Laboratory water supply system includes experimental water supply system, domestic water supply system and fire water supply system. The experimental water supply system is divided into general experimental water and experimental pure water. The laboratory pure water system belongs to an independent water supply system, which will be described separately in the chapter of "Laboratory Pure Water System". Domestic water supply system and fire water supply system are consistent with the water supply system of general buildings, and can usually be combined into one system with the general experimental water supply system.
 
 
 
Different laboratories have different requirements for experimental water, and the circulating cooling water quality of experimental instruments should meet the different requirements of various instruments for water quality; Where the experiment of strong acid, strong alkali and highly toxic liquid is carried out and there is the possibility of splash explosion, emergency spraying facilities should be set up nearby. When the water head of emergency eye irrigator is greater than 1m, decompression measures should be taken; Sterile rooms and radioisotope laboratories are equipped with hot water shower devices, The faucet adopts foot switch, elbow switch or photoelectric switch. If the radioisotope laboratory adopts a unified water supply system for scientific research, living and fire fighting, the water in the polluted area must pass through the cut-off water tank, the indoor fire hydrant should be set in the clean area, and the pipeline entrance of the water supply system should usually be set in the clean area, and the upward and downward water supply pipe network should be adopted to avoid diffusion pollution.
 
 
 
Indoor fire-fighting water supply system includes common fire-fighting system, automatic sprinkler fire-fighting water supply system and water curtain fire-fighting water supply system, etc. When necessary, buildings such as laboratory buildings and warehouses should set up outdoor fire water supply systems, which are composed of outdoor fire water supply pipes, outdoor fire hydrants and fire pumps.
 
 
Second, the laboratory water supply method
 
 
 
The laboratory water supply system shall ensure the necessary pressure, water quality and quantity, For large-scale high-rise laboratory buildings, when the outdoor pipe network cannot meet the water demand of the upper laboratory, or when the water pressure of the outdoor pipe network is periodically insufficient, especially in order to ensure the safe water supply of the laboratory, the layout pressurization equipment or roof water tank and water pump should be set for the upper laboratory. For chemical laboratories, due to the installation of emergency shower, emergency eye washer, etc., the water flow should be large enough, and the response should be quick when opening the water discharge valve. Commonly used water supply methods are as follows:
 
 
 
1. Direct water supply. Under the condition that the number of outer layers of the laboratory is not high and the water pressure and water quantity can be met, direct water supply can be generally adopted. In this way, there is no pressurized water pump indoors, which is usually connected to the outdoor water supply network.
 
 
 
2. Water supply mode with high-level water tank. This method can be adopted when the water pressure in the outdoor pipe network drops during the peak period of water use, so that it can not meet the water demand of the upper floor of the building, or when the water pressure in the outdoor pipe network is periodically insufficient.
 
 
 
3. Water supply mode with pressurized water pump. When the water pressure of outdoor pipe network is lower than the water pressure required by experiment, living and fire fighting, and the water consumption is uneven, this method can be adopted.
 
 
 
Third, the laboratory drainage system
 
 
 
According to the composition, nature, flow rate and discharge law of the waste water discharged from the laboratory, the corresponding drainage system is set up in the laboratory drainage system. Cooling water and drainage of laboratory equipment or other wastewater containing only harmless suspended solids or gelatinous substances and not seriously polluted can be discharged directly to the outdoor drainage pipe network without treatment. Wastewater containing various components, toxic and harmful substances, which can interact with each other, damage pipelines or cause accidents should be separated from domestic sewage, and pretreated to make it meet the national standards before being discharged into outdoor drainage pipe network or diverted. For pure solvent waste liquid or valuable reagent, it should be recycled after technical and economic comparison. If the discharged wastewater needs to be reused, it should be treated accordingly. For the drainage system of radioisotope laboratory, long-life and short-life nuclide wastewater should be diverted, and the flow direction of wastewater should be from clean area to polluted area. The layout and laying of radionuclide drainage pipeline, the selection of pipes and accessories should conform to the provisions of Radiation Protection Regulations.
 
 
IV. Precautions for Design of Laboratory Water Supply and Drainage System
 
 
 
1. The water supply and drainage system of the laboratory should be designed scientifically to ensure that the drinking water source is not polluted. If the water source of experimental water and drinking water is different, the faucets of drinking water and experimental water should be marked separately to avoid confusion.
 
 
 
2. The laboratory building should be equipped with a standby water source. When the water supply of the public tap water system is insufficient or stopped, the standby water source can ensure the normal supply of cooling water for various instruments, eye washer water, distiller water and condenser pipe water for distillation bottles.
 
 
 
3. The water supply and drainage system should be consistent with the laboratory module, reasonably arranged and convenient for maintenance, and the pipelines should be as short as possible to avoid crossing. Water supply pipes and drainage pipes should be arranged along walls, columns, pipe wells, clamping cavities of test bench, lining plates of fume hoods, etc., and should not be arranged beside articles that will decompose rapidly when encountering water, causing combustion, explosion or damage, and above valuable instruments and equipment; Pipes in general laboratories can be laid in the open, and in laboratories with high safety requirements, they should be installed in the dark as far as possible. All pipes laid in the dark should be provided with manholes at the control valves for maintenance.
 
 
 
4. The water supply and drainage system should be designed flexibly, and some facilities should be reserved to ensure the reliability and continuous operation of the laboratory.
 
 
 
Downward and upward water supply transverse trunk pipe should be laid above the bottom walkway or under the basement roof; Upward and downward water supply transverse trunk pipes should be laid in the technical layer of the top pipeline or above the top walkway; Non-freezing areas can be laid on the roof, and valves should be installed on each branch pipe leading into the laboratory from the main water supply pipe.
 
 
 
5. The location of each water point in the laboratory must be scientifically positioned and laid in advance, and the water point should be located against the wall as far as possible, so as to facilitate the setting of water point and meet the needs of future transformation.