Due to the working relationship, I contacted some design units of HVAC engineering design, control "Heating Ventilation and Air Conditioning Design Code" GBJ 19-87 (hereinafter referred to as "Design Code"), "fire protection design of high-rise civil buildings" GB 50045-95 (hereinafter referred to as "high regulation"), "Heating Ventilation and Air Conditioning Drawing Standard" GBJ 114-88 (hereinafter referred to as "drawing standard"), "depth of construction engineering design documents" Depth regulations ") and other related norms, regulations and standards, found that the current HVAC designers in the implementation of the existing norms, regulations, standards, in the system design, equipment selection, pipe network layout there are many problems. Now found problems and causes analysis and solutions are summarized below. First, the implementation of HVAC design specifications, the standard problems 1.1 Indoor and outdoor air parameters do not meet the requirements of the "Design Code" provides that winter indoor air calculation parameters, toilets, toilets should not be less than 12 ℃, the bathroom should not Below 25 ℃. However, some public buildings toilets, toilet (with external windows, external walls), residential building bathroom (winter bathing hot water supply should be treated as a bathroom) without a radiator, it is difficult to reach room temperature not lower than 12 ℃ and 25 ℃ requirements. There are no residential building kitchen radiator, I think it is inappropriate, the indoor kitchen temperature should be no less than 12 ℃ set the required heat sink. "Design Code" provides that outdoor weather parameters in some major cities should be used in accordance with Appendix II of the code. According to the Appendix II, Beijing winter heating outside the calculation of temperature in addition to Yanqing, Miyun outside should be -9 ℃. Some projects are located in the suburbs of Beijing, but access to -12 ℃, obviously not appropriate. 1.2 Heating heat load calculation with missing items and wrong items "Design Code" stipulates that the heating load in winter heating system should include the heat from the doors and windows cracks into the indoor cooling air consumption. However, some projects did not calculate this part of the heat load when calculating the heat load, resulting in a large heating and exhausting load. The "Design Code" clearly defined the rate of correction for the heat consumption of the enclosure structure, with North 0-10 %, East-west-5% and south -15% -30%. However, some projects change the heading correction rate to 20% of the north, 15% of the east and west, and -5% of the south, which is contrary to the standard requirements. 1.3 bathroom radiator inappropriate choice of "Design Code" provides that the relative humidity of the room should be cast iron radiator. However, it is improper for many projects to use steel radiators in their restrooms and no enhanced anti-corrosion measures. I have seen some office toilets using steel closed radiator, but did not use a few years, radiator string was corroded, and the remaining two light pipes are also serious corrosion. Practice has proved that such places the best cast iron radiator or aluminum radiator. 1.4 Radiator staircases, branch pipe not separately configured "Design Code" provides that staircases or other places with a risk of freezing, the radiator should be a separate stand, branch pipe heating, and shall not be fitted with regulating valve. However, some projects share the same riser with the radiator of the adjacent room heating room, using double-sided connection, one side is connected with the radiator of the staircase, the other side is connected with the radiator of the adjacent room, and the radiator branch pipe Set the valve. In this way, it is difficult to ensure hermeticity in the stairwell. If the heating fails, it may affect the heating effect in the adjacent room or even freeze the heat sink. 1.5 Heating pipeline laying slope does not meet the regulatory requirements "Design Code" provides that the heating pipe laying should have a certain slope, hot water pipe slope should adopt 0.003, not less than 0.002. However, some engineering heating and water supply pipe slope is only 0.001 ~ 0.001 5. Of course, if indeed due to conditions, hot water pipelines even without slope laying, but at this time should ensure that the water flow in the tube shall not be less than 0.25 m / s. 1.6 Problems with Ventilation in Kitchen Operations The Code for Design of Dietetic Building (JGJ 64-89) specifies the ventilation of the kitchen operating room: (1) 65% of the calculated amount of exhaust air is discharged to the outside through the hood, (2) Exhaust hood suction speed generally should not be less than 0.5 m / s, the speed of the exhaust pipe should not be less than 10 m / s; (3) 70% of the air volume, the negative pressure value of the room should not exceed 5 Pa. However, some of the project's kitchens do not have a hood and only have several exhaust fans on the outside wall. Some exhaust hoods are installed, but the hood suction speed is much less than 0.5 m / s. An optional row Fan air flow is insufficient. Most projects did not set a comprehensive ventilation device, also did not consider the makeup device, it is difficult to ensure the indoor environment requirements and negative pressure requirements. 1.7 Expansion tank and hot (cold) water system does not meet the requirements of the specification "Boiler Room Design Code" (GB 50041-92) provides that high expansion tank and hot water system should not be installed on the connecting pipe valve. The connecting pipe mentioned here means an expansion pipe and a circulation pipe. This article is also suitable for air conditioning chilled water system. However, some air-conditioning chilled water system expansion tank high expansion tank connected to the freezer water collector and the installation of the valve, it is not allowed. Once the operation is wrong, it will endanger the system security. 