【 Weak current College 】 HVAC engineering installation quality problems

1 manufacture and installation of air duct
1.1 sheet steel rectangular duct of stiffness is not enough
1.1.1 manifestations on the edge of the large wind pipe with varying degrees of sinking, the two side small edge is slightly outward, visible distortion.
1.1.2 harmful system operation, wind pipe surface fibrillation generate noise, resulting in noise pollution, reduce wind tube life.
Analysis of the causes of 1.1.3
① windpipe of plate thickness does not meet the construction and acceptance;
② bite form select inappropriate;
③ not in accordance with the construction and acceptance of requirements for side length ≥ 630mm or insulation air pipe ≥ 800mm, its length is more than 1200mm, strengthening measures should be taken.
1.2 sheet steel rectangular duct distortions, Alice Kok
1.2.1 manifestations wind pipe surface uneven; diagonal lines are not equal; adjacent surface non-vertical; two relative surface is not parallel and two tubes are not parallel to the plane.
1.2.2 damage duct produces distortions, Alice Kok phenomena, makes the wind pipe and duct connections are not affected by force, not tight flange gasket, increase the amount of air leakage; at the same time air duct system is not up to the construction and acceptance of flat, affect its appearance and reduce the service life.
Analysis of the causes of 1.2.3
① rectangle sheet metal cutting, not on the four corners of the rigorous measurement of angular side;
② air duct of big edge or small edges of two opposing side of the sheet metal is not equal to the length and width;
③ duct of the four corners of the bite does not equal the width;
④ handmade bite force stitching.
1.3 sheet steel rectangular elbow angle not accurate
1.3.1 manifestations elbows surface uneven, tube diagonal lines are not equal, the bite is not strict.
1.3.2 harmful influences and elbow connection of pipes and a draught of coordinates, and increase the amount of air leakage.
1.3.3 analysis
① elbow side walls, elbows bent back and the head of the slice size not accurate;
② two large material not strictly angular side;
③ elbow back and bend head of radian inaccurate;
④ as manual joint angle-Pittsburgh, Pittsburgh area width is not equal.
1.4 circular duct different heart
1.4.1 manifestations duct is not straight, two port surface uneven, pipe diameter smaller.
1.4.2 damage to connect after duct, its horizontal and vertical to the construction and acceptance of, and influence the duct system.
1.4.3 an analysis of the causes of
① production with diameter circular air ducts, cutting angle side right angle is not accurate;
② make reducing is heart circle duct, expand the following material is not accurate;
③ bite width is not equal.
1.5 round elbow angle not accurate
1.5.1 manifestations elbow angle line offset, diameter and shape of contorted, etc.
1.5.2 hazardous elbow and other parts and accessories for the connection, the influencing its coordinates accuracy and lead pipes system contorted, and other ills.
Analysis of the causes of 1.5.3
① expand dash inaccurate;
② Bend bite tightness;
③ elbow mount when sections of the corresponding expanded line of misalignment.
④ elbow adopts single bite, sections of single and double bit width of the mouth are not equal, the angle of the elbow is not accurate, bend bite loose or cracking the funds.
1.6 round tee angle strictly prohibited, bite
1.6.1 forms three point line offset, occlusal force
Air leakage.
1.6.2 dangerous due to the three angles, when other parts, accessories, affecting its coordinates accuracy, and to increase the amount of air leakage.
Analysis of the causes of 1.6.3
① expand stock dash inaccurate;
② Pittsburgh's width;
③ cuttings machining of dimensions is not accurate.
1.7 flange interchangeability difference
1.7.1 manifestations flange surface roughness, round flange rotate any angle and rectangle flange rotate 180. , And the same specifications flange bolt hole cannot coincide; round flange roundness deviation, rectangle flange of diagonal lines are not equal; round flange diameter or rectangle flange inner dimensions exceed the acceptance criterion and the quality inspection and assessment standards of tolerance.
1.7.2 harmfulness ' flange interchangeability blunder affects wind pipe, part at the construction site in the normal Assembly. Flange bias smaller increase installation process is not necessary to modify the work, drilling, etc.; deviations larger will rework and waste of resources.
