G 1 1/2" Female British BSPP to NPT Male Brass Adapter – Lead-Free

Looking for a reliable solution to join BSPP and NPT pipe threads? This G 1 1/2" Female British BSPP to 1 1/2" Male NPT Adapter offers a secure and durable connection between parallel and tapered threading systems. Crafted from lead-free brass, this adapter is safe for drinking water and ideal for both residential and commercial plumbing.
Designed with precision, the adapter features a British BSPP (G thread) female connection with a constant diameter, paired with a tapered NPT male thread. While washers are not typically required for G thread fittings, we include one in the package for added convenience.

Key Features:

• Material: High-quality, lead-free brass
• Size: 1 1/2" Female British BSPP (G) to 1 1/2" Male NPT
• Built for longevity and corrosion resistance
• Provides a smooth transition between British BSPP and NPT connections
• Simple, hassle-free installation

Ideal For:

• Potable water systems
• Irrigation setups
• Residential & industrial plumbing
• Commercial installations requiring a British BSPP to NPT thread conversion

Whether you're upgrading fittings or working on a new installation, this female G to male NPT adapter provides a dependable connection that holds up under pressure—up to 300 psi. It's a go-to fitting for professionals who require accuracy, safety, and performance.

Package Includes:

• 1 × 1 1/2" Female British BSPP (G) to 1 1/2" Male NPT Adapter
• 1 × Washer (included for added convenience)

Specifications:

• Material: Lead-Free Brass
• Thread Type: British BSPP (G) Female to NPT Male
• MPN: CSSL56162350
• Maximum Working Pressure: Up to 300 PSI
• Temperature Range: -65°F to +250°F (-53°C to +121°C)
• Warranty: Lifetime

Secure your plumbing system with this high-performance brass fitting—engineered to deliver a reliable connection between G thread and NPT components.

Will This Adapter Fit? — Quick Thread & Size Check

Before ordering, run through these five checks to confirm compatibility:

1. Side match — male vs. female: This adapter has a G (BSPP) female socket and an NPT male thread. Your existing G/BSPP fitting must be male; your NPT port must be female (internal threads).
2. Nominal size: Both ends are nominal 1 1/2". Verify the size stamped or listed on your existing fitting. G 1 1/2" and NPT 1 1/2" share the same nominal designation, so a 1 1/2" fixture on each side is what this adapter is designed for.
3. Thread family — G/BSPP (parallel) vs. NPT (tapered): G threads run parallel (constant diameter) and seal on a face/gasket. NPT threads are tapered and seal by thread engagement with thread tape or sealant. Do not mix up G with BSPT (tapered British threads) — BSPT looks similar but tapers and will not seal the same way as G. If your fixture says BSP or G without a "T," it is parallel (G/BSPP) and is correct for this adapter's female side.
4. Sealing method:
   • G (BSPP) side: Use the included flat washer/gasket — do not apply thread tape to the parallel G threads. Tape on parallel threads does not seal; it just adds friction.
   • NPT side: Apply PTFE thread tape or pipe-thread sealant to the male NPT threads before threading into your female NPT port.
5. Common shower-arm question — G 1/2" fixtures on NPT shower arms: Many imported shower heads and body jets use G 1/2" (BSPP) male threads, while U.S. shower arms are typically 1/2" NPT female. These are different sizes from this 1 1/2" adapter. If you are adapting a G 1/2" shower fitting to a 1/2" NPT arm, you need a 1/2" G-to-NPT adapter, not this 1 1/2" unit. See our G-Thread to NPT compatibility guide for more on thread-family selection across sizes.

If all five checks pass, this adapter is your fit. If any check fails, please reach out before ordering — our team is happy to help identify the right fitting.