Airflow FAQs

There isn’t a specific legal requirement to have airflow indicators or similar fitted to an extraction. But as an employer you do by law have to make sure your LEV system keeps working properly. One of main reasons why LEV doesn’t do what it should is because the airflow falls for some reason (eg build-up of material, damage to ducting etc), becomes inadequate and effective control is lost.

One simple way of checking this is the use of airflow indicators at the hood and this will provide you reassurance that the flow-rate is maintained,that the protection for employees is there and that you’re not wasting money. There are other ways of checking airflow such as using anemometer, or a dust-lamp or smoke tracer (with the work process running). However, an airflow indicator is currently the only method that will show the operator or supervisor immediately if there’s a problem, and HSE’s LEV guidance HSG 258 recommends these are fitted.

It is not possible to gauge effectively the speed (velocity) of the air entering an LEV hood ‘by hand’. A suitable airflow indicator should make it easy to see whether airflow is adequate.

It is not a specific legal requirement, but you should have some way of checking that adequate airflow is being maintained. If you decide to get airflow indicators, you should identify which LEV systems or parts of systems need to be addressed first.

Factors to consider in your decision include:

  • The risk of exposure
  • Whether the operator has to set the hood airflow
  • Whether other checks are practical
  • The cost

New LEV systems will soon be fitted with airflow indicators as standard.

Not for all LEV. For instance, a manometer, measuring static pressure across the filter unit, can provide sufficient indication, for a simple LEV system consisting of a fan, an air-cleaner (e.g. filter), a duct and a hood.

It depends on the level of potential health risks. If risk is low, a simple indicator will be appropriate. More hazardous substances and circumstances may require more sophisticated, and potentially more costly, indicators e.g. with an alarm if airflow drops too low.

Whatever indicator is chosen, it will need to show clearly whether the airflow is adequate.

‘Tell-tales’ such as pieces of paper or plastic hung to bend in the LEV hood airflow, do not provide an effective indication of airflow and they are delicate and easily damaged.

In all but very simple systems, extracting low hazard substances, they will not be effective, adequate or suitable.

No – there is no specific legal requirement on employers or examiners to label LEV.

The law is that the employer must maintain LEV system performance and should also arrange a thoroughly examination and test at least every 14 months.

The employer needs to know whether or not an examination has been done or when it’s due, and so do supervisors and operators. Critically, they also need to know when a hood (or LEV system) has failed. Attaching labels is an effective way of easily providing this information.

HSE guidance recommends examiners label each hood with a test record. Alternatively, the test record label could alternatively be placed nearby, for instance, close to the system on-off switch. It should be clearly visible to the supervisor and operators.
HSE guidance recommends that a red ‘Failed’ should be put on any hoods (or system) that has failed, to warn supervisors and operators directly and explicitly. This could be done by the examiner with agreement from the employer (client). Or, the label could be issued to the employer’s responsible person.

With the label should come a short ’emergency’ written report containing a clear description of what’s wrong and a list of practical remedial actions.
Once the employer has had the LEV hood or system repaired, a competent person needs to check that it is effective and adequately controls exposure. The ‘Failed’ label can then be removed.

Labels are recommended as a means of providing clear and simple indication that a hood/system is not functioning satisfactorily. Other means can be used, as long as it is clear to the employer and to the operators that the equipment requires rapid attention.

LEV Competence FAQs for Employers

Competence is a combination of knowledge, skills and application experience that enables a person to do an effective and reliable job.

You have a legal responsibility to ensure that employee exposure to dust/fumes etc. is minimised and well controlled. LEV is an excellent way of doing this. People who supply, examine and maintain LEV need to be competent otherwise your LEV may not work properly, putting people’s health at risk.

Competent people have the right mix of skills, knowledge and experience to do a good job. Ask about relevant qualifications and training, experience and previous work. A competent supplier will be able to supply references or testimonials – ask for them. If the cost is high, it might be worth visiting other sites and viewing other LEV installed by the supplier. A good supplier should also be able to train your staff to maintain the LEV.

Some trade associations keep lists of members who claim LEV competence. Prepare a simple description of the work you want the person to do and give it to them. Ask them what qualifications, experience and types of LEV system they have designed or supplied before.

No. A training course by itself will not make a person competent. Competence comes from a combination of knowledge, skills and experience. Some people with lots of experience, but with no formal qualifications, may be competent.

No. HSE mentions certain training courses in its guidance, as examples, but does not require suppliers to have these qualifications. CDI engineers have the recommended P601 and/or P602 qualifications.

Thorough Examination and Test FAQs for Employers

Health and safety law says you must assess the risks to your workers from hazardous substances – dusts, fumes, vapours, etc. – and decide what measures to use to protect their health.

If the measures you adopt include extraction systems (LEV) to remove the dusts, fumes, vapours etc. produced by your work processes or activities, then you must maintain the LEV in efficient working order so it continues to provide the necessary protection. You should also have a periodic thorough examination and test (at least every 14 months) and must keep this record for at least 5 years. In addition, you should have information on the installed LEV system to confirm it provides adequate protection, which should be kept for the life of the equipment.

It is a check that your LEV is still working as effectively as originally intended and is helping to protect your employees’ health. To be able to tell if it is still working as it should, you should be able to provide the examiner with information about the intended or designed performance of your system e.g. hood type and position relative to the process, airflow and other measurements.

This information might be in the form of an initial appraisal or commissioning report, if one was carried out, or for simple ‘stand alone’ systems it could have been provided as standard operating data by the suppliers of extraction equipment. Alternatively, it might be found in recognised guidance (including that from HSE) on simple processes/systems. If none of this is available, you could consider getting someone competent to advise you.

Carrying out a thorough examination and test of LEV equipment requires specialist skills and although it is possible to undertake this on your own, most businesses engage someone with specialist knowledge, experience and skills (See What is competence?) It is important that the person who undertakes the thorough examination and test is competent to do so.

The examiner will use information about your equipment’s intended performance to undertake the necessary examinations, tests and measurements to verify whether it is still meeting this level of performance. The report that they provide for you should clearly show whether this is the case and if it isn’t, the report should clearly show what is wrong and what needs to be done to correct it.

It is important that you:

  • Read and understand your thorough examination and test report
  • Ask the examiner questions if you don’t understand anything that it says
  • Make sure you act on the recommendations in the report.

To assess if the LEV is still working properly, the examiner ideally needs to know what it was originally intended to do. When you obtained the LEV equipment, the supplier should have tested it on installation (or ‘commissioned’ it) to check it was working effectively and providing the necessary protection, as specified. If this did not happen then other sources of information may be available. See ‘What is the purpose of a thorough examination and test?’.

The person doing the examination should let you know whether the information you provide is adequate for assessing whether the LEV is working as intended. Many examiners can help you identify intended performance information.

The law says that a record of the thorough examination and test should be kept. The HSE Approved Code of Practice gives practical advice on what the report should contain, which includes details of the system’s intended operating performance. It is strongly recommended that you get a report that follows this guidance. If you do so you will probably be doing enough to comply with the legal requirement to keep a record.

The person who undertakes your thorough examination and test must be competent to do so. See – Why do I need to employ or use competent people? for more information on competence. If you don’t understand what the examiner is saying or what the report means, then ask. A good examiner will be able to tell you beforehand whether they have enough information for them to be able to check if your LEV system is working as intended.

Thorough Examination and Test FAQs for Examiners

The user or owner of the LEV equipment has the duty in law to get thorough examinations and tests done. You will have been engaged to provide the necessary competent support the user/owner needs to do this, and they will expect you to provide adequate service and advice. The purpose of the thorough examination and test you undertake is to ensure that the LEV system is still performing as originally intended and contributing to the adequate exposure control. You should make sure you have sufficient information to be able to do this work.

You should undertake sufficient work to provide a report that shows whether the LEV system is performing as originally intended and contributing to the adequate control of exposure, and where it isn’t, provide advice on the adjustments or repairs necessary for it to do so. Note that in most circumstances, you may need to ask the employer (client) to have the process running under normal operating conditions for you to assess the LEV’s performance.

In the case of simple or standard LEV equipment, the employer (client) could be advised to obtain information on its intended operating performance, such as performance data and other information from the equipment suppliers. HSE guidance such as COSHH essentials sheets and users own COSHH risk assessments may be useful in comparing with current performance. If such information is not available, you may, in the case of unmodified, single-point, standard systems, be able to use your own knowledge