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)

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.

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