Steam line water hammer can best be prevented by…
A. keeping steam pipes drained and insulated
B. replacing all 90 degree elbows with capped tees
C. always opening steam valves rapidly
D. keeping steam temperature below saturation point
The answer is…
A. keeping steam pipes drained and insulated
One type of water hammer is Differential Shock
Steam flow over accumulated condensate can create waves that grow as they are pushed downstream. If the steam is moving fast enough and the condensate is sufficiently abundant, the waves will grow until they block the pipe completely. This traveling slug of condensate can accelerate and grow in size, stopping only when something intervenes or they’re suddenly diverted by equipment or a bend in the piping. This can be a dangerous situation and can lead to catastrophic valve or fitting failure.
Differential Shock can best be prevented by reducing condensate accumulation wherever possible, both by draining the condensate from steam lines at regular intervals and at every change in elevation, and by minimizing the condensing rate with proper insulation.