A threaded pipe is a pipe with screw-threaded ends for assembly. The threaded pipes used in some plumbing installations for the delivery of gases or fluids under pressure have a threaded section that is slightly conical (in contrast to the cylindrical section commonly found on bolts and leadscrews). The seal provided by a threaded pipe joint depends upon the labyrinth seal created by the threads; upon a positive seal between the threads created by the deformation of the threads when they are tightened to the proper torque; and sometimes on the presence of a sealing coating, such as thread seal tape ("Teflon tape"), or a liquid or paste pipe sealant such as pipe dope. Accurate threads are known as "dry fit" or "dry seal" meaning that no sealant is required for a gas-tight seal. Such threads are needed where the sealant would contaminate or react with the media inside the piping (i.e. oxygen).
Dryseal pipe threads gauges ASME B1.20.5 have been recently added.
Updated formulas include now following standards:
NPT American Standard Pipe Taper Thread
NPSC American Standard Straight Coupling Pipe Thread
NPTR American Standard Taper Railing Pipe Thread
NPSM American Standard Straight Mechanical Pipe Thread
NPSL American Standard Straight Locknut Pipe Thread
NPTF American Standard Pipe Thread Tapered (Dryseal)
BSPP British Standard Pipe Thread Parallel
BSPT British Standard Pipe Thread Tapered
Significative updates have been made here, especially or MJ threads, often referred to as “J” threads, mainly used in the aerospace industry, and dryseal thread B1.20.5, the full list at today (November 2011) of supported standards is:
Pipe threads for tubes and fittings BS21:1985
Pipe threads ANSI/ASME B1.20.1-1983 (NPT)
Pipe threads ISO 7/2 - 1982(E)
Pipe threads ISO 7/2:2000 (EN 10226:2005)
Pipe threads DIN 2999
Whitworth pipe threads DIN 3858/Factory standard
Pipe threads DIN 158
Gas valve threads DIN 477
Dryseal pipe threads ASME B1.20.5
Taper pipe threads JIS B 0253 -1985
ISO metric threads DIN ISO 965:1998
Trapezoidical threads DIN 103:1997
Thread tapes according to DIN 802
Unified threads ANSI/ASME B1.1-1989(R2001)/B1.2
Unified threads ANSI/ASME B1.1-2003 / ASME B1.2
UNJ Aerospace threads ISO 3161:1999 (ASME B1.15)
Pipe threads according to ISO 228:2000
Steel conduit threads DIN 40431:1972
Whitworth threads acc.BS 84:2007, BS 919-2:2007
Pipe threads according to DIN 259 (old)
Metrical HELICOIL threads BOELLHOFF standard
Knuckle threads according to DIN 405:1997
Unified threads ANSI B1.1-1989/BS 919-1:2007
Unified threads ANSI B1.1-2003/BS 919-1:2007
Buttress threads DIN 513/Factory standard
MJ threads DIN ISO 5855 : 2009
Bolt (external) screw thread for transition fits tol. zone (DIN 13, part 51)
Unified HELICOIL threads Boellhoff standard
Unified HELICOIL threads MS 33537-1994
NPSM Cyl.pipe threads ANSI/ASME B1.20.1-1983 (2001)
NPSF Cyl. Dryseal Pipe Threads ANSI B1.20.3-1976
Threads for valves DIN 7756 - February 1979
Threads for valves ETRTO V.7 - 1999
Gages for ISO metric threads ANSI B1.16-M
Gages for ISO metric threads BS919-3:2007
Metric M screw threads NF E 03-152/153
Unified threads French standard CNOMO GE40-008N
ACME screw threads ASME/ANSI B1.5-1997
Stub ACME screw threads ASME/ANSI B1.8-1988
Buttress Threads 7 deg. 45 deg. ANSI B1.9-1973
Metric thread inserts DIN 8140:1999
Galvanized threads DIN ISO 965 (Parts 4,5):2002
Thread setting gauges DIN 2241
Threads for bicycles DIN 79012:1960
Thread gauges according to "VW Norm 13003"
Thread gauges according DIN 11 (old standard, still common)
Gas cylinder connections DIN 477 (Part 1)
Thread gauges according Swiss Standard NIHS 60-30
ACME threads with clearance for rail vehicles DIN 263:2000
Buttress threads DIN 20401:1984 / Factory standard
Cycle threads "BSC" BS 811:1950 / BS 919-2:2007
