Protect Your Team from Arc Flash & Arc Blast Injury
Updated: Apr 1, 2021
According to the Australasian Mine Safety Journal, Arc flash incidents kill 40 people every year in Australia, and more than 2000 people are admitted to burn centres with severe arc fault burns annually.
In response, Avid Edge now supply a new range of Arc Flash PPE gear developed and rigorously tested by Australian based manufacturer of quality safety gear and PPE, Elliotts.
Speaking with Anthony Elliott, Managing Director of Elliotts, “We’re very excited to launch the new ArcSafe® X50 range to our already successful selection of ArcSafe® T40 and T9 ranges. We have spent two years researching and testing many different fabrics and fabric combinations before finally arriving at the ArcSafe X50”.
The brand new ArcSafe® X50 range includes the new state-of-the-art Lift Front hood as well as a traditional arc flash hood which both include the new grey-coloured highly transparent face shield which allows full colour recognition. The range doesn’t stop at hoods, the X50 range also includes a Jacket and Trouser or Coat and legging combinations, both available with and without Reflective Trim.
What is an Arc Fault?
When an arc fault occurs, there’s a massive electrical explosion. Both arc flash and arc blast are separate by-products of that electrical explosion. The arc flash is the light and heat from the explosion, while the arc blast is a pressure wave that follows.
What is an Arc Flash?
An arc flash is an explosive release of energy from an electrical arc when the electrical current passes through ionized air. Temperatures of an arc flash can reach as much as 2,800 to 19,000 °C. To illustrate just how hot that is, the temperature of the surface of the sun is estimated at 5,500 °C.
These extreme temperatures can ignite the clothing and burn the skin of anyone within a few metres, and are even capable of explosively vaporizing metals such as copper, aluminum, and steel. The arc flash can also cause major limb and spinal injuries, respiratory and eyesight damage, toxic exposure and even lead to hospitalization or death.
What is an Arc Blast?
The arc blast is the pressure wave created after an arc fault. The pressure wave can cause panels to rupture, create flying debris, rupture eardrums and collapse a person’s lungs. In the absence of appropriate pressure relief, arc flash incidents have been known to collapse entire substation buildings.
What causes Arc Faults?
One of the major causes of arc flash is voltage transients (spikes), resulting from switching reactive loads or lightning strikes. The transient might last only microseconds, but it can carry thousands of amps of energy. If this happens while measurements are being taken, a plasma arc can form; either inside the measurement tool or outside.
Other causes of arc faults include situations as simple as:
Touching a test probe to the wrong surface
Worn or loose connections
Gaps in insulation
Improperly installed parts
Dust
Corrosion
How to Minimise the Effect of an Arc Fault
Circuit overcurrent protection devices (OCPD) constitute first line of defence against the uncontrolled power released during electric arcing fault. Personal protective equipment (PPE), including clothing, is a second line of defence for people working on live electrical infrastructure.
Arc Flash Boundary
The arc flash boundary is quantified as that distance where the incident energy is no longer considered a major hazard to unprotected personnel (i.e. wearing minimum PPE). This is taken to be the distance where the incident energy equals 1.2cal/cm2 or 5J/cm2 (threshold for a second degree burn). IEEE equations are used to establish the arc flash boundary for analysed equipment. No person is permitted to enter the arc flash boundary during switching, racking, electrical work, testing, cover removal or visual inspection unless they are wearing the appropriate PPE.
Arc-Rated Clothing and Personal Protective Equipment (PPE)
In the case of arc flash hazard, the main purpose of Personal Protective Equipment (PPE) is to reduce burn injury to worker to a level of curable burn (second degree).
The most common and industry accepted PPE that protects the body from arc flash is arc-rated clothing. Arc-rated clothing is tested for performance under exposure to electric arc. This is different from flame- resistant clothing, though arc-rated clothing is also flame-resistant.
Some of the main considerations of PPE inside arc flash boundaries are:
All employees within the arc flash boundary are required to wear arc flash PPE appropriate for the incident energy exposure (Note: this time is dependent on the task being performed so should be specific to the risk assessment requirements);
PPE should cover all other clothing that can be ignited;
PPE should not restrict visibility and movement;
Non-conductive protective head wear is required when in contact with live parts or when there is a possibility of electrical explosion. The face, neck and chin must be protected;
Eye protection is required;
Hearing protection is required;
Body protection is required using arc-rated clothing when the estimated incident energy at the body may cause a second degree (curable) burn (1.2 cal/cm2);
Heavy-duty leather or arc-rated gloves are required to protect the hand;
If incident energy exceeds 4 cal/cm2, heavy-duty boots are required to protect the feet.
Incorrect use of arc flash PPE will compromise its ability to reduce the incident energy that reaches the skin of the wearer. Common issues include exposure of skin, typically the hands, forearms and neck, and the wearing of fasteners or jewellery that will absorb heat in an arc flash, resulting in continuing burns.
Why?
Exposed skin is not protected and will burn under arc flash;
Synthetics and non-arc flash rated material at risk of melting and/or igniting under the extreme temperature, increasing the burn injuries;
Metal fasteners and jewellery heat up and continue to burn under the extreme temperatures;
Safety glasses (clear or tinted as appropriate) worn, even under face shields to protect the eyes. Face shields without side and chin protection can act as a scoop, directing the arc flash around the face;
Hearing protection (with in ear canal inserts) to minimise hearing loss from the arc blast.
Personal protective equipment may, or may not, provide adequate protection in the case of arc flash exposure.
It is important that workers understand the use, care, and limitations. Workers must not treat PPE as a substitute for common sense and safe work practices.
Hierarchy of Controls:
NEED AN ARC FLASH CLOTHING OR PPE QUOTE?
Are you looking for a comprehensive range of arc flash protection options for your workplace? From lift front hoods to arc flash protective jackets, coats, trousers and leggings, our range of arc flash safety garments and personal protection products from Elliotts are state-of-the-art, safety tested and an industry must.
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