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Regulators practice questions

27 questions from the gas fitting (natural gas and lp) practice test.

Regulators practice test

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

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Sample questions

What outlet pressure does a second-stage propane regulator normally deliver to the house piping?

  1. 3.5 in. w.c.
  2. 7 in. w.c.
  3. 11 in. w.c.
  4. 10 psi
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C. 11 in. w.c.

The second-stage regulator delivers about 11 in. w.c., the standard supply pressure for propane appliances. Ten psi is the first-stage outlet pressure, far too high for appliance controls.

Reference: NFPA 58 Section 6.10 (regulators); regulator manufacturer data

Most residential appliance gas controls are rated for a maximum inlet pressure of 1/2 psi. About how many inches of water column is that?

  1. 7 in. w.c.
  2. 14 in. w.c.
  3. 28 in. w.c.
  4. 55 in. w.c.
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B. 14 in. w.c.

Half a psi is 0.5 x 27.7 = about 14 in. w.c. Higher pressure can damage the control, which is why 2 psi systems need a line regulator ahead of each appliance or group of appliances.

Reference: ANSI Z21.78 gas control ratings; IFGC 2021 Section 410

Convert 14 in. w.c. to psi. (1 psi = 27.7 in. w.c.)

Answer in psi.

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0.505 psi

Pressure = 14 in. w.c. / 27.7 in. w.c. per psi = 0.505 psi.

Reference: Pressure unit conversions

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