Domestic gas pipe size change?

Question

Domestic gas pipe size change?

Answer 1

What about it ?

Answer 2

Most combi boilers now have a 22mm gas supply as they need to burn more gas at a quicker rate to heat water quicker to give a better flow rate.

Pipe sizing is worked out by considering the volume of gas  each appliance will burn,the distance the pipes have to be run,the number of bends on the pipe work.

Tables are found in gas regulations hand book to work out pipe sizes required.