1.7.3 analysis
① material size is not accurate, the cutting of steel angle is not looking after being straightening, flange bore or inner size exceeds the allowed deviation;
② round flange with manual hot stewed, due to the distortion of the surface of unfairness and roundness deviation of ills;
③ round flange mechanical cold bending, appear as a result of bending machine is not adjusted well in an irregular status;
④ rectangle flange tire tool right angle is not accurate;
⑤ flange welding deformation;
⑥ flange bolt hole by hole pattern into a displacement;
⑦ flange drilling hole punching or displacement of the Center.
1.8 flange riveting eccentric
1.8.1 manifestations of flange and duct is not vertical, air operations center offset; set after duct flange bite cracking.
1.8.2 damage duct system Assembly after its horizontal or vertical alignment error, up to the construction of the acceptance of regulations, affect its appearance.
Analysis of the causes of 1.8.3
① circular duct concentricity deviation;
② round flange of roundness; rectangle flange is not left side;
③ flange diameter or inner dimensions greater than wind pipe outside diameter or outside dimensions of, more than the construction and acceptance, cause the flange and after duct rivetingThe wind pipes offset to one side;
④ flange diameter or inner dimensions smaller than the diameter of air duct or outside dimensions, flange force the duct liner, duct bite crack.
1.9 after duct flange riveting loosely
1.9.1 manifestations of riveting, uneven surface wind pipe, air leak too much.
1.9.2 harmful system operation after due to air leakage and vibration and noise, air cooling, heat loss caused by and affect clean air cleaning system.
Analysis of the causes of 1.9.3
① rivet spacing, resulting in uneven surface wind pipe;
② small rivet diameter, length, and nail hole with no tight so that rivets loose, riveting is not strict;
③ duct on the flange is not enough for flanging quantity;
④ air duct flange square corner cracking or bite overlap.
1.10 duct sealing gasket and duct connection does not meet the requirements
1.10.1 manifestations duct flange connection air leakage and air duct system noise increase.
1.10.2 damage increase wind pipes system cooling, heat loss, or increase the amount of harmful gas leakage and contamination of the environment.
1.10.3 analysis
① ventilation, air conditioning system chosen flange gasket material not in conformity with the construction of the acceptance of the request;
② the thickness of the flange gaskets are not sufficient, thus affecting the degree of elasticity and fastening;
③ flange gasket convex in the duct;
④ flange bolts clamping of the surrounding the extent of the inconsistency.
1.11 unable to connect to LAN air duct is not closely
1.11.1 manifestations of duct with the flange of the gap is too large, system operation after a larger air leakage phenomenon.
1.11.2 harm due to air hose connection not closely, system of air leakage, the increase in energy consumption, running or even lack of air conditioning system, air conditioning in room temperature, humidity, and increase the environmental noise.
1.11.3 analysis
① repression of cuttings flange shape irregular;
② cuttings flange structure forms of improper selection;
Û u-cuttings, duct flange dimensions not accurate;
④ has not taken the smudge sealant and other sealing measures.
1.12 stainless steel duct poor corrosion resistance
1.12.1 manifestations wind pipe surface scratches, clean the hair defects and spatter welding slag, weld surface rendering black, yellow and mottled. Even ventilation duct corrosion.
1.12.2 harm reduction stainless steel ventilation system for corrosion resistance, shorten the service life. At the same time as the wind pipe corrosion, lowers the tightness of the ventilation system, enabling the proliferation of harmful gases to the environment, affecting the health of staff.
1.12.3 analysis
① air duct plate cutting, machining of misconduct;
② during operation, the carbon steel and stainless steel exposed to surface corrosion centres, the oxide layer of film;
③ selection of welding process, should be used for Argon-arc welding, DC arc welding, but may not use oxygen-acetylene welding.
④ welding process is not taken to prevent the welding slag splash directly to the air duct plate on the measures to be applied in the weld surface on both sides; the Cretaceous powder
⑤ the surface not cleaned after soldering, welding slag removal of oil, and spatter and pickling, passivating hot water washing and disposal;
⑥ in weld and the edge of the opening, will make the hole deformation, as well as secondary welding and metallurgical structure changes;
⑦ duct stent used carbon steel bracket is not taken to isolation measures;
⑧ duct flange bolts and nuts are not made of stainless steel fasteners; such as carbon steel fasteners should be brushing acid coating.
1.13 aluminium duct reduces the corrosion resistance
1.13.1 manifestations wind pipe surface scratches, weld slag and within legacy brazing, duct local corrosion.
1.13.2 harmfulness reduction of aluminium ventilation pipe corrosion resistance, shorten the service life.
