Worth to know
In some systems the drain is for discharge of waste fluids, such as the drain in a sink in which the water is drained when it is no longer needed.
In the United Kingdom, plumbers refer to waste water as 'bad water'. This is under the premise that the water they are moving from one area to another via the use of a drain is not needed and can be removed from the area, like a 'bad apple' being removed from a fruit bowl.
In other systems, such as fountains or swimming pools where waste fluid is recirculated, the drain is the input to the recirculating pumping machine.
In the last case, there is an obvious safety issue, because many people do not expect to encounter more than the head of water above the drain when touching a drain. For example, in a recent case, a lifeguard went to the bottom of a pool to retrieve something and his hand got stuck because of the extra pressure from the pump. When there is a recirculating pump, the risk of suction consists of the head of water, plus the suction of the pump (up to a maximum of 1 atmosphere).
Types of plastic pipes
There are three basic types of plastic pipes:
Solid wall pipeedit
Extruded pipes consisting of one layer of a homogeneous matrix of thermoplastic material which is ready for use in a pipeline
Structured wall pipeedit
Structured-wall pipes and fittings are products which have an optimized design with regard to material usage to achieve the physical, mechanical and performance requirements. Structured Wall Pipes are tailor made solutions of piping systems, for a variety of applications and in most cases developed in cooperation with users
Pipe incorporating a flexible metallic layer as the middle of three bonded layers. Barrier pipe is used, for example, to provide additional protection for the contents passing through the pipe (particularly drinking water) from aggressive chemicals or other pollution when laid in ground contaminated by previous use.
Most plastic pipe systems are made from thermoplastic materials. The production method involves melting the material, shaping and then cooling. Pipes are normally produced by extrusion.1
Plastic pipes - standards
Plastic pipe systems fulfill a variety of service requirements. Product standards for plastics pipe systems are prepared within the CEN/TC155 standards committee. These requirements are described in a set of European Product Standards for each application alongside their specific characteristics, for example:
Conveyance of drinking water: Hygienic requirements
Conveyance of gas: Highest Safety requirements
Plastic pipes for radiant heating and floor heating: Temperature resistance over decades
Sewer applications: High chemical resistance
Plastic pipes are capable of fulfilling the specific requirement for each application. They do so over a long lifetime and with reliability and safety.citation needed The key success factor is achieved by maintaining consistently high quality levels. For plastic pipe products, these levels are defined by the different standards. Two aspects are fundamentally important for the performance of plastic pipes: flexibility and long lifetime.2