Most piping threads are produced to national or industry group standards describing threads form - threads angle, pitch and diameter. Common standards are
- ANSI/ASME B1.1-1989, Unified Inch Screw Threads (UN and UNR Thread Forms)
- ANSI/ASME B1.20.1-1983 (R1992), Pipe Threads, General Purpose (Inch)
- DIN 2999, Pipe threads for tubes and fittings - parallel internal thread and taper external thread
- ISO 724 ISO general-purpose metric screw threads -- Basic dimensions
In general pitch refers to threads per inch (TPI) for fractional screw threads and pipe threads. For metric screw threads pitch refers to the distance between threads.
Common piping thread standards in the United States are
- NPT - American Standard Pipe Taper Thread (also known as ANSI/ASME B1.20.1)
- NPTF - National Pipe Thread Tapered Fine
- NPTR - American Standard Taper Railing Pipe Thread
- NPS - American National Standard Straight Pipe Thread
- NPSC - American Standard Straight Coupling Pipe Thread
- NPSM - American Standard Straight Mechanical Pipe Thread
- NPSL - American Standard Straight Locknut Pipe Thread
Other common piping thread standards
- ISO 7 Tapered Pipe Threads - also known as DIN 2999, BSP 21, JIS B0203
- ISO 228 Parallel Pipe Threads - equivalent to DIN ISO 228/1, BSP PL, JIS B0202, G 1/8 and G 1/4 etc.
- BS 21 BSP British standard pipe thread - Whitworth (withdrawn)
More about standards applied for piping threads .
Sizes and dimensions of pipes and tubes, and their fittings - inside and outside diameter, weight and more.
Thread data - metric, unified, ACME and others.
NPS pressure tight straight pipe threads with lubricant or sealer.
NPT and NPTF pipe threads - dimensions according ANSI/ASME B1.20.1/3.
A survey of one of the most important pressure pipe codes - ASME B31, earlier known as ANSI B31.
British Brass Thread is an imperial unit based screw thread.
British Standard Cycle is a British Imperial screw thread standard.
BSPT - British Standard Pipe Taper threads & BSP or BSPF - British Standard Pipe Parallel (Straight) threads.
Pipe threads where pressure tight joints are made on the threads - Part 1: Taper external threads and parallel internal threads.
International Organization for Standardization - ISO - pipe, tube and fittings standards and specifications.
Requirements for thread form, dimensions, tolerances and designation for fastening pipe threads, thread sizes.
Metric threads spark plugs according ISO 28741.
Pressure-tight joints made on the pipe threads.
Dimensions of metric threads according ISO 724.
Minimum ultimate tensile and proof loads for metric bolts with coarse or fine threads.
NPT - Briggs Standard Pipe threads - Taps and Drill Sizes.
Fractional vs. decimal inches.
Applied threaded standards used for piping connections.
BSPP (G) - British Standard Pipe Parallel and BSPT (R/Rp) – British Standard Tapered Pipe for pipes and tapered threads - G/R/Rp.
Taps and drill sizes used for Whitworth - ISO 7 and ISO 228 threads.