ABSTRACT: The hospital is an important place to provide public medical services and rehabilitation services and rebuild the healthy body of patients. In the air purification areas such as operation Department and ICU, all the patients with serious or even dangerous life-safety diseases are admitted to the hospital. Medical and nursing personnel need to use them in the process of treating such patients. To many life support equipment and rescue equipment, it is of great significance to ensure the security and stability of power supply in these areas.
Key words: purification engineering; lighting system; power system; grounding.
Hospital purification engineering generally refers to the internal decoration, clean heating and ventilation, electrical, intelligent, medical gas, water supply and drainage of operating department, ICU, PICU, NICU, blood ward, maternity room and other departments. The above areas are not only for air. Cleanliness requirements are strict, while the rationality, stability and safety of power supply are also greatly required. Reasonable power supply is conducive to the realization of wireless or micro-wired medical places, avoiding obstruction of access and delay of rescue time caused by too long equipment lines, and stable power supply is conducive to avoiding medical interruption caused by power failure. Accidents and safe power supply are conducive to ensuring the safety of life and property of medical staff and patients. Following will be from the lighting system configuration, power system configuration, construction technology three links one by one analysis of the hospital purification project electrical construction related points.
1 Lighting System Configuration

The lighting system of the hospital purification project is different from that of the conventional public buildings. Because the air in the purification area needs to be purified, the number of dust particles and the solubility of bacteria should be controlled within the prescribed range. This requires that the lighting system should have certain pertinence. The main points are as follows: (1) All lighting fixtures should be suitable. Closed LED lamps should be installed with embedded ceiling; (2) Emergency lighting should not be wall-mounted, emergency lamp panels with built-in batteries should be installed with embedded ceiling, and emergency lighting should be adopted in control circuit; (3) General lighting circuit should adopt three-wire system and emergency lighting circuit should adopt four-wire system. Grounding measures should be taken well; (4) Operating room lighting Belt should adopt anti-glare sealed special clean lamp disc, embedded installation to avoid dust accumulation; (5) Operating room writing table should be equipped with embedded lighting; (6) Anesthesia recovery room, ICU, PICU, NICU treatment area beds should be equipped with equipment belt. Bedside lamps should be installed with embedded equipment; (7) Explosion-proof lamps should be used for lighting in interlayer of high-temperature sterilizer equipment; (8) lighting in corridor (e.g. corridor of clean area, corridor of dirt, etc.) should be controlled by lamp partition, and control switches should be centralized; (9) the lowest illumination in operating room should be above 350 LUX, the most in auxiliary room and corridor. Low illumination should be above 150 LUX; (10) Emergency lighting in the operating room should be arranged in a way not less than 50% of the total illumination.

Power system configuration
The power system of hospital purification project includes the distribution of medical equipment (such as anesthesia machine, ventilator, suspension tower, operation shadowless lamp, operating bed, rescue equipment etc.), purification air conditioning equipment, electric door, etc. These equipment are used frequently in the whole medical work. The main points of configuration are as follows: (1) the power of hospital purification project. The system should adopt the TN-S system loop; at the same time, it should adopt double power supply, in which the municipal power supply should not be less than two lines, and diesel generator should be used as standby power supply; (2) emergency power supply should also be installed in the operating room, ICU and other areas with life-supporting electrical equipment, such as UPS, EPS, and so on. Online switching must be realized. (3) Distribution boxes for lighting, sockets, air conditioning and equipment should be set up separately. In order to ensure the stability of power supply, each operating room should be equipped with a special distribution box not less than 8KVA. Electricity in the operating room should be separated from that in the auxiliary room; (4) Distribution boxes should be located in non-clean areas, and should not be installed in corridors, clean auxiliary rooms and auxiliary rooms in clean areas. Operating room, ICU treatment area and other areas; (5) To avoid the occurrence of micro-electric shock, cardiac surgery operating room must be equipped with an isolation transformer, installed in the special distribution box of the operating room, the operating room should be equipped with leakage alarm panel; (6) The total harmonic distortion rate of the input voltage of operating room, ICU and so on should not be greater than 2.6%. The total harmonic distortion rate of current should not be more than 15%; (7) A set of medical IT system should be set up in each operating room and every three ICU beds (including ICU, PICU and NICU), and an insulation monitoring and alarming device should also be set up; (8) 4 electrical socket boxes for treatment equipment should be set up in each operating room (one with three-phase socket). (9) All metal enclosure equipment, shadow-less lamp, suspension tower, operating bed and metal wall in operating room should be equipotentially grounded, among which the suspension tower should be grounded by 16 square halogen-free low smoke flame retardant single core cable, and others should be grounded by other methods. 6 square halogen-free low smoke flame retardant single core cable grounding.
3. Construction Technology
Technical leaders and builders should fully perform the design submission work with designers and the technical submission work with builders before construction to ensure that the forthcoming construction technology meets the design and use requirements, patrol inspection work should be done in the construction process, and re-inspection work should be done in the rework process; the main points of construction technology are as follows: (1) The distribution boxes must be installed horizontally and vertically, and the distribution equipment of the distribution boxes must be arranged neatly. (2) Installation lines such as lighting and power should be laid with concealed pipes. Pipes should be laid within walls and ceiling, and threading work should be done well before wall surface layer and ceiling construction. (3) All wires and cables shall be halogen-free, low smoke and flame-retardant, and metal pipes shall be used in the pipes. (4) The installed nozzle must be polished to ensure no burrs or debris. (5) The direction of the pipeline should be laid near to reduce bending. Thick-walled pipes or additional casing should be used when crossing the floor, and rust-proof paint should be brushed inside and outside. (6) When laying pipelines, boxes must be installed in excess of the following lengths to facilitate construction and maintenance: no bending more than 30 m; one bending more than 20 m; and three bends more than 8 M. (7) Before laying the cable, the length of the cable should be calculated accurately according to the design and site conditions to ensure that the design and construction requirements are met; (8) reliable safety measures should be taken for laying the cable in the live area. (9) All wires shall not be exposed, and metal hoses shall be used at the connection between the bridge and the metal pipe; (10) All switches shall be opened in the same direction and be able to cut off the fire wire; (11) Installation of the socket box in the operating room shall be embedded to ensure no dust accumulation; (12) Signboards shall be set for the wires and cables. Indicate the line number, if not, the cable type and the starting and ending place. The sign should be clear and not fall off.
4 Concluding remarks
Historically, some painful medical accidents caused by power supply problems warn us that the construction of electrical engineering in hospitals should not be sloppy at all. We must permeate the links of lighting, power and grounding in an all-round way to ensure the safety and stability of power supply, so as to ensure the safety of life and property of the broad masses of the people. (Source: China Papers Network
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Reference:
[1] GB50333-2013, Building Technical Specification of Hospital Clean Surgery Department [S]. Beijing: China Construction Industry Press, 2013.
Author's brief introduction: Lin Guangyuan (1985.8-), male, Fujian Guode Medical Science and Technology Co., Ltd., undergraduate, engineer, enterprise technical director, research direction: hospital purification engineering.