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The pleasure of swirling flowing water is the essence of the modern bathroom. Every time you step into the shower or turn on a tap, there should be a pulse of enjoyment. Without adequate pressure and water flow this is impossible.
In continental Europe and America water supplies in the house are connected to the mains water supply (unvented systems) often giving a very high water pressure (in excess of 2 bar). Due to historical reasons, British water systems are generally connected to a water tank in the loft. These are referred to as low pressure vented gravity systems relying on the height of the cold water storage tank in the loft to provide the pressure and water flow to the house. Given the restriction of the height of the tank, such houses suffer from low pressure (often less than half a bar.) Britain is the only Western country that
routinely uses gravity systems. Consequently all research and
development by tap and shower manufacturers concentrates on high
water pressure systems leaving the British consumer "high
and dry". This area outlines the generic product information for the three areas that make up the shower sector. This sector will give an overview of the differences between each product. To help either the consumer or the installer to gain a basic understanding what each product type needs for a successful installation and the differences between the three areas. Mixer Showers
Technical requirements for mixer showers High Pressure Mixer Showers - site requirements Minimum running water
pressure: 1.6 bar
Pressure reducing valves suitable for individual site conditions
should be fitted on installations which exceed the above specifications. Installation Installation should be carried out by competent tradesmen in accordance with the detailed fitting instructions (supplied with every unit) and Water Regulations and Bye-Laws. A copy of the fitting instructions should be available on request from all of the relevant manufacturer's Customer Service Departments if it would help when planning your installation. The high pressure valve is suitable for fully modulating type combination boilers and multi-point hot water heaters. It is important to note that before installing with a gas instantaneous water heater, ensure the appliance is capable of hot water delivery at a minimum switch on flow rate per minute recommended by the manufacturers. Dependent on the technical details of the unit it may have requirements for a minimum temperature reach over a set flow rate. Water temperature at the inlet to the mixer must remain relatively constant when flow rate adjustments are made. Technical requirements
for a Shower cabin The pump must be permanently connected to the electricity supply
via a double pole isolating switch with a minimum contact gap
of 3mm in both poles. The switch must be readily accessible but
out of reach of a person using a fixed bath or shower, except
for the cord of a pull cord operated switch. The wiring must be
connected to the switch without the use of a plug or socket outlet.
The supply cable selected for installation must conform to the
relevant table in the I.E.E. regulations. To enhance electrical
safety a 30mA RCD (Residual Current Device) should be installed
in all UK electric and pumped shower circuits. This may be part
of the consumer unit or a separate unit. (often supplied already
fitted within the shower cabin, depending on model ordered. The cabin must be permanently connected to the electricity supply via a double pole isolating switch with a minimum contact gap of 3mm in both poles. The switch must be readily accessible but out of reach of a person using a fixed bath or shower, except for the cord of a pull cord operated switch. The wiring must be connected to the switch without the use of a plug or socket outlet. The supply cable selected for installation must conform to the relevant table in the I.E.E. regulations. To enhance electrical safety a 30mA RCD (Residual Current Device) should be installed in all UK electric and pumped shower circuits. This may be part of the consumer unit or a separate unit. (often supplied already fitted within the shower cabin, depending on model ordered. The electrical requirements for the 2068 / 2056 / 7690 and 7692 cabins are : 240Vac 13a mains, to run the 3Kv Steam generator The requirements for the 301/ 302 / 803/ 811/ 815/ 701 / 702 and 703 cabins are : 240Vac 16a mains, to run the 3.6Kv Steam generator There are no electrical requirements for the shower panels ** These electrical appliances must be earthed ** Site Requirements - Water - if a shower pump is to be fitted To ensure correct operation the cabin must be connected to a cistern fed supply of hot and cold water at nominally equal pressures. The cold water cistern must always be above the pump (if fitted) to ensure priming of the unit. The hot water storage cylinder and cold water cistern should each have a minimum storage capacity of 114 litres in order to ensure adequate infill rate. If supplying a number of outlets, it is recommended that the cold water cistern should have a minimum capacity of 230 litres in order to ensure adequate infill rate. Both hot and cold water supplies to the pump must be dedicated and separate from any other outlets or connections.
