Tag Archives: pipes

How to Replace Soil Plumbing Pipes

Soil pipes are replaced in the same way as plastic waste pipes but are much bigger – about 100mm (4in) in diameter- so they take longer to fit. They also have some different fittings, such as a soil branch for use where the outlet pipe joins the stack, and access fittings with bolted removable plates for inspection. There are also special connectors to link to the WC pan, via a special gasket, and to link to the underground drainage system which is traditionally made of vitrified clay.

The accurate moulding of the fittings and the ease of assembly means that you can confidently tackle complete replacement of a soil system.

soil plumbing pipes How to Replace Soil Plumbing Pipes

1. Soil pipes are joined in the same way as their narrower waste counterparts, but as they’re bigger take special care with cutting and chamfering.

2. You have got a lot more area to cover with the solvent cement so you must work speedily – but don’t neglect accurate application.

3. The soil branch pipe has a swept entry into the main stack fitting. This is one of the most important joints in the system, so make sure you get it right.

4. When you finally push the pipe into the fitting socket make quite sure that it goes right home against the pipe stop inside the fitting.

How to Improve Domestic Plumbing System by Joining New Pipework into Old

Improvements or additions to a domestic plumbing system inevitably involve joining new pipework into old. How you do this depends largely upon whether the existing pipework is made of lead, iron or more modern materials -copper, polythene or even unplasticised PVC.

The principle of joining into existing pipework is quite straightforward. You decide where you will need your new water supply – at a bedroom basin or an outside tap, for example – and then pick a convenient point on the plumbing system to connect up your ‘branch line At this point you have to cut out a small section of the old pipe and insert a tee junction into which the branch pipe will be fitted. That’s all there is to it: laying the branch pipe will simply involve routine cutting bending and joining of new pipe, and final connection to the new tap or appliance at the other end.

domestic plumbing How to Improve Domestic Plumbing System by Joining New Pipework into Old

Before you can begin the job, however, you have to do some reconnaissance work to identify what sort of existing pipework you have. You might be tempted to relate the plumbing to the age of the house, thinking that an old house will have an old system with lead or iron pipework But this isn’t a reliable guide Many old properties have been modernised and so may actually have a more up-to-date system than a house built relatively recently.

Until the 1950s the only types of pipe used in domestic plumbing were lead and iron, but then these were superseded by thin-walled copper piping. Today there are other alternatives too: stainless steel is sometimes used as an alternative to copper, and polythene and UPVC (unplasticised polyvinyl chloride) pipes can be installed for cold water supplies only.

Check the table for the type of pipe you can use. While copper is the most common one for new work, it must never be joined to galvanised iron because of the severe risk of electrolytic corrosion of the iron if the galvanising is not in perfect condition

First things first

Before cutting into a pipe run you’ll first have to turn off the water supply to the pipe and then drain it by opening any taps or drain cocks connected to it. But this need not be too inconvenient if you make up the complete branch line before you turn the water off so you are without water only while you make the final branch connection.

Connecting into lead pipe

Inserting a tee junction into lead pipe involves joining the run of the tee into two ‘wiped’ soldered joints Join short lengths of new copper pipe into opposite ends of a compression tee. Measure the length of this assembly, and cut out 25mm (1 in) less of lead pipe. Join the assembly in with wiped soldered joints – a job that takes a lot of practice, and one you may prefer to leave to a professional plumber until you have acquired the skill. You then connect the branch pipe to the third leg of the tee

Connecting into iron

Existing iron pipework will be at least 25 years old, and likely to be showing signs of corrosion. Extending such a system is not advisable – you would have difficulty connecting into it, and any extension would have to be in stainless steel. The best course is to replace the piping completely with new copper piping.

Connecting into polythene pipe

If you have to fit a branch into a polythene pipe it’s not a difficult job, especially if you use the same material. Polythene pipes are joined by compression fittings similar to those used for copper. Polythene hasn’t yet been metricated in the UK and each nominal pipe size has a larger outside diameter than its copper equivalent. So you’ll have to use either special gunmetal fittings for polythene pipe (still made to imperial sizes) or else an ordinary metric brass fitting a size larger than the pipe – 22mm for 1/2in polythene.

