For SS welded pipe in NH3, what diameter range qualifies it as Sch 40?

The correct answer pertains to the sizing of Schedule 40 stainless steel (SS) welded pipe specifically used in ammonia (NH3) applications. Schedule 40 refers to the wall thickness and dimensions of the pipe, which determine its pressure-handling capabilities.

For stainless steel welded pipes, the diameter range that qualifies as Schedule 40 typically falls between 3/4 inch and 6 inches. This range aligns with industry standards where Schedule 40 is commonly used for pipes in these dimensions due to its balanced strength and weight profile, making it suitable for a variety of applications, including those involving corrosive substances like ammonia.

Choosing a diameter smaller than 3/4 inch or larger than 6 inches would not fit the criteria for Schedule 40 as these sizes may transition into different schedules or materials, which might not provide the same level of performance necessary for handling the specific pressures and chemical properties related to NH3.