1.8 Ventilation and air conditioning system fire damper settings do not meet the regulatory requirements "High Regulations" provides that the duct should not be through the firewall or deformation joints, such as must be through, should be through the fire wall at the fire damper; through the deformation joints, Fire damper should be set on both sides. However, in some high-rise buildings, the air duct passes through the fire wall without a fire damper, and when some air ducts pass through the deformation slit, there is only a fire damper on one side and not on the other side. In addition, some engineering fire damper position is not set properly. According to the requirements of the fire damper should be set close to the firewall, and connected to the fire damper wall thickness δ ≥ 1.6 mm, 2 m on both sides of the wall of the duct should be non-combustible material insulation. However, some project ventilation and air conditioning duct fire damper set up at random, away from the firewall, the duct between the neither thick, nor did any protection measures, there is a hidden danger. 1.9 Prevent smoke staircase room front air supply air outlet to determine the problem "High Regulations" on the high-rise building anti-smoking staircase anterior chamber pressurized air supply made the provisions, and sub-circumstances given the specific value of the wind. The note in the note states that the speed of the wind passing through the door when opening the door should not be less than 0.7 m / s; the description of the provisions stipulates the number of doors to be opened, and the number of doors below 20 floors is 3. "High regulation" also provides that the anti-smoking staircase anterior chamber pressure supply should be located on each floor. According to these regulations, it can be estimated that the air volume of the air vents in the front room of each floor should be L / 2 (below 20 floors) or L / 3 (above 20 floors, L is the total pressurized air supply of the front room). However, in some projects, the volume of air in the antechamber of the anti-smoking stairwell is marked as L / n (n is the number of buildings), apparently much smaller. For example, in a 12-storey building, the total amount of pressurized air in the antechamber of the smoke-proof stairwell shall be 16 000 m3 / h, but the air volume of the air in each front chamber shall be marked as 16 000 / 12≈1 300 (m3 / h) Apparently its outlet with a small. Correct labeling should be 16 000/2 = 8 000 (m3 / h). The size of the tuyere should be configured accordingly. 1.10 mistakenly divided by the smoke district exhaust air volume calculation mixed with the calculation of the exhaust fan air volume "high regulation" on the exhaust fan air flow made a clear provision: to assume a smoke district smoke, the area should be divided by the smoke m2 is not less than 60 m3 / h. If two or more smoke-free zones are to be covered, the maximum smoke-free zone area should be calculated as not less than 120 m3 / h per m2. Please note that this refers to the selection of exhaust fan exhaust air volume does not mean double the amount of exhaust ventilation area (for each of the smoke exhaust ventilation area is still divided by the smoke area of ​​not less than 60 m3 / h calculation), but when the exhaust fan fan whether horizontal or vertical direction to take two or more smoke prevention zone exhaust, only by two smoke zone at the same time to determine the exhaust fan exhaust fan air volume. However, some project smoke exhaust fan horizontal direction to undertake the area size of 2 to 3 smoke area of ​​smoke, the design mistakenly exhaust fan air volume according to its 2 to 3 total smoke area Calculated per m2 not less than 60 m3 / h, rather than one of the maximum area of ​​smoke-free m2 per m2 is not less than 120 m3 / h calculation, resulting in small exhaust fan air volume, difficult to meet the fire protection requirements. There are exhaust fan (system) perpendicular to the direction of more than two smoke prevention zone (within the walkway) of the smoke, the design mistakenly layers of smoke partition (within the walkway) of the exhaust volume of each area not less than m2 120 m3 / h, not calculated according to their respective area of ​​not less than 60 m3 / h per m2, virtually doubling the exhaust volume of each vertical smoke control zone (inner walkway) Road, tuyere configuration is too large. 1.11 High-rise building exhaust system exhaust port improper selection "High Regulation" provides that (ventilation and air conditioning) duct through the fire partition partition walls should be set fire damper. I believe that the exhaust duct should not be through the firewall, such as must pass through, should be set to wear a firewall at the flue gas temperature exceeds 280 ℃ can automatically shut down the fire damper, and exhaust fan interlock. However, some projects are negligent at design time. For example, a smoke exhaust system in a basement of a project undertakes smoke evacuation of three rooms and an inner walkway (the doors between the rooms and the inner walkways are fireproof doors), and a smoke exhaust fire damper is arranged on the exhaust manifold, Exhaust ports of the room and the walkway are single-layer louvered vents, and the exhaust pipes pass through the firewalls and are not provided with fire damper. This brings the problem is: the fire doors in all rooms useless, once a room fire, will bring disaster to other rooms through the exhaust pipe. The correct approach is: after a