Gas PipingQuestion 233 of 360

Under what condition is copper tubing generally permitted for a natural gas distribution system?

a.Copper is never allowed for any fuel gas
b.Copper is allowed for propane but never natural gas
c.Copper is always allowed with no conditions
d.Only where the gas supply is not corrosive to copper, i.e., low hydrogen sulfide content

Explanation

Copper may be used for fuel gas only where the delivered gas will not corrode it, which means a low hydrogen sulfide (sulfur) content below the code threshold. Many utilities do not guarantee this, so black steel is the default choice. Where copper is used it must be listed for gas and properly identified, and interior surfaces must not shed material that could plug controls.

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