Head, Face & Hearing Protection against Arc Flash Hazards

 

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Anti Electric Arc System		    
What is an Arc Flash? An electrical arc flash / blast is an unrestricted LV or HV high current fault occurring between two or more conductors – either Phase to Phase, or Phase to Earth, or a combination of both.

Arc Flash

When could an Arc Flash injury occur?
Below are some examples:
•While live cable jointing
•During phasing in operations
•Racking in and out of switchgear
•Reclosing of electrical switchgear onto a fault
•Mal-operation or failure of switchgear
•Excavating near live cables
•Accidental contact with live conductors during maintenance

Over 70% of Arc-Flash incidents in Europe occur during or immediately after electrical maintenance.

What are the main Injury Risks from Arc Flash?
Risks to the head, face and respiratory system, from:
• Radiant Heat
• Ionised Gas Stream
• Blast Debris
• Smoke & Toxic Gas

Which could cause possible:
• Burns caused by radiant and convective energy.
• Lung damage from inhalation of arc products.
• Barotrauma – the effect of pressure waves on the brain, nervous system and lungs.
• Hearing damage.
• Temporary or permanent blindness.

 


Arc Flash Switchgear Explosion

Video of Arc Flash Switchgear
Explosion




Considerable consideration is given to the design and manufacture of flame retardant clothing to protect against arc-flash hazards - the protection of the head and face
against arc flash has however not always been considered when designing new PPE products.

FR Clothing

Image courtesy of TAS Engineering Consultants, Stockton on Tees www.tas.co.uk

Arc Flash DamageTo the left is an example of standard PPE Fire Retardant
clothing and non-Arc Flash Resistant PPE head protection (consisting of
Helmet, Face Mask and Goggles) after an actual Arc Flash incident.

To the right is the result of the head injuries sustained as a result of this incident.

European Standards

Head Protection (EN 397)
There is no provision in the current standard for the risks posed by Arc Flash hazards. EN 397 does provide provision for electrical resistance (up
to 1000V with ANSI up to 20,000V). An optional provision exists in the standard for protection against molten metal splash, but this is not specific
to Arc Flash hazards.

Face Protection (EN 166)
The current standard has provision for Arc Flash protection (para 7.2.7 – option number 8). The
standard claims protection against an Arc of 12kA, 440V for a duration of 1 second. All face
shields made from Polycarbonate, Cellulose Acetate or Cellulose Proprionate with a minimum
thickness of 1.4mm are deemed to meet this standard. As with EN397, EN166 has an optional provision for molten metal splash. ArcPro meets and exceeds the requirements of EN166 para 7.2.7 - option 8.

Arc Flash Rating

Fabrics or materials are tested to ascertain their arc rating. The arc rating is the maximum incident energy resistance demonstrated by a material prior to breakopen or at the onset of a second-degree skin burn.
Arc rating is normally expressed in cal/cm2 (or calories of heat energy per square centimeter). The tests for determining arc rating is defined in ASTM F1506 Standard Performance Specification for Flame Resistant Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.

Independent tests carried out for Centurion:
Arc Pro prior to test ArcPro after testing









  Polycarbonate Screen with Centurion Polycarbonate Browguard before and after exposure.  

Guidance when choosing PPE
• When selecting safety helmets for protection against arc flash risks, choose a helmet which has a high temperature performance shell (ie Glassfibre or ABS) - Centurion Concept, Vision or Vulcan
Concept, Vision, Vulcan

• Use a non metallic and Nylon free Face Screen Carrier which has high temperature performance.
Face Screen Carrier

• Ensure the Face Screen carries an anti-arc approval from the manufacturer (backed up by independent testing/verification) and is approved to the relevant options within EN 166.

• It is advisable to use ear defenders that have no exposed metallic parts, making them suitable for use in areas of arc flash risk.

Ear Defenders


• When using a sweatband, use a non Nylon content sweatband, such as Leather or Vabon (see below the difference in damage to Brushed Nylon, Hydro-Flock and Vabon sweatbands when a heat gun was placed 25mm away for 10 seconds).

Sweatbands
For information on the Centurion ArcPro range click here

Links to Information Sources