ASME B1.20.1 - Thread & Engineering Standards

NPS – National Pipe Straight Thread

The National Pipe Straight (NPS) thread is part of the American National Pipe Thread (NPT) family, but unlike NPT (which is tapered), NPS threads are parallel (straight). This means NPS threads do not provide a pressure-tight seal on their own and require sealing washers, O-rings, or gaskets to ensure a leak-proof connection. NPS is commonly … Read more

NPT – National Pipe Thread

The National Pipe Thread (NPT) standard is widely used in the United States, Canada, and other regions for plumbing, hydraulic, and gas connections. Unlike parallel threads, NPT threads are tapered, which allows them to create a tight, leak-proof seal without requiring additional sealing elements like O-rings. NPT is governed by ANSI B1.20.1, with variations including:✔ … Read more