Commissioning and supervision of HVAC engineering in clean room

2019-02-16 10:27:02   Editor: jushong shares    0

With the development of society and the continuous improvement of people's living standards, improving work and living environment to improve work efficiency and quality of life has received more and more attention. In recent years, large and medium-sized buildings built and renovated at home and abroad have paid more and more attention to the installation of HVAC facilities, especially the facilities of clean rooms. In general, HVAC investment accounts for about 10% to 20% of the total construction investment, and energy consumption in operation accounts for about 60% of the entire building energy consumption. Such a large entry should naturally receive its corresponding return. In order to achieve the desired goals, we must grasp every aspect of the implementation process of design, construction and operation management. After accepting the entrustment of the owner, the supervision engineer should understand the owner's construction intention as soon as possible, and clarify the purpose and use characteristics of each room in detail. When assisting the owner to prepare the design requirements documents, the temperature, humidity, fresh air volume, wind speed, dust content and noise index of each room should be as specific as possible to avoid large-scale, resulting in a small number of rooms not meeting the requirements. When designing the system, it is necessary to make technical and economic comparisons of 2 to 3 programs to achieve program optimization. This is critical to the investment and operating costs of the entire project, and often the design institute has less economic considerations for operation. The rationality, reliability and economy of equipment selection and matching should be carefully reviewed. Adequate investigations should be conducted prior to equipment selection, and special attention should be paid to visiting users who have already been put into use.

   For the insulation measures of water pipes, we strive to achieve the difference between indoor and outdoor, exposure and concealment, to prevent hidden dangers caused by general, and to be economical, practical and durable. The cooperation with civil engineering, water, electricity, fire protection, self-control and other related majors should be strictly examined to avoid mistakes, leaks, bumps and shortages, and to ensure the operability of drawings. This aspect is often the main factor causing construction conflicts and increasing investment. Review the construction organization design submitted by the construction unit and submit written review opinions in time. This is one of the important basis for supervision work. Moreover, it is possible to further understand the management level and technical level of the construction unit, so as to improve the supervision rules in a targeted manner and strengthen the pre-control. Strive to check the installation and operation instructions of the equipment before the equipment arrives to determine whether the installation space, equipment foundation, water and electricity interface, etc. can meet the requirements. For the installation of the chilled water system, in addition to the work pressure according to the "heating and sanitary engineering construction and acceptance specifications" or "industrial pipeline engineering construction and acceptance specifications", pay attention to the appropriate increase of automatic exhaust to eliminate air in the system. Special attention should be paid to the separation of steam and finished products during the insulation of the pipeline to avoid dripping in the future operation. When passing the condensate system, the water test must be done to ensure smooth flow. In the construction of the duct, pay attention to the installation of the fire damper. When the fire damper cannot be close to the firewall, it is necessary to make a thickened air duct according to the standard drawing requirements, and use 3cm thick cement mortar to cover the organization and coordinate work. After the completion of the main body of the building, there will be water, electricity, fire, air conditioning, communication, monitoring, indoor and outdoor decoration and other types of work, multi-subcontracting units cross-operation, and often the construction drawings of all majors can not clearly express the relationship between all facilities, This requires proper adjustment of the position of the tuyere, lamps, nozzles, probes, etc., on the premise of satisfying their respective functions and not affecting the aesthetics. The adjustment should follow the principle that the water pipes allow the ducts, the small tubes to be large tubes, and the pressure to be pressure-free. Strive to achieve a reasonable layout, neat and beautiful. In addition to regular coordination meetings every week, it is also necessary to strengthen the coordination work on the spot to prevent mutual interference and timely handle the visas for adjusting the workload.

Before the installation project is delivered for use, the owner should be advised to arrange the operation and maintenance management personnel to enter the site to familiarize themselves with the situation and conduct technical training in order to smoothly carry out system commissioning, completion acceptance and operation management.

 At present, most of the owners are contracting themselves with suppliers and contractors. For various reasons, there are often some ambiguities in the contracts signed, which in most cases bring some trouble to the owners and cause certain economic losses. When the supervision unit participates in the contract management, it is recommended that in addition to the general routine provisions, attention should be paid to the quality control of the equipment purchase contract, the pressure of the cold system operation, the temperature, the flow rate and other technical parameters, and the anti-smoke system positive pressure air supply before the chamber static pressure Determination and so on. Before commissioning, the construction unit is urged to check the accuracy of the measuring instrument to determine that its precision level is higher than the measured parameter level. The eligibility criteria for system commissioning shall comply with the specifications and relevant documentation requirements. There are many methods for measuring the air volume of a tuyere. If the tuyere is located outside, there are many types, the shape is different, and the measurement data requirements are not very precise, the tuyere method is adopted. If the tuyere air volume requires higher accuracy measurement data, the auxiliary duct method can be used. For example, the smoke control system has become the focus of air conditioning ventilation system testing in recent years. The area of measurement is generally in the elevator room front room, safety stairs and small rooms. According to the "Construction and Acceptance Specifications for Ventilation and Air Conditioning Engineering", it is advisable to use smoke touch. Proposed method, and should be rectified and debugged first, and the measurement parameters must meet the safety requirements. The data of this stage directly reflects the performance of the system. For the failures caused by the debugging, the reasons should be improved and recorded in time. If the design parameters cannot be reached, the parameters should be adjusted to meet the design requirements. After the commissioning of the production-free load system is completed, the comprehensive performance measurement with the production load is performed. There are many contents in the comprehensive performance measurement with production load. For example, according to the general comfort air conditioning system, it includes the measurement and adjustment of the air state parameters of the return air outlet, the performance parameter adjustment of the air conditioning unit, the measurement of indoor noise, and the measurement of indoor air temperature and humidity. , measurement of air flow rate, etc. For the constant temperature and humidity system, more static pressure test, air conditioning unit functional section debugging, airflow organization measurement and other projects.

Because the engineering changes from design to completion acceptance, it can run under the conditions of production load, and after a period of adjustment, you can get better results. If there is a problem that is contrary to the design, it should be resolved by the construction contractor and the design unit. For problems that arise during debugging, list them and rectify them one by one. Supervisors should control their rectification in a timely manner so that they can achieve satisfactory results in the official operation.

   Engineering commissioning is a work involving construction, installation, production process, decoration, design, equipment supply, etc. It should be the responsibility of the construction unit, and the design, supervision and construction units should cooperate. The commissioning is also a complicated process, but as long as Grasping the key in quality control, controlling the steps, can get twice the result with half the effort, and also obtain conclusive data and reliable basis for the future official operation, laying a good foundation for the completion acceptance, so we should also pay attention to the following points:

(1) In addition to the type and specification of the equipment, the main technical parameters should be indicated.

(2) It is necessary to make clear requirements for the packaging of the equipment. Failure to properly protect the equipment will result in unnecessary losses.

(3) It is required that the supplier shall provide the purchaser with the product installation and operation instructions that have the same effect as the random documents as soon as possible after the contract is signed, in order to facilitate the preparation before installation and the unpacking inspection after the equipment arrives.

(4) Responding to whether the supplier is responsible for the installation, commissioning, after-sales service period and all expenses incurred thereby shall be clearly stated in the contract.

(5) For engineering contracting, the scope of responsibility between water supply and drainage, strong electricity, fire protection, self-control, civil engineering, decoration and other projects should be clearly defined to avoid repeated payment and mutual skinning.