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Information Specification documents threads

American conical pipe thread acc. ANSI/ASME B 1.20.1 - 1983 inside thread conical, outside thread conical

 
Thread:   American conical pipe thread acc. ANSI/ASME B 1.20.1 - 1983
Abbreviation:   NPT
Designation:   3/8 - 18 NPT
Type of thread:   Inside thread conical
outside thread conical (cone 1:16)
Application:   Pipe threads for pipes and tube connections with sealing tapes (see pages 8 – 10) are sealing inside the threads.
 
Description:   The conical NPT-outside thread shows at the relating level &147;. The adjustment power created by using of a suitable tool increases the thread reach and seals the screw connection supported by a suitable sealant (e.g. hemp or Teflon). Since both inside and outside threads are conical, more thread-turns contribute to better sealing and power admission. The little thread-flattening causes a small leakage space.
 

  thread   outside Ø of pipe   number of threads   P   h   effective Ø E1   L1   i  
 
  1/8" NPT   10,287   27   0,941   0,753   9,489   4,102   6,703  
  1/4" NPT   13,761   18   1,411   1,129   12,487   5,786   10,206  
  3/8" NPT   17,145   18   1,411   1,129   15,926   6,096   10,358  
  1/2" NPT   21,336   14   1,814   1,451   19,772   8,128   13,556  
  3/4" NPT   26,670   14   1,814   1,451   25,117   8,611   13,861  
  1" NPT   33,401   11 1/2   2,209   1,767   31,461   10,160   17,343  
  1 1/4" NPT   42,164   11 1/2   2,209   1,767   40,218   10,668   17,953  
  1 1/2" NPT   48,260   11 1/2   2,209   1,767   46,287   10,668   18,377  
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