An arc flash suit (also called an arc flash protective suit or arc suit) is used to protect a person from the hazards of an electric arc. An arc flash is a discharge of electricity through the air that can generate extremely high temperatures, explosions, shock waves, and intense radiation. This can cause severe burns, eye damage, hearing injuries, or even death.
The suit is made of special materials resistant to fire and extreme heat, such as Nomex, Kevlar, or other treated fabrics. Its purpose is to:
- Reduce the risk of burns from the heat of the arc.
- Protect the skin and ordinary clothing from direct exposure.
- Minimize damage from pressure waves or molten material that may be thrown off.
- Fully cover the body, sometimes including a helmet, face shield, and specialized gloves.
These suits are used in high-risk electrical work, such as:
- Maintenance of electrical substations.
- Work on high-voltage switchboards.
- Repairs on industrial electrical systems.
A 31 calorie/cm² arc flash suit (also called a 31 cal suit) is designed to protect the worker from an arc flash explosion whose incident energy can reach up to 31 cal/cm².
What does “31 calories/cm²” mean?
It is a measure of thermal energy. In this context, it indicates how much heat energy per square centimeter the suit can withstand without causing severe (second-degree) burns to the skin. For reference:
- 1-4 cal/cm²: may cause mild redness.
- 8-10 cal/cm²: may cause second-degree burns.
- >25 cal/cm²: may cause fatal injuries without adequate protection.
So a 31 cal/cm² suit offers a high level of protection, and is normally used in high-risk environments, such as:
- High-voltage substations.
- Medium- or high-voltage power circuit breakers.
- Industrial motor control centers.
- Maintenance operations on energized electrical systems with a high short-circuit level.
What does a 31 cal suit include?
It generally comes as a complete kit, which includes:
- Coveralls or jacket/pants made of arc-rated material.
- Dielectric gloves with outer protection.
- Face shield with helmet or “bee-keeper” style hood.
- Neck and ear protection.
