What’s the difference between Electrical Hazard, Static Dissipative, and Conductive Safety Shoes?
The 3 distinct types of conductivity found in Safety Shoes are Electrical Hazard (EH), Static Dissipative (SD), and Conductive (CD). These are tested according to the ASTM (American Society of Testing and Materials) standards F2412-05 and F2413-05.
The differences between these classifications of Safety Shoes are that Electrical Hazard shoes are designed to impede (reduce significantly) the flow of electricity through the shoe and to ground, thereby reducing the possibility of electrocution. Electrical Hazard Safety Shoes will have an “EH” clearly visible on the ASTM label sewn inside the safety shoes. (ASTM F2413-05 Sec. 188.8.131.52) Only safety shoes can have the Electrical Hazard designation. (ASTM F2413-05 Sec. 5.5.1),
IMPORTANT: Electrical Hazard shoes are not designed to be the primary source of protection in an Electrical Hazard environment. They are designed to be only a secondary source of protection in an Electrical Hazard environment, and that is clearly stated in the ASTM standards for Electrical Hazard Safety Shoes. (ASTM F2413-05 Sec. 5.5.4 & Sec 5.5.2),
Static Dissipating Safety Shoes and Soft-Toe shoes are designed to dissipate (reduce) the amount of static electricity build-up on your body. Unlike Electrical Hazard Safety Shoes, Static Dissipating Shoes can be either safety toe or non-safety (or soft-toe). Static Dissipating shoes actually conduct static electricity through the linings and insole, cement, and outsole and into ground. Static Dissipating Safety Shoes and non-Safety Shoes have a “SD” clearly visible on the ASTM label sewn inside the safety shoes. (ASTM F2413-05 Sec. 184.108.40.206),
To accomplish Static Dissipating environments consistently, several things must be controlled. First, you cannot add any kind of insole to the shoe, except a specially designed Static Dissipating insole. If a non-Static Dissipating insole is added to the shoe, Static Electricity will not flow through the insole. When the insole becomes non-conductive; the shoe will not Dissipate Static Electricity. Also, the floor and sole of the shoe must remain clean and free of dust and other foreign matter to maintain good contact between the sole and the floor. This allows the Static Electricity to Dissipate, or flow through the sole and into ground. (This assumes that floor is “grounded” and Static Electricity will flow through to the floor material.)
Static Dissipating Shoes and Safety Shoes are worn in mainly two types of environments: Computer component handling facilities and nuisance Static Electricity environments, like plants where the process and machinery create a large Static Electricity field in the manufacturing process. Typically, this field creates a build-up of static electricity on employees working in the environment, and then discharges when the employee touches metal that goes to ground or has a neutral or less charge than the body has. This Static Discharge “shocks” the person, creating momentary discomfort and annoyance. Static Dissipating shoes can help this situation, but the floor, mats, and machinery, also need to be grounded to reduce the Static Electricity field in the environment.
Conductive Safety Shoes are designed to “conduct” Static Electricity through the shoes and into ground. Conductive Safety Shoes are similar to Static Dissipating Safety Shoes because both are designed to dissipate Static Electricity. Conductive Safety Shoes (CD) Dissipate Static Electricity much faster and more completely than Static Dissipating Safety Shoes (SD). The reason is that Conductive Safety Shoes are worn in environments that are highly flammable and explosive, which means that reducing the possibility of a Static Spark or Discharge is critical to the safety of not only the employee, but the other employees in the immediate area and even citizens in the vicinity of the explosive area. According to the ASTM Standard, Conductive (CD rated) Shoes must be Safety Shoes (ASTM F2413-05 Sec. 5.4.1), and the Conductive Safety Shoes have a “CD” clearly visible on the ASTM label sewn inside the safety shoes. (ASTM F2413-05 Sec. 220.127.116.11),
Important: Because Conductive Safety Shoes (CD) conduct electricity, employees wearing these shoes must avoid wearing Conductive Safety Shoes in Electrical Hazard (EH) environments. Obviously, this could be a very dangerous situation. (ASTM F2413-05 Sec. 18.104.22.168),