1.13.3 analysis
① air duct plate marking material is not placed in the shop with rubber plate on the table. Lofting dash cannot use metal cross stitch, otherwise it will damage has antiseptic properties of aluminum oxide films;
② welding without measures, namely the Elimination of welding without welding and welding wire of oxide, etc.;
③ wind pipe welding does not use hot water cleaning weld seams and removal of welding slag welding, brazing;
④ flange and duct is not the same material, produced using electrochemical corrosion, the steel angle manufacture flanges, flange angle is not galvanized surface made of varnished or spraying, etc-electrochemical corrosion of insulation;
⑤ the wind pipe and flange connections used for carbon steel rivets,
Do not use 4 ~ 6ITLrn aluminum rivets;
⑥ anticorrosion insulation bracket has not taken measures;
⑦ flange bolts, nuts and wind pipe material, such as the use of galvanized bolt, nut, both sides of the flange were not mat galvanized washer increased contact surface to prevent scratching the flange is nuts.
1.14 hard PVC plastic rectangular duct distortions, Alice Kok
1.14.1 manifestations of wind tube surface uneven, diagonal lines are not equal, the adjacent surface non-vertical, both pipe ends are not parallel to the plane.
1.14.2 hazardous wind pipes produce distortions, Alice Kok phenomena, so that the wind pipe and duct connections are not affected by force, not tight flange gasket, increase the amount of air leakage; wind pipes system due to flat and stress are not damaged, lower service life.
Analysis of the causes of 1.14.3
① hard PVC plastic plate is made of laminated method into the windpipe is heated again in the process, because the plate there anisotropy and residual stress, cooling after shrinking phenomenon appears. Cutting before doing on each batch of test amount of shrinkage of sheet to determine shrinkage values, crossed the shrinkage of parts of the release, further cutting;
② in sheet marking material, not the two opposing sides of equal length and width;BR > ③ heated folding side not accurate;
④ welding Groove is not correct, do not press the construction and acceptance of the request.
1.15 hard PVC plastic duct to the poor quality of welding
1.15.1 manifestations of weld strength is low, the welding point raised, weld bonding is not close, cracks and other defects.
Harm 1.15.2 air duct Union place of strength decreased; tightness, affect the results.
Analysis of the causes of 1.15.3
① welding temperature is not appropriate. Welding of air temperature should be controlled at 210-250 ℃;
② electrode diameter does not match with the welding nozzle diameter. General welding torch of welding nozzle diameter closest electrode diameter is the highest of weld strength;
③ welds form must adapt to the air duct, part of the structure characteristics, not the construction and acceptance of requirements;
④ welding method is incorrect.
2 air cleaning system fabrication and installation
2.1 clean system air duct splice excessive
2.1.1 manifestations of air duct cleaning system with horizontal concatenation bite joints and large side < 800ITll ' n the bottom edge of the longitudinal seam stitching bite.
2.1.2 hazards increase the system's dust in the wind pipe, increasing the load on the air filters, and shorten the life of the filter and clean results.
Analysis of the causes of 2.1.3
① According to the construction and acceptance of the windpipe to minimize concatenation. Rectangular duct bottom width within the 800ITLITI, there should not be abutted; 800iilln above, minimize longitudinal seam. However, no transverse seam;
② one-sided reduction loss to save materials;
③ duct material did not.
2.2 air filter box does not close
2.2.1 manifestations of air leakage air filter box; filter box with filter frame is not strict.
2.2.2 dangerous due to the filter box not tight, causing the air leakage to the outside environment, not only increases the cooling load, thermal energy consumption and reduce the clean effect because the filter frame and filtration tank seams not tight, so that without the filter of the air flow, reduce clean cleanliness of the room.
2.2.3 analysis
① tank plate connection methods. The form may take bite bite and the corner joint angle bite, try to avoid using the restorative bite outlets;
② tank and filter frame connection is not strict. Box with filter frame bolts fastening, the gap must cushion gasket, prevent the air flow through without filters;
③ framework of verticality and horizontality;
④ tank plate connection slot, housing and frame of treatment gap has closed.
2.3 clean system does not close
2.3.1 presentation of duct cleaning system of Pittsburgh seam, flange connections, duct flange four corners, air flow control valve exposed moving parts, and other Department of air leakage.
2.3.2 harm due to connection parts not tight, causing the system to excessive air leakage rate is not only increase the loss of cold, heat and clean cleanliness of the room.
