Comparison of Standards

Dear Specialists,

I am working for a piping system consisting of SS pipes and fittings. Need some clarification please -

a. The specification says - The Stainless Steel Pipes to be as per ASTMA312 GrTP316L with dimensions to ANSI B36.19 Sch. 40. The clarification solicited is "Can understand ASTM A312 Gr TP refers to Austenitic Stainless Steel Pipe of which 304, 316, 321 and 347 are grades. But I dont see the additional version "L" as ASTMA312Gr.TP316 L. Is it also a common variety?"

b. The specification for fittings upto 50 mm reads - Line Joint upto 50 NB to be socket welded as per ANSI B 16.11. Material of construction to be ASTMA403Gr.WP316. Dimension to be as per ANSIB16.9 Sch.40S.

Clarification - 1: The clarification solicted are ANSI B16.11 seems to show the dimensions and weight and similarly ANSI B16.9 seems to show the dimensions and weight. Then please clarify the difference.

Clarification - 2: Does ANSI B 16.11 refer to the NPT threading / buttwelding required?

Clarification - 3: Also how to rate the 3000 lbs to the pressure in psi or kg(f)/sq.cm working?

Clarification - 4: Is there any reference chart for the same?

c. The specification for sizes above 50 NB to be line joint butt welded as per ANSIB16.25. Material of construction to be ASTMA403Gr.WP316. Dimension to be as per ANSIB16.9 Sch.40S.

Similar to above, please clarify on about ANSI B16.25 and ANSI B16.9.

Also why some standards say 3000 lbs, others say 150 lbs.

Probably a lot of queries but solicit feedback.

Thanks

K.Muthukrishnan