IAPMO PS 25-2019 covers metallic fittings joining polyethylene pipe intended for water service and yard piping applications and specifies requirements for materials, physical characteristics, performance testing, and markings.

Metallic fittings joining polyethylene pipe shall be installed only outside the foundation of any building or structure or parts thereof and on water pressures not to exceed 160 psi maximum. No material shall be run exposed. The term "building or structure or parts thereof" shall include structures such as porches and steps, whether covered or uncovered, breezeways, roofed portecocheres, carports, covered walks, covered driveways, and similar structures or appurtenances.