2.3.3 analysis
① air duct bite form select inappropriate;
② air duct sealing the cracks is not taken;
③ flange of bedding material, thickness and connect the form to select it improperly;
④ the flatness of the flange, the bolt hole and rivet hole spacing does not comply with the requirements;
⑤ air flow control valve hole not strict;
⑥ duct flange flange small amount.
2.4 HEPA filter installation quality does not meet the requirements
2.4.1 manifestations of high efficiency filter ontology damage, and high-performance filter outlet frame or HEPA filter framework connection does not close, check for leaks.
2.4.2 harmfulness of clean room cleanliness does not meet the design requirements.
2.4.3 analysis
① efficient filter not factory logo vertical handling and storage;
② high efficiency filter installation should check the filter frame or edge mouth end of Spondylitis, face roughness tolerances ≯ 1mm per each. If the surface roughness of the variances, you cannot modify the filter's bounding box;
③ HEPA filter installation of air flow direction and the bounding box does not match the arrow mark;
④ corrugated plate combination of filters under vertical installation without vertical ground;
⑤ HEPA filter and seal the bad connection between frames.
2.5 fabricated Cleanroom enclosure is not closely
2.5.1 presentation of clean room ceiling panels, and other parts of the air leakage at the seams, indoor low static pressure.
2.5.2 hazardous clean room due to the tight envelope does not result in air leakage, indoor static pressure is low, the cleanliness of precision is affected.
2.5.3 analysis
① wall or roof of machine size large deviation;
② siding on both sides of the bezel seal not closely:
③ roof and frame sealing was not strict;
④ panels and roof connection not seal:
⑤ ceiling or wall and lighting, transfer window, the part is not seal:
⑥ through panels, roof of various pipe holes not sealing;
2.6 air shower room blowing rain effect difference
2.6.1 representation of air shower room of two door interlock, nozzle flow not uniform, staff into blowing spray unit has the sense of vibration and cold wind.
2.6.2 harmful air blowing from ventricular blowing rain effect, reducing the physical purification, clean cleanliness of the room.
Analysis of the causes of 2.6.3
① air blowing from ventricular Foundation (or ground), to be flat and mat thickness 5 mm rubber plate ≮;
② air blowing from ventricular post-installation failure of technical papers on the various actions required to carry out a pilot to adjust to meet the requirements of various indicators. If the fan starts, electric heater for people blowing spray air heating,Two door interlock and time relay test adjustment, etc.;
③ the angle of the nozzle should be adjusted. In order to ensure air nozzle shoot out (on both sides along the tangent direction) blow to be blown spray staff body, the angle of blowing spray nozzle General adjustment to: 20 top down. The level of error 10 on both sides.
3 air conditioning equipment installation and debugging system
3.1 poor quality combined air conditioner installation
3.1.1 manifestations of the whole surface rugged, air treatment segment seamless connections, air handling units and there is a clear gap between the siding, the adverse effects of vibration, drainage pipe leakage.
3.1.2 hazards affecting air treatment effect, increases the consumption of heat and cold sources, air conditioning system operating noise increase.
3.1.3 analysis
① air conditioner-coordinate location of the deviation is too large, is not up to the construction and acceptance of equipment installation and baseline of plane location and elevation of tolerance requirements. The permissible deviations are: plane position ± 10mm; elevation ± 20 ~ 10mm;
② air conditioner in the air handling section of some products for on-site Assembly, makes the KD Panel surface is not flat, or even excessive geometry size deviation;
③ air conditioner the air handling section of the connection between the thickness of the gasket, 6 ~ 8Hun should be used with a certain flexibility of gaskets;
④ air conditioner air filters, surface coolers, heaters and air conditioners box connection slot no closed;
⑤ retaining plate slice distance, angular and design requirements, install the reverse; should ensure accurate angular, excellent water board length and width deviation ≯ 2mm, tablets and Tablet general control of spacing in 25mm range;
⑥ air conditioner free of vibration reduction measures, general air conditioner and basis between pad thickness 5 mm rubber plate ≮;
⑦ drain without water; water seal height should be based on wind pressure of the air conditioning system.
3.2 fan damper force does not have
3.2.1 manifestations of shock absorber compression height not consistent slant, fan, operation when static swinging.
3.2.2 hazard absorber fan long-term unequal force in the State of operation, increasing fan Yun, reduce fan noise.
