API 602
Gate, Globe and Check Valves for Petroleum and Natural Gas - Compact
Compact forged steel valves, NPS 4 / DN 100 and smaller
What it covers
- Compact gate, globe and check valves NPS 4 / DN 100 and smaller
- Forged and cast body construction for small bore
- Socket weld, threaded, butt weld and flanged ends
- Wall thickness basis for compact valves
- Standard, extended and full bore designations
What it does not cover
- Valves above NPS 4 - those fall under API 600 or the manufacturer standard
- Pressure-temperature ratings, which come from ASME B16.34
- Pressure seal bonnet construction, which is uncommon at these sizes
This section exists because standards are routinely listed on valve datasheets in positions where they do not apply. Knowing the boundary is what makes the reference useful.
Why the small-bore standard is separate
A NPS 1 valve on an instrument connection has different practical requirements from a NPS 12 line valve: it is often threaded or socket welded, it is handled during installation, and the wall thickness basis reflects that. API 602 exists because applying the heavy-duty gate valve standard to compact valves would produce something needlessly heavy and expensive.
Bore designations matter
API 602 defines standard, extended and full bore. They are not interchangeable - a standard-bore NPS 1 valve has a smaller through-bore than the pipe. If your piping class requires full bore for a drain or a sampling line, it has to be stated, because standard bore is the default.
Where it applies in our range
The small-bore end of the forged valve range: drains, vents, instrument and sampling connections. We state API 602 on those items and not on the large-bore valves, where it does not apply.
Products this applies to
Verify it yourself
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