Personnel can be protected from some of the shock and flash hazards by wearing personal protective equipment (PPE). Until equipment is placed in a safe work condition per NFPA 70E 2000 Part II 2-1.1.3, it is considered live. It is important to note that conductors and equipment are considered live when checking for voltage while putting equipment in a safe work condition. PPE includes clothing, gloves, tools, face protection, and glasses. The purpose of PPE is to prevent burns to the body that could cause death. The head and chest areas are the most critical and must be protected. Although burns on the person's limbs are serious, they usually are not likely to cause death. Different types of clothing have different ratings. For example, gloves have a voltage rating to protect from electrical shock. Cotton and fire retardant (FR) clothing all have thermal ratings. Table below is usually used to determine the minimum rating of Personal Protective Equipment in calories per centimeter squared, with the intent to protect the worker from the thermal effects of the arc flash. It has the personal protective equipment (PPE) requirements divided into five hazard levels.
|Hazard Level||Personal Protective Equipment ( PPE )||Minimum Arc Rating (1)|
|0||Untreated natural fiber long sleeve shirt & pants with a fabric weight of at least 4.5 oz/yd^2, safety glasses, ear canal inserts, heavy duty leather gloves.||0|
|1||Arc rated (AR) shirt and AR pants or AR coverall, AR face shield, AR jacket, safety glasses, hard hat, ear canal inserts, heavy duty leather gloves, leather footwear.||4|
|2||Arc rated (AR) shirt and AR pants or AR coverall, AR flash suit hood, AR jacket, safety glasses, hard hat, ear canal inserts, heavy duty leather gloves, leather footwear.||8|
|3||Arc rated (AR) coverall over AR shirt and AR pants, AR flash suit, AR hood, safety glasses, hard hat, ear canal inserts, AR gloves, leather footwear.||25|
|4||Multilayer arc rated (AR) flash suit over AR coverall over AR shirt and AR pants, AR flash suit hood, safety glasses, hard hat, ear canal inserts, AR gloves, leather work shoes.||40|
(1)- Defined in ASTM F 1959-99 as the incident energy on a fabric or material that result in sufficient heat transfer through the fabric or material to cause the onset of a second-degree burn.
© 2016 ARCAD INC. All rights reserved.