Use this table as a guide to choosing new pipework – the first material mentioned is the best or most usual choice. Existing pipe copper lead iron stainless steel polythene UPVC New pipework copper, stainless steel, polythene iron, stainless steel, polythene stainless steel, copper, polythene polythene, copper, stainless steel copper, stainless steel, polythene
CONNECTING OLD TO NEW
Fitting metric to imperial pipework can be complicated by the slight differences in pipe diameters. The problem connections are: copper to copper (compression fittings)
• some metric fittings can be used directly with imperial-sized pipes (eg, 15mm fittings with 1/2in pipe and 28mm fittings with 1 in pipe)
• with other sizes you need to buy special adaptors or larger olives to replace those inside the fittings, so to connect a 15mm branch into existing 3/4in pipe you’ll need a tee 22 x 22 x 15mm with special olives for the 22mm ends of the tee. copper to copper (capillary fittings)
• metric capillary fittings with integral solder rings are not compatible with imperial pipes, but straight adaptors are available to connect the two sizes of pipe
• use these to join in short lengths of metric pipe, the other ends of which are connected to opposite ends of the metric tee
• with end-feed type fittings, extra solder can be added to make a good joint with imperial-sized pipe. copper to stainless steel – as for copper to copper connections, but usually compression fittings only. stainless steel to copper – copper to stainless steel. as above for stainless steel to stainless steel – copper to copper.