Section 143.540 - Pumps, pipes, valves, and fittings for essential systems(a) Pumps, pipes, valves, and fittings in essential systems on vessels must meet ABS Rules for Building and Classing Steel Vessels Under 90 Meters (295 Feet) in Length (incorporated by reference, see § 136.112 of this subchapter), Part 4, Chapter 4.(b) Pumps, pipes, valves, and fittings in essential systems on towing vessels operating exclusively on rivers or intracoastal waterways may meet ABS Rules for Building and Classing Steel Vessels for Service on Rivers and Intracoastal Waterways (incorporated by reference, see § 136.112 of this subchapter), Part 4, Chapter 3.