Unit 04 Common processes and techniques

Quick recap LO1 – hand and power tools

Remember, you don’t have to rush out and buy everything we’ve shown you in the last session get the essentials first to start with and then build up your tool kit over time. By essentials we’re looking at:

 Tape measure, spirit level and pencil  Hacksaw - frame and junior  cutters – 3 to 30mm and 3 to 22mm adjustable  Trimming knife  pipe cutters  Round file, flat file, rasp and wire wool  Pry/nail bar  Claw and club hammer  16mm and 32mm wood chisels  Cold chisel and bolster  15 and 22mm bending spring (or hand lever bender or both)  Water pump pliers  Adjustable pipe wrench – 250mm  Adjustable spanner – 150mm  Swivel action adjustable wrench  Pliers  Mole grips  Range of drill bits  Screwdriver set or ratchet driver  Pointing trowel  Blow lamp  Tool box  18 or 20v Combination hammer drill  18v circular saw

Remember, buy the best quality you can afford and look after your tools ensuring that they are regularly cleaned and maintained.

Activity 5

We think it would be a great idea if, using the list above as a guide, you made your own list by using the Ridgid and DeWalt websites selecting the tools you like. Whilst you’re doing this, make a note of the prices and see what the total cost is at the end.

Once you’ve done that, it’s time to move on to LO 2, types of domestic and heating

pipework and their jointing principles.

Unit 04 Common processes and techniques

LO 2: Know types of domestic plumbing and heating pipework and their jointing principles

At the end of this session:

You will know types of domestic plumbing and heating pipework and their jointing principles

To achieve this, you will be able to:

 Identify pipework materials and sizes used in dwellings  State methods of jointing new hot and cold water pipe to existing lead

pipework

 Identify fitting types used in dwellings  Describe methods of jointing pipework used in dwellings

 Describe methods of bending pipework used in dwellings

So far then we’ve looked at the range of hand and power tools that plumbers’ use to carry out their various plumbing tasks.

Next we’re going to look at the various pipework materials that plumbers work with, together with the techniques they use for joining and bending them. This is a really big LO section, so make sure you take plenty of breaks.

Let’s get started with AC 1.

AC 1 Identify pipework materials and sizes used in dwellings

What do you think are the pipework materials that are used by plumbers? Jot down your thoughts against the bullet point list.

   

If you put down  Copper  Steel  Plastic  Lead

Unit 04 Common processes and techniques

You’re on the right lines; let’s take a look at this list in more detail.

Copper

There are a number of copper tube products on the market. One of the market leaders is Yorkshire Copper Tube. They have a number of brands that are classified under ‘plain tube’ and ‘covered tube’, more about that later.

For now, copper tube for plumbing comes in three categories, these are:

 R220  R250  R290.

They used to be categorised as table Y, table X and table W, but are now classified under BS EN 1057, temper condition (material strength) and designated with an ‘R’ number; the higher number indicating a stronger material.

BS and EN is an abbreviation for British Standard European Norm, which in short means it’s a standard recognised throughout Europe.

 Soft condition is denoted R220  Half hard R250 and  Hard R290.

Because of the variety of sizes, both diameter and thickness should be specified when ordering to BS EN 1057. This will normally be specified on a larger contract by the design engineer. For smaller jobs, particularly when pipe bending rather than fittings are required, half hard R250 if ideal.

It’s important however that you’re aware of the different categories as it will have a bearing on the types of jobs they’re used for, let’s take a look.

Plain tube

R220 (formerly known as Table W):

R220 tube is used for minibore (small diameter) heating pipework, and is fully annealed. Minibore sizes include 6, 8 and 10mm diameters and tubes are supplied in lengths of up to 50 meters. Typical lengths being 3, 10, 20, 25 and 50m.

Do you know what we mean by the term ‘annealed’? This is a process of heating the copper and then allowing it to cool; the process changes the properties of the copper, in this case making it softer to work with.

