Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
I did my changeover about 4 years ago, you dont need a portfolio but it would be handy to get some experience in with the different kinds of appliances. To be honest i found it easier than the domestic but I was working with a firm doing commercial stuff at the time. I don't do much now as I'm self employed and the demand doesn't seem to be worth re-taking it.
Good Luck.
Reply to the thread, titled "changing over from domestic gas to commercial gas ticket??" which is posted in Industrial Plumbing Advice Forum on Plumbers Forums.
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