1. Characteristics of the HVAC system of this project.
This project is the nanotechnology research and development building of the park, which has extremely high requirements for air temperature, humidity, wind speed and airflow organization, fresh air volume, return air organization form, automatic control, etc., according to this characteristic should be set up ** air conditioning system, ** air conditioning system is characterized by the system should be able to meet the use requirements according to different functional requirements. Therefore, the system form of energy saving, environmental protection, low noise, simple control and convenient maintenance and management should be preferred.
At the same time, the project is a basement parking lot, and the fire-fighting facilities should be perfect, and the positive pressure air supply and smoke exhaust system requirements are higher.
In view of this characteristic, the air-conditioning system of this project should include air duct system, water pipe system, positive pressure air supply system, smoke prevention and exhaust system, refrigeration machine room and boiler room equipment installation, anti-corrosion and thermal insulation engineering, air-conditioning unit, fan and other equipment installation, automatic control system installation, etc.
Second, according to the characteristics,Ventilationand air-conditioning engineering supervision and control countermeasures.
The supervision of ventilation and air-conditioning projects should take the safety of the project as the primary task, and must ensure the safety of structures and system facilities, and all mandatory provisions in the construction acceptance code are related to safety. The second task is to ensure the functional and operational reliability of structures and systems, for which the professional supervision engineer should determine the focus of quality control according to the various stages of the project progress.
1. In the construction preparation stage, the focus of the supervision engineer's work is to review the contractor's qualificationsConscientiously familiar with the drawings, assist the owner to do a good job in the selection and ordering management of materials, equipment and components;Review the construction organization design and construction plan;Supervise and urge contractors to improve the quality assurance system and improve the on-site quality management systemOrganize or participate in design disclosure and drawing review;Do a good job of communication and exchange between supervisors and owners and contractors.
2. In the construction stage, the focus of the supervision engineer's work is to assist the owner to select and determine the appropriate ventilation and air-conditioning engineering contractor and carry out "three control, two management and one coordination" of the project
l Emphasize the construction according to the drawings. If the construction unit finds that the drawings are unreasonable, imperfect or unable to be implemented, etc., they shall be resolved in the review of the drawings organized by the supervising engineer.
l Review the construction organization design or construction plan submitted by the construction unit. The problems existing in the construction organization design or construction plan submitted by the construction unit should be put forward in writing, and the construction unit should be required to revise and then report, and the quality assurance system and safety assurance system of the construction unit should be required to be in place with systems, personnel and measures.
l Strictly control the acceptance of materials and equipment. All types of raw materials, various types of valves, filters, air conditioning units, pumps, tuyeres and large equipment need to be carefully inspected, and on-site visual inspection and necessary measurement tests are carried out, and unqualified products are strictly prohibited from being used in this project.
l Strengthen the inspection and acceptance of each process in the construction process, and pay special attention to the verification of quality control points such as reserved pre-embedding and positioning pay-off, pipeline support and pipeline connection, pipeline pressure test and air duct anti-corrosion and thermal insulation.
3. In the commissioning and operation stage, the focus of the supervision engineer's work is to check whether the function of the professional system meets the design requirements and the owner's requirementsCheck the feasibility and operability of the system as well as maintainability;On the basis of the commissioning of each sub-department of the specialty, special attention should be paid to the linkage commissioning with other specialties to ensure that the functions of the entire building work in harmony and to meet the comprehensive functional requirements and use requirements of the design. During the commissioning and acceptance, the professional supervision engineer should do a good job in the inspection and acceptance of the general project while accepting the main control project, test the main technical parameters of each important part, and record the data in detail.
4. In the process of supervision, it is necessary to pay attention to strict control of engineering changes. In order to control the project cost and prevent the budget target from being breached, it is necessary to strictly control and try to avoid or reduce the number and scope of project changes. For all engineering changes (including design changes and owner changes), the supervisor should analyze the technical feasibility and economic rationality, put forward supervision opinions for the reference of the design or the owner in a timely manner, and do a good job of visa measurement for the identified project changes in a timely manner, so as to reduce the occurrence of rip-off in the later claim process.
