly popular as garment combinations certified to this method can give figures that are more relevant in risk assessments or arc flash calculations.
For workwear within the HAZTEC® product range, a single layer garment that is sold with an Arc certification is commonly certified to Class 1 on the Box Test method.
About Layering
Box Test Method – Class 1, 4KA and Class 2, 7KA
When garments are tested using the Box Test method an arc rating of either Class 1 or Class 2 is achieved.
Adding a Class 1 garment with another Class 1 garment does not necessarily give you a Class 2 rating and the combined result can only be confirmed when the garments are tested together.
Open Arc Method – ATPV or EBT Ratings
When garments are tested using this method a rating per garment is achieved. When worn in combination with other garments, these ratings can be added together (as a guide to some degree) but the total protective value of the Combination is only known when the garments are tested as a combined set.
Wearing of non-ARC certified garments with your ARC Garments
Outer Layers
It is important to remember that the outermost layer of your protective clothing must be FR and ARC rated. To add a non-FR layer over your Arc rated garments defeats the whole purpose of wearing arc rating garments – if that outer layer was to ignite the heat can transfer through your inner arc garments to your body.
Inner Layers
Wearing non-arc rated garments beneath your arc rated garments can also be the cause of serious burn injuries. We recommend that if non-arc rated undergarments are worn that these are natural non-melting fibres e.g. 100% Cotton. Polyester type fibres or similar fabrics that can melt should not be worn if there is a Flame, Heat or Arc hazard present in your workplace role as can cause serious burn injuries.
