Discussion between mom and girl for steel pipe

One day, the girl asked her mom why there is difference in surface for the steel pipe of transmitting water and gas in kitchen. The mom told her girl that they are two kinds of steel pipe, one is seamless steel pipe and another is ERW steel pipe. So here is the discussion:

Girl: Why seamless steel pipe for gas and ERW steel pipe for water?

Mom: You would know that generally speaking, gas and oil would category into the high pressure product and water low pressure. So this means that gas leakage would be danger than water. So we should select high quality steel pipes for transportation. Due to the special production process of seamless steel pipe, so it was been chosen for oil and gas transportation.

Girl: And the price?

Mom: Security would be the first consideration all the time. And more information, we can have a discussion with the supplier one day.