You also need to slip a special metal liner inside the end of the pipe before assembling each joint to prevent the pipe from collapsing as the cap-nuts are tightened. In addition, polythene rings are used instead of metal olives in brass fittings. Apart from these points, however, inserting a tee in a length of polythene pipework follows the same sequence as inserting one into copper.

Connecting into UPVC pipe

As with polythene it’s an easy job to cut in a solvent weld tee – a simple collar fitting over the ends of the pipe and the branch After you’ve cut the pipe run with a hacksaw you have to roughen the outsides of the cut ends and the insides of the tee sockets with abrasive paper and then clean the surfaces with a spirit cleaner and degreaser. Solvent weld cement is smeared on the pipe ends and the insides of the sockets, and the pipe ends are then ‘sprung’ into the sockets.

You have to work quickly as the solvent begins the welding action as soon as the pipes meet. Wipe surplus cement off immediately, and hold the joint securely for 15 seconds. After this you can fit your branch pipe to the outlet of the tee.

How to Identify Old Plumbing Pipes

Here are some examples of pipework that you may find in your home. Most plumbing these days is done with plastic pipes and fittings, but it is still important to be able to recognise the type of plumbing you have in your home before work can begin. It is also worth noting, that although it is not illegal to still have in your home, lead pipes should be replaced with modern plastic pipework. If you find lead pipes in your home, we strongly reccommend that you contact a reputable plumber for advice

1. Lead pipes are grey and give a dull thud when knocked. You can nick the surface with a knife. Look for smooth bends and neat even swellings – these are ‘wiped’ soldered joints. Repairs are now made using copper pipe.

2. Iron pipes have a grey galvanised or black finish and give a clanging sound when knocked. A knife will only scrape along the surface. Look for the large threaded joints which appear as a collar on the pipe or at a bend.

plumbing pipe How to Identify Old Plumbing Pipes

3. Copper pipes are recognised by their familiar copper color. Changes of direction are often made by bends in the pipe itself or by using angled fittings. The joints will be either the compression or capillary type.

4. Stainless steel pipes have a bright silvery surface. They come in the same sizes as copper and can be joined in the same way. Bends are only found in sizes up to 15mm. These pipes are not commonly used in the home.

5 Polythene pipes are usually black and are soft enough to be slightly compressed between the fingers. Joints are made with metal compression fittings which require special gunmetal olives and liners.

6. UPVC pipes are grey and rigid. Connections and changes in direction are made by angled joints which fit like slim collars over the ends of the pipes. These are fixed in place using solvent weld cement.

How to Buy New Plastic Pipe

When buying plastic pipe and components it is wise to stick to one brand only Pipes and fittings from different makers, though of the same size, are not necessarily interchangeable Most suppliers stock the systems of only one manufacturer, although the same manufacturer may make both PP and either PVC or ABS systems.

It is worth asking the supplier if there is an instruction leaflet supplied by the maker. There are slight variations in the methods of using each particular make of pipe and fitting. The manufacturer’s instructions, if available, should be followed to the letter.

Existing waste pipe is likely to be imperial in size – 1 1/2in internal diameter for a sink or bath and 1 1/4in internal diameter for a wash basin.

plastic pipe How to Buy New Plastic Pipe

Metric sized plastic pipes are normally described – like thin-walled copper tubes -by their external diameter, though at least one well-known manufacturer adds to the confusion by using the internal diameter. Both internal and external diameters may vary slightly – usually by less than one millimetre between makes. This is yet another reason for sticking to one make of pipe for any single project.

The outside diameter of a plastic tube that is the equivalent of a 11/4in imperial sized metal tube is likely to be 36mm and the inside diameter 32mm. The outside diameter of the equivalent of a 11/2in pipe is likely to be 43mm and the inside diameter 39mm. If in doubt, it is usually sufficient to ask the supplier for waste pipe fittings for a basin waste or – as the case may be – a bath or sink waste. Plain-ended plastic pipe is usually supplied in 3m (10ft) lengths, though a supplier will probably cut you off a shorter piece.

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