IAPMO PS 50-2019 covers flush valves with dual flush device for OEM use in water closets and water closet tanks with integral flush valves with a dual flush device and specifies requirements for materials, physical characteristics, performance testing, and markings.

Devices shall be permitted to be used as a retrofit component when they comply with Table 1. Performance may vary since product was not tested on all models of water closets. Water closet tanks with integral flush valve shall be permitted to be used as a retrofit component with other manufacture's water closet bowls. Manufacturer of tanks shall provide lists of approved water closet bowls.