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Hexagonal galvanized iron locknut with internal threads

Value Brand

Value Brand 1/2" FNPT Galvanized Hex Locknut

SKU CH-VETY-DZW5R

A 1/2" FNPT galvanized malleable iron hex locknut rated to 300 psi WOG and listed to NSF-61, AB1953, UL and FM standards

  • Galvanised malleable iron resists corrosion in plumbing systems
  • FNPT threads allow direct connection to male NPT fittings
  • Class 150 rating handles 300 psi water, oil and gas at 150 °F
  • FM, NSF-61, AB1953 and UL listings confirm code compliance
  • Meets ASME B 16.3, B 16.4, ASTM A-197 and A47 standards

1/2" FNPT Galvanized Hex Locknut

This 1/2 inch FNPT galvanized hex locknut fits standard pipe threads for plumbing and mechanical assemblies. It is manufactured from galvanized malleable iron to Class 150 specifications. The fitting meets ASME B16.3, B16.4, ASTM A197, ASTM A47, FM, NSF-61, AB1953 and UL standards. It is supplied new for residential, commercial or industrial piping systems.

Pressure and temperature limits

The locknut is rated for a maximum working pressure of 300 psi at 150 degrees Fahrenheit WOG. Saturated steam service is limited to 150 psi. These ratings define the practical operating envelope for water, oil, gas and low-pressure steam lines. Exceeding these limits risks joint failure or leakage. The galvanized coating provides corrosion resistance within these service conditions.

Compliance determines suitability

NSF-61 and AB1953 listings confirm the fitting meets low-lead requirements for potable water systems. FM and UL listings indicate acceptance for fire protection and safety-related installations. California Proposition 65 warnings apply due to chemical content. Buyers without these regulatory needs may select a non-listed alternative.

Highlights

  • Galvanised malleable iron resists corrosion in plumbing systems
  • FNPT threads allow direct connection to male NPT fittings
  • Class 150 rating handles 300 psi water, oil and gas at 150 °F
  • FM, NSF-61, AB1953 and UL listings confirm code compliance
  • Meets ASME B 16.3, B 16.4, ASTM A-197 and A47 standards

Specifications

BrandZoro Select

Questions about this item

Which hex locknut size matches a half-inch FNPT connection?

The 1/2 in FNPT galvanized hex locknut is the only size listed for this fitting.

What does the 300 psi rating mean when the locknut is installed?

It indicates a maximum working pressure of 300 psi at 150 °F water, oil or gas.

Which standards apply to the ASME B 16.3 and B 16.4 threads?

Those standards cover the thread dimensions and pressure class for Class 150 malleable iron fittings.

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