What is BSP Thread?

BSP (British Standard Pipe) threads are a standard for screw threads used to connect and seal pipe fittings. Developed in Britain, BSP threads are widely used in plumbing and heating systems in many countries around the world. And BSP threads have a 55-degree thread angle. There are two types of BSP threads, BSPP and BSPT:

BSPP (British Standard Pipe Parallel)- ISO 228-1

Standards: BSPP threads are defined by the ISO 228-1 standard.

Thread Designation: Sometimes referred to as "G" threads. And most of the time, when we say “BSP”, It referres to BSPP thread.

Characteristics: The threads are parallel, meaning the thread crests and roots are evenly spaced and do not taper. BSPP threads provide a consistent diameter along the length of the threaded portion.

Sealing Method: Typically employs a sealing washer or O-ring at the mating surface to achieve a leak-free connection. The threads themselves do not provide a seal but create a secure mechanical connection.

Application: Common in both low-pressure and high-pressure applications where the use of a compression washer is suitable.

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BSPT (British Standard Pipe Tapered)- ISO 7-1

Standards: BSPT threads are defined by the ISO 7-1 standard.

Thread Designation: Sometimes referred to as "R" threads.

Characteristics: The threads are tapered, meaning they gradually decrease in diameter from the end of the pipe to the start of the threads, providing a tighter fit as the connection is tightened.

Sealing Method: The threads themselves form a tight seal as they are screwed together. This is often augmented with the use of thread sealants, such as PTFE tape or pipe dope, to ensure a leak-free connection.

Application: Ideal for applications where a tight seal is necessary and where sealing compounds can be used to enhance the seal.

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Data for BSP threads

BSPP VS BSPT BS NPT THREAD

What is NPT Thread?

NPT (National Pipe Thread)- ASME B1.20.1

NPT is a U.S. standard for tapered threads used on threaded pipes and fittings. It's recognized for its ability to create a strong seal due to the tapering design, which compresses the threads together when tightened. Here’s a comprehensive overview of NPT threads:

Standards: NPT threads are defined by the ASME B1.20.1 standard.

Characteristics of NPT Threads

Thread Angle: NPT threads have a 60-degree thread angle.

Taper: The threads are tapered, meaning that the diameter decreases from the end of the pipe inward. This taper is 1/16 inch per inch (1.5875 mm per 25.4 mm) of length.

Seal Type: NPT threads create a seal by the interference fit between the male and female threads, which tightens as they are screwed together.

Sealing Compounds: Typically, thread sealants like PTFE tape (Teflon tape) or pipe dope (thread sealant paste) are used to enhance the seal and ensure a leak-proof connection.

Thread Pitch: The number of threads per inch (TPI) varies based on the nominal size of the thread.

Applications of NPT Threads

Plumbing Systems: Commonly used in residential and commercial plumbing within the U.S. and countries that follow U.S. standards.

Gas and Oil: Widely applied in the gas and oil industry for secure and reliable piping connections.

Hydraulics and Pneumatics: Often found in hydraulic and pneumatic systems due to their strong and reliable sealing properties.

Industrial Applications: Used across various industrial applications, including air lines and water supply systems.

Data for NPT Threads

NPT Thread VS BSP Thread

NPT vs. BSP

Other Thread Types

*JIS Tapered Pipe Thread Type – PT

JIS (Japanese Industrial Standards) Tapered Pipe Thread, also known as PT thread, is a type of tapered pipe thread standard used in Japan. Here are the key points about JIS Tapered Pipe Thread:

Interchangeability: JIS PT thread is identical and interchangeable with BSPT (British Standard Pipe Taper) thread. However, since the male PT thread does not have a 30-degree flare, it will not mate with the BSPP female swivel with conical seat. Also, we recommended using thread sealant with PT threads to ensure a leak-free seal.

Thread Taper: Both JIS PT and BSPT threads have a taper of 1° 47' (1 inch per 16 inches).

Thread Angle: JIS PT threads have a 55° thread angle, with rounded truncation of roots and crests.

Thread Pitch: The pitch of JIS PT threads is typically measured in threads per inch (TPI), with a different number of threads per inch compared to NPT threads.

Sealing: JIS PT threads require a pipe thread sealant, such as thread sealing tape, to provide a leak-tight seal.

Compatibility: While JIS PT threads are interchangeable with BSPT, they are not compatible with NPT threads due to differences in thread angle and pitch.

Standards: JIS PT threads are defined in the Japanese Industrial Standard JIS B0205, which is equivalent to the British Standard BS 21 and DIN 2999

*SAE Thread Type – Straight Thread O-Ring Boss

SAE Thread Type refers to a series of thread standards developed by the Society of Automotive Engineers (SAE) for various applications, particularly in automotive and hydraulic systems.

* Metric Tapered/Parallel Thread Type

Metric Tapered and Parallel Thread Types are standardized thread profiles used primarily in Europe and other regions that follow the metric system.

It has a cylindrical inner and outer diameter precise in millimeters. The fine taper of metric tapered thread allows for the best possible force transmission. In writing, you can identify metric threads by a capital “M” plus an indication of their nominal outside diameter (ex. M22 x 1.5). Lastly, when measuring pitch size make sure you’re using a metric pitch gauge.

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