Cold water

Direct boosted cold water

Boosted Cold Water Systems for Industrial & Commercial Buildings

A boosted cold water system provides a constant supply of pressurised water, to high rise residential, commercial and industrial buildings. This image shows a direct system taking water directly from the mains network, this is not favoured by the water undertaker as it can adversely affect the supplies to other consumers at high demand periods.

indirect boosted cold water

Boosted Cold Water Systems for Industrial & Commercial Buildings

A boosted cold water system provides a constant supply of pressurised water, to high rise residential, commercial and industrial buildings. This image shows an indirect system which is favoured by the water undertaker as it takes the water from a large break cistern that stores the water and will not affect other consumers at peak demand.

whole site protection

Type BA backflow prevention device with reduced pressure zone. Used to protect wholesome water when there is a risk of backflow from industrial/chemical processes. This image highlights the entire area being protected hence the term WHOLE SITE.

zoned protection

Type BA backflow prevention device with reduced pressure zone. Used to protect wholesome water when there is a risk of backflow from industrial/chemical processes. This image highlights two different zones, one with industrial processes being undertaken and another supplying wholesome water for everyday use. Hence the term ZONED PROTECTION.

reverse osmosis

Reverse Osmosis is a technology that is used to remove a large majority of contaminants from water by pushing the water under pressure through a semi-permeable membrane. This process can be repeated many times and is capable of removing up to 99%+ of the dissolved salts (ions), particles, colloids, organics, bacteria and pyrogens from the feed water (although an RO system should not be relied upon to remove 100% of bacteria and viruses)

domestic uv sterilisation

UV Sterilisation Systems are often used on private water supplies to neutralise viruses and organisms that may be present in the water. UV sterilisation (or Ultraviolet sterilisation to use the full term) works by dissociating the DNA structure of living cells this preventing their multiplication. The UV disinfection unit comprises of an enclosed chamber with an inner sleeve of high-purity quartz, which contains one or more shortwave ultraviolet lamps.

Water passes through the chamber and is subjected to the UVC, which is transmitted through the quarts sleeve. As the genetic structure of bacteria or viruses in the water is exposed to the UVC it will be destroyed.

shock arrestor

Water hammer arrestors are used to absorb the shock when water flowing in a piping system suddenly stops due to fast closing shutoff valves, dishwashers, and clothes washers. This action protects against annoying and potentially damaging effects of water hammer.

pressure reducing valve

The water supply pressure in the UK can vary from 1bar to 20bar . A pressure reducing valve is a valve which takes a high inlet pressure and reduces it to a lower outlet pressure. The best way to control high pressure is by installing a pressure reducing valve. These take a high pressure at the inlet, then the valve reduces it to a lower pressure at the outlet as desired, under both flow and no-flow conditions.

infra red taps

With electricity supply, the sensor can detect an object, like a hand opposite the basin tap. The solenoid valve opens when an obstruction is perceived. This way, water flows through the pipe and spout. When there is no object in front of the sensor, this device sends the correspondent signal. The water passes through a blending valve to make sure the water delivered at the outlet is of a safe temperature.

infra red urinal control

This urinal control works when it senses movement in the area of the room via the sensor. This sends a signal to the solenoid valve which opens and begins to fill the cistern. The cistern has an automatic flushing siphon installed and when the cistern is full the siphon will empty the cistern to the slab or bowl urinals. This process will stop when there is no movement picked up by the sensor.

mechanical urinal control

Installed on the supply pipe to the cistern, the hydraulic valve uses a mechanism that ensures the cistern is only filled and can only flush when the washroom is used.

The valve is activated by short-term pressure drops created by use of taps and WCs on the same supply. When it is activated, it opens and water passes to the cistern until the pressures on both sides of the valve are equalised.

When the cistern is full, the auto-siphon will flush. The length of time it remains open can be adjusted.

When the washroom is not in use, the valve remains closed, preventing water passing into the cistern.

flow limiting valve

Quarter turn Servicing Valve with a ball capable of accepting an Automatic Flow Limiting Cartridge to limit the flow of hot and cold water according to its flow rate. A side port allows the Cartridge to be fitted inside the ball after the valve has been installed. Cartridges can be removed in service through the side port without draining the system. Knowing the maximum flow rate enables the designer to accurately size pipes, pumps, heaters and the supply system.

Legislation

Water undertaker

A company who has statutory powers and duties to supply water and/or sewerage services to premises within an appointed geographical area under the Water Industry Act 1991. These are the incumbent water companies and inset appointees. The undertaker has complete control of the water supply and/or sewerage system in its appointment area. Licensees must therefore “use” their networks in order to serve or supply customers.

private water supply

Provision of a water supply other than by means of the public distribution network. Private water supply is regulated by local authorities.