The shower must be permanently connected to the electricity supply via a double pole isolating switch with a minimum contact gap of 3mm in both poles. The switch must be readily accessible but out of reach of a person using a fixed bath or shower, except for the cord of a pull cord operated switch. The wiring must be connected to the switch without the use of a plug or socket outlet. The supply cable selected for installation must conform to the relevant table in the current I.E.E. regulations. The size of cable required is determined by the kW rating of the shower, the distance between the shower and the consumer unit and the way the cable is to be fitted. The minimum size will be 6mm2 but in some cases 10mm2 or larger will be required. For showers rated above 8kW a minimum cable size of 10mm2 is strongly recommended. To enhance electrical safety a 30mA RCD (Residual Current Device) should be installed in all UK electric and pumped shower circuits. This may be part of the consumer unit or a separate unit. IMPORTANT! If upgrading to a higher Kilowatt shower it is essential to ensure the electrical supply and shower cable is adequate for the increased load. Site Requirements - Water An isolation valve must be fitted in a convenient position in the supply pipe to allow the shower to be serviced. Where installation could result in the sprayhead falling below the top of the bath or shower tray, it will be necessary to fit a Double Check Valve to the inlet to prevent back flow, in accordance with water regulations and By-Laws. Water Inlet Connection 15mm diameter Water Outlet Connection
Threaded 1/2" BSP To reduce the effects
of condensation ---------------------- The steam generated
during a steam session, is normally washed away during the
subsequent shower down, combined with the fact that steam
cabins do not leak large amounts of steam out into the room. Planning a showerWater pressure at the shower head is important. If it is too low, the flow of water from the rose will be weak. For a shower mixer supplied from the household's stored hot and cold supplies, the bottom of the cold-water cistern needs to be at least 900mm - and preferably 1.5m - above the fixed shower head for pressure to be adequate. For an instantaneous shower supplied direct from the mains, the pressure requirement varies according to the model, but in most homes it is unlikely to be too low, unless, perhaps, you live on the top floor of a block of flats, or in an old house converted into flats. Contact your local water company if in doubt.  Water supply and drainageLittle or no pipework is involved in installing a shower bath, but supply and drainage routes must be worked out for a shower in a separate cubicle. The drainage is often more difficult to arrange than the water supply to the shower, and you may need to get approval from your local authority Building Control Officer. Use 15mm diameter supply pipes. To minimise loss of pressure, pipe runs to the shower should be as short and straight as possible. Avoid using elbow joints at corners - instead, bend pipes if possible to minimise resistance to flow. When routeing a pipe, ensure that fixings will not interfere with electric cables or gas pipes. Showers that do mean extra pipework over a bath are instantaneous electric showers and mixer types. For an instantaneous shower you need a cold supply pipe taken direct from the rising main; for a mixer shower, you need hot and cold supply pipes. Pipework for a shower mixerFor a manual mixer, take the cold supply pipe direct from the cold water cistern to avoid risk of scalding when other cold taps are turned on. Take the hot supply from the hot water cylinder distribution pipe - tee in above cylinder height. For a thermostatic mixer, which has a temperature stabiliser, you can tee in to bathroom supply pipes. Shower mixersIf you are installing a manual shower mixer over a bath or in a cubicle, you must take the cold supply direct from the storage cistern. Taking the supply from a branch pipe supplying other taps or cisterns is unsafe because when the other fitting is in use, the cold supply to the shower could be reduced so much that the shower becomes scalding hot. Hot water for the shower mixer can be taken from a branch pipe, because there is no danger if the hot supply to the shower is reduced – though it can give you a nasty chilly spray. If you take the hot supply from the cylinder distribution pipe, make the connection at a point above the height of the cylinder top. With a thermostatic shower mixer, however, both hot and cold water can be taken from the branch pipes, as the water temperature is automatically controlled. Achieving adequate pressure If you do not have sufficient water pressure to supply a shower at the required position, there are two ways to increase it: you can either raise the height of the cistern or have a booster pump installed. Boosting water pressure with a dual pumpThis boosts hot and cold water tap supplies separately. Some types of pump have a hot supply pipe direct from the cylinder casing, some from the vent pipe. A dual booster pump should be fitted by a plumber. Raising the cisternThe cold water cistern can be raised by fitting a strong wooden platform beneath it, constructed from timber struts and blockboard. You will also have to lengthen the rising main to reach the cistern, as well as the distribution pipes from the cistern. Booster pumpsThese incorporate an electric motor and must be wired into the power supply. There are two main types. A single pump is fitted between the shower mixer control and the spray and boosts the mixed supply to the spray. A dual pump is fitted to the supply pipes and boosts the hot and cold supplies separately before they reach the mixer. Depending on the model, a booster pump will provide sufficient pressure with as little as 150mm height difference between the water level in the cistern and the spray head. Most dual pumps need to be at least 300mm below the cold tank, but some will provide sufficient pressure to a shower head sited higher than the cold water storage cistern, which allows a shower to be installed in an attic. Pipework for an instantaneous showerHere, only a cold supply, direct from the rising main, is needed. This is useful where there is no cold water storage cistern, as mains cold water and stored hot water cannot, by law, be mixed in one fitting.
