What are the quality control points of HVAC engineering?

What are the key points of quality control in HVAC engineering? Here, Zhong Da Consulting Bidding Teacher will answer your questions for your reference.

Ventilation and air conditioning engineering is an important branch project of large office buildings, shopping malls and hotels, and it is also a construction difficulty of civil building installation engineering. The installation quality of HVAC engineering is related to whether the building can be used normally. In order to ensure the engineering quality, the following links should be strictly controlled.

1, actively participate in the blue prints.the design, and find the design drawings in advance.

(1) Check the space size and position of each pipeline well, ventilation well and machine room on the architectural drawing, and check whether the space can meet the orderly arrangement of equipment or pipelines and whether there is a maintenance position. If the room is designed to install ceiling air conditioning, check whether the clear height between the top plate and the decoration top surface is enough for equipment installation; Whether the distance between the air outlet of the roof or external wall and the new air outlet is enough, if the distance between the air outlet and the new air outlet is too close, it will easily lead to air short circuit, which will lead to the quality of fresh air can not be guaranteed; Corridor and other places that need to transport equipment can ensure that the equipment is transported to the computer room.

(2) Selection of air conditioning system. In the hotel lobby, conference room, multi-function hall and other places that need quiet environment, it is best to use all-air system. If the air water adding system is selected, the following problems are easy to occur: First, the ceiling of this kind of room is generally complex in shape, with high ceiling elevation requirements, tight installation space, insufficient slope height of air conditioning drainage pipes, and difficult to discharge condensate; Second, the noise of the unit is easy to make the scene environment noisy.

(3) The fresh air shaft and the exhaust shaft are best replaced by air ducts. This has two advantages: first, the air duct has good sealing performance and smooth surface, which can reduce air resistance and ensure fresh air quality; Second, many civil engineering installation units are different, which can avoid mutual prevarication when blocking the intersection of air duct and shaft, resulting in air leakage in shaft.

(4) The choice of terminal equipment, such as fan coil units, air conditioning models and performance parameters, can meet the requirements of air conditioning in this area. In addition to the guest room factor, the fan coil should choose high static pressure to achieve better heat and cold exchange effect.

2, completes the material equipment in acceptance.

(1) Check the air ducts, water pipes, insulation materials, valves and air conditioners one by one against the design drawings and technical documents, and conduct sampling inspection on air conditioning performance equipment to check whether their parameters meet the design requirements;

(2) The valve shall be tested for strength and tightness. The electric control box of electric valves and equipment should be reserved with the interface of building automatic control system, and the control box of fire fan should be linked with the fire monitoring center;

(3) The fan coil unit should also check whether the water pipe connection direction is consistent with the drawing.

3. Quality control of installation process

(1) Fabrication and installation of support. Attention should be paid to whether the specifications of derrick and section steel used are qualified, whether the support can bear the maximum load of pipeline or equipment and whether the anti-corrosion treatment is qualified. Equipment and large pipe hangers should be fixed through the floor, and anti-skid brackets should be set for vertical air conditioning pipes.

(2) The air duct shall be installed straight, and shall pass through the deformation joint or be connected with the equipment in a soft way, so as to avoid unnecessary turning and increase the resistance; Water pipes should be installed straight. When turning or climbing, try to take a 45 elbow to reduce air retention, and connect the hose through the deformation of the building. When installing a valve with directional requirements, pay attention to whether it is consistent with the direction of water flow and whether there is a gap around it. The installation position of fan coil valve and filter should be set in the sump as far as possible to facilitate drainage during maintenance. The condensate drain pipe should be an independent system and should not be used with other drains.

(3) Equipment installation. Before equipment installation, the ground of the computer room should be ready, the wall surface should be painted and the equipment foundation should be accepted. The direction of the equipment should correspond to the direction of the pipeline as far as possible, and whether there is maintenance space around the equipment should also be considered. The installation of the fan coil unit should be coordinated with the height of the decorative ceiling and the position of the air return opening, and the orientation of the water collecting tray should be consistent with the drainage direction.

(4) Thermal insulation construction. Thermal insulation engineering is also an important part of HVAC construction. Poor heat preservation technology directly leads to the leakage of condensed water droplets generated during system operation, which not only wastes energy, but also affects the normal use of the system. The difficulty of HVAC insulation lies in the construction of water system, which should be carried out in strict accordance with the regulations. Insulation construction should be completed before the pipeline pressure test is qualified and the ceiling keel is installed. The main quality problems that are easy to occur in construction are insufficient coverage of valve insulation layer, weak bonding between insulation material and skid, improper skid, and excessive pore between skid and pipeline.

(5) tuyere installation. The HVAC construction drawing should be reviewed together with the decoration construction drawing, especially for the large space ceilings such as conference rooms, multi-function halls and lobbies, which have complex shapes, and the layout of tuyeres, lamps and fire sprinklers should be coordinated with the decoration modeling. Therefore, the tuyere of this kind of room should not be opened when the air duct is installed, and it should be opened after the tuyere is positioned after the installation and decoration drawings are checked together. In actual construction, in order to ensure the perfection of decorative modeling, some projects require the tuyere to be positioned or changed in small section according to the decoration drawings, which leads to problems that affect the use function of the system, such as too many elbows of the air duct, increased resistance, insufficient air supply, and loud noise of the air return port. Therefore, we must adhere to the premise of ensuring the air conditioning function before agreeing to adjust the tuyere. In addition, tuyeres and manholes are generally opened by decoration construction units. In order to avoid omission or wrong opening size or position, the HVAC installation unit should be required to mark the size and position of the air outlet on the decoration drawing and provide it to the decoration unit.

(6) Check the plugging of reserved holes. After HVAC pipeline construction, there are many reserved holes in the wall or floor, which are generally not blocked by the installation unit. If the seal is not good, it will cause air leakage, resulting in insufficient fresh air volume, or exhaust gas can not be emptied and ventilated. Therefore, the relevant units should be urged to seal in time to avoid omissions.

(7) to do a good job of finished product protection. Most of the pipes and equipment of HVAC specialty are concealed by suspended ceiling. Because there are other specialties under construction in the follow-up process of this specialty, such as ceiling construction, which is generally undertaken by the decoration unit, the pipelines completed by HVAC specialty may be damaged during the construction process. Therefore, after the decoration construction is completed, the concealed works in the ceiling should be re-examined and the damaged parts should be repaired in time.

4. Causes of problems in system debugging

(1) The air volume is insufficient. The reason is that the regulating valve is not opened, the air duct is not installed as shown, the fan is reversed or the filter screen is blocked, or the equipment selection is too small.

(2) The air outlet temperature is not up to standard. The valve of the water system is not opened, the filter is blocked, the air supplied to return pipe is not completely discharged, and the water supply temperature of the main engine does not meet the requirements.

(3) The room temperature adjustment does not meet the requirements. One is that the air volume or outlet temperature is not enough, and the other is that the equipment capacity is too small.

(4) Too much noise. The noise of the equipment itself exceeds the standard, the shock absorption measures of the ceiling air conditioning bracket are improper, the muffler is not installed at the outlet of the fan, and the cross section of the air return port is too small.

(5) water leakage. Pipeline insulation does not meet the requirements, the slope of condensate drain pipe is not enough, the fan sump is too inclined, the valve seal is not tight, and the exhaust valve leaks.

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