Overview
ASME B16.15 covers dimensions and pressure-temperature ratings for cast copper alloy (brass and bronze) threaded fittings. These are utilized extensively in domestic water, marine environments, and specialized clean gas applications.
Scope & Applicability
Applies To Industries
Covers — cast copper alloy threaded fittings:
- Sizes from NPS 1/8 to NPS 4.
- Pressure classes: Class 125 and Class 250.
- Fittings: Elbows, tees, crosses, returns, and couplings.
Does NOT cover (exclusions) — the following are governed elsewhere:
- Solder-joint (sweat) copper fittings (e.g., ASME B16.18 / B16.22).
Key Requirements
The standard establishes minimum wall thicknesses and exact thread engagement lengths to ensure safe pressure containment for brass and bronze fittings used with NPT threads, compensating for the softer nature of copper alloys compared to steel.
Technical Details
B16.15 fittings are the historical and practical standard choice for potable water systems, compressed air lines, and marine (seawater) environments where the inherent corrosion resistance of copper alloys is mandated, and a threaded assembly is preferred over soldering or brazing.
Engineering Notes
In modern industrial systems, stainless steel threaded fittings (B16.11) have increasingly replaced copper alloy fittings due to better overall chemical resistance, higher mechanical strength, and decreasing cost differentials between stainless steel and brass.
Source, Edition & Status
- Publisher
- ASME
- Industries
- Plumbing, Marine, General Industry, Waterworks
- Last Reviewed
- 2026-07-01
- Last Updated
- 2026-07-01
- Verified By
- Engineering content reviewer
- Content Status
- reviewed