How should we consider ventilation in workshops dealing with hazardous chemicals?

Using an axial flow fan for ventilation is safe, convenient, and fast – so why is it necessary to connect air ducts leading to the roof?

If the factory is surrounded by employee housing or is located close to local residents, it is best not to use axial flow fans, as the gases emitted are not healthy, and this could lead to civil disputes. The height of the exhaust stack for the exhaust fan is determined by the engine displacement and the properties of the hazardous chemicals.

This post was last edited by shanyee on 2009-6-12 22:55. Appropriate measures still need to be taken based on production requirements. Initially, we designed the system to use axial flow fans for exhaust; however, after it was put into operation, this approach proved insufficient. Therefore, high-pressure fans were added to facilitate exhaust at higher points, and this solution yielded better results.

In my opinion, it is more reasonable to collect through pipelines, process them centrally, and then discharge them!

Based on the properties of the hazardous chemicals, production requirements, and the conditions surrounding the factory, appropriate measures should be taken; regardless of the ventilation method used, its effectiveness must be taken into consideration.

This is not only a problem related to axial flow fans; hazardous chemicals must be treated and purified after removing the air from the workshop before they can be released into the atmosphere. Otherwise, it will pollute the atmospheric environment, pose a threat to public health, and in particular, cause public safety incidents that could lead to the bankruptcy of the company. The meaning must not be altered.

Managing the sources such as processes, equipment, and raw materials is key; especially regarding equipment, it is necessary to prevent leaks and spills

What are the characteristics of hazardous chemicals? Flammable, explosive? Toxic? Is it corrosive? Hazardous chemicals certainly should not be released directly into the atmosphere; they must be treated first. For chemicals that are flammable and explosive, it is essential to take into account their ignition points, as well as the upper and lower limits for explosion. Strict requirements are placed on indoor temperatures, and efforts should be made to reduce the frequency of air exchange in those areas. For toxic and corrosive hazardous chemicals, it is essential to consider the direction of air flow as well as the location of the operators; exhaust systems should preferably not be installed on the roof, as this will cause air to flow upward and affect the operators’ breathing. Generally, a sealed suction hood is required for the source of hazardous gases; if operation is difficult, a semi-sealed suction hood can be used. If neither of the above options is feasible, a side suction hood or a bottom suction hood can be employed. If the diffusion speed of the hazardous gas is high, an air flow can be applied to force the hazardous gas to enter the suction hood as quickly as possible. The fan to be used on the pipeline should be an explosion-proof fan or a corrosion-resistant fan, depending on the properties of the gas. The choice between an axial flow fan and other models depends on the specific wind pressure and airflow requirements.

According to the standards, extreme care is required; flammable, explosive, and toxic substances must be removed from the power shadow zone and the positive pressure zone. Since this involves accident ventilation, it requires comprehensive ventilation. But what is done in practice?