5. In the process of professional supervision, we should pay attention to the coordination of the project. This profession has a close relationship with strong and weak electricity, water supply and drainage, civil engineering, decoration and other professions, and professional supervision engineers should do a good job in the coordination and cooperation of professional contractors and other professional contractorsBefore construction, the professional supervision engineer shall require the contractor to draw a comprehensive pipeline section diagram on the basis of the design drawings with other professional contractors, and draw a comprehensive pipeline section diagram for the more concentrated parts of the pipeline and other professional supervision engineers, and supervise the contractor to implement the plan according to the determination, and coordinate and deal with the current problems in the construction process.
6. In the construction, the construction unit is not in accordance with the design, specification and determined program process, after negotiation and ineffective stopping, the supervision shall take necessary measures, including the construction of the supervision and acceptance, not to pay the progress payment of this part of the project, the settlement of the relevant engineering quantity and other corresponding measures, at the same time caused by the detection, rectification and rework and other related losses, are borne by the construction unit, and in the settlement of the project to be cashed.
7. Supervision side station system.
In the supervision of the construction stage, the supervisors supervise the construction quality of key parts and key processes in the whole process of on-site supervision, and the main parts of the side station are: valve test, pipeline pressure test, air duct leakage test, pipeline flushing, system commissioning, etc.
The side station supervision personnel should conscientiously perform their duties, the key parts and key processes that need to be supervised at the construction site, and timely find and deal with the quality problems in the process of side station supervision, and truthfully and accurately do a good job of side station supervision records. Do the following work when the supervisor stands next to him:
Inspect the on-site quality inspection personnel of the construction enterprise, the special types of personnel holding certificates, and the preparation of construction machinery and building materialsSupervise the construction of key parts and key processes, implement the construction plan and the mandatory standards for engineering construction on siteDo a good job of side station supervision records and supervision diary, and save the original data of side station supervision;The side station supervision personnel and the on-site quality inspection personnel of the construction enterprise shall sign the side station supervision record (see annex), otherwise the next process construction shall not be carried out. When the supervision personnel of the side station carry out the supervision of the side station, if it is found that the construction enterprise has violated the mandatory standards for engineering construction, it has the right to order the construction enterprise to immediately rectify and report to the chief engineer in a timely manner, and the chief engineer shall issue a partial suspension of construction instructions or take other emergency measures. The supervision record of the side station is an important basis for the supervising engineer or the supervising engineer to exercise the right to sign in accordance with the law.
3. Difficulties and control countermeasures in the supervision of ventilation and air-conditioning projects.
1. Construction of air conditioning water supply and return system.
Check whether the specifications and models of the approach pipe and the wall thickness of the pipe meet the requirements of the design and construction specifications, and the riser at the vertical wellhead should be provided with load-bearing supports every 2-3 layers. A fixed bracket must be arranged at the part where the expansion joint is installed, and its structural form and fixed position should meet the design requirements, and should be fixed before compensating for pre-stretching or pre-compression.
The installation and test requirements of water supply and return pipelines and valves are the same as those of water supply and drainage professional fire pipelines. At the same time, the supervisor should carefully check that the installation slope of the water supply and return pipeline meets the design and specification requirements, the installation of the water supply and return pipeline support should meet the design and specification requirements, and the setting of the skids should meet the requirements of pipeline insulation, and should meet the design and specification requirements.
2. The installation requirements of the air conditioning pump are the same as those of the water supply and drainage professional fire pump.
3. Production and installation of air ducts and accessories.
The quality of air ducts and accessories directly affects the use effect of air conditioning return air system. When making and installing air ducts and fittings, the supervision engineer controls the requirements as follows:
When galvanized steel is used for air ducts and fittings, the thickness of galvanized steel should be controlled to meet the requirements of design and construction acceptance specifications, and the thickness sampling frequency of galvanized steel should be strengthenedSecondly, the processing equipment used in the production of air duct and fittings should be able to meet the processing requirements of various air ducts and fittings of the project, the quality of the processing equipment directly affects the quality of the air duct and fittings produced, and the supervision should be after the processing equipment enters the site, that is, the construction unit is required to prefabricate a few standard pipe sections and fittings to be used in the project, check whether the production of these pipe sections meets the requirements of the specification, so as to determine whether the processing equipment can meet the production requirements;In addition, the supervisor should strengthen the inspection of the air duct and accessories production site, and timely find the human factors in the production process, resulting in the decline of quality.
