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 are different valve pipe sizes, threads and flanges.
View and search for 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 G 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" BSP | 28 | 0.383 | 9.7282 |
| 1/4" BSP | 19 | 0.518 | 13.1572 |
| 3/8" BSP | 19 | 0.656 | 16.6624 |
| 1/2" BSP | 14 | 0.825 | 20.955 |
| 3/4" BSP | 14 | 1.041 | 26.4414 |
| 1" BSP | 11 | 1.309 | 33.2486 |
| 11/4" BSP | 11 | 1.65 | 41.91 |
| 11/2" BSP | 11 | 1.882 | 47.8028 |
| 2" BSP | 11 | 2.347 | 59.6138 |
| 21/2" BSP | 11 | 2.96 | 75.184 |
| 3" BSP | 11 | 3.46 | 87.884 |
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 ( maybe 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 designation 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 designation, 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.
View thread torque settings according to thread size and material.
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