NFPA 505 is the National Fire Protection Association standard for fire safety of powered industrial trucks, defining truck type designations and the areas, including hazardous locations, where each type may be used.
NFPA 505 assigns designations by power source and by the level of fire and explosion safeguards, such as D and DS for diesel, G and GS for gasoline, LP and LPS for propane, E, ES and EE for electric, and EX for trucks built for classified hazardous atmospheres. It also covers refueling and battery charging areas, maintenance, and the marking of trucks with their designation. The current edition is the 2024 edition.
OSHA 1910.178 uses a similar designation scheme and restricts which truck types may operate in hazardous locations, so NFPA 505 is the practical reference when a site handles flammable liquids, gases or combustible dust. Under 1910.178(a)(4), modifications that affect capacity or safe operation need the manufacturer’s prior written approval, and detection or telematics hardware added to a rated truck must not compromise its designation. See NFPA 505 forklift fire safety.