This is the common UL and ULC Standard for Rating and Fire Testing of Fire Extinguishers. It is the fourth edition of CAN/ULC-S508, including Amendment 2, and the seventh edition of UL 711. This common standard has been jointly revised on June 1, 2007. These requirements cover rating, and performance during fire tests, of fire extinguishers intended for use in attacking Class A, B, C, D, and K fires as defined herein. These requirements also cover performance during fire tests of fire extinguishing agents for application on Class D fires. The ultimate rating of an extinguisher or the prescribed use of an extinguisher or fire extinguishing agent is based on its fire-extinguishing potential as determined by fire tests and presupposes installation and use in accordance to the United States with the Standard for Portable fire Extinguishers, NFPA 10, and with the National Fire Code of Canada. Fire extinguishers, fire extinguishing agents, or both shall also comply with the requirements for construction and performance as applicable to specific types, designs, sizes, and arrangements. Such additional requirements are not within the scope of these requirements.