Piping Components 5 — Questions and Answers
Question 1: What is the purpose of a pressure relief valve (PRV) in a piping system?
- To maintain a constant downstream pressure regardless of flow
- To automatically release pressure when it exceeds a preset safe limit (Correct answer)
- To prevent backflow in domestic water supply lines
- To regulate flow velocity through a pipeline
Correct answer: To automatically release pressure when it exceeds a preset safe limit
A pressure relief valve automatically opens to vent excess pressure when system pressure exceeds a set point, protecting equipment from overpressure damage.
Question 2: What distinguishes a globe valve from a gate valve in terms of application?
- Globe valves are used only for gas; gate valves only for liquids
- Globe valves are suited for throttling flow; gate valves are for on/off service (Correct answer)
- Globe valves have a lower pressure drop than gate valves when fully open
- Globe valves are always threaded while gate valves are always flanged
Correct answer: Globe valves are suited for throttling flow; gate valves are for on/off service
Globe valves have a disc that moves perpendicular to the flow seat, making them excellent for throttling and flow regulation.
Question 3: What is the role of a trap in a steam piping system?
- To increase steam pressure before it enters equipment
- To automatically discharge condensate and air while retaining live steam (Correct answer)
- To prevent steam from flowing backward in the line
- To reduce the velocity of steam to prevent erosion
Correct answer: To automatically discharge condensate and air while retaining live steam
A steam trap automatically separates and discharges condensate and non-condensable gases from steam systems without allowing live steam to escape.
Question 4: Which gasket material is typically used for flanged connections in high-temperature steam applications?
- Rubber or neoprene
- Spiral-wound stainless steel with graphite filler (Correct answer)
- PVC or PTFE sheet
- Cork composite
Correct answer: Spiral-wound stainless steel with graphite filler
Spiral-wound gaskets with stainless steel winding and graphite filler are designed to handle high temperature and pressure in steam service.
Question 5: What is the function of a pressure-reducing valve (PRV) in a domestic water supply?
- To increase water pressure entering the building from the main
- To reduce and regulate high incoming main pressure to a safe working pressure (Correct answer)
- To stop backflow from the building into the municipal main
- To filter sediment and debris from incoming water
Correct answer: To reduce and regulate high incoming main pressure to a safe working pressure
A pressure-reducing valve steps down high municipal water supply pressure (often 80–150 psi) to a safe level (typically 40–80 psi) for building fixtures.
Question 6: What is a 'saddle fitting' (pipe saddle) used for in piping?
- To support and anchor a pipe to a structural member
- To add a branch tap to an existing pipe without cutting it out of service (Correct answer)
- To reduce vibration transmitted from pumps to the piping
- To connect two pipes at a right angle permanently
Correct answer: To add a branch tap to an existing pipe without cutting it out of service
A pipe saddle fitting clamps onto an existing pipe and allows drilling a new branch connection without removing the pipe from service.
Question 7: Which pipe component is specifically designed to isolate sections of piping for maintenance while allowing the rest of the system to remain operational?
- Pipe nipple
- Isolation valve (Correct answer)
- Expansion joint
- Reducing coupling
Correct answer: Isolation valve
Isolation valves (such as gate, ball, or butterfly valves) are installed to shut off specific sections of piping for repair or maintenance without interrupting the whole system.
Piping Components 5
What is the purpose of a pressure relief valve (PRV) in a piping system?