Measure the outer diameter of your pipe threads and match it to the nominal BSP size. As a general guide:

• 1/8" BSP ≈ 9.7mm (≈3/8")
• 1/4" BSP ≈ 13.2mm (≈1/2")
• 3/8" BSP ≈ 16.7mm (≈21/32")
• 1/2" BSP ≈ 20.9mm (≈13/16")
• 3/4" BSP ≈ 26.4mm (≈1")
• 1" BSP ≈ 33.2mm (≈1-5/16")

When in doubt, size up to avoid thread damage. If you're unsure, contact us with your pipe's outer diameter and we'll help confirm the correct size.

304 stainless steel BSP tee fittings generally handle working pressures up to 150 PSI for water and air applications at ambient temperatures. Actual ratings vary by size and wall thickness — contact us to confirm for your specific application, especially for high-pressure or elevated-temperature service.

Yes. 304 stainless steel offers good corrosion resistance in most outdoor environments, including rain, humidity, and mild atmospheric exposure. For coastal or high-salinity marine environments, 316 stainless steel is typically recommended for superior chloride resistance. These fittings are a solid choice for standard outdoor irrigation and water supply applications.

No — BSP (British Standard Pipe) and NPT (National Pipe Thread) are not directly interchangeable. BSP threads have a 55° thread angle while NPT uses 60°. In some sizes they may appear to thread together but will not seal reliably and can damage threads. Always match BSP fittings to BSP-threaded pipes and fittings. If your system uses NPT threads, you will need an NPT fitting instead.

Male BSP fittings have external threads on the outside of the fitting body that screw into a female-threaded port, coupling, or valve. Female BSP fittings have internal threads that accept a male-threaded pipe end or fitting. Choose based on the thread type of the mating component in your system — if your pipe has external threads, you need a female tee; if your valve or manifold has internal threads, you need a male tee.

Yes, in most cases. BSPT (tapered) threads generally require PTFE tape or thread sealant compound applied to the male threads to achieve a leak-free seal. BSPP (parallel) threads typically require a bonded seal washer or O-ring at the seating face rather than tape on the threads. Check which BSP thread form your fitting uses and apply the appropriate sealant before installation. Do not overtighten stainless-to-stainless connections to avoid galling.

304 stainless steel BSP tee fittings are generally compatible with water, compressed air, mild chemicals, and food-grade liquids in non-corrosive service. They are not recommended for strong acids, concentrated chlorinated solutions, or highly corrosive media without an engineering review. If you're handling a specific chemical, contact us with the fluid details and we can advise on suitability.