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Ventilation systems engineering requirements
Ventilation systems engineering requirements
 
First, the technical standard
According to "Heating, Ventilation Design Manual" and the relevant provisions of the specification GBJ19-87 "DB42 laboratory ventilation systems design and construction specifications" to determine the fume hood cabinet ,, digestion, atomic absorption enclosures ventilation equipment, full indoor ventilation ventilation the amount: 
1) design, according to the indoor heat, residual humidity, guaranteed minimum ventilation of indoor sanitary conditions were calculated. Ventilation general chemistry laboratory: 10-12 times / hour
Gas chambers, organic synthesis, ventilation rate of bacteria culture: 15-20 times / hour 2) fume hood (hood) must remain negative pressure ventilation Face, fume hood face velocity: VAV state 0.5m / s ± 0.1m / s or other values ​​set according to user requirements. Manual mode 0.3m / s ~ 1m / s, the level of the window does not affect the surface of the set wind speed; 3) the ventilation system using a terminal noise ≤55dB, fume hood face air changes: not less than 15 times; 4) the main duct design Winds less than 9-12m / s, branch duct design wind speed is less than 5-7m / s 5) exhaust volume: fume hood 1500m3 / h; 6) fast execution response time ≤1s.
Second, the control system technology capabilities and performance indicators
(A) laboratory ventilation system requirements
1) VAV variable air volume control frequency regulation, to ensure the system more than the fume hood (hood) running simultaneously, each
Self-adjusted independently, not interfere with each other.
2) good laboratory airflow, air velocity and turbulence intensity can be controlled within a smaller range,
In order to avoid disturbances caused by indoor gas detoxification cabinet gas spill.
3) different models and specifications should be circular or rectangular single variable air volume valves, to meet the different requirements and the amount of wind
Consistent with the design drawings;
4) combined with laboratory ventilation control system including variable air volume valves, muffler provides laboratory ventilation
Complete solution control.
5) laboratory in duct corrosion better choice, high hardness materials. The project involves all duct
Can use a good anti-corrosion PVC / UPVC material, fans are all good corrosion glass blower.
6) Control panel character display, can display more information about the ventilation system is running. Automatic and manual
Compatible with multiple operating modes settings control the power outlet and turn on lighting, you can adjust the angle of the damper.
7) good laboratory airflow, air velocity and return air turbulence can control in a smaller range
Inner circle, so as not to cause disturbance indoor gas detoxification cabinet gas spill.
(Ii) products with Ge and technical requirements:
1, the product requirements with Ge
a) damper actuators, 0 ° to 90 ° adjustable running time ≤3s, valve response time <1s. b) anti-corrosion body, one-type molding, PVC casing corrosion. c) The controller has a display and operating functions, real-time display of the data. d) the system response time within 3 seconds e) the damper resistance is less than 150Pa
f) into a variety of output cable by the original manufacturers supporting 2, the control system requirements
a) the use of advanced laboratory ventilation system control programs and equipment, high-quality and reliable security controls to maintain the negative pressure within the air laboratory parameters. System main ventilation ducts and ventilation VAV function, ventilation by the group control system.
b) the original design using multiple devices share the roof ventilation fans should be used automatic frequency VAV variable air volume control, so that not all the time be able to use the equipment in the energy saving. Each ventilation equipment using intelligent electric valve control switch and inverter control system and fan interaction, VAV fume hood according to the height of the user can open the window automatically adjust the air flow so that the fume hood face velocity constant, in order to achieve as much as possible to ensure the safety of users under the premise of saving .
C) When the ventilation system fully consider the peak temperature (cover) of laboratory fume hoods equipped with the disposal of multiple use, a variety of situations on duty at night minimum ventilation and other conditions, the capacity of the ventilation system to achieve both maximum ventilation requirements, but also give full consideration to its regulatory flexibility, achieve economic operation. You should consider the equipment at the same factor, so that the system device with Ge tends to be more reasonable. Control system should be able to support devices simultaneously function coefficients.
d) electrical transformation control each and every roof fan control switches are mounted to a common ventilation equipment, control set point Ge, and the interlocking switch interlock control, different rooms on different floors of the device is not affected, with user-friendly operation .
e) To ensure that the air volume balance for each ventilation outlet, adjustable dampers must be installed in each duct outlet to adjust commissioning, commissioning after installation professionally balanced to work properly. f) to examine the lab after pipeline installation, aesthetics, interior lighting and other effects, design of piping systems from storey structure, columns position and hinder the possible departure beam pipe should be designed as far as possible not to exceed 400mm thickness calculated design to meet the overall requirements of laboratory. 3, surface wind speed monitoring and control system requirements
a) fume hood with a function, automatic and manual operation mode is compatible with a variety of settings that control electrical socket
Open source and lighting, etc.
b) a variety of variable air volume control valve response speed <1 second, with a digital network communication, within Ge rich
Control functions, reserved for future system upgrades and software monitoring functions
c) the frequency variable air volume control valve can be designed in accordance with the requirements of independence to complete a single fume hood or hoods
VAV control, effective and timely manner from the emissions of toxic gases and particulate pollution, safe and reliable work. When moving up and down the door, can automatically control the VAV valves to control the surface wind speed within the required range (≥0.5m / s).
d) All parts in contact with the exhaust requirements of corrosion-resistant material, to avoid corrosion. e) the damper pressure loss is smaller, so that the operation of the economy. Operating pressure range is wider, variable air volume control adjustment
System to ensure a plurality of exhaust system cabinet running simultaneously and independently adjusted, do not interfere with each other f) and other laboratory ventilation equipment to work together to achieve the control room as an ideal form of air balance
State and the pressure in the chamber. Requirements of various valves reaction rate should be fast response, Flow Control reaction speed is less than 3 seconds, in order to facilitate rapid equilibrium fume hood (hood) and room air volume; 4, the fan design requirements
â‘  fan: FRP centrifugal fan.
