Mark the welding depth on the joining end of pipe.

Most persons will use the tape measures. Firstly check the operation manual, according to the fusion standards table to measure the welding depth for socket fusion. 

Somebody will use measuring pad , but most measuring pad in the market is flat , the size from 20mm to 125mm. Now we according to fusion stardards table to design the measuring pad. This depth gauge tool is designed according to the radin of ppr pipe. The size of ppr pipe from 16mm to 160mm. You can use a pencil or marking pen to mark and draw the line by hole in pad. It's more easy and quickly.