NPT Thread Dimensions ¼"" ASME B1.20.1 — ASME B1.20.1
NPT Thread Dimensions ¼"" ASME B1.20.1 to ASME B1.20.1: threads — per inch 18 mm, pitch — mm 1.411 mm, pipe od — mm 13.72 mm, l1 — hand-tight, mm 5.79 mm, l2 — effective thread, mm 10.21 mm.
Dimensions of NPT Thread Dimensions ¼"" ASME B1.20.1
| Symbol | Dimension | Value |
|---|---|---|
| · | Threads — per inch | 18 mm (0.709 in) |
| · | Pitch — mm | 1.411 mm (0.056 in) |
| · | Pipe OD — mm | 13.72 mm (0.540 in) |
| · | L1 — Hand-tight, mm | 5.79 mm (0.228 in) |
| · | L2 — Effective thread, mm | 10.21 mm (0.402 in) |
| · | E0 — Pitch dia at end, mm | 12.126 mm (0.477 in) |
| · | E1 — Pitch dia at hand-tight, mm | 12.487 mm (0.492 in) |
| · | Tap drill — mm, approx. | 11.11 mm (0.437 in) |
SKU TSH-OTHER-ASME-B1-20-1-ASME-B1-20-1-¼" · Standard ASME B1.20.1 · teshi-web
Purchase description
NPT THREAD DIMENSIONS, ¼"", ASME B1.20.1, AS PER SPECIFICATION, ASME B1.20.1
Available materials: As per specification.
Notes
- Millimetre values are conversions of the inch dimensions in ASME B1.20.1.
- Tap drill sizes are commonly recommended values and are not part of the standard; they depend on whether the hole is reamed.
Other sizes — NPT Thread Dimensions, ASME B1.20.1
1⁄16""⅛""⅜""½""¾""1""1¼""1½""2""2½""3""3½""4""5""6""8""10""12""
Frequently asked questions
What are the main types of pipe flanges?
Weld neck (WN), slip-on (SO), blind (BL), socket weld (SW), threaded (THD), lap joint (LJ) and plate flanges. Special types include orifice, long weld neck, reducing flanges and spectacle blinds.
When should I use a weld neck flange instead of a slip-on?
Use weld neck flanges for high pressure, high or cycling temperature, and lines with vibration or fatigue loading. The tapered hub and full-penetration butt weld spread stress smoothly. Slip-on flanges are cheaper and easier to align, but their fatigue life is roughly one third of a WN.
What does Class 150, 300 or 600 mean on a flange?
The ASME class is a pressure-rating designation, not a pressure in psi. The allowable pressure depends on the material group and temperature. A Class 150 A105 flange is rated 19.6 bar at 38 °C but 13.8 bar at 200 °C.
Is a 150# flange rated for 150 psi?
No. A Class 150 carbon-steel flange is rated about 285 psi (19.6 bar) at ambient temperature, and about 170 psi (11.7 bar) at 260 °C. The "150" is a class number.