After the selection of the air purification system is completed, the installation of the purification system is followed. In the process of construction and installation, compared with the hidden works of civil engineering, there are not many hidden works involved in the installation of the purification air-conditioning system. But there are still some contents that need to be understood in the process of on-site construction communication and coordination.
On-site construction and installation of HVAC System
According to the space division of construction, the on-site installation and construction of HVAC system can be divided into three areas, namely the air-conditioning room, the technical interlayer and the clean area. The following describes the relevant concerns from these three aspects:
1.Construction and installation of air-conditioning room
The construction and installation of the air-conditioning room mainly includes the installation of air-conditioning units, fresh air outlets, public medium pipes, main air supply pipes and main return air pipes. For the overall installation of the computer room, which need to meet the principles of simplicity, neatness and convenience (refer to the management requirements of 5S construction)
（1）The installation platform of the air-conditioning unit. Generally, an installation platform can be set up for the installation of the air-conditioning unit to facilitate the distribution and shock absorption of the overall load. This platform can be a steel structure or a cement platform alone in the machine room;（2）The insulation of the chilled water pipeline should ensure the insulation effect to avoid condensation and water leakage in summer;
（3）The steam condensate pipeline is preferably made of stainless steel to avoid later corrosion and water leakage;
（4）It is best not to use the same drainage pipeline for steam condensate and surface condenser condensate, and manage them separately;
（5）It is recommended to use stainless steel for the water storage tray to avoid rust in the later stage
（6）The selected range of the micro-pressure difference meter of the primary filter/medium efficiency filter/high efficiency filter should be consistent with the control requirements;
（7）The insulation of the steam pipeline shall be made of rock wool, etc., and the relevant valves shall also be insulated;
（8）Soft connections such as air ducts should be well sealed to avoid leakage;
（9）The relevant lines above the air-conditioning unit should be horizontal and level to ensure that the lines are installed in good condition;
（10）The identification of each air-conditioning unit should be clear, including the direction and normal status of each automatic control valve;
（11）After the unit is installed, it is necessary to pay attention to the sealing condition of the whhole unit.
2. Installation of technical interlayer
The technical interlayer is mainly for the installation of air ducts. The main installation materials are roughly divided into galvanized air ducts, thermal insulation rubber and plastic cotton, air valves, threaded steel bars, angle steel and bolts.
（1）After the galvanized steel panel has passed the acceptance, it needs to be cleaned, mainly to ensure the cleanliness after installation;（2）After the galvanized air duct is installed, the air duct sealing test should be carried out. Generally, the test of the light pipe in the pipeline can be used, and the overall sealing condition can be checked by checking the light leakage point;
（3）After the relevant sealing test is completed, the installation of rubber and plastic cotton insulation is carried out. The rubber and plastic cotton used should be checked for the fire resistance rating;
（4）The installation of the air duct support should be able to meet the stability. For some main pipes and elbows, it should be able to meet the needs of the master (the air duct should not be stepped on during the management process) to ensure that it is firm;
（5）Due to the installation of the static pressure box, the installation height and direction of the return air duct and the exhaust duct should avoid the interference of inspection lights and air supply ducts; (The direction will be comprehensively considered during the preliminary design of the drawings, and may not be considered too much during the later construction changes, so it is necessary to pay special attention to the construction)
（6）The direction and identification of the air duct should be marked, especially the control area of the relevant air valve, which is particularly critical for the subsequent room air volume adjustment;
（7）The hoisting of the static pressure box and the installation of the soft connection should be stable and well sealed to ensure stable operation;
（8）The installation methods of the hanging bars are divided into welding and bolt connection. The structure of the secondary steel beam should be combined to determine the appropriate connection method.
Installation of clean area
The installation of the clean area is mainly the installation of the air supply port and the return/exhaust port. The installation is mainly to ensure the regularity and stability of the installation.
(1) Combined with the equipment layout in the clean area, the installation of the air outlet should avoid the blockage of the equipment;(2) Considering the replacement or cleaning of the filter screen, the louvers/diffusers of the return air outlet should be easy to disassemble.
The premise of the on-site installation of the purification AHU is the acceptance of the relevant materials and the construction acceptance of the process. Through the arrangement of the relevant construction materials and the formation of files, the corresponding material certificates or records are provided for the subsequent confirmation work to ensure the smooth passage of the confirmation of the installation of HVAC system.