Pipe is only as strong as its weakest component. ASME B31.3 requires that flanges, valves, and fittings have a pressure class (150, 300, 600, 900, 1500, 2500) equal to or greater than the pipe MAWP.

In the design of any process plant, piping is one of the most significant cost centers, accounting for roughly 25-35% of the initial fixed capital cost and up to 50% of engineering man-hours. Improperly sized pipes or incorrectly rated components can lead to anything from inefficiency and high operational costs to catastrophic failures and plant shutdowns.

Steady-state calculations assume constant flow. However, operational changes cause transients.