Brass plumbing fittings are generally either of compression type or threaded type with the compression type used as an alternative to copper soldered fittings. The range of compression fittings is more limited than copper fittings, with standard couplings, elbows and tees being the most common. Fittings described as chrome fittings are also brass plumbing fittings but with a polished chrome finish applied.
Brass compression plumbing fittings are often a direct replacement and generally more expensive than copper plumbing fittings but offer some distinct advantages. Firstly they are easier to install than copper fittings requiring little skill, as soldering copper fittings can be challenging for the less experienced. This can be a significant advantage for small pipework additions or repair work, but as the fittings are more expensive, an installation requiring a large number of fittings would be more cost effective by investing in a soldering torch and some practice using soldered plumbing fittings.
Another large advantage of compression fitting is that work can be carried out without the need for a naked flame, offering a safer alternative particularly in confined areas. Also if the fitting leaks after pressurisation it is a simple task to simply isolate the water supply and tighten the fitting a little more. It can also be an easier alternative in installations where a little water remains in the pipework. In order to use copper soldered fitting the presence of even a little water in the pipework close to the working area prevents the copper pipe and fitting from heating up properly and can therefore make soldering quite difficult. Additionally if the working area is close to a fitted component such as a valve or pump then not only can the heat damage the component, it can absorb the heat again making it virtually impossible to heat the area enough to melt the solder.
Compression fittings utilise a soft olive to crimp onto the pipe. The inside of the fittings is tapered so that when assembled, the action of tightening the nut “squashes” the olive on the copper pipe and the inside of the fitting walls to produce a water tight seal. The nut should be tightened firmly but not over tightened. One very useful compression fitting is a repair coupling used to repair water pipework. It is basically a compression coupling with a long body so that the damaged section of pipe can be cut out with a pipe cutter and the repair coupling used to bridge the gap.
When connecting copper pipe to a component such as a tap, pump, tank or other threaded fitting then a brass threaded plumbing fitting would be the method used, often called an adapter or threaded adapter. One side of the brass fitting is fitted to the pipe using the compression end as with a standard brass fitting and the other screwed to the component of other threaded fitting. Threaded fittings come in male and female threaded varieties, straight or angled and also the male versions come in tapered thread and parallel thread variety, for different types of installations. The threads can be sealed using a little PTFE tape or other paste sealants for extra security although care should be taken not to over apply the additional sealant as it may prevent the thread from screwing down enough and may even weaken the walls of the compression fitting.
Only gas approved compression fittings should be used on gas pipework and installed by a fully qualified engineer.