Typical uses for minibore includes:

 Central heating R220 minibore supplied in coils  Behind dry wall liners Unit 04 Common processes and techniques

 Under suspended floors  Through false ceilings  Cabling applications  Unobtrusive surface fitting

The pipe lengths can be formed into wide radius bends or offsets without the use of bending equipment. For short radius bends a number of purpose made hand formers are on the market, remember the tribender in the tool section? That would be used for bending microbore tube.

What do you think would be an advantage of using R220 tubes? Because R220 is supplied in long coils it can be used in long lengths without the need for joints, so it’s great for use under suspended floors and behind dry wall linings where there’s no chance of a leak from a fitting.

R220 tubes are also available in diameters of 12, 15 and 22 OD. You’ll see the OD reference used for copper pipe sizes; it simply means that the measurement is taken from the ‘outside diameter’ of the pipe. 12, 15mm and 22mm R220 tubes are supplied in 20m lengths.

Typical uses for 12 15, and 22mm R220 includes:

 Drinking water  Central heating  Sanitation  Gas  Underground services (plastic coated, more about plastic coated later).

R250 half hard lengths

R250 is widely used for domestic installations. It’s classified as half hard, which means it can be easily bent without annealing. It has pipe diameters ranging from 12mm to 54mm, although for domestic purposes, 28mm is likely to be the largest diameter used.

As with R220, its diameter is always specified as its external measurement; the tubes are normally available in 6m lengths (or in some cases 5.8m), although most merchants will also supply in 1, 2 and 3m lengths. R250 tube should not be used for underground services.

Typical uses for R250 includes:

 Drinking Water  Central Heating  Sanitation  Hot and cold water  Gas

Unit 04 Common processes and techniques

R290 hard lengths

R290 is known as hard or ‘hard drawn’ tube. It’s available in straight lengths straight but only in diameters from 35mm to 159mm for the plumbing industry.

R290 tube cannot be bent without localised annealing and tends to be used on large scale industrial or commercial heating systems

Chromium plated R250 and R290 tube is also available in diameters, for us in plumbing, of 15, 22 and 28mm and in lengths of 2 or 3 meters.

Where do you think plumbers would find the need to use chromium plated copper tube?

Chrome plating used where pipework is exposed to the eye, and an attractive finish is required. A typical example is where a cold water pipe is mounted on a tiled wall surface on its way to an instantaneous electric shower unit.

Covered tube

This where copper tube is coated in a seamless plastic cover which protects the it against aggressive materials. The cover eliminates time-consuming wrapping operations.

It’s also colour coded to identify the services carried in accordance with UK local authority specifications and BS 1710: 1984, “Specification for identification of pipelines and services”.

Typical colours:

Yellow ochre – gases (except air) Green or blue – water White – hot water systems

Minibore tube is covered in PVC (Polyvinylchloride) whilst other products are covered in LDPE (Low Density Polythene)

That’s about it on copper tube, but we’ve got a couple of great links. Firstly a link to the product section of the Yorkshire Copper Tube site: http://yorkshirecopper.com/our-products/

Please take time to have a look at this area, it shows the products that we’ve been talking about here, and while you’re on the site why not having a general look around.

The other thing you need to do is click the ‘Technical Guide’ link on their website, or click on the link below. You need to download this PDF and save it to a folder.

Don’t try to read through it all now, but have a look at paragraph 1.3 ‘Copper Tube Development’ and the tables showing the various pipe sizes etc. Keep the document handy, it will be a really useful reference later on. http://yorkshirecopper.com/wp-content/uploads/Technical-Guide-full-issue-02_14_Really2.pdf

Unit 04 Common processes and techniques

Steel

If you put down steel earlier, we’ll give you that, but more accurately plumbers’ use low carbon steel and even more specifically medium grade. In the trade, it’s often referred to as mild steel.

