ISO 11999-3:2015 specifies the minimum design and performance requirements for clothing as part of personal protective equipment (PPE) to be used by firefighters, primarily but not solely to protect against exposure to flame and high thermal loads. To assist with choice based on user risk assessment, a number of levels of protection are included. ISO 11999-3:2015 describes types, design, and performance of clothing, the specific requirements for clothing, marking, and manufacturer's instructions.