Laboratory ventilation design specifications Laboratory ventilation standards, fume hood control standards, chemical laboratory
Chemical laboratory control objectives generally include: ensuring safety (local exhaust, such as fume hoods, room pressure, fan emissions, monitoring alarms, etc.), reducing energy consumption, comfort (meeting room temperature and humidity requirements), easy maintenance management, and flexible system (easy Reconstruction and expansion, etc.). Countries have clear regulatory requirements for the safety of chemical laboratories. Usually chemical laboratory standards and design specifications usually include:
EN/BS14175 (EU/UK National Standards Institute)
BS7258 (British National Standards Institute)
DIN12924 (German National Standards Institute)
ASHRAE110 (American Society of Heating, Refrigerating and Air-Conditioning Engineers)
ANSI/AIHA Z9.5-92 (American National Standards / Industrial Hygiene Association)
SEFA1.2 (American Association of Scientific Equipment and Laboratory Furniture)
JG/T222-2007 (China Construction Industry Industry Standard)
JB/T6412-1999 (China Machinery Industry Standard)
Because China's national standards are relatively inconspicuous, both standards are only for fume hood control requirements and acceptance criteria, but for other rooms such as room air supply, pressure requirements, operational requirements, etc. are not detailed, therefore, domestic projects are designed according to EN14175 and ASHRAE110 More. For laboratory requirements, standards generally include:
1) Ventilation panel surface wind speed: control target 0.5m / s, acceptance criteria 0.5 ± 20%, it is not recommended to operate the fume hood below 0.3m / s, at any time, the operating state of the fume hood surface wind speed should not approach or exceed 0.75 m/s. When the fume hood is free from spoilage and unmanned operation, the surface wind speed can be appropriately reduced to 0.3 m/s.
2) Gas leakage concentration of fume hood: In the acceptance criteria, ASHRAE110 and EN14175 both stipulate that the leakage concentration of the fume hood should not exceed 0.05ppm during acceptance. The Chinese national standard is 0.5ppm. The German DIN standard is 0.6 ppm.
3) ASHRAE110 and EN14175 standards stipulate that the airflow interference before the fume hood should be less than 30% of the surface wind speed, and the upper limit is 20%. If the surface wind speed is 0.5m/s, the front spoiler of the fume hood should be lower than 0.15m/s. Otherwise it will affect the control effect. The control system should be able to cope with the front of the fume hood.
4) The fume hood monitors the alarm on site. Fume hoods are used as hazardous operating facilities in chemical laboratories. National regulations require local monitoring and alarm of fume hood surface wind speed. When the wind speed of the fume hood is lower than 0.3m/s, it is necessary to generate an in-situ alarm, prompting the user to use or stop using it cautiously.
5) The minimum exhaust air volume of the fume hood. At any time, the exhaust air volume of the fume hood should not be lower than the operating area of 460 cubic meters / hour / square meter cabinet or the operating width of 280 cubic meters / hour / meter fume hood.
6) The minimum number of air changes in the room is 6-12 times. The specific choice is confirmed according to the type of laboratory and the degree of experimental hazard.
7) The chemical laboratory requires a new wind system design. No indoor gas can be reused.
8) Unless it can be confirmed, in any case, the concentration of pollution in the exhaust should be reduced to a safe value, otherwise a minimum jet velocity of 15.2 m/s is required. In order to ensure the safety of the person on the roof, the exhaust gas discharge point should be kept at least 3m away from the highest point of the roof plane.