What approach ensures that the highest hydraulic pressure in a system does not exceed equipment limits?

• A. Increase pipe roughness to lower pressure.
• B. Ignore pressure distribution and assume constant pressure.
• C. Only use larger diameter pipes without any device.
• D. Compute pressure distribution with energy equation; use reducers, relief valves, proper elevations, or pressure-regulating devices to keep within limits.

Answer: (D)

The main idea is to actively determine how pressure varies throughout the system and then control it with appropriate components, rather than hoping it stays within limits by guesswork or simple changes. To do this well you start with the energy equation for steady flow, accounting for pressure head, elevation head, and losses from friction and fittings. By computing the pressure distribution along the piping, you see where the highest pressures occur and how big they are relative to equipment limits.

Once you know the pressure profile, you design and place controls to keep those peaks from exceeding what equipment can handle. This includes using reducers to step down pressure before sensitive sections, installing pressure-relief or safety valves to vent excess pressure, arranging proper elevations to manage static head, and adding pressure-regulating devices that hold pressure at a safe level throughout the system. This combined approach ensures the system operates within its rated limits under normal and anticipated conditions.

Relying on increasing roughness to lower pressure isn’t a controlled or reliable method, and ignoring distribution leads to unanticipated spikes. Simply using a larger diameter pipe without any regulating devices may reduce some losses but won’t guarantee that peak pressures stay within limits. The calculated pressure distribution plus appropriate control devices is the robust way to keep pressures in check.