Looking for a definition of "Sufficiently Impervious"

[FastEddy26]

Hi, I'm looking to define "sufficiently impervious" so that I can evaluate oil storage containment. Have seen state of NH definition permeability requirements as 1 ft/72 hours. I don't live/work in NH. Does anyone have a quantified definition of "sufficiently impervious" from a national code or standard?

 

[r13]

See the linked document, Link. Suggest to check with EPA too.

 

[FastEddy26]

Yes, thanks retired13. SPCC Section 4.4.2 defines it well enough for me right now, as retention time should be sufficient to allow for cleanup to occur without impact to water resources. As presented, this loose definition provides design flexibility and is a system performance standard.