Local Exhaust Ventilation (LEV) systems are engineering controls that extract/remove or reduce airborne hazardous substances from the workplace to prevent human exposure. They typically consist of a hood either enclosing the source of the hazard or positioned close to it. This may be fume, smoke, dust, oil mist, which is carried away by a fan, through duct work and passed through a filter to clean the air before being discharged.

TExT is short for Thorough Examination and Test. This is the statutory inspection that must be carried out at intervals not exceeding a 14 month period as stated in the COSHH Regulations 2002 (as amended). This must be carried out by a competent person, a competent person will have adequate knowledge, training and expertise in the design of processes, control measures, including ventilation and PPE and why these systems can fail to protect.

Health and safety law says you must assess the risks to your workers from hazardous substances – dusts, fumes, vapours, etc. and take suitable measures to use to protect their health. Where the hazard cannot be eliminated or substituted other controls must be used, engineering controls (typically LEV) is the next step in the hierarchy of control.

The Control of Substances Hazardous to Heath Regulation 9 (4) states that "Every employer shall keep a suitable record of the examinations and tests carried out in accordance with paragraphs (2) and (3) and of repairs carried out as a result of those examinations and tests, and that record or a suitable summary thereof shall be kept available for at least 5 years from the date on which it was made." . These can be kept electronically or a hard copy.

There isn't a specific legal requirement to have airflow indicators but you must make sure your LEV is working properly and protecting your employees. An airflow indicator is a quick visual method of assurance that the system has airflow within its design parameters. Faults, blockages or failure can quickly be identified. The HSE guidance document HSG258 recommends these are fitted.

The main document is the HSE published document HSG258, which gives an overview of LEV systems and design performance criteria. Industry specific guidance can be found on the HSE's COSHH Essentials page. Further guidance can be found via The Building Engineering Services Association (BESA) document TR40 - A Guide to Good Practice for Local Exhaust Ventilation. It is always best to seek professional help when looking to design, install and commission LEV systems.

Respiratory protection equipment (RPE) is the last line control measure in the hierarchy of control, all other steps further up the hierarchy should be carried out first. If, after implementing all of the controls further up the hierarchy exposure is till too high then RPE can and should be used. It is worth remembering that although RPE protects the individual, LEV protects the entire working environment

People carrying out examinations and tests on LEV must have adequate knowledge, training and expertise in examination methods and techniques. Examiners will be able to show they hold, as minimum, qualifications from the BOHS such as the P601 for testing systems. Training alone does not make them competent, experience and knowledge are required too and the tester should be able to answer any questions you may have.

If your extract system does not control the hazard it will be failed and a red label attached, stating it has failed. The test engineer will be able to advise on remedial works and temporary controls to keep your business operating and agree a time frame with you to have the repair works carried out before having the system re-inspected. If the system is beyond economical repair a new system can be designed.

Yes, COSHH Regulation 9 states that where engineering controls are provided to meet the requirements of regulation 7, the employer shall ensure that thorough examination and testing of those controls is carried out. In the case of local exhaust ventilation plant, at least once every 14 months. There are other specific processes that require more frequent testing intervals. as detailed in Column 1 of Schedule 4 of the COSHH regulations.