Are you making good use of local exhaust devices

In workplaces that use organic solvents, specific chemical substances, etc., I think local exhaust devices are installed and operated, but they may not be effectively used depending on how they operate and the surrounding environment.

This time, I would like to introduce cases commonly seen in practice when carrying out work environment measurements at workplaces, and examples of countermeasures.

・An external hood is installed away from the source.

Even if sufficient exhaust air volume can be confirmed on the opening surface of an external hood, when the distance away from the source, the exhaust air volume drops significantly.

The exhaust air volume at the hood opening surface is inversely proportional to the square of the distance to the emission source, so if the distance is 2 times farther, the exhaust air volume will be 1/4.

Conversely, if the distance is reduced in half, the suction wind speed will increase by 4 times, so we recommend working with the hood and the exhaust source as close as possible. Also, since exhaust air volume can be improved by installing a flange on the opening surface, please consider installing it if the exhaust air volume is weak.

・The blower is operated near the local exhaust device.
If the airflow from a blower etc. is too strong, it may interfere with the exhaust airflow of local exhaust devices in some cases and spread hazardous substances. We recommend that you consider the air volume and wind direction when operating the blower near the exhaust device.

・Obstacles are placed near the exhaust surface.
When using an external hood or push-pull ventilator, if materials etc. are placed near the exhaust surface, disturbances in the exhaust airflow may occur and exhaust efficiency may decrease, so we recommend that you do not place anything near the exhaust surface as much as possible.

We have multiple local exhaust equipment instructors and regular voluntary inspectors for local exhaust equipment, etc., and in addition to the above, we can make proposals on local exhaust devices from various perspectives.

If you have any problems, please do not hesitate to contact us.