Bath and shower enclosure installation
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A Consumers Guide To Bathroom Taps |
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Low Pressure Taps v High Pressure TapsFirst the good news, if you have a combi-boiler or un-vented hot water system then you don't need to worry about pressure, both high pressure and low pressure taps will work well with your system. However, if you have a traditional gravity fed system, with a cold water storage tank in the loft, and a hot water cylinder then you will need to be more careful. Firstly you need to work out how much water pressure you have: Measure the distance, in metres, from the base of the cold water storage tank, to the outlet of the tap and multiply by 0.1 to give you the pressure in bar:
If you want a bath/shower mixer with a showering handset, then you must measure the distance from the base of the cold water storage tank to the height at which the handset will be used, not the height of the tap, or the handset when it rests in the cradle. You also need to be aware that elongated pipe work runs quickly use up any pressure within a system, so if your taps are a long way from the cold storage tank then you will need to reduce the calculated pressure to take account of this. Once you have a good idea of your water pressure then you need to check that whatever taps you are looking to buy will work at that pressure. As a rule of thumb many "designer" taps come from Europe where the water systems have higher pressure than in the UK and these taps won't work if you have very low pressure. Designer taps made specifically to work on low pressure systems are generally more expensive and the retailer will highlight the fact that the taps are suitable for low pressure systems. If it doesn't say specifically that the taps will work with low pressure then assume the worst and don't buy without asking the retailer to confirm the pressure requirements. |
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Ceramic Disc Taps v Spindle TapsCeramic disc and spindle refer to the way the internal mechanism of the tap operates: Ceramic disc technology is commonly used on more expensive taps, as they perform better and last longer. When the handle is turned, two ceramic discs are parted opening the valve and allowing the water to flow. The traditional spindle design is commonly used on lower quality, cheaper tap designs. The tap has a spindle through the centre, with the valve seat connected via a screw thread. A standard tap washer (either ½" or ¾") is fixed to the end of the valve seat. As the handle is turned the spindle rotates and the screw thread moves the valve seat up and down to regulate the flow of water
There are two key things to remember.
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Standards and Byelaws for TapsBritish Standards The first thing that confuses many people is that British Standards for taps are not quality guarantees. They simply specify certain things that a tap meeting with the standard should do. There is also no requirement that any product is tested by a third party to confirm it actually meets the standard, so a claim that a product meets BS5412 is only as reliable as the company making the claim ! The British Standards represent the minimum that a tap should meet to perform a specific application. The main British Standards applied to taps are:
There is no British Standard at all for Ceramic Disc taps. So the very fact that someone quotes that the tap complies with BS5412 or BS1010 let's you know that it is an inferior design spindle tap! Water Byelaws All products connected to the UK potable (drinking) water supply must be compliant to the UK Water Byelaws. There are independent testing and certification schemes in place to prove conformity, however these are not mandatory in the UK. The cost of external certification is high and many reputable tap manufacturers choose not to pay for certification. Any taps that have KIWA or WRAS approval have been tested for compliance and should be of a good quality, all taps installed in the UK, must by law comply with the Water Byelaws. |
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Flexible Connectors v Rigid Connectors (Tails)Mono Basin & Bidet mixers are connected to the water supply by connectors, sometimes referred to tap tails. These come in two types, flexible and rigid and the customer generally doesn't get a choice within a range of taps. Both types connect directly to standard 15mm copper pipe work. The tap manufacturer generally decides what sort of connectors each range of tap he makes will have. Which type is most suitable for you depends on where the taps are being installed and who is doing the installation.
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What's the tap made of ?Taps can be made from a variety of materials of varying quality and cost. A general rule of thumb is that the heavier the tap the better the quality of materials used ! Plastic Standard Brass ABS/Mazac Many tap components (such as handles) can be made from ABS (plastic) or an alternative material often referred to as Mazac (Pot Metal). These are cheaper than using brass, and whilst the quality is often very good, brass offers a better finish and longevity. DZR Brass The solution to this problem is a dezincification resistant alloy, commonly referred to as DZR brass. This is the Rolls Royce material for taps and the highest quality product will be made from DZR brass without any ABS or Mazac components |
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Different Types of Basin Tap
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Different Types of Bath Tap
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