What is the difference between BSPP, BSPT and R threads?

The main difference between BSPP and BSPT threads lies in their shape and sealing method: BSPP (British Standard Pipe Parallel) is a parallel (cylindrical) thread that requires an additional seal such as an O-ring or a sealing compound for sealing. BSPT (British Standard Pipe Tapered) is a tapered (conical) thread that seals itself due to its shape and does not require additional sealing elements. 

BSPP(British Standard Pipe Parallel)

• Shape:Cylindrical/Parallel.
  
• Designation:Is often referred to by the letter G.
  
• Sealing:Creates a purely mechanical connection and requires an additional sealing medium, such as a bonded ring or sealing tape, to create a tight connection.
  
• Application:Is commonly used in applications where a simple mechanical connection is desired and the seal is applied separately.
  

BSPT(British Standard Pipe Tapered)

• Shape:
  Tapered/Conical.
  
• Designation:
  Corresponds to the taperedexternal thread Rand the cylindrical internal thread Rp according to ISO 7/1.
  
• Sealing:
  The taper of the thread allows for a self-sealing connection by pressing the thread flanks together.
  
• Application:
  Ideal for industrial applications, especially for water treatment systems where leakage at the connection must be minimised.
  

Summary Table