BSPT Pipe Thread vs. Garden Hose Thread
Comparing 2 standards across 10 specifications. 10 key differences identified.
BSPT (British Standard Pipe Taper), designated as the 'R' series under ISO 7-1 and EN 10226, is a 55° Whitworth pipe thread with a 1:16 taper rate. Commonly used in European, Commonwealth, and Japanese plumbing systems, external tapered R threads mate with either internal parallel Rp threads or internal tapered Rc threads to achieve pressure-tight joint sealing.
Garden Hose Thread (GHT) is the standardized North American outdoor water coupling governed by ANSI/ASME B1.20.7. Specified as 3/4"-11.5 NH, it features a straight, non-tapered thread with a 1.0625-inch (27.0 mm) major diameter that seals via axial compression against a flat rubber washer inside the female swivel coupling.
Specification Comparison Table
10 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standard Governing Body
|
ISO 7-1 / EN 10226-1 / BS 21 / DIN 2999 | ANSI / ASME B1.20.7 |
|
Thread Designation
|
R (Male taper), Rc (Female taper), Rp (Female parallel) | 3/4"-11.5 NH (National Hose) |
|
Thread Form & Flank Angle
|
55° Whitworth with radiused crests and roots | 60° American National straight parallel thread |
|
Sealing Mechanism
|
Metal-to-metal flank wedging + jointing paste/PTFE tape | Flat elastomeric washer compressed in female swivel seat |
|
Taper Ratio
|
1:16 (0.75 in/ft or 1° 47' with centerline) | — |
|
Common Pitches (TPI)
|
R 1/8": 28 TPI | R 1/4"-3/8": 19 TPI | R 1/2"-3/4": 14 TPI | R 1"-2": 11 TPI | — |
|
Primary Geographical Region
|
Europe, United Kingdom, Japan (JIS B 0203), Commonwealth | — |
|
Major Diameter (Male Outer ø)
|
— | 1.0625 inches (27.0 mm) |
|
Thread Pitch / TPI
|
— | 11.5 TPI (2.209 mm pitch) |
|
Operating Water Pressure
|
— | 40–80 PSI typical residential (up to 150 PSI burst) |