That’s a CSA and only applicable if code has adopted it, which isn’t universally across the board either. The gas codes will pull what they need, the plumbing code will pull what they need… you’re attributing multiple trades into 1 while specifically only refering to 1 code they are bound by. You didn’t mention anything g else other than “gas code”. Now you’re talking about plumbing and exhaust.

I did talk to them, they said the guy online is full of shit and knows just enough to make a fool of themselves since they make standards for agencies to adopt what they need out of for their codes.

And you realize you are bound by those codes and standards if you’re a gas fitter doing paid work, yeah? A homeowner installing a gas appliance doesn’t need to, the code ends at the gas connection to the appliance.

You made the claims onus is on you, but I’ll do you a favour. The old documents don’t exist, that’s a lie, and even if they did, shits changed. And for posterity, what are they called, I’ll look them up if you won’t. I doubt you I’ll do this though since again they don’t exist.

Theres not some magical list that says what insurance of modifications that insurance will and will not cover, that’s addressed by them having to prove it caused the issue.