NPT (National Pipe Thread) and BSP (British Standard Pipe) are two of the most common thread standards used for pipe fittings. Both standards are used to create a seal between two pipes.
NPT threads fittings are tapered, which means that the diameter of the thread decreases as you move away from the end of the pipe. This taper creates a tighter seal than a straight thread, but it also makes it more difficult to assemble and disassemble NPT fittings.
BSP threads fittings are straight, which means that the diameter of the thread remains the same throughout the length of the pipe. This makes BSP fittings easier to assemble and disassemble than NPT fittings, but it also means that they are not as leak-proof.