When the air duct and accessories are made of inorganic FRP composite air duct, according to the JC-643-1997 standard, in order to ensure the quality of this kind of air duct, 50 tons should be sampled in batches, and the raw materials for the production of air ducts such as fiber cloth, the material and bulk density of the insulation material in the insulation air duct are inspected, and the use of high-alkali fiber cloth is strictly prohibited. The strength of the made air duct should also be inspected to ensure that it meets the design and specification requirements. At the same time, if this kind of air duct is used, when ordering all kinds of dampers, silencing elbows and other equipment connected with this air duct, the flange side of these equipment should be widened to ensure the tightness of the connection.
When the air duct and accessories are made of composite fiberboard air duct, the supervisor should check whether the glass fiber material of the air duct is dry and flat, whether the outer air insulation layer and the three-dimensional material are firmly bonded, and whether the inner surface and section have a protective layer against blowing.
Regardless of the type of pipe used, it is very important to check the strength of the pipe.
4. Light leakage test of air duct.
After the installation of the air duct is completed, the light leakage test must be carried out, and the air duct that has not undergone the light leakage test shall not be insulated and other next processes.
The supervisor should select important parts that are prone to quality problems according to the requirements of the specification for air duct light leakage inspection to ensure that the air leakage volume of the system meets the requirements of the specification. During the light leakage test, the supervisor should implement the side station supervision, and the test process should be recorded in detail. The construction unit should be ordered to rectify the light leakage parts in the inspection process, and the parts with serious light leakage shall not be glued.
5. Installation of ventilation and air-conditioning equipment.
Before the installation of the equipment installed on the ground, the supervisor shall organize the relevant personnel to carry out intermediate handover inspection of the equipment foundation, mainly to check whether the elevation, location, number and size of the reserved holes of the equipment foundation are consistent with the design drawings and equipment foundation drawings and make acceptance records.
Before the installation of hoisting equipment, a power-on experiment should be carried out, and the supervision of the side station should be implemented. Shock-absorbing hooks or spring shock absorbers should be used when hoisting, and the air-conditioning box installed in the ceiling of the general room should also be required to take silencing measures, such as using sound-absorbing materials to close the equipment.
The connection between the equipment and the water pipe should be elastic connection, and the pipe slope should be checked at the same time.
Protective covers (nets) or other safety measures must be installed on the exposed parts of the ventilator rotation device and the inlet directly into the atmosphere. The supervising engineer inspects each unit one by one.
If the axial fan is installed on a non-shock-absorbing bracket, it should be padded with a rubber sheet with a thickness of 4 5mm on request, and fixed after leveling and aligning, and pay attention to the airflow direction of the fan.
6. Installation of aisle integrated pipelines and room tuyeres.
Before the installation of the comprehensive pipeline of each floor, each professional will be held to review the drawings to discharge the most reasonable direction and ensure the ceiling elevation. The installation of air outlets in each room should be closely coordinated with the decoration for construction. The installation of tuyeres requires that the same space be lined and rowed. The connection between the tuyere, the air duct and the equipment should meet the design and specification requirements.
7. Installation of large-scale refrigeration units and water pumps.
Before pouring the foundation of the equipment, the refrigeration machine room should check the design drawings with the construction unit at the site of the machine room. Due to the large refrigeration capacity of the air conditioning in this project, the diameter of the pipeline is larger, and the size of the corresponding pipe fittings connected by the pipeline is also larger, such as soft connection, reducer pipe, elbow, etc., and the water pipe in the design drawing is often a single-line drawing method, which may cause the contradiction between the inlet and outlet water pipes of the equipment and the civil wall beam, and the position of the equipment needs to be fine-tuned to ensure that the piping can be connected smoothly.
