Plumbing

The art or science of conveying stuff around using pipes. Sometimes metaphorically cf.Internet Plumbing.

The name derives from the Latin plumbum through OFr plomb meaning lead [ref SOED]. Nowadays lead is almost completely absent from pipework, although part of the traditional plumbing craft training is sheet leadwork.

Water

In general 'Plumbing' refers to hot and cold water systems.

Hot Water

Is made from cold water by Domestic Hot Water Systems

cold water

is best for drinking

Gas

Plumbing for Gas is more commonly referred to as 'Gas Fitting' or 'Gas Installation'. It is regulated by law: specifically the Statutory Instrument known as the Gas Safety (Installation and Use) Regulations 1998

Pipework

Lead

• Lead piping is no longer installed. Much lead pipe remains in use. Most dwellings that are pre-1960 will likely still have the original lead pipe from the street to inside, even if all the downsteam plumbing is no longer in lead.
• In hard water areas, scale forms inside the pipe and prevents water contacting the lead directly. Amount of leaching is very low in these circumstances, and not generally regarded as problematic.
• In soft water areas, scale does not form and the water continues to have direct access to the lead pipe walls. Lead leaching levels are significantly higher than with lead pipe in hard water areas.

Copper

• Fishtanks should not be filled with water from newly fitted copper piping, as the water's copper levels are typically too high for fish survival.
• Copper pipes are joined by soldering, using a compression fitting, or pushfit connectors. Some fittings for soldering come ready locaded with solder these are known as Yorkshire or Solder ring fittings.
• Chromium plated copper pipe can connected either by removing the chromium or by using compression fittings which are also sold chrome plated.
• It is sometimes said that when copper comes into damp cement, concrete or mortar the copper will corrode. However it does not seem to be a significant problem in practice.
• Long runs of copper pipe in concrete are liable to break due to differential thermal expansion.
• When cemented or plastered over, denso tape or other flexible wrapping should be used to avoid expansion stresses.

Plastic

• MDPE is coloured blue, comes in outside diameters of 20,25,32mm and larger sizes. It is intended to be buried.
• Other types are intended to be interchangeable with copper pipes in outside diameters but have a smaller inside diameter. Some type are less flexible than others. Some types have a laminated wall containing a layer to reduce gas permeability these are known as barrier pipe, used for heating circuits.
• They are usually supplied in a coil but some of the stiffer types can be bought in straight lengths.
• All plastic pipes require the use of the correct support tubes (some are stainless steel others are plastic) at every end. These keep the pipe round and prevent other troubles.
• ABS and PVC are used for waste and drainage pipes.

Iron/Steel

• These are used for compressed air and still used for gas supply pipes. They may also be found on older installations as part of the plumbing or heating system.
• They are installed by cutting stock tube to length and then threading the ends with a die.
• A selection of fittings are available for joining the threaded ends together.
• The threads conform to an international standard that is a metric adoption of the imperial British Standard Pipe.
• The letter R designates this so R0.75 means a 3/4" BSP thread.
• The threads can be cut onto a slightly tapered pipe end or parallel.
• Cast Iron is used for older waste and drainage pipes.

Stainless Steel

• Comes as a direct substitute for copper pipe but can only be joined with compression fittings.
• Comes in form that is equivalent to mild steel pipe. Used when greater strength or corrosion resistance than steel is required. Used when food grade hygiene standards are needed.