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).
Źródło: https://en.wikipedia.org/wiki/Drain_(plumbing)
Standards of plastic pipes
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
Źródło: https://en.wikipedia.org/wiki/Plastic_pipework
Reasons for replacement with a new bath bathroom
After some time the use of the bath can choose to replace it. The reason for such a decision may be pouring the water out of the tub while taking a bath, which may indicate that the bath does not have a good run-off. But the replacement of the bath may be caused by the desire to be placed in the bathroom of a new sanitary facilities, which will look more modern and well-maintained. To be able to replace the bath with a new, employed by us plumber will have to weld the plate, in which the tub is built, and then remove the old tub from the bathroom. Installation of a new bathroom bathtub may be combined with replacement pipes for water from the tub so that it will serve us to reliably for many years.