After the equipment foundation is poured and the equipment is in place, it is advisable to arrange the pipeline reasonably with the construction unit according to the actual space situation of the site and without changing the design sequence of the pipeline connection, so that all pipelines can be reasonably hoisted in layers to ensure that the installation of the machine room is practical and beautiful. In addition, the hoisting of the pipeline in the computer room should require the construction unit to use a vibration damping spring hanger to reduce the impact of the vibration of the computer room on the surrounding environment.
8. Positive pressure air supply and smoke prevention and exhaust system.
When the air duct of the positive pressure air supply system adopts the civil air duct, the civil construction should be strictly controlled in conjunction with the civil engineering supervision engineer to strictly control the quality of the painting of the civil air duct, and it is necessary to ensure that the wall is plastered with the masonry, and there shall be no gaps, and the civil air duct should be cleaned up in time. During the commissioning of the positive pressure air supply system, it should be carefully inspected, and measures should be taken to deal with the large air leakage in time.
After the smoke exhaust valve (tuyere) enters the site, the supervisor should check whether the fusing temperature of various fuse elements is consistent with the design, and check whether the opening state and action conditions of the damper (tuyere) are consistent with the design one by one. The installation direction of the valve should meet the design requirements and should not be reversed.
9. Pipeline insulation.
Pipeline insulation can only be carried out after the end of the pipeline installation pressure test, and the supervision of pipeline insulation construction should strengthen the inspection, and the supervision inspection focuses on checking the following contents: whether the thickness of the insulation material is uniform, the surface is smooth, and whether the contact with the pipeline is firm or reinforcement measures are taken (such as nailing, etc.);Whether the pipe through the wall, the junction with the equipment and the part that is prone to condensation should be tight and seamless, and the valve should not cover the marked opening and closing direction. The insulation of the refrigeration pipe, whether its ends and ends are closed.
After the air duct light leakage test is qualified, it can be insulated. The air duct insulation requirements and inspection focus are the same as the water pipe insulation, and it is also necessary to check whether the air duct flange and ribbing are also insulated, and whether the insulation meets the requirements of the specification.
10. System debugging.
The system linkage test shall be organized by the construction unit, and the construction unit and the supervisor shall participate, and the equipment manufacturer and the design unit shall be notified to participate as appropriate. The commissioning must be carried out after the installation and acceptance of all equipment in the system and the stand-alone commissioning, as well as the installation of all pipelines in the system and the qualification of the pressure test. Before the commission, the test acceptance outline should be prepared, the test requirements, testing items, as well as the time, steps, and division of labor should be prepared and the test record should be made.
Fourth, the supervision of rationalization suggestions:
Due to the extremely high requirements for air conditioning comfort in this project, CO2 concentration detectors should be set up in the mall to control the air quality of this space, and when the concentration exceeds the set value, the proportion of fresh air supply will be automatically increased to ensure the freshness of the air.
The selection of cold and heat sources is very important for the later operation and management costs, and the host should be carefully studied by experts in what form should be taken before implementation.
Before the installation of the end system of the air conditioning system, it is advisable to cooperate with the fine decoration, that is, after the fine decoration design is out, the air conditioning, water and electricity should be designed twice, only in this way can the decoration effect and the air conditioning effect be perfectly unified, and at the same time reduce the amount of rework, reduce the contradiction of on-site construction, and improve the progress of the project.
Due to the relatively high decoration requirements of this project, it is recommended that the contractor draw a comprehensive pipeline drawing of the plane and section, and proofread it with the decoration drawings.
Variable frequency water pump can be used for the air-conditioning circulating water pump, which can adjust the air-conditioning water circulation volume when the air-conditioning load changes, and change the air supply volume less, which is not only energy-saving, but also can ensure the number of indoor air changes and improve the indoor air quality.
The basement garage air supply system can use an inducer fan to supply air, which can reduce the impact of the air supply pipe on the garage space and improve the utilization rate of the garage space.