PROTECTING WORKERS FROM FLASH BURNS

Protecting workers should be the highest priority for businesses, but recent incidents have shown workplaces overlook potential of injury or death as a result of arc and clothing ignition flashes. Non-compliance with testing and tagging regulation, ineffective control measures, untrained workers, poor repair and maintenance practices, and improper personal protective equipment (PPE) and clothing are all important risk factors that must be addressed and are often overlooked. A recent incident in Western Australia left an electrician with first-degree burns to the head, face and neck. An arc flash and blast occurred as a result of poor workplace procedures, with an investigation finding that many of the risk factors mentioned above had not been addressed. If you are a person conducting a business or undertaking (PCBU), or an interested worker, the following article will discuss flash burns, those at risk, OH&S standards, as well as tips on preventing flash burns.

WHAT IS THE PRIMARY CAUSE OF FLASH BURNS?

The primary cause of flash burns are risks associated with electrical hazards. When high voltage differences exist across a gap between conductors, this creates a powerful, high-amp current that travels through the air. A rapid release of large amounts of energy follows, which is known as an arc flash or arc blast. These arc flashes have recorded temperatures as high as 20,000 ̊C, and can cause serious injuries or death.

DO NOT OVERLOOK:

Workers who engage in welding, working hot metals, handling flammable liquids, gases or vapours are exposed to flash ignition and the inevitable risk of serious burns leading to death.

WHO IS AFFECTED?

Workers considered at risk are those working in:

• Electrical Utilities
• Electrical Maintenance
• Foundry & Smelter
• Oil & Gas Industry
• Volatile Chemical Manufacturing
• All Welding Trades
• Firefighters & Fire Support
• Maritime Emergency
• SES

A PCBU is responsible for identifying flash risks in the workplace. It is important that the PCBU carries out an effective risk assessment to ensure appropriate control measures are in place. Such control measures should include enforcing PPE requirements, which will be discussed below.

REFERENCE MATERIALS & STANDARDS

The US standard NFPA 70E is used as a credible guide in Australia. This resource, along with the AS/NZS 4836:2011, are useful for PCBUs looking to maintain electrical safety standards.

OTHER REFERENCES…

• NFPA 70E:2009 – (US) Standard for Electrical Safety in the Workplace
• ASNZS 4836:2011 Safe working on or near low-voltage electrical installations and equipment
• ASTM F1506-10a – Standard Performance Specification for Flame Resistant and Arc Rated textile materials
• ENA NENS 09-2006 – Selection, use and maintenance of personal protective equipment for electrical hazards
• ASNZS 4967:2009/amdt 1:2010 – Protective clothing for firefighters

The highly regarded NFPA 70E uses two metrics for risk assessment that need explanation:

• ATPV – An Arc Thermal Protective Value (ATPV) refers to the maximum incident energy (in calories per centimetre squared) that protective equipment can be exposed to without allowing onset of a second-degree burn. Ratings are based upon the total weight of the fabric. Appropriate clothing ranges from untreated cotton, wool, rayon, or silk materials with a fabric weight of at least 4.5 ounces per square yard to flame retardant (treated) clothing worn in layers. Wearing layers of clothing is thought to confer greater ATPV than the sum of the values for both garments worn, but this has not been confirmed by testing, so the cumulative values remain the standard. There is value in the discussion of FR rated underclothing for this very reason.
• HRC – Hazard Risk Category. This is calibrated from 0 to 4, in ascending order of hazard. It is determined by the calories per square centimetre

(cal/cm²) needed to have a 50% risk of inflicting a 2^nd or 3^rd degree burn. All credible FR Clothing and PPE manufacturers clearly label all FR rated products with a HRC number.

FLASH BURN PREVENTION & SOLUTIONS

The potential for any flash ignition should be minimised through the risk control processes prescribed by Safe Work Australia, but will always include, elimination or substitution, engineering controls, and administrative controls like training and, of course, training in the selection and maintenance of suitable PPE.

Workers can wear two types of fabric for flash protection. Inherently protected garments may char but will not catch fire, flash or burn over a given service lifetime. Users should be aware that chemically treated garments may use a retardant that washes out over time. Chemically treated garments may prove a suitable option depending on the life cycle of the garment itself . Determining which garment best suits your work environment will depend on a combination of factors, such as the heat potential of the ignition source, and the heat protection calorific value of garments and other PPE, especially face and eye protection (conventional eye and face protection can melt and also offer no intense light and heat protection to the eyes) .

SafetyQuip can offer a range of workwear solutions depending on the application for consideration when protecting workers against flash burn, such as TenCate TecaSafe Plus Workwear. as the inherent protection will never wash or wear out. The following brands are available at SafetyQuip stores and online:

• Bisley provides premium protection from arc flash and flash fire, with flame resistant ventilation to combat heat stress.
• Elliotts’ provides unbeatable electric arc and flash fire protection, with soft and lightweight fabric providing unmatched comfort.

There can be quite job specific risks that have not been identified in a workplace or may not be known or understood in a particular location, industry or nature of work. For this reason it is recommended that an OH&S professional be consulted.

REFERENCES

Significant Incident Report – Government of Western Australia, Department of Mines and Petroleum: View PDF