ENA NENS 09 2014
Energy Networks Australia (ENA) Guideline for the selection, use and maintenance of Personal Protective Equipment for arc flash protection in the Australian context.
Energy Networks Australia (ENA) NENS 09 National Guideline
The NENS 09 Guideline was developed by ENA to promote nationally consistent practices within the Australian Energy Industry.
Key Points
Australian Origin and Scope
The guideline is published by Energy Networks Australia and is intended for use by workers within the Australian electrical supply industry. Compliance with NENS 09 is often linked to Australian work health and safety legislation and state-based regulations.
Reference to International Standards
While NENS 09 is an Australian guideline, it often refers to and aligns with international standards for testing and performance levels, such as NFPA 70E, IEEE 1584 and various ASTM and ISO standards for testing materials. For example, the 2014 revision brought the guideline in line with developments in testing and flame retardant clothing that use international test methods.
International Recognition
NENS 09 itself is not an internationally recognised or mandated standard in other countries, which typically have their own relevant standards and guidelines (e.g. NFPA 70E in the united States).
In summary, NENS 09 is a national Australian guideline, but the technical requirements and testing methods it references are often based on international standards.
NENS 09 Arc Rated PPE Protection Levels
It is generally accepted that PPE clothing falls into two main categories: primary protection and secondary protection.
However, the NENS 09 Guideline provides a more detailed grouping in relation to PPE types. The following summarises the NENS 09 groupings.
Undergarment Protection
Undergarment protection plays an essential role protecting workers against serious and more common nuisance burns. In dangerous situations, undergarments add an additional layer of defence next to the skin, which can buy the wearer critical time to escape hazards without severe or life-threatening injuries. Undergarments are designed to be worn underneath regular workwear and serve in managing moisture by wicking perspiration away from the skin. By keeping the wearer dry, undergarment protection helps regulate the body's temperature and prevents workers feeling uncomfortable in challenging conditions.
Base Layer Protection
Base layer protection is everyday workwear and is designed to be more comfortable, while still providing a shield between the worker and nearby hazards. Should a hazard penetrate outerwear protection, base layer protection provides an additional protective barrier to keep the hazard away from the skin. Typically, garments are long-sleeved shirts, trousers, coveralls and bib-style trousers. The primary benefit of base layer protection is that it prevents the constant wearing of heavier outerwear protection from being overly restrictive and protects against risks that outerwear might not fully cover.
Base layer garments must be manufactured from arc rated materials where there is possible exposure to incident energy levels of:
- 1.2 cal/cm2.
- Above the minimum ATPV for secondary level protection, which is 4 cal/cm2.
Thermal Outerwear Protection
Thermal outerwear protection is designed to be worn over base layer protection to provide multi-hazard protection for workers in high-risk environments. It offers protection against arc flash, flash fire and extreme temperature hazards. Thermal outerwear protection also provides protection against severe burns caused by chemical splash and steam and hot liquids. Thermal outerwear protection is engineered to ensure worker safety while also focusing on comfort, functionality and high-visibility.
Arc Rated Outerwear Protection
Arc rated outerwear protection protects workers from the direct thermal and blast energy of an arc flash, minimising the risk of severe burns and other injuries. It includes specialised garments such as face shields, glasses, hoods, coveralls, switching coats, jackets, bib-style overalls, leggings, voltage rated rubber gloves and leather/other gloves that are rated to withstand a specific amount of incident energy, typically measured in calories per centimetre squared (cal/cm2).
Rainwear Protection
Arc rated rainwear provides vital protection from both arc flash hazards and harsh weather, shielding wearers form electric arcs while remaining waterproof and breathable. Its benefits include reducing the risk of burns by creating a barrier against the heat of an arc flash, maintaining wearer comfort with lightweight breathable materials and offering durable waterproof protection for extended periods in wet conditions.
Rainwear is designed to be worn over base layer protection and should be flame retardant in accordance with ISO 14116 and arc rated in accordance with ASTM F1891.
Calorie
Specifically, a calorie is the amount of heat energy required to raise the temperature of one gram of water 1 degree Celsius. To take the definition one step further, Calorie with an upper Case "C" is shorthand for kilocalorie (kCal) - the amount of heat energy required to raise the temperature of one kilogram of water 1 degree Celsius.
Electric Arc Incident Energy
Electric arc incident energy is the thermal energy a person is potentially exposed to during an arc flash, measured in calories per centimetre squared (cal/cm2). This energy determines the severity of potential burns, as even a low incident energy of 1.2 cal/cm2 can cause second-degree burns. The incident energy is calculated at a specific working distance from the arc and is crucial for selecting the correct personal protective equipment to ensure worker safety.