Thread Standards Used for Piping and Fluid Connectors

Thread designations and standards for threads used in piping and fluid connectors

Straight Pipes Standards

NPSC - American Standard Straight Pipe Threads in Pipe Couplings Couplings

Applicable Standards

  • ANSI B1.20.1 PIPE THREADS, GENERAL PURPOSE (INCH)
  • FED-STD-H28/7 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 7 PIPE THREADS - GENERAL PURPOSE

NPSF - Dryseal American Standard Fuel Internal Straight Pipe Threads

Applicable Standards

  • SAE J476 DRYSEAL PIPE THREADS
  • ANSI B1.20.3 DRYSEAL PIPE THREADS (INCH)
  • FED-STD-H28/8 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 8 DRYSEAL PIPE THREADS

NPSI - Dryseal American Intermediate Internal Straight Pipe Threads

Applicable Standards

  • SAE J476 DRYSEAL PIPE THREADS
  • ANSI B1.20.3 DRYSEAL PIPE THREADS (INCH)
  • FED-STD-H28/8 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 8 DRYSEAL PIPE THREADS

NPSM - American Standard Straight Pipe Threads for Free-Fitting Mechanical Joints for Fixtures (these threads fit freely over NPTF threads. They are used in swivel nuts of 07 adapters)

Applicable Standards

  • ANSI B1.20.1 PIPE THREADS, GENERAL PURPOSE (INCH)
  • FED-STD-H28/7 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 7 PIPE THREADS - GENERAL PURPOSE

Taper Pipe Standards

ANPT - Aeronautical National Taper Pipe Threads

Applicable Standards

  • MIL-P-7105 PIPE THREADS, TAPER, AERONAUTICAL NATIONAL FORM, SYMBOL ANPT, GENERAL REQUIREMENTS

NPT - American Standard Taper Pipe Threads for General Use

Applicable Standards

  • ANSI B1.20.1 PIPE THREADS, GENERAL PURPOSE (INCH)
  • FED-STD-H28/7 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 7 PIPE THREADS - GENERAL PURPOSE

NPTF - Dryseal American Standard Taper Pipe Threads

Applicable Standards

  • SAE J476 DRYSEAL PIPE THREADS
  • ANSI B1.20.3 DRYSEAL PIPE THREADS (INCH)
  • FED-STD-H28/8 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 8 DRYSEAL PIPE THREADS

PTF - SAE Short - Dryseal SAE Short Taper Pipe Threads

PTF - SAE Short is mainly used in low pressure pneumatic and fuel applications.

Applicable Standards

  • ANSI B1.20.3 DRYSEAL PIPE THREADS (INCH)

PTF SPL Short & SPL Extra Short - Dryseal Special Short Taper Pipe Threads

Are used in some pneumatic components where shortened thread depth is required because of size limitations.

Applicable Standards

  • ANSI B1.20.3 DRYSEAL PIPE THREADS (INCH)

AWWA - American Water Works Association

  •  ANSI/AWWA C800-05 UNDERGROUND SERVICE LINE VALVES AND FITTINGS

Unified Thread Standards

UN - Unified Constant Pitch Threads (standard series: 4, 6, 8, 12, 16, 20, 28, 32)

Applicable Standards

  • ASME B1.1 UNIFIED INCH SCREW THREADS (UN & UNR THREAD FORM)
  • FED-STD-H28/2 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 2 UNIFIED INCH SCREW THREADS-UN AND UNR THREAD FORMS

UNC - Unified Coarse Threads

Applicable Standards

  • ASME B1.1 UNIFIED INCH SCREW THREADS (UN & UNR THREAD FORM)
  • FED-STD-H28/2 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 2 UNIFIED INCH SCREW THREADS-UN AND UNR THREAD FORMS

UNEF - Unifed Extra Fine Threads

Applicable Standards

  • ASME B1.1 UNIFIED INCH SCREW THREADS (UN & UNR THREAD FORM)
  • FED-STD-H28/2 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 2 UNIFIED INCH SCREW THREADS-UN AND UNR THREAD FORMS

