Ventilation is extremely important in manufacturing plants and industrial sites, since it ensures a healthy and safe environment for workers. Most facilities use LEV (local exhaust ventilation) systems, extremely performing and efficient when chosen properly. These devices are made of several parts and you may need LEV testing to keep them functioning in normal parameters. To understand how the system works, read on to find out the main components of such a system.
The hood is maybe the most important component of a LEV system, since it has to capture the contaminated air directly from its source. For this reason, it has been especially created to gather dust or fume, and its design has a crucial role in controlling the emissions of toxic chemicals. The air speed both at the opening and inside the hood has to be powerful enough to capture and transport the contaminants towards the filter. For this reason, the hood must be completely enclosed and situated extremely close to the toxic source, in order to prevent air loss and accidents. There are many types of hoods – for almost any industrial process and operation there is a special LEV opening, specially designed to provide effective control.
The ducting system
Once the contaminant is captured by the hood, the air needs to be carried through the local exhaust system. In order for this operation to take place effectively, pipes or tubes are necessary to make the connection between the opening and the filter. The ducting network needs to suit the amount and strength of airflow, because slow movement can lead to setting out of dust and clogging the pipe, while fast movement is a complete waste of power.
Also known as air cleaners, these components of the ventilation systems are in charge with separating dust and fume, when the amount of contaminant is too large. In some instances, filters are lacking because the system is used for remote operations. What is very important for you to know is that air cleaners depend not only on the amount of contaminant to be removed, but also by the chemical concentration, its nature and other variables.
Although the other components are important too, the fans are the core of a local exhaust ventilation system. These push the dust and dirt outside the ventilator and the clean air back, ensuring the proper functionality of the entire LEV. Taking into consideration their importance, fans must have the appropriate size and be the right type, in order to make ventilation efficient. The dimension is quite important since it enables the fan to provide enough air pressure or suction to capture contaminants, on one hand, and replace air, on the other.
The exhaust stack
This part is also very relevant and has to be properly designed and located, to support efficient operation of the LEV system. The stack has to be placed far enough from the source, because this is how it will be able to build fresh air intake and prevent re circulation of contaminants. The minimum recommended distance is 50 feet.