Best Material for a Natural Gas Line

You should be fine with A53 or A106 pipe, unless you have some really foul gas.

Are you designing to a code? ASME, NFPA 54, .........?

I don't understand what you are asking regarding the routing of your pipe, and even then, can not answer without knowing more details (soil conditions, loadings, etc ...). If it is not too inconvenient, it may be best to keep the pipe above ground as the external corrosion protection may be easier, also monitoring/repairing would be easier, and then you don't have those pesky hidden lines underground when you have to dig.

....... oh yeah, and what is your MDMT?

usually a carbon steel is enough for a natural gas.. if there is no water (condensing)inside the pipe..

S

corrosion prevention

Plastics are now used throughout the distribution network in the UK. They need to be buried.

Any news of Spiky?

You should be fine with A53 or A106 pipe, unless you have some really foul gas

AS XMECH said. We use this in Pakistan . The Gas Company too is using this. But now also laying underground mains with flexible Dadex T-flex pipes manufactured from polyethylene (PE) compound because they have excellent abrasion resistence, superb impact resistance, and extra ordinary toughness. These pipes are resistant to a broad range of corrosive chemicals, they do not support biological growth, and resist the adherence of scale deposits.They have an agreement with the manufacturer for exclusive selling rights (monopoly) and the manufacturer Dadex cannot sell to anybody except them only. hence we use Ms pipes of above grades after the Gas meter room.