Threads commonly used in Piping
Thread Standards
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
TPI/Pitch
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.
Piping 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- BS 21 BSP British standard pipe thread - Whitworth (withdrawn)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 .
Related Topics
• Dimensions
Sizes and dimensions of pipes and tubes, and their fittings - inside and outside diameter, weight and more.
• Threads
Thread data - metric, unified, ACME and others.
Related Documents
ANSI B1.20.1 - NPS - American National Standard Straight Pipe Threads
NPS pressure tight straight pipe threads with lubricant or sealer.
ANSI B1.20.1 - NPT - American National Standard Taper Pipe Threads
NPT and NPTF pipe threads - dimensions according ANSI/ASME B1.20.1/3.
ASME B31 Pressure Piping - Overview
A survey of one of the most important pressure pipe codes - ASME B31, earlier known as ANSI B31.
British Standard Brass Threads
British Brass Thread is an imperial unit based screw thread.
British Standard Cycle Threads
British Standard Cycle is a British Imperial screw thread standard.
BS 21 - Pressure Tight Pipe Thread Joints
BSPT - British Standard Pipe Taper threads & BSP or BSPF - British Standard Pipe Parallel (Straight) threads.
EN 10226 - Pipe Threads where pressure tight joints are made on the threads - Dimensions
Pipe threads where pressure tight joints are made on the threads - Part 1: Taper external threads and parallel internal threads.
ISO - Pipe, Tube and Fittings Standards and Specifications
International Organization for Standardization - ISO - pipe, tube and fittings standards and specifications.
ISO 228 - Pipe Threads where Pressure Tight Joints are not made on the Threads
Requirements for thread form, dimensions, tolerances and designation for fastening pipe threads, thread sizes.
ISO 2841 - Spark Plugs Metric Threads
Metric threads spark plugs according ISO 28741.
ISO 7 - Pipe Threads where Pressure-tight Joints are made on the Threads
Pressure-tight joints made on the pipe threads.
ISO 724 - Metric Threads
Dimensions of metric threads according ISO 724.
Metric Bolts - Minimum Ultimate Tensile and Proof Loads
Minimum ultimate tensile and proof loads for metric bolts with coarse or fine threads.
NPT Threads - Taps and Drill Sizes
NPT - Briggs Standard Pipe threads - Taps and Drill Sizes.
Pipes - Fractional Equivalents
Fractional vs. decimal inches.
Standards Applied for Piping Threads
Applied threaded standards used for piping connections.
Whitworth Pipe Threads
BSPP (G) - British Standard Pipe Parallel and BSPT (R/Rp) – British Standard Tapered Pipe for pipes and tapered threads - G/R/Rp.
Withworth Threads - Taps and Drill Sizes
Taps and drill sizes used for Whitworth - ISO 7 and ISO 228 threads.