HAZCHEM Catalogue - Flipbook - Page 19
ARC FLASH
LAYERING
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 Testing Methods
About Layering
There are two test methods for Arc Flash protective
clothing:
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.
• 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.
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.
Donside Safety T: +44 (0)1224 707468
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