When pressure exceeds 100 psi, what schedule should boiler low off fittings be?

Choosing Schedule 80 for boiler low off fittings when pressure exceeds 100 psi is grounded in the material's ability to withstand higher pressures and temperatures. Schedule 80 pipe and fittings have thicker walls compared to Schedule 40, which translates to increased durability and resistance to potential failure under high-pressure conditions. This added strength is particularly important in boiler applications, where maintaining integrity is crucial to safety and operation.

Schedule 40, while commonly used for a variety of plumbing and piping applications, does not provide the necessary margin of safety for pressures above 100 psi. Similarly, Schedule 60 is generally less utilized and does not offer a standardized strength that competes with Schedule 80 in high-pressure situations. Although there is a Schedule 100, it is not commonly referenced, and in practical applications, Schedule 80 is preferred due to its established reliability and availability.

In summary, Schedule 80 fittings are designed to withstand the mechanical stresses associated with the higher pressures found in boiler systems, making them the suitable choice when pressures exceed 100 psi.