What must portable radio devices be?

• A. Radiation shielded
• B. Intrinsically safe (green dot on bottom of radio)
• C. Waterproof
• D. Long-range

Answer: (B)

In areas where flammable vapors or fuels may be present, portable radios must be intrinsically safe. Intrinsic safety means the device is designed so that its electrical energy and any possible electrical arc or heat cannot ignite a surrounding explosive atmosphere. The green dot on the bottom of the radio indicates it has been certified as intrinsically safe for use in those hazardous environments. This reduces the risk of ignition in fuel-related facilities, which is why intrinsic safety is the required standard. Other features like being radiation shielded, waterproof, or simply long-range don’t address ignition risk in explosive atmospheres and thus aren’t the required requirement here.