BSP and NPT and other worldwide Thread Information

Standard European Solenoid Valves are normally BSP (British Standard Pipe) female thread, but you can have BSP P parallel and BSP T Tapered Threads also known as "G". However in the US for example the standard thread is NPT (National Pipe Thread).

Helpful Hint: Parallel Internal and External threads are Fastening Threads and require the use of a gasket or cone seal. Tapered threads are Joining Threads and create a pressure tight seal when used with jointing compound or PTFE tape.

Here is different valve pipe sizes, threads and flanges.

View valves according to thread and flange size here.

Pipe Thread Acronyms

NPT

American Standard Pipe Taper Thread (National Pipe Thread)

FPT

American Standard female Pipe Taper Thread

NPSC

American Standard Straight Coupling Pipe Thread

BSP

British Standard Pipe (can mean either BSPP or BSPT)

BSPP

British Standard Pipe Parallel

BSPT

British Standard Pipe Taper

GHT

Garden Hose Thread

G Thread

British Gas – Parallel (same as BSPP)

R Thread

British Tapered (same as BSPT)

  Please find below guide for NPT threads per inch and outside diameters of threads for reference.

NPT – National Pipe Thread (US Standard)

Nominal
Pipe Size
(Inches)
Threads
per
Inch
(TPI)
Outside
Diameter
(Inches)
Outside
Diameter
(mm)

1/8”

27

0.405

10.3

1/4”

18

0.540

13.7

3/8

18

0.675

17.15

1/2

14

0.84

17.9

3/4

14

1.05

26.67

1

11.5

1.315

33.40

11/4

11.5

1.660

42.16

11/2

11.5

1.90

48.26

2

11.5

2.375

60.33

21/2

8

2.875

73.03

Please find below guide for BSP threads per inch and outside diameters of threads for reference. 

BSP – British Straight and Tapered

Nominal Pipe Size (Inches)Threads per Inch (TPI)Major Diameter (Inches)Outside Diameter (mm)
1/8" BSP280.3839.7282
1/4" BSP190.51813.1572
3/8" BSP190.65616.6624
1/2" BSP140.82520.955
3/4" BSP141.04126.4414
1" BSP111.30933.2486
11/4" BSP111.6541.91
11/2" BSP111.88247.8028
2" BSP112.34759.6138
21/2" BSP112.9675.184
3" BSP113.4687.884

It is not recommended to cross fit different types of thread, even if the threads per inch are the same. The reason being that the thread designs are different, NPT is a sharp thread and BSP is a rounded thread. ISO threads have 55o taper angle versus 60o for NPT. The NPT root and crest configurations are also different from ISO. For ISO threads pitch is usually measured in millimetres ( may be expressed in Inch). The pitch is different.

International Straight Pipe Standard Threads

NPSC - American Standard Straight Pipe Threads in Pipe Couplings  

Applicable Standards are:

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 - Unified 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


View flange dimension tables for PN16, PN40, JIS10K, ANSI flanges.