UNF - Unified Fine Threads

Applicable Standards

  • ASME B1.1 UNIFIED INCH SCREW THREADS (UN & UNR THREAD FORM)
  • FED-STD-H28/2 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 2 UNIFIED INCH SCREW THREADS-UN AND UNR THREAD FORMS

UNS - Unified Special Pitch Threads

Applicable Standards

  • ASME B1.1 UNIFIED INCH SCREW THREADS (UN & UNR THREAD FORM)
  • SCREW-THREAD STANDARDS FOR FEDERAL SERVICES-SEC. 3

UNJ - Unified Controlled Root Radius Threads

Applicable Standards

  • ANSI B1.15 UNIFIED INCH SCREW THREADS (UNJ THREAD FORM)
  • FED-STD-H28/4 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES SECTION 4 CONTROLLED RADIUS ROOT SCREW THREADS, UNJ SYMBOL

Metric Thread Standards

M - Metric Screw Threads M profile

Applicable Standards

  • ISO 261 ISO GENERAL PURPOSE METRIC SCREW THREADS - GENERAL PLAN
  • ASME B1.13M METRIC SCREW THREADS: M PROFILE
  • FED-STD-H28/21 METRIC SCREW-THREADS

M Keg Metric Taper Threads

Mainly used in Germany.

Applicable Standards

  • DIN 158-1 METRIC EXTERNAL TAPER SCREW THREADS AND MATING INTERNAL PARALLEL SCREW THREADS - PART 1. NOMINAL SIZES, LIMIT DEVIATIONS, LIMITS OF SIZE AND VERIFICATION
  • DIN 158-2 METRIC EXTERNAL TAPER SCREW THREAD AND MATING INTERNAL PARALLEL SCREW THREADS - PART 2. GAUGING SYSTEM, USE OF GAUGES, CALCULATION OF GAUGE DIMENSIONS AND GENERAL FEATURES

BSi - British Standards

R (BSPT) - British Standard Taper Pipe Threads, External

Applicable Standards

  • BS 21 PIPE THREADS FOR TUBES AND FITTINGS WHERE PRESSURE-TIGHT JOINTS ARE MADE ON THE THREADS (METRIC DIMENSIONS)
  • ISO 7/1 PIPE THREADS: DESIGNATION, DIMENSIONS/TOLERANCES

Rc (BSPT) - British Standard Taper Pipe Threads, Internal

Applicable Standards

  • BS 21 PIPE THREADS FOR TUBES AND FITTINGS WHERE PRESSURE-TIGHT JOINTS ARE MADE ON THE THREADS (METRIC DIMENSIONS)
  • ISO 7/1 PIPE THREADS: DESIGNATION, DIMENSIONS/TOLERANCES

Rp or G (BSPP) - British Standard Pipe (Parallel) Threads

Applicable Standards

  • BS 2779 PIPE THREADS FOR TUBES & FITTINGS WHERE PRESSURE-TIGHT JOINTS ARE NOT MADE ON THE THREADS (METRIC DIMENSIONS)
  • ISO 228/1 PIPE THREADS PT 1: DESIGNATION, DIMENSIONS, TOLERANCE

Japanese Standards

PF - JIS Parallel Pipe Threads

PF threads are functionally interchangeable with BSPP. This is an old designations replaced with G.

Applicable Standards

  • JIS B 202 PARALLEL PIPE THREADS
  • ISO 228/1 PIPE THREADS PT 1: DESIGNATION, DIMENSIONS, TOLERANCE

PT - JIS Taper Pipe Threads

PT threads are functionally interchangeable with BSPT threads. This is an old designations replaced with and R and Rc.

Applicable Standards

  • JIS B 0203 TAPER PIPE THREADS
  • ISO 7/1 PIPE THREADS: DESIGNATION, DIMENSIONS/TOLERANCES

PS - JIS Parallel Internal Pipe Threads (to mate with PT threads)

Applicable Standards

  • JIS B 0203 TAPER PIPE THREADS

More about pipe thread standards.

Related Topics

  • Dimensions - Sizes and dimensions of pipes and tubes, and their fittings - inside and outside diameter, weight and more

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