Question relating to water undertaker and private supply

understanding cold water system layouts

At the top of this page you will see a number of images detailing the layout features for multi-storey dwellings.

Definitions before we continue-

  • Single occupancy dwelling (a house, flat or apartment for example where one family lives)

  • Multi occupancy dwelling (a block of flats, apartments or public building where more than one family lives/works)

Controls and components for a Single occupancy dwelling

The main supply to the property

In the image below there are three pipes that bring the water to the property. The local main is in the street, which is connected to the communication pipe which is separated by the external stop tap leaving the service pipe to go to the dwelling. In the stand guard pipe where the stop tap is housed there may also be an external water meter.

  1. Local main

  2. Communication pipe

  3. Service pipe

In addition to these three pipes there is a component called the external stop tap. Which isolates the water supply to the property. To protect the pipes there are maximum and minimum depths that these pipes must be and they are as follows,

Maximum depth 1350mm

Minimum depth 750mm


questions relating to single occupancy

inside a single occupancy dwelling

Within a dwelling being fed directly from the water undertakers main there are a number of options available to the plumber, depending on type of dwelling, how many people reside in the dwelling and water pressure to name but a few.

Let us look at the options one by one. Firstly the type of dwelling.

All dwellings should have a wholesome supply of drinking water. In most domestic premises this will be at the kitchen sink. A plumber needs to consider the needs of the customer and the size of the property to begin with, in addition to this the supply to the property will play a significant role in the type of system installed. There are two basic systems of cold water used in domestic dwellings.

  1. the direct system of cold water

  2. the indirect system of cold water


pipe sizes for both systems

Pipe sizing depends on the system design and requirements however, in general

  • a 15mm rising main will be large enough to supply most cold water demands for a 3-4 bedroom house with cold water outlets whether it is direct or indirect.

An overview of the direct supply and the indirect supply can be found in the images above. We will now look at components used a single occupancy dwelling. The list is not exhaustive below but it shows some key components for a cold water supply. Specialist components feature in the website at the top of the page with further components to come after this initial section.

Internal stop tap

Used to isolate the water supply to the property, connects the service pipe to the rising main.

https://www.ukstocksale.com/product/brass-20mm-mdpe-poly-to-15mm-copper-stop-tap/

Drain off valve

Used to drain the water from the system, usually located at the lowest point of the system directly after the stop tap

https://www.screwfix.com/p/drain-cock-15mm/99939

Gate valve

Used on low pressure side of the system to isolate sections of the system and components

https://uk.rs-online.com/web/p/gate-valves/7845721/?cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Plumbing_%26_Pipeline_Whoop-_-Gate+Valves_Whoop-_-7845721&matchtype=&pla-371508550444&gclid=Cj0KCQjw4cOEBhDMARIsAA3XDRhhwhh_uc2bWafWjaDYYKt8fiCe9hr11JpGsSRPsIf_hf-as-q9jSIaAlZJEALw_wcB&gclsrc=aw.ds

Gate valve

Drain off valve

Internal stop tap (MDPE to copper)

Spherical plug valve

used to isolate appliances throughout the system and capable of withstanding high pressure.

Images of components

Click on the arrows to see a range of images to be installed onto a cold water system, the list here is not exhaustive but does cover a wide range. Your tutor will cover how these are installed and for what purpose during your sessions in college.

questions on single occupancy

private water supply - single occupancy

What is a private water supply? A private water supply is one which is not provided by a water company. Approximately 1% of the population in England and Wales has a private water supply to their homes. Most private water supplies are in rural locations and are from wells, boreholes, springs or streams.


boosted cold water

Component parts for a direct or indirect boosted cold water system to a multiple occupancy dwelling. At the top of the page are some images on boosted cold water showing the basic layout of the systems and some components.

The image carousel feature's the following components found on a boosted supply;

  • one piece cistern

  • sectional cistern

  • transducer

  • pressure operated valve

  • solenoid valve

  • keraflo valve

one piece cistern- A large cistern that comes ready made to suit the installation purposes

sectional cistern- Usually 1 square metre sections that can be bolted together to whatever size and shape you require

transducer- In large-scale, multi-storey water systems, electronic sensors known as transducers sense variations in system pressure and send a signal to activate either the boosting pumps or the compressor, which feeds the pressure

vessel to boost the pressure


Pressure operated valve- The pressure-operated FOV utilises the pressure of the cold water main to aid valve closure via a pilot valve controlled by the lever and the float


Solenoid valve- A solenoid valve is an electro-mechanical device, which controls the flow of water into the cistern. A solenoid comprises of an electro-magnet that operates when an electrical current passes through the coil.


Keraflo valve- The Keraflo Aylesbury type delayed action float valve is an alternative way to fill a cistern. This type of valve achieves a fast fill and only opens when the water falls to a pre-set level in the cistern.





check on progress