csst too close to water heater flue

[John Dirks Jr]

Would you consider the yellow CSST sheathing a combustible material and therefore say it should not be so close to the water heater flue?

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[Marc]

This is all I could find. It's from the Gastite Installation Manual for CSST:

LOCAL BUILDING CODES are controlling, however, as a general practice, fuel gas piping, including CSST, should not be installed within a chase or enclosure that houses a metallic chimney liner or appliance vent that protrudes through the roof. In the event such an installation is necessary and conforms to local building codes, the metallic chimney liner or vent must be bonded and grounded by a qualified electrical professional, and a separation distance, as specifically permitted by the applicable local building code between the CSST and the metallic chimney liner or vent, is required. Physical contact between CSST and the metallic chimney liner and/or vent is prohibited. If this physical separation cannot be specifically identified in the local building code and achieved or any local building code requirements cannot be met along the entire length, then rerouting of the CSST is required unless such installation is specifically permitted by the local building inspector.

Marc

[Mike Lamb]

I would say it needs a 6" min. clearance from single walled gas appliance vent. I doubt the plastic coating is non-combustible.

[John Dirks Jr]

Although Marc showed that the CSST guide did not specifically prohibit the installation in question, I was thinking along the lines with Mike in that the polyester sheathing is combustible so therefore it must be at least 6" from the single wall vent of this gas appliance.

Thanks for the discussion on the matter.