Depending which country you live in will depend on depth. Consulte your local municipality for the laws applying to you. In South Africa, depending on the size, Diameter of pipe, less than 75mm, not less than 650mm below the surface of the ground. More than 75mm but less than 110mm, not less than 1500 below the surface of the ground. More than 110mm, not less than 2000mm below the surface of the ground.
Gas piping in California will have to have 18" of ground cover over it. So and 18" trench with a one inch pipe will be an inch too short. 2007 upc where damage is not likely to happen, steel gas piping can be instaled with 12" of ground cover. Warning it will be up to the inspector to decide where damage might be a problem.
Depending where you are at but most gas lines from mains to homes are about 18" to 30" deep. I would call locates to have them find out exactly where and how deep your gas line is and its free even if all you want to do is know.
18 inches
My house was built in 1960 how deep were gas lines buried back then when building a home
24 inches.
24 inches.
Yes it should be
Do you mean the old black alkathene? Yes it can and should be.
When a pipe shrinks
In a lawn irrigation application it should generally be deep enough not to be hit by the lawn-mower, or rototiller if you plan to use one
Yes.
You need to give more info than simply "rigid pipe". What kind of "rigid pipe", what pressure will it have and where you are burying it.
Below the frost line of your area. Your local building code will tell you what the requirements are.
Sir Walter Raleigh was buried with a pipe and tobacco. His coffin was also "lined throughout with the wood of my old Havana cigar-boxes."
Francis Drake
100 feet