These requirements cover backflow special check valves of 3/4-inch (19.1-mm) through 10-inch (254-mm) nominal pipe size used in piping systems supplying water for fire protection service. The backflow special check valves covered by these requirements are intended for installation and use in accordance with the Standards for: a) Low Expansion Foam and Combined Agent Systems, NFPA 11; b) Installation of Sprinkler Systems, NFPA 13; c) Installation of Standpipe and Hose Systems, NFPA 14; d) Water Spray Fixed Systems for Fire Protection, NFPA 15; e) Deluge Foam-Water Sprinkler and Spray Systems, NFPA 16; f) Installation of Centrifugal Fire Pumps, NFPA 20; g) Water Tanks for Private Fire Protection, NFPA 22; and h) Installation of Private Fire Service Mains and Their Appurtenances, NFPA 24. A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard and that involve a risk of fire, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the acceptable level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard cannot be judged to comply with this standard. Where considered appropriate, revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.