Low carbon steel (LCS) pipe is supplied in three grades:

 Light – which is identified by the colour code brown  Medium – colour code blue  Heavy – colour code red

It’s available either in a painted black or red finish (the colour coding is a painted band on the pipe), or with galvanised coating (galvanizing is a process that provides a coat of zinc to LCS pipe and provides resistance to corrosion).

Galvanised pipe was used in domestic plumbing systems in houses built before the 1960s but it’s not used for this purpose any more. You’ll find it used these days in industrial buildings where protection from external corrosion of the pipework is required.

Black painted pipe is used for plumbing and must only be used on wet heating systems, or oil and gas supply pipework. It must not be used on cold and hot water supplies. Why do you think that is?

LCS pipes carrying water will, overtime, begin to oxidise (rust) inside the pipe and this in turn will discolour and affect the quality of the water. This is fine for heating systems but not acceptable for drinking and washing purposes.

Generally speaking, light grade tube isn’t used on plumbing pipework and as we’ve said, you’re most likely to work on medium grade pipes, and occasionally possibly heavy grade.

Medium and heavy grades are available in 6m lengths, ranging from 6mm to 150mm diameter, specified as nominal bore. Nominal bore means that it’s not the actual bore of the pipe as this will vary depending on the thickness of the pipe wall, which in turn will be determined by the grade.

In domestic plumbing you’ll most likely work on LCS medium grade pipe of ½”, ¾” and 1” diameter. You’ll have noticed that LCS pipe is specified in imperial and not metric sizes like copper tube.

Plastic

Plastic for use in plumbing systems has numerous applications; we’ll look at the technical specifications for plastic pipe as a material in the unit called ‘Common Scientific Principles’ later in more detail. For now we want to give you an idea of the terminology and typical uses of plastic in plumbing.

One thing to note here is there are a number of manufacturers of plastic pipe for use in domestic plumbing systems, together with loads of different products and product brand names.

So, what follows next is an overview of the main type of materials that are used by plumbers installing domestic systems.

Unit 04 Common processes and techniques

Here we’re going to spilt plastic under two headings:

 Plastic pipework for use with hot, cold and heating systems, this includes: . (MDPE) .

 Plastic pipework for use with sanitary systems, this includes: . PVC-u . . MuPVC . ABS

Plastic pipework for use with hot, cold and heating systems

Polyethylene (MDPE)

MDPE is short for medium density polyethylene and is for use on below ground cold water service pipework. It’s coloured blue and is available in diameters of 20 or 25mm for domestic plumbing although it is available in diameters of up to 63mm for larger systems.

It’s supplied in 50m coils. It’s manufactured to BS EN 12056-2:2000 and is a hardwearing plastic, resistant to fractures and has good performance in freezing conditions.

It’s susceptible to Ultraviolet (UV) light and direct sunlight and it’s recommended that a maximum of 150mm of pipe is left showing where it enters a building.

MDPE barrier pipe is also available and is designed for the safe transportation of drinking water through ‘brownfield sites’ and other types of contaminated land.

A brownfield site is where a building or development used to exist, a typical example being old steel works that has been demolished to make way for new housing schemes. Brownfield sites, depending on what’s been built on them previously, can in some instances hold contaminants within the existing ground.

MDPE barrier pipe combines all the advantages of traditional MDPE pipe but with a barrier layer to prevent permeation of potential contaminants.

Black polythene pipes up to 63mm are also available for above ground supply of wholesome water, but are most likely to be found in non-domestic premises.

MDPE pipe is not suitable for solvent welded joining techniques.

Did you know that polythene and polyethylene are one and the same material, the latter being the preferred term of the British Standards Institution?

Unit 04 Common processes and techniques

Polybutylene (PB-1)

Polybutylene can be used for most plumbing and heating pipework installations in domestic dwellings, such as hot and cold water, and central heating systems including underfloor heating applications. Polybutylene is not suitable for solvent welded jointing techniques.

