Pressure/temperature rating ≤ ASME B16.5 Class 300 or equivalent recognized national standard. For steam piping additionally limited to pipe sizes d ≤ NPS 100 mm (4 in.) Slip-on flanges for higher ratings, which comply with ASME or other recognized standards, will be subject to special consideration. [Ref. 2-4-2/9.5.3, 2-4-4/5.7 and 2-4-4/17.5 of the ABS Rules for Materials and Welding (Part 2)]