single layer of vents exhaust port (exhaust duct through the firewall) additional smoke damper (280 ℃ automatically shut down) or the single layer of vents to a special exhaust vent (normally closed, Automatically open the smoke when the fire, 280 ℃ to re-close). Second, the existing problems in the design 2.1 heating entrance set too much When setting the heating entrance, it is necessary to consider the rationality of the indoor heating system, but also consider the rationality of convergence with outdoor pipelines, not only the interior system design convenience, save trouble , Regardless of outdoor pipe network system. However, some engineering heating entrance set too much. If a 7-storey building, the indoor heating system is divided into 10 loops (1 ~ 2 floors 4, 3 ~ 7 floors 6), the heating entrance set up to 10 as many as the junction with the outside too much, a few All directions, not only to the construction of the outside trouble, but also to the future inconvenience to the adjustment of indoor systems. 2.2 heating system design unreasonable heating system design there is unreasonable: ①some heating system by a main legislation (dry) pipe introduction, divided into several loops, the sub-ring does not set the valve to the system operation regulation, maintenance Management caused inconvenience. ② Some heating pipe layout is not reasonable, and the building profession is not easy to coordinate, or stand on the window directly on the heating, both affect the use, but also unsightly; or laying of heating pipes in the channel of the ground, both affect walking, but also inconvenient Item placement. ③ Some for, back to the high dry drain pipe leak exhaust device, once the gas, it is difficult to rule out, affecting the system. ④ Some heating systems with the same program, a loop length of 300 m, resulting in supply and return pipe slope is difficult to meet the norms of not less than 0.002 requirements. ⑤ some heating systems are connected on both sides, both sides of the heat load and the number of radiators vary greatly, while the two radiator for the return water pipe but take the same diameter, both sides of the hydraulic imbalance, difficult to design flow distribution . 2.3 Exhaust system design is not reasonable, such as a project of the basement of the dark toilet (bathroom) and a number of other residential buildings and equipment room with an exhaust system, horizontal duct length 60 m, section only 200 mm × 200 mm, Large; selection of roof fan exhaust, but fans installed on the wall, it is very uncoordinated. There are a number of private rooms in the basement of the project (all darkrooms). Ceiling exhaust fans are used in all the rooms. Exhaust air is discharged to the outside through horizontal ducts of several tens of m in length. The duct section is only 150 mm × 150 mm, Large resistance, poor exhaust effect. 2.4 The choice of air conditioning system is unreasonable If a project has a command hall, conference room, computer room, the use of such properties, the ideal air conditioning system should be low speed air duct system, but the design has adopted the fan coil system, And no fresh air supply system is clearly unreasonable. Another example is that a project requires the indoor design parameters of some rooms: winter tn = 18-22 ℃, φ = 55% ± 5%, summer tn = 25-26 ℃, φ = 60% ± 5%; the other part of the room tn = 22 ± 2 ℃, φ = 40% ~ 60%, cleanliness level less than 10,000, fresh air 40 ~ 60 m3 / (h * people). The nature of these two types of space, the design used in all fan coil system, and no fresh air supply system. Such a system can not meet the requirements of Party A. 2.5 Toilet fan coil is not added When the new wind toilet not only meet the temperature requirements, but also to eliminate the odor, to ensure hygiene requirements. However, some toilets have neither ventilation nor fresh air supply. Simply using horizontal concealed fan coil for cooling and heating causes the odor to cycle itself, which is not appropriate. 2.6 balance valve settings and caliber selection problems Air conditioning chilled water system should set the balance valve, generally should be located in the return pipe. And some projects fresh air unit chilled water supply, return pipe are set on the same caliber and diameter balance valve. I believe that there is no need to set the balance valve on the water supply pipe, water pipe can only be set. Balance valve diameter should be confirmed by the calculation. Third, the design drawings of the existing problems 3.1 Design Description is not complete "Design Depth Provisions" HVAC design description should be included in the content made a clear provision. Design description should have indoor and outdoor design parameters; heat source, cold source conditions; heat medium, refrigerant parameters; heating load and heat consumption indicators, the total system resistance; radiator models; air conditioning cold and heat load; system form and control methods; Sound, vibration isolation, fire prevention, anti-corrosion, insulation; duct, pipe material selection, installation requirements; system pressure test requirements. However, some of the engineering design instructions are incomplete. 3.2 plan depth is not enough, some should be drawn omission "design depth regulations" on the HVAC plan to express the content of the detailed provisions. However, a considerable number of engineering design is not fully drawn up according to the regulations. The main problems are: heating floor plan, some unmarked horizontal pipe diameters and positioning dimensions; some stand pipes are not numbered; while some are marked with stand pipe numbers, But it will stand upright and slippery; some from the second floor to the top draw a floor plan, and the number of heat sinks is labeled in layers, but no corresponding level is indicated; some only draw the first floor heating level, Draw two to the top floor heating. Ventilation and air conditioning plans, some do not specify a variety of device numbers and positioning dimensions; some did not specify the chilled water pipe diameter and positioning size. There are public buildings design, the kitchen part of the heating, ventilation, air conditioning and other content left to the kitchen equipment manufacturers to do, it is not appropriate. 