Steam 101
100: What are the two main types of steam used in industrial systems?
Answer: Saturated steam and superheated steam
100: Why is it important to control steam velocity in piping systems, especially at high pressures?
Answer: Uncontrolled or excessive steam velocity can cause noise, erosion of pipe walls, increased pressure drop, and poor heat transfer at the point of use. High velocity may also damage equipment or reduce trap effectiveness.
100: What is the primary job of a steam trap?
Answer: To remove condensate without losing live steam.
100: What causes flash steam to form?
Answer: A drop in pressure from high-pressure condensate.
100: What sound is often a sign of waterhammer?
Answer: Loud banging or knocking in the pipes
200: What type of heat is required to change water into steam without raising its temperature?
Answer: Latent heat
200: Explain how pipe slope impacts condensate drainage and system efficiency.
Answer: Proper pipe slope allows condensate to flow naturally toward steam traps and away from steam-using equipment. Without correct slope, condensate can pool, leading to waterhammer, corrosion, and decreased system efficiency.
200: Name one common type of steam trap.
Answer: Thermodynamic, thermostatic, or mechanical
200: Where is flash steam most commonly captured?
Answer: In a flash tank.
200: What might cause a trap to constantly blow steam?
Answer: Trap failed open, incorrect sizing, or misapplication
300: What is condensate and why is it valuable?
Answer: Condensate is the liquid left after steam gives up its heat; it's valuable because it's hot and purified—ideal for reuse.
300: Describe the basic function of a pressure reducing valve (PRV) and why it’s used in a steam system.
Answer: A PRV reduces steam pressure from a higher level to a stable, lower level that matches equipment needs. It protects downstream components, improves control, and helps maintain consistent temperature and process conditions.
300: What problem occurs when a trap fails closed?
Answer: Condensate backs up, causing waterlogging and possible damage.
300: What % of flash steam is typically produced when 100 PSIG condensate is released to 0 PSIG?
Answer: About 13%
300: What kind of pump should be used for high-temperature condensate in a closed system?
Answer: Pressure-powered pump (non-electric)
400: What is the difference between sensible heat and latent heat?
Answer: Sensible heat changes temperature; latent heat changes phase without temperature change.
400: What are two differences between a direct-acting PRV and a pilot-operated PRV?
Answer:
Control Method: Direct-acting valves use a spring and diaphragm to directly sense pressure; pilot-operated valves use a separate pilot valve to control the main valve’s movement.
Response & Stability: Pilot-operated PRVs provide more precise pressure regulation, better for fluctuating loads; direct-acting PRVs are simpler but less stable under variable flow.
400: Why do condensate lines need proper slope and sizing?
Answer: To allow free drainage and avoid waterhammer.
400: What can happen if flash steam is vented to atmosphere?
Answer: Energy and water are wasted, and it may be a safety concern.
400: A section of tracing is overheating. What could be wrong?
Answer: Failed trap, incorrect control valve, or no temperature regulation
500: Why is it important to remove non-condensable gases from a steam system?
Answer: They act as insulators and reduce heat transfer efficiency.
500: Describe how poor piping layout or undersizing can lead to pressure drop, inefficiency, or waterhammer in a steam system.
Answer:
Undersized pipes increase friction loss and pressure drop, reducing system efficiency. Poor layout, like sharp turns or back-pitched lines, can cause condensate to accumulate, leading to waterhammer—a dangerous and damaging surge caused by steam slamming into trapped water. These issues compromise performance and safety.
500: What is one method used to test a steam trap?
Answer: Ultrasonic, temperature, visual, or conductivity testing
500: Name one process where flash steam can be reused.
Answer: Low-pressure heating, preheating boiler feedwater, or washdown stations
500: You see steam venting from a condensate receiver. What might this indicate?
Answer: Flash steam from high-temp condensate is not being recovered or system is not vented properly