It’s grey or white in colour and available in coils from 10 to 100m in length and diameters of 10, 12, 15, 22 and 28mm. Some polybutylene pipe is also available in straight lengths, usually 3 or 6m.

Polybutylene is very flexible, so it can be cabled quickly and easily through joists during the installation process. It also has:  High temperature and pressure resistance  Low noise transmission  Low thermal expansion  Low thermal transmission

Polybutylene barrier pipe is also available and has a ‘barrier layer’ which reduces oxygen This is what we mean by cabling pipework. You can see ingress into the system through the pipe wall. where it has been passed through the joists. There’s Barrier pipe is available in white or grey, but also a good example of two linear manifolds in PB-1 for white is only available in barrier version. the heating system

Manufacturers of barrier pipe recommend its use specifically for central heating systems, why do you think this is?

Many plastic plumbing systems are manufactured from polybutylene which, as we’ve mentioned, allows the permeation of oxygen through the pipe wall as its microporous. Oxygen in the system will create conditions where oxidisation or corrosion takes place.

When PB-1 was first introduced in the late 1980s, many heating systems failed due to black oxide sludge created by excess air in the system. PB-1 barrier pipe prevents permeation of oxygen.

Barrier pipe should ideally be used in vented and sealed heating systems, reducing the risk of system corrosion to metallic components in the system such as radiators and central heating pumps.

PEX pipe

PEX pipe with an oxygen diffusion layer of EVOH (ethylene vinyl alcohol) is used for low temperature heating systems. Complying with e.g. EN 15875 ‘ systems for hot and cold water installations – Cross-linked polyethylene’ it meets the requirement for oxygen diffusion resistance.

 Malfunction temperature 100°C  Design pressure 6 bar at 70°C.

Unit 04 Common processes and techniques

Plastic pipework for use with sanitary systems

PVC-u

PVC-u is an abbreviation for ‘Unplasticised ’ and the material is most widely used on plastic pipework installations for soil and sanitary waste pipes, overflow pipes, below ground drainage, and gutters and rainwater pipes. It’s not suitable for hot water installations.

It has good resistance to UV light but can suffer from photodegradation (which means the Example of PVC-u 110mm soil pipe in grey chemical composition of the plastic deteriorates for use with push-fit fittings over time in light) especially in light colours such as white and grey. PVC-u has a high coefficient of linear expansion which we’ll talk more about in the science unit.

It’s also used for cold water mains in buildings, but usually for industrial/commercial systems.

It is rigid, versatile, and has excellent chemical resistance which, when combined with smoothness of bore, eliminates build-up of scale and gives good flow characteristics.

Pipes are available in a variety of colours including black, white and grey (above ground) and in brown for below ground drainage.

Sizes for soil systems are available in 75mm, 110mm or 160mm diameter and usually in 6 metre lengths and for waste systems are 32, 40 or 50mm diameter and usually in 3 meter lengths. PVC-U pipes can be used with either push-fit or solvent weld joints.

We’ll talk more about jointing later in this unit.

Polypropylene (PP)

Polypropylene (PP) pipes are widely used in plumbing waste systems and for overflow pipework. It’s supplied in 3 metre lengths, typical sizes are 32, 40 and 50mm diameters (21.5mm for overflow pipes). Its light in weight yet has high impact strength and it also offers good abrasion resistance; it feels slightly greasy to touch. It’s resistant to most acids and alkalis.

PP is affected by direct sunlight, and it melts at relatively low temperatures (160oC) and softens at 100oC, so its use on domestic waste systems is acceptable.

It’s used for waste and overflow pipework systems, and cannot be solvent welded; the sizes and pipe lengths are the same as PVC-U.

MuPVC

MuPVC (Modified unplasticised polyvinyl chloride) pipe is used for above ground waste systems and overflow pipes and is jointed using solvent weld or push-fit techniques. It’s available in 32, 40 and Unit 04 Common processes and techniques

50mm diameters (21.5mm for overflow pipes) and usually sold in 3 m lengths. It’s more durable than PVCu and performs better than other plastic, particularly at higher temperatures.

