gas piping below buildings

transmission or distribution fuel piping? likely distribution...

residential or industrial location - area classification is a consideration.

try international fuel gas code (public and residential applications) or asme b31.8 (likely choice).

make certain the pipe is protected from external corrosion.
-pmover

above 60 psig and in power plant service, some folks use B31.1 power piping for such fuel gas piping.

whoops! ASME b31.8 is for tranmission pipelines. had a brain spasm i guess. sorry for the mix-up.
-pmover

I personally do not like to have fuel gas pipe running close to electrical room or house especially underneath. If you have a leak, you will can fill up the room with explosive gas and your electical equipment is the ignition source for explosion.

Running a 200 psig fuel gas line beneath a building floor slab is very, very bad practice. Any leaks and you have big problems.

I assume the fuel gas line is for a engine or turbine in the power house. Run the gas line in a trench with grating or overhead. Do not use floor plate as it traps the gas.

Be sure to adequately ventilate the room. 6 air changes are a minimum.

homerak, Just one question, "What happens when the foundations and building settles over time, which it will, can the gas and fuel oil lines support the building and equipment?" If the code doesn't take this into account, I would reject it. Good practice would be be to bring the lines up above grade just outside of the foundation line with an emergency block valve, run them into the building, then take them overhead as a header and provide valved line drops at point of use.

Remember, "Common sense and safe practice is the foundation and intent of all codes and standards."

Hope this helps.
saxon