As the fit out work progresses all off the pipework gets hidden and forgotten. However it is critically important that the pipe work is properly installed and not subject to any kind of failure. Any leaks could be catastrophic to the continued operation of the business. In my travels I've come across a UK manufacturer who produces a handy range of plastic pipes for building infrastructure work. They are called Durapipe. In many cases the plastic performs better than the usual metal pipework. The plastic pipes are also cheaper and quicker to install. It is worth looking at their website to discover their range of products.
One word of warning. Remember to think carefully how you'd deal with any plastic pipes which traverse the fire resistant walls of a data centre or techology rooms.