3.2.3 analysis
① the same specifications absorber free does not equal the height;
② Spring damper spring centerline horizontal not vertical, different heart;
③ each shock absorber at the same height, are not affected by force;
④ damper specification size improper selection should be based on manual selection of the sample or manufacturers;
⑤ absorber layout position of gravity offset.
3.3 automatic winding type filter is malfunctioning
3.3.1 manifestations filter filter deviate, filters the material cannot be automatic winding.
3.3.2 harmful air filter cannot function properly, the impact of the use of air conditioning systems.
3.3.3 analysis
① filter framework in the air conditioner was not formed in the installation;
② the filter cartridge and the filter are not parallel to the barrel;
③ filter filters the material volume is not a tightness;
④ pressure regulating device not sensitive;
3.4 fan coil pipe connection wrong
3.4.1 manifestations of fan coil of cold (or hot) water pipes connection leaks, condensate tray out of the condensate drain out.
3.4.2 harm because of cold and hot water and condensate leak, for horizontal dark mounted fan-coil will be suspended ceiling, decorative widget pollution, damage.
3.4.3 causes analysis
① fan-coil and cold and hot water pipes adopt hard connection such as a system thread a bit skewed, it will cause damage to the coil interface and leaking; generally use semi-rigid connection of annealed copper tube or flexible connection of high pressure rubber pipe, etc.;
② condensate pipe slope counter slope or gradient too small, the condensate cannot drain and overflow from the condensate tray;
③ some production air blower plate Tube manufacturers due to poor quality, a drip pan drain out up top.
3.5 cooling cooling-performing
3.5.1 form high cooling water temperature, air conditioning and refrigeration systems for condensing temperature and condensing pressure rise.
3.5.2 harmfulness reduction of cooling capacity of the refrigeration system and affect the normal operation of the system.
3.5.3 analysis
① cooling tower on axial exhaust fan is not turning or reverse; cooling operation must be carried out on the motor unit test to confirm that the correct direction of rotation of the motor;
② water distributor of hole plug, water test or test run, you should check and process the water distributor unimpeded;
③ rotating water distributor of speed is not working properly in the commissioning of the inlet pressure to adjust and tube tunnel installation angle to change water distributor of rotation speed and improve cooling towers of cooling capacity;
④ packing accompanied by reduced heat nigou, thermal area of the cooling tower at the time of installation to avoid falling into and test before cleaning, packing, accompanied by the clear nigou and other debris;
⑤ cooling tower on axial blower pressure head smaller, are not allowed in the cooling air exhaust vents on short tube or other parts, increase resistance and reduce the exhaust fan, reducing the cooling in the cooling tower.
3.6 centrifugal fan is malfunctioning
3.6.1 forms fan trial run produce beat, noise, impeller sweep to lag, triangular belt wear and start current large exception.
3.6.2 harmfulness fan not properly, affecting the entire system uses, if not, will shorten the life of the fan.
3.6.3 analysis
① fan of rotor quality uneven, static balancing poor performance;
② triangle belt drive of fan, the pulley width, Center plane displacement and drive shaft level of variance; fan after installation, you must use the party level on the drive shaft of the level of checks in the level in the bearing surface of the two apart 180 ºA location, its allowable deviation ≯ 0.02 ‰; pulley wheel width centre plane displacement should be in the main, the driven pulley end line with steel ruler measurement, its allowable deviation ≯ 1mm;
③ motor directly drive of fan, its coupling concentricity tolerance, its tolerance, radial displacement is zero zero five parts per million, the axial displacement to 100 parts per second;
④ triangle belt too tight or too loose; belt tightness of hand beat has been installed in the middle of the belt, slightly beat prevail or press down with their hands, their press distance strap thickness is appropriate;
⑤ the same specifications does not equal the belt circumference;
⑥ triangle pulley wheel Division section size does not fit with the triangular belt;
⑦ 55 k W above fan vote have the start valve.
3.7 insufficient export air flow centrifugal fan
3.7.1 manifestations of fan motor running current difference than the rated current, System total air volume is too small.
3.7.2 harmful system of total air volume, air conditioning or wet clean room temperature or cleanness cannot be guaranteed.
