Fume And Dust Extraction
Potentially dangerous dusts, vapours and gases are present in even the most modern industries, threatening the health and well being of the employees involved.
With new legislation governing exposure limits and emissions to atmosphere, companies have to look more closely at the efficiency of extraction systems. Local Exhaust Ventilation or LEV now falls within COSHH regulations and can be divided into four main categories.

Receptor systems where the contaminant enters the system without inducement. The fan in the system is used to provide airflow to transport the contaminant from the enclosure through the ducting to a collection system.

Capture systems where the air flows into the hood capturing the contaminant outside the hood and induces it to flow into the system. Low volume high velocity where air extracted at high velocity through small apertures close to the source of contaminant. Dilution ventilation is used where it is not possible to extract the contaminant close to the point of origin. Used where the level of contaminant is small and the toxicity is low it may be possible to dilute the fumes by inducing large volumes of air through the contaminated area

Ventilation Systems

Ventilation is to design a system capable of restricting the high-level temperature rise inside the building to a pre-determined level above the prevailing outside ambient temperature by creating a minimum air change rate per hour (ACH). These systems provide positive, fresh air movement to central working areas within the building that in turn provide evaporative cooling for the operatives at their respective workstations. Due to the relatively low capital cost, in relation to the highly desirable conditions achieved, this is the most common approach within industrial buildings today.

Air Handling
For general industrial ventilation systems, clean rooms or process ventilation can be provided by the use of centralised Air Handling Units (AHU). These direct or indirect drive, backward or forward curved fan units are purposely designed and installed to incorporate supply and return ducting and can be fitted with various components such as mixing boxes, various types of filtration, heater batteries, cooling coils and heat recovery wheels. AHU are usually double skin, insulated, pentapost construction and additional acoustic treatment can be provided, if required. Purposefully designed for industrial ventilation systems.

 

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