I have never seen abbreviation used on any drawing before and I worked construction for 45 years with many different engineering firms doing the design. The size is all they needed to spec since the ASTM spec is given.Thanks Gary,
That's exactly what I needed to know.
The 1.83 SWSP is actually referencing the pipe 1.83 meter diameter Smooth Wall Steel Pipe, 12.7mm wall thickness and ASTM A252 Pipe Specification