Depending upon which code you are under, copper may not be acceptable. If using black pipe, it ought to be coated AND taped to prevent corrosion. It's a poor choice regardless, particularly under a slab where pockets of gas may be trapped an explode. And don't forget your tracer wire. You may also want to check the legality of running this pipe yourself - in many areas, unless you are specifically licensed for this type of work, you may not do it yourself. At the very least, have the work inspected - a leaking gas line under a slab is a serious matter. There is a reason the estimate was high.

I've been talking to the natural gas company to find out if my existing gas meter is large enough to deal with everything I have planned for it and the response was that it needs to be upgraded. However, they want to charge me $1325 to upgrade the meter. Major OUCH! I asked what the BTUs are for the existing meter so I could gauge how much of what I have it supports and the response I got was 300,000 CFH. I did some Googling of converting CFH to BTUs and didn't understand the responses. Anyone know how to convert the 300,000 CFH figure the gas company gave me to see how many BTUs it will cover (from my list of BTUs above)? If I have to shell out $1325 to the gas company I'd guess switching the electric water heater to tankless is a "no go" based on way too expensive with tacking on the meter upgrade, just would make more sense to keep an electric water heater, I don't like it but it's hard to justify massive amounts of $$ to go tankless. But if my meter is close enough (the reality is only two people live in the house, all of the above things would not be running simultaneous) then perhaps it is a go and I skip the gas meter upgrade.0 Thanks!

We had one added when we had our pool built a couple of years ago. Ours has flagstone walls and coping with lava rock in the center that covers a gas ring. Our biggest problem is that the moisture in the lava rock can cause the lava rock to explode after the heat has been running for some time (like an hour) at a about a medium setting on the gas valve. We are looking to get a screen to cover the rock as hearing the pop and exploding bits of lava rock hit the house gutters kind of hoses the relaxation around the fire pit.

(Even though this is a year late) I do not know what brand you have, but the clearances to combustible materials are going to be about the same for any of them. I do not know of any that would allow that base/enclosure to be framed out of wood. The dotted line represents the entire noncombustible zone. Your base/enclosure is just the smaller highlighted object in the middle. Make the structure out of brick or concrete block when you redo it.