3.7.3 analysis
① fan speed dropped to excessive;
② fan of actual speed and design does not meet the requirements of the revolution;
③ fan impeller reverse;
④ System total, stem, branch pipes and air inlet air flow control valve is not fully open;
⑤ wind pipes system design is not reasonable, excessive local resistance;
⑥ design selection of fan pressure too small.
3.8 air-conditioning refrigeration unit cooling capacity inadequate
3.8.1 manifestations of refrigeration compressor ontology operation without obvious anomalies, but air conditioning room temperature drop down.
3.8.2 harm cannot satisfy the production process or staff comfort requirements.
3.8.3 analysis
① refrigerant is insufficient; refrigerant shortage can hear from the expansion valve is continuous severe acoustic, liquid flow is low, the expansion valve on the pipeline after Frost;
② cooling system leaks parts;
③ condenser cooling water shortage or cooling water temperature is too high;
④ thermostatic expansion valve to open degree not appropriate;
⑤ thermostatic expansion valve and sensor installation doesn't fit; General requirements expanded valve should be installed vertically, the sensor is installed in the back to the standard parts of gas pipeline; in a set oil elbow, the sensor should be installed in set before oil elbow; when the evaporator outlet is equipped with a gas-liquid exchanger, the sensor should be installed before the gas-liquid exchanger.
3.9 air-conditioning refrigeration compression system is malfunctioning
3.9.1 forms compressor discharge pressure is too high or too low, the suction pressure is too high or too low, high and low voltage relay often actions, the compressor is started in the 90s suddenly stop and oil pressure too low.
3.9.2 harmful air conditioning compressor does spins, the air conditioning system required cooling capacity cannot guarantee that the system cannot be put into operation.
3.9.3 analysis
① air into the refrigeration system; cold water for cooling the suspect is insufficient, the amount of refrigerant filling in, so that the accumulated too many people reduce condensation area; condenser tube condenser head cover water separators, short circuit flow leakage; exhaust valve is not fully; excessive cooling water flow and exhaust valve slice leakage;
② inspiratory valve opening is too large; suction valve, valve seat, piston ring leakage; uninstall device failure, or air conditioning load reduction; suction filter blockage; system filled refrigerant is insufficient;
③ high and low voltage relay pressure value adjustment is not appropriate; suction valve does not open;
④ pressure controller (oil pressure relays) actions;
⑤ pump defective; oil pressure regulator is too low; oil filter clogging and compressors operate in high vacuum.
3.10 ventilation, air conditioning system for the measurement of total air volume too small
3.10.1 manifestations fan and motor speed normal, fan operation, without exception, the motor operating current is too small, and motor rated current difference is large, the air (or outlet) to export wind speed is very small.
3.10.2 harmful system is not up to the total air flow design, ventilation, air conditioning systems, other parameters cannot guarantee the normal operation of the system.
3.10.3 analysis
① air conditioner air filters, surface coolers, heaters plug;
② total air pipe and support tube air flow control valve closing or opening is not great;
③ air valve quality is not high, the leaves fall off air valve;
④ air duct system design is not reasonable, excessive local resistance;
⑤ design chosen air conditioner properly;
⑥ design selection of fan full pressure too small.
3.11 ventilation, air conditioning system for the measurement of total air volume is too large
3.11.1 manifestations of fan operation is normal, motor running current exceeds the rated current, the draught of large export wind speed.
3.11.2 harmfulness of ventilation, air conditioning system in a test or test the adjustment process, such as the motor is overloaded for a long time to run, the motor will be burnt down.
3.11.3 analysis
① for air cleaning system is due to levels of air filters of low resistance;
② System total wind pipe without control valve or regulator malfunction;
③ fan improper selection.
3.12 system total air volume or branch pipe air flow adjustment of excessive data deviations
3.12.1 manifestations of air volume and the system measured fan motor operation does not match the current values, the air in the room's air too large or too small.
3.12.2 harmful air flow is too small, the air conditioning room temperature and humidity can not be guaranteed; cleanliness of room air cleaner is not up to requirements. Air flow too big not only wastes energy, and motor overload, easy for long periods.
3.12.3 analysis
① selection of type of measuring instrument are not appropriate;
② test hole in the duct parts does not meet the requirements;
③ test hole in the duct cross-section distribution is not uniform;
④ determination officer operation error;
⑤ measurement instrumentThe accuracy of measurement and identification has been made;
⑥ the dynamic pressure values do not meet the requirements calculated finish.
Actual project which occur problems, want to work to avoid problems.