Brass BSP Blanking Cap Plug — 1/8" to 2" Male & Female Stop End with Washer

BSP sizes refer to the nominal bore of the pipe, not the outer diameter of the fitting thread. For reference: 1/2" BSP has a thread OD of approximately 20.9 mm (≈0.82"); 3/4" BSP is approximately 26.4 mm (≈1.04"); 1" BSP is approximately 33.2 mm (≈1.31"). Measure the outer diameter of your existing male thread or the inner diameter of your female port, then match it to a BSP nominal size chart. When in doubt, contact us with your measurement before ordering.

The Standard cap is the most common choice for general-purpose pipe sealing in domestic plumbing and light industrial use. The Thickened variant has a heavier wall section, making it better suited for applications requiring higher torque during installation or elevated working pressures. The Convex variant features a domed head profile — typically chosen where a rounded exterior is preferred and flush installation is not required.

Brass BSP blanking caps generally handle working pressures up to approximately 150–200 PSI (10–14 bar) in standard configurations, depending on size and wall thickness. Thickened variants typically support higher pressures. Always use PTFE tape or thread sealant on taper threads, and install the included washer on parallel-thread female ports to ensure a leak-free seal. For critical pressure applications, verify the rated pressure with your system engineer.

Brass has naturally good corrosion resistance and is suitable for many outdoor and wet applications, including garden irrigation manifolds, outdoor plumbing, and compressed air systems. The Plating variants offer an additional protective surface layer for environments with higher moisture exposure. For highly corrosive environments — such as saltwater or strong chemical exposure — stainless steel fittings are generally recommended instead.

These fittings use BSP (British Standard Pipe) threads, which are standard in the UK, Europe, Australia, and many other regions. BSP and NPT (National Pipe Thread, common in the US) are not directly interchangeable — they have different thread angles (55° BSP vs 60° NPT) and different pitches. Forcing a BSP fitting onto an NPT port will not seal correctly and may damage the threads. If your system uses NPT threads, a BSP-to-NPT adapter is required.

The included washer acts as a face seal at the port seating surface. It is particularly important for female blanking caps used on parallel-thread (BSPP) ports, where the washer — not the thread — provides the primary pressure seal. Always fit the washer before tightening the cap. For male taper-thread (BSPT) fittings, PTFE tape or thread sealant on the threads provides the primary seal, and the washer serves as a secondary backup.

For male taper-thread (BSPT) fittings, PTFE tape or a thread sealant compound is generally recommended to achieve a leak-free seal. For parallel-thread (BSPP) female caps, the included washer provides the primary face seal and PTFE tape on the threads is typically not required. If you are unsure whether your port uses taper or parallel threads, check the equipment documentation or contact us.