American Standard Pipe Thread

Technical Terms

  1. A.S.P.T.
  2. N.P.S.
  3. A.P.S.
  4. O.D.
  5. I.D.
  6. MIP
  7. FIP
  8. Thread Taper
  9. Thread Pitch
  10. Thread Angle
  11. Running Thread
  12. Right Hand Thread
  13. Left Hand Thread


American Standard Pipe Thread

Nominal Pipe Size

Actual Pipe Size

Outside Diameter

Inside Diameter

Male Iron Pipe

Female Iron Pipe

Necessary for pipe to tighten into fitting

Number of threads per inch

60 degrees

Long thread without taper

Normal direction for threads

Opposite direction



Suitable materials to use as a sealant are hemp, cement, teflon tapes and pipe dopes.

Pipe dopes can be metallic and non-metallic.


7.3.2.3. Screwed Joints

  1. In making a screwed joint the ends of the pipe shall be reamed or filed out to the size of the bore and all chips and cuttings shall be removed.
  2. No pipe-joint cement or paint shall be allied to the internal threads.
  3. Aluminum DWV pipe shall not be used with a screwed joint.