Manufactured Housing (C-47) · Lesson 5 of 6

Gas Supply at the Home Site: Demand, Burial, Valves and Air Test

"Gas Supply at the Home Site: Demand, Burial, Valves and Air Test" is lesson 5 of 6 in the Manufactured Housing (C-47) Learning Hub. It opens with "Where the Rules Are" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Where the Rules Are
  2. The Site Outlet, Conduit and Shutoff Valve
  3. Meters, Burial and Materials
  4. Demand and Pressure
  5. Connect and Test the Home

The worked example in the course applies this lesson to a realistic job in 6 steps, from "Single site outlet" through "Test the home piping".

What you'll be able to do

  • Explain the main idea of "Gas Supply at the Home Site: Demand, Burial, Valves and Air Test" in plain language you can use on the exam.
  • Apply this step with confidence: "Meters, Burial and Materials".
  • Apply this step with confidence: "Demand and Pressure".
  • Apply this step with confidence: "Connect and Test the Home".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Gas Supply at the Home SiteSITE GAS OUTLET (ELEVATION)HOMEGRADEgas pipeother underground utilitycap or plugshutoff valve4 ft max to stand6 in min18 incover12 inclearValve is never under the home (D 103.2)TABLE D 107.1 DEMAND BY SITE COUNT1 site: 125,000 Btu/h5 sites: 92,000 each11-20 sites: 66,000 each14 x 66,000 = 924,000 Btu/h5-site branch: 5 x 92,000 = 460,000Supply 7 to 14 in WC at full loadAir test 10 to 14 in WC, 10 minFlexible connector 6 ft maxMain section for 14 sites: 924,000 Btu/h18 in cover, 12 in from other utilities, riser coated 6 in above groundPiping under the home site only inside an open-ended gastight conduitSource: 2025 CMC Appendix D: D 101.3, D 103.2, D 107.1 / Table D 107.1, D 108.2, D 110.1, D 113.5.1.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Where the Rules Are

16 CCR 832.47(b) lets a C-47 contractor connect gas to the home on a single-family individual site. The 2025 California Mechanical Code Appendix D, Fuel Supply for Manufactured/Mobile Home Parks, prints the site rules. Like the plumbing appendix, it is not mandatory unless adopted by a state agency or referenced in the adopting ordinance. D 101.1 says gas piping serving manufactured homes is designed and constructed per CMC Chapter 13 or NFPA 54 and 58, so pipe sizing itself is a Chapter 13 matter; this lesson covers what Appendix D prints.

Step 2: The Site Outlet, Conduit and Shutoff Valve

D 101.3: the gas supply to the home is located within 4 feet of the home stand (with an exception for permanent foundations built to the local building code). D 102.1.1: underground gas piping may not run beneath the part of a site reserved for the home unless it is in an open-ended gastight conduit. D 102.1.2: the conduit is at least Schedule 40, its inside diameter is at least 1/2 inch larger than the gas pipe outside diameter, it extends at least 4 inches beyond the outside wall, and its outer ends are not sealed. D 103.2: a listed shutoff valve upstream of the site outlet, on the riser at least 6 inches above grade, never under the home, with a cap or plug on the outlet when no home is connected.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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