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Steam practice questions

30 questions from the pipefitting and steamfitting practice test.

Steam practice test

10 questions, graded as you go, with the reason for every answer. No sign-up.

What this covers

Sample questions

About how much heat does one pound of steam at atmospheric pressure give up as it condenses to water at 212 F?

  1. 144 Btu
  2. 180 Btu
  3. 970 Btu
  4. 1,150 Btu
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C. 970 Btu

The latent heat of vaporization at atmospheric pressure is about 970 Btu per pound. 180 Btu is the sensible heat to bring a pound of water from 32 F to 212 F, and 144 Btu is the latent heat of melting ice.

Reference: Steam tables: latent heat at atmospheric pressure

What is superheated steam?

  1. Steam above saturation temperature for its pressure
  2. Steam carrying fine droplets of water along with it
  3. Steam at any pressure higher than 15 psig
  4. Steam that has just flashed from hot condensate
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A. Steam above saturation temperature for its pressure

Superheated steam has been heated beyond its boiling point at that pressure and holds no moisture. Steam carrying water droplets is wet steam, which is the opposite condition.

Reference: Steam fundamentals: saturated and superheated steam

Under the ASME Code, a low-pressure steam heating boiler operates at no more than what pressure?

  1. 5 psig
  2. 30 psig
  3. 160 psig
  4. 15 psig
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D. 15 psig

Section IV heating boilers are limited to 15 psig steam. The 160 psig figure is the limit for hot water heating boilers (together with 250 F), and 30 psig is a common hot water relief valve setting, so both are tempting.

Reference: ASME Boiler and Pressure Vessel Code, Section IV scope

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