As we all know, laboratory decoration must be well designed for ventilation, so how can we do well for ventilation design? The ventilation design in the laboratory decoration is embodied in 4 aspects, namely: the selection of the number of air changes, the form of exhaust and air supply, the room pressure difference, and the control system. Below, let me introduce the first two.

I. The choice of ventilation frequency

The ventilation design in the laboratory decoration, for the selection of the ventilation frequency in the laboratory decoration, according to the regulations, the minimum indoor ventilation rate is 6 times/h~8 times/h. Specifically, the overall number of indoor air changes is determined by three aspects of air volume, namely: the total air volume exhausted from local exhaust equipment or other room exhaust, the cooling air volume required to take away the heat load of the room, and the minimum number of air changes required.

Although the minimum indoor ventilation rate is 6 times/h to 8 times/h, more than 10 times/h is also suitable. However, it should be noted that if there are analytical equipment that generates high heat load in the laboratory, or there is a larger amount of local exhaust, then it may be necessary to increase the ventilation volume accordingly.

The calculation of the minimum suction surface velocity of the fume hood operation port in the laboratory should refer to the light, moderate hazard or dangerous hazardous substances. Generally speaking, the minimum suction surface velocity is 0.5m/s. As for the utilization rate, when the number of fume hoods is greater than 2, the simultaneous utilization rate of 60%~70% shall be taken.

The calculation of the heating furnace in the laboratory should refer to the heat balance law of maintaining the heating temperature in the furnace, so that a safe exhaust air volume can be obtained. In addition, the air-conditioning air volume calculated by the load is compared with the minimum number of air changes 10 times, and the maximum of the three is taken.

II. Air exhaust and air supply form

For the exhaust and air supply forms in the laboratory decoration, if the indoor exhaust volume is large, an outdoor fresh air supply system must be installed and the fresh air load shall be included. All indoor exhaust devices should share an exhaust system, and laboratories that need to continuously use the exhaust system should install an air supply system, and the air supply volume is 70% of the exhaust air volume.

The gas exhausted from the laboratory must be discharged outdoors, so unless there is a need for cleanliness in the room, it is necessary to maintain a negative pressure for the adjacent area. As for whether to choose a 100% fresh air supply system, this is also an important part of laboratory risk assessment. The 100% brand new air supply system is suitable for the fume hood environment, and it is not necessary for ordinary laboratories.

This article introduces you to the selection of ventilation frequency, exhaust and air supply in the ventilation design of the laboratory decoration. As for the room pressure difference and control system, I will introduce it in the next article. Please pay more attention.