To calculate likely incident energy from a switchboard is time consuming, onerous, and technical. Variables include voltage, current, fault current, switchboard materials, switchboard opening dimensions and much more. Australian Standards acknowledges this, by virtue of AS4836, which gives a layman, conservative approach to choosing arc flash equipment in table 9.1. It is still always recommended to do full and proper arc flash calculations to choose the exact correct rating of clothing.
| Personal Protective Equipment (PPE) | Requirements to AS/NZS 4836:2011 | Clarification |
| Eye protection | No metal, complying with AS/NZS1337 and selected in accordance with AS/NZS 1336. | Heat resistant, no metal |
| Arc Flash Face Shield | Certified to 10cam/cm2 | Tested to 10cal |
| Arc Flash suit and hood | Certified to 40cam/cm2 | Tested to 40cal |
| Insulating gloves | AS2225 or Equivalent, rated to appropriate voltage, air tested before use. | IEC, ASTM and EN gloves acceptable |
| Flame-resistant (Flame Retardant) gloves | Gloves made from leather or other non-melting heat-resistance material | Complying with AS/NZS2161.4 |
| Protective Clothing | Flame-resistant, full body clothing with no metal. | Cotton not suitable. Must be Flame Retardant rated and tested fabric. |
What key points are most important when choosing Flame Retardant or Arc Rated garments?
In choosing the right Flame Retardant garments for your workforce, there are several qualities that you should consider: thermal protection, static resistance, arc rating (if any), comfort, durability, stability, employee satisfaction, overall appearance, ease of laundry care, and relative cost. But most importantly, it is essential that you choose the Flame Retardant garments that provide the appropriate level of protection based on your hazard risk analysis.
Is it safe to roll up the sleeves of a Flame Retardant or Arc Rated garment?
Flame Retardant clothing can only provide protection where it separates the wearer from the ignition source. If the sleeves are rolled up or cut off, the exposed body parts are completely unprotected and will suffer the same injuries as if the garments had never been worn. Some company policies may allow for employees to unbutton their shirts or roll up their sleeves when not working around energized parts or other potential ignition hazards.
Why do I need Flame Retardant clothing? I’ve never had an accident?
Accidents can happen anytime, anywhere, and to anybody, regardless of past performance. The fact is that equipment breaks, people make mistakes and eventually a situation will arise with the potential of causing serious injury. The use of Flame Retardant clothing and other personal protective equipment is the last line of defence when these incidents occur.
How does Flame Retardant Clothing help protect against burn injury?
Flame Retardant and Arc Rated will provide thermal protection, which if exposed to electric arcs or flash fires, will self extinguish after the source of ignition is removed, limiting the degree of burn and body burn percentage. The flame-resistant fabrics are impregnated with chemicals that extinguish flames and help char the fabric. It is not designed to be flame proof; however, it is flame-resistant.
Will normal 100% cotton, wool and other natural fibers help protect against possible burn injury from arc flash?
Non-treated cotton and wool are flammable fibres. If exposed to electric arcs and flash fires, these materials will continue to burn causing possible severe injury and death. In fact, cotton burns very hot, and whilst it will not melt like some polyester fibres, it does not extinguish and burns at a high temperature, making it potentially extremely harmful to the wearer.