🔍 Key Concepts

• Water hammer as a sudden pressure surge when flow is started or stopped quickly in a pipe • Role of the air cushion in a hydro‑pneumatic (compression) tank in absorbing pressure shocks • Difference between a tank containing both air and water versus a tank that is nearly solid water with little or no trapped air

💭 Think About

• Looking at the illustration, what component is supposed to act like a shock absorber for sudden pressure changes from the pumps? • In which listed condition would that component lose its ability to compress and ‘cushion’ rapid changes in flow or valve position? • Which option would mainly affect pump suction conditions or capacity, rather than how pressure surges are absorbed in the discharge line?

✅ Before You Answer

• Identify which condition would make the compression tank have minimal compressible volume (air) and thus transmit shocks directly into the piping. • Distinguish between issues that cause loss of pressure or pump capacity and those that cause sudden pressure spikes. • Confirm, from the sketch, that the potable water pumps discharge through the compression tank into the distribution system, so any loss of air cushion there would directly affect water‑hammer protection.