see below... This is my main gas line coming into my home(after the meter of course)
My question:
Can I replace the street elbow here with a T and use the extra output as the source my natural gas grill? Is it ok to tap into the main line? Should I look for any special fittings for this purpose? Anything else to look out for?
Yes you can (and fortunately for you, there is a union right there to make your work easier.)
Replacing the this joint is easy enough, but remember you are working with gas. Professionals are recommended and required in some places, as are permits.
I would use a T directly on the main pipe into the wall, a short nipple to the lower main from the ground, and whatever reducer you need for the grill line with a shutoff valve. Depending on your grill and local pressure, you many also need a regulator for the grill itself.
If you do all this yourself, remember to use the gas rated tape or dope for joints, and use soapy water, gas line tester, or use a static pressure test (Check the meter, then shut off as much as possible inside the house and turn on the main between the meter & your work. After 15-30 minutes, the meter should not have changed. If it does you have a leak.)
If your state has licensing laws a plumber can not work on this, you will need someone with a heating license. Most states with these laws have a system by which you can look up a persons license number and verify they are licensed and may even be able to find out if they have made any violations or scams.
I would suggest changing as many of those fittings with new as possible while you have it open. Some people will tell you that you can't use a street fitting or a bushing, in a few areas and canadia this is true, but for 99% of the us it's fine. If you're worried about the male threads cut in the cast fitting it's very easy to pipe it differently and I don't see you needing them here anyway.
There are a couple important things though: 1-Pressure! Make sure the line is at the proper pressure for your grill, you will need a regulator, you might be able to use the one that came with your grill.
2-Gas type, if the grill is meant for propane and you give it natural gas which has a lower energy density it might not heat enough.
3-Drip leg, before the appliance, 99% of code requires a drip leg, a tee with a 3" or so nipple and cap pointing down, basically a dead end, it catches dirt, rust, whatever. Some guys argue they are dumb, I have seen exactly one drip leg with stuff in it, but it was a good amount, not worth the risk of clogging any thing in my opinion, just put one on.
4-In line with the drip leg issue, I wouldn't use ptfe tape, there are approved tapes but if a small piece tore of from the joint it's very light and could flutter down the pipe. Just use an approved pipe dope.