3.3 System diagram depth is not enough "Design depth requirements" HVAC system drawing has a clear requirement. However, some engineering design is not implemented as required. The main problems are: heating system map, and some standpipe unnumbered, instead of building axis number; some pipe number note the slope, aspect, but did not indicate the beginning or end of the pipe elevation; some pipe Change Office (steering) elevation leakage Note; some did not even draw heating system map or riser. Air conditioning and ventilation design, some projects did not draw air conditioning chilled water system diagram and wind system diagram (if the plan fully explain clearly, you can not draw the system diagram, but for some more complex ventilation and air conditioning design, the plan is difficult to express alone). 3.4 boiler room design is too simplified "design depth requirements" on the boiler room construction drawings made detailed provisions. However, some boiler room designs only draw a plan, without any profile and system diagram. Many of the contents that should be explained have not been confronted yet, far from the design depth requirements. 3.5 Calculation of the book incomplete or even blank "Design Depth Provisions" on the HVAC design calculations should be included in the content of the provisions of the provisions. However, a considerable part of engineering design without HVAC design calculations. Although some heating air conditioning design calculations, but the content is incomplete. Some heating design, only the calculation of heat consumption, without the calculation of hydraulic balance and radiator selection calculation; some high-rise building central air conditioning and smoke control design, only the summer cooling load calculation, without air conditioning and water system hydraulic system Calculation, no refrigeration air conditioning equipment selection calculation, no anti-smoke calculation. Some air-conditioning design, regardless of room size, orientation, level, location (middle or end) are the same indicators to estimate the summer air-conditioning cooling load and winter air-conditioning heat load, and in order to configure the air-conditioning equipment, which is not appropriate of. 3.6 HVAC equipment unnumbered list said the picture is complicated "Drawing Standard" provides that heating, ventilation and air conditioning equipment, parts, parts should be numbered list that its type, performance should be filled in the form complete, clear, in the pattern Only indicate the number. However, some HVAC design is not implemented according to this provision, but the name of the various equipment, components, models and even performance are written on the surface, the text on the surface is complicated, both effort and note write incomplete, Unclear 3.7 Plan, section and system diagram inconsistencies HVAC design, flat, section and system diagram of the corresponding part of the equipment, size and other content should be exactly the same, otherwise it will give construction and installation, the use of management to bring trouble. However, some heating design, the number of radiators, plan and system diagram is inconsistent; supply, back to the main pipe diameter, plan and system diagram is inconsistent; pipe connections, plan and system diagram is inconsistent. Some air-conditioning ventilation design, duct size, plan and system diagram is inconsistent; equipment, parts location size, plan and section are inconsistent; equipment number, quantity, drawings and equipment table is inconsistent; air-conditioning and other air- Plan, system diagram and equipment table notes different, people know what to do. 3.8 Design drawings inconsistent with the calculation of HVAC design, all the equipment, pipes, parts of the choice are determined by calculation, in a sense, the design drawings that reflect the calculation of the book, so the design drawings and calculations should be Exactly the same. But some heating design, the number of radiators, dry pipe diameter and other design drawings and calculations are inconsistent, or even quite different, the calculation of the book does not appear on the drawings, the calculation of small books, drawings on the enlarged, Large, reduced on the drawings. Calculation is completed, when drawing drawings found unreasonable, allowing adjustments, but there should be adjustments to adjust the book or adjustment instructions, the final design drawings and calculations together. Fourth, the causes of the problem and overcome 4.1 on the current design specifications, regulations, standards of learning is not enough, the implementation is not enough, it should strengthen the current design specifications, rules and standards of learning, improve the implementation of the design specifications of the consciousness. 4.2 The lack of multi-program design process Technical and economic comparison, randomness larger. Should be the same as the architectural design, multi-program comparison, to make a reasonable design. 4.3 Blueprint censorship or even mere formality. Should adhere to the third trial (self-trial, review, validation) system, to ensure that the design (including drawings, calculations) quality, put an end to errors.