Thats what I'm trying to find out. I guess I could not run them both at the same time if that were the only issue. But is it generally ok to just tap off of that? I recall that possibly being an issue a few years back when my propane company did not like that my garage furnace was just tapped off of a copper line.

My understanding black iron is used for gas lines, not copper.

I think you should hire the job out with someone who has the equipment to cut and thread black iron.

Apparently copper is ok for propane. My house had all copper piping (the soft stuff sold in rolls) run from the propane tank to the water heater, stove and dryer. It had a tee inside made of a compression fitting after it came into the house. So I see no reason you can't do it. Obviously, soap test after install.

Thanks

Although I have run natural gas lines myself, I strongly recommend hiring a qualified plumber to do the job. Copper pipe may be allowed in your area, but my experience has been with black pipe for main runs and CSST flexible pipe for short runs within buildings. There is also a flexible pipe approved for exterior applications, but I don't know the name or specification. Many brands of gas pipe fittings are not readily available to consumers because the manufacturer requires certification before you can buy them.

The inspector will require pressure testing before your permit is approved. Leak testing and finding leaks is a very tedious process if all the joints were not done properly.

Bruce

If you join copper pipe to iron pipe you run the risk of galvanic corrosion over time due to using two dissimilar metals. This is more of a problem with water pipes where people don't use dielectric unions, but I could see this happening over time for iron-copper gas pipes. I don't know if dielectric unions are specifically made with gas-resistant seals for your application.

In addition, if the gas has any odorant added to it as a leak warning, these smelly compounds are sulfur-containing, which can also corrode the copper pipe from the inside.

I'd get some professional help on this one if I were you.