ASME A112.18.3 pdf download PERFORMANCEREQUIREMENTS FORBACKFLOWPROTECTION DEVICES AND SYSTEMS IN PLUMBING FIXTUREFITTINGS 6 GENERAL REQUIREMENTS FOR BACKFLOW PREVENTION DEVICES 6.1 Functional Backflow prevention devices shall be designed to pre- vent pollution and contamination of the potable water system. 6.2 Materials Materials in contact with potable water shall comply with the requirements of ASME A112.18.1M. 6.3 Environment 6.3.1 WorkingPressure. Backflow prevention...