â‘¡ chassis, all-wheel by fiberglass material made of other metal parts in the body and transporting gas are in direct contact with fiberglass embalmed, fan selection must be designed in accordance with the accounting and left margin laboratory ventilation systems.
  5, duct design requirements
Duct using PVC / UPVC material, duct light weight, chemical stability, with anti-corrosion properties, smooth wall, ventilation is good, beautiful appearance. Support and hanger tube made of A3 steel hoop duct, through the use of square tube boom angle fastening rust treatment to support the duct. All piping design pressure less than 1500Pa.
According to the building conditions, taking into account the beauty of the room, duct affect firmness and interior noise, exhaust duct system for the preparation of PVC / UPVC material, the main duct, branch duct thickness implementing national standards, the duct Selection , duct thickness do thickening process, reduce noise and air leakage rate.
PVC / UPVC duct using the plug-in connection, to meet the duct requirements of the premise, to minimize duct space.
6, the muffler design requirements style: complex cellular impedance;
Material: shell is made of PVC production, disposal within the silencing material; muffler cotton thickness not less than 100mm Connection: flange connection or socket connection; fixing the fan with a soft docking connector, resistant to corrosion.
Performance: can effectively reduce the noise 5-10 dB.
Pipe horizontal mounting: connect with square and round butt joint sealing requirements; 7, soft connection design requirements:
1) PP moisture-proof, airtight, easy to mold the flexible material. 2) flexible short tube installation, an appropriate degree, no significant distortion.
Length 3) flexible short tube, less than 500mm, its junction should be tight, solid, and reliable. 8, vibration design requirements
1) Due to the large centrifugal fan vibration running is higher, the fan is running, the vibration does not affect the surrounding environment, damping measures must be taken on the fan: the fan base with concrete foundation, the concrete between the fan base and the damping spring or rubber shock absorber damping pad.
2) Install the fan inlet flexible joint, so that noise and vibration generated when the fan is running not to pass through the layers of duct laboratory.
Third, the construction requirements
1, the overall trend claim duct short, smooth, straight, flat, n, the actual construction of the wind direction in case of the presence of nature and the construction site on the conflict, the designer would like to explain the situation, and then take appropriate action;
2, the construction of the ventilation system to ensure air-tightness requirements, maximize the use of 45-degree elbows and tees, to reduce system resistance;
3, can not change the effective flow area of ​​the ventilation system, but not for a small tube instead of bassoon use; 4, the wind pipe, muffler and fans installed to solid stable, prevent system vibration, excessive noise; 5, should be removed before installation the inner tube and outer debris, and make cleaning and protection; 6, the radius of curvature of the elbow duct is generally twice the side length, a minimum of not less than 200mm;
7, duct installation bit Ge, elevation, direction, meet the design requirements, to achieve smooth vertical and horizontal, bolted flange should be evenly tightened its nut on the same side;
8, site duct interface with Ge can not reduce its effective cross section duct connection interface should be tight and firm; air duct flange gasket material shall meet the requirements of the system function, thickness not less than 3mm, no gasket It should protrude into the pipe, and is not projecting outer flange;
9, all the necessary disposal duct provided support, hangers, pipe supports according to the national standard manufacture; 10, the flexible short tube installation, an appropriate degree, no significant distortion;
11, can not be laid within duct wires, cables, fan duct outer edge of the line of control in the wind pipe laying; 12, duct connection interface with brick, concrete duct should be inserted along the direction of gas flow, and shall take sealing measures, wind pipe piercing the roof there shall be installed rain Ge;
13, surrounded by slot plug-type duct should be consistent, no bending or wrinkles; sealant coating should be complete within the outer adhesive sealing tape should be solid paste, complete no defects;
14, all kinds of adjustment means of production and disposal should be installed properly and securely, flexible regulation, convenient operation, fire and exhaust valves, and other closed tight, reliable operation;
15, using the straight-shaped anti-corrosion impedance muffler, import and export air nozzle size and consistency, muffler cotton thickness not less than 100mm, and the fan with a soft docking connector is fixed;
16, due to the centrifugal fan at runtime larger vibration, it should be fixed in concrete, based on a basis between fan and damper springs or rubber shock absorber;
17, the fan outlet duct diameter can only be larger, not smaller, the outlet to install the utility network, to be increased when the wind and rain cap bias on the wind.
Fourth, the ventilation control system with Ge quality requirements
System control devices, components should use foreign brands or Chinese authorities recognized domestic or technological innovation with independent intellectual property products.