ABS

ABS (acrylonitrile butadiene styrene) is also used for above ground waste systems. It’s lightweight, easy to cut, easy to joint and install and is available in 32mm, 40mm and 50mm sizes, with a choice of white, black and grey colour options.

ABS can be solvent welded; it’s also used for potable water supplies but mostly for commercial installations. ABS severely degrades when exposed to direct sunlight, but has extremely good impact and mechanical strength which makes it ideal for domestic plumbing pipework installations.

Wavin http://www.wavin.co.uk/

Polypipe http://www.polypipe.com/housing www.totallyplumbing.com

Lead The name ‘plumber’ originates from the Latin plumberium ‘worker of lead’. Lead has been used throughout the ages due to its resistance to corrosion and in early properties lead pipe was used to supply hot and cold water for washing and drinking.

The use of lead pipes for internal plumbing was stopped in 1970, so it’s illegal in the UK to use lead solder or lead pipes in systems used for drinking water. However, there are some older systems that do contain lead. Lead is still used in plumbing, but only for sheet roof weatherings such as chimney flashings etc.

The water flowing through systems with lead pipework pick up lead particles which can then be ingested. Lead dust when inhaled has the same effect, both can cause serious poisoning.

What you should do? Firstly, if you find lead pipework in someone’s property you need to advise the owner of the dangers associated with lead and that it’s their responsibility to replace the lead pipework. You should also advise the people living in the house (if it’s not the owner).

Lead pipe that runs from the mains to the external stop tap is the responsibility of the water company and they should replace lead pipes at the request of the home owner.

If there is a high lead content in the water it’s recommended by the Drinking Water Inspectorate that users’ should:

 Refrain from drinking water that has been left standing in the pipes for more than a few hours. Draw off a washing-up bowl full of water to clear out the water (if your lead pipework is longer than 40 metres you will have to draw off more water)  Replace any lead pipework between the stop between the outside of your home to your kitchen tap; Unit 04 Common processes and techniques

 Ask your water company to replace its service pipe (if made of lead) between the water main in the street and the stop valve  Always drink from taps in the kitchen - don't drink from bathroom taps  If you do remove lead pipe make sure it was not used as an earth for electricity in your home.

Consumer information regarding lead, can be obtained from the Drinking Water Inspectorate's site at www.dwi.gov.uk

Secondly, as a plumber, you also need to be aware of the dangers of working with lead as you may be required to strip lead pipe out when replacing it with plastic or copper, jointing to an existing lead pipe, or you could work with it on sheet weathering jobs as mentioned, including lead welding.

To protect yourself from lead poisoning when working with lead you should:

 Have information and training on working safely with lead  Know what to do in an emergency  Know how to make full use of all control measures, systems of work and equipment provided by your employer  Keep your immediate work area as clean and tidy as possible  Clear up and dispose of any lead waste at the end of each day or shift  Don't take home any protective clothing or protective footwear for washing or cleaning  Wear protective clothing and respiratory equipment when you need it and return it to the proper place when your work has ended  Report any damaged or defective ventilation plant or protective equipment (e.g. if lead welding)  Only eat, drink and smoke in places free from lead contamination  Wash your hands and face and scrub your nails before eating/drinking/smoking  Wash and/or shower and change your clothes before you go home  Keep your medical appointments with the doctor where you work.

There’s a leaflet available from the HSE called ‘Lead and you’, you can download it from this link. Please take time to look through it. http://www.hse.gov.uk/pubns/indg305.pdf

Ok, that takes care of identifying pipework materials and sizes used in dwellings, next we’ll take a look at methods of jointing new hot and cold water pipe to existing lead pipework.

End of extract

If you’d like to discuss this material in more detail, please e-mail Steve on: [email protected]