LEV Testing

Airflow in a centrifugal spray booth is a vital safety requirement set in place to reduce the concentration of flammable material and particulate in a booth. Airflow is measured in linear feet per minute (LFM) – a measure that’s usually calculated first in an empty booth, with a cross-sectioned area of the airflow direction. According to the International Fire Code (IFC), a spray booth needs 100 linear feet per minute to meet minimum requirements.

LEV Testing should be conducted every 14 months to ensure that systems are functioning properly and to identify any potential problems.

Local exhaust ventilation is measured by a number of factors. These include: • Duct velocity • Face velocity • Capture velocity • Performance, or horsepower, of the booth fan

There are two primary limitations to implementing local exhaust ventilation: • Maintenance – the system requires regular cleaning, inspection and upkeep • Cost – the system may require a large capital investment up front to pay for design, installation and implementation

These are the most common factors affecting the efficiency of a LEV system: • Poor design • Lack of regular and planned testing • Neglect and lack of maintenance • Damaged or blocked ducting and filters • Unauthorised system changes • Incorrect system calibrations • Faults in the fan or vents

Control of Substances Hazardous to Health (COSHH) regulations state this is a legal requirement, however testing frequency varies depending on the application – some applications require testing as often as once a month. Full details can be found on page 85 of HSG258 ‘Controlling airborne contaminants at work A guide to local exhaust ventilation (LEV). The Health and Safety Executive (HSE) has extensive powers – it can prosecute companies if they fail to comply with improvement orders which can result in hefty fines. From a responsible employer’s point of view, it is common sense. The financial outlay of regular testing is minimal when compared to the fines that can be incurred through a HSE prosecution.

Local Exhaust Ventilation (LEV) systems capture, contain and treat air contaminated with oil mist, fume, smoke and dust at source before it has an opportunity to escape into the wider working environment. LEV systems include a hood (or multiple hoods), ducting, a filter, a fan and a discharge mechanism.

Employers have a legal responsibility under the Health and Safety at Work etc Act 1974 as follows: (1) It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees. (2) Without prejudice to the generality of an employer’s duty under the preceding subsection, the matters to which that duty extends include in particular— (a) the provision and maintenance of plant and systems of work that are, so far as is reasonably practicable, safe and without risks to health; In addition to fulfilling legal requirements, ensuring a clean, safe workplace also has a number of other benefits: It can help to attract and retain employees Help to lower cleaning bills Reduce hazards associated with a build-up of airborne particles such as dust and oil mist particles Increase productivity by reducing days lost to worker ill-health Help to maintain product quality

Regular airflow readings can identify any problems with the system’s performance. Blocked or saturated filters, or damaged ducting can impact on the extraction capability - meaning the system is less able to cope with the volume of air which needs cleaning. The test records the current reading as well as results from previous tests, or the original design requirement. The inspector can cross reference all of the data to ensure the system is operating as intended.

The reports that Filtermist issues are legal documents which consist of the following: Full company details and date of test Details of the substance/process being controlled A photo of the LEV system being tested or a schematic drawing Test data including water gauge static pressure, velocity in m/sec and volume flow rate Readings from all extraction points Improvement recommendations Pass / fail Inspector’s statement of competency Safety policy Method statement Risk assessment Report observations Details of next recommended visit NB: It’s important to remember that if HSE asks for a copy of the report, you must supply the whole document – not just the sheet with the test results as it won’t mean anything without the rest of the report.

The length of time it takes to carry out an LEV Test varies depending on factors including the accessibility of the system, and the type of installation it is. The first visit is always the longest as the our appointed engineer will complete a risk assessment form, take photos of the systems that need testing and record all of the other details needed for the report. If nothing has changed in terms of the system set-up, the time it takes to carry out subsequent tests dramatically decreases.

Regular LEV Testing is crucial for two reasons: 1. To protect employees from the health risks associated with exposure to airborne contaminants 2. To protect employers from HSE prosecution.