Spray booths, fume extraction and dust extraction systems for airborne contaminants.
The Control of Substances Hazardous to Health 2002 (COSHH) law requires that Local Exhaust Ventilation (LEV) systems used to eliminate dust, fumes and other substances be regularly and thoroughly examined. The frequency of inspections depends on the type of pollutant being controlled, with inspections required every 6 or 12 months, or a frequency agreed by a competent person.
Our engineers measure the effectiveness of the equipment and provide guidance on any remedial action required for safe use in line with your statutory obligations.
In addition to the examinations, LEV equipment must be regularly maintained and inspected by the user. The Thurra team is a good source of reference and guidance on these requirements; more detailed information and resources are available on the Health and Safety Executive website: www.hse.gov.uk/lev/
Common defects of Local Exhaust Ventilation (LEV) Systems
The most common faults with fume or dust extraction systems, more commonly known as local exhaust ventilation (LEV).Effective LEV can carry away airborne contaminants before they can be breathed in. The LEV system removes air from the area of work, whether that is a school laboratory, or a factory. It then filters the air to remove contaminants before expelling the air outside or recirculating it back into the working environment. The air quality in these areas can be contaminated by a range of airborne contaminants that are hazardous when breathed in. Airborne contaminants may occur as vapours, dust particles, fibres, fumes or gases or combinations of these. Breathing in high levels of contaminants or low levels over a long period of time can overwhelm the human body’s defence system resulting in disease. Exposure to certain airborne contaminants has the potential to cause or worsen a wide range of serious respiratory diseases including:
- Cancers of the respiratory system
- Chronic obstructive pulmonary disease
- Blocked filter. Blockages in the LEV filtration system can occur because of many different reasons. The main reason generally happens as a result of poor maintenance. In such circumstances the effective extraction capability becomes less and less. Thereby not removing the required contaminated air from the area where people are working. At every scheduled inspection, Thurra’s engineer will measure the efficiency of the filter and visually inspect the filters condition. On completion, Thurra’s engineer will discuss their findings, whilst bringing any areas of concern to attention.
- Obstruction in the extraction ducting. Wood working workshops are notorious for collecting heavier particles at certain parts of the system. At such points in the extraction ducting the efficiency of the system will be reduced and thereby have the knock-on effect of not extracting all the dust particles that it was designed to do. In this condition the system would not remove the contaminated air from the designated place of work. Thurra’s engineer will study the results of their examination and using a logical approach identify the location of the blockage / restricted flow and inform the owner of the extraction system where the blockage is. All conversations with the system owner are supported by a report of examination which would identify any areas of concern.
- Extraction hood incorrectly positioned. The positioning of the extraction hood can have a very significant effect on the operation of the LEV system. If the system is not correctly positioned, the system could be extracting air from the work area less efficiently than necessary, leaving contaminants to continue to circulate around personnel and inhaled without knowledge. The physical positioning of extraction hoods is assessed at every visit with all concerns brought to the attention of the on-site representative.
- Holed / damaged extraction hood. All extraction systems are designed to remove contaminated air from the area of work. If the system is damaged and has holes in the trunking, the efficiency of the system will be reduced. The physical integrity of the system is assessed at every examination with damaged areas including holes reported to the customer. Such holes reduce the efficiency of the system and increase the risk to those working in the environment.
- System not appropriate for the removal of all contaminants. Having the appropriate system in place to remove contaminants from the workplace is an essential requirement. In the majority of cases, the original systems fitted are appropriate. However, over time additional extraction points are quite often added and in doing so the capability of the system is compromised. At every thorough examination a ‘fit for purpose’ assessment is conducted and the results are communicated to the customer. Additional extraction points in a LEV system reduce the efficiency to remove contaminants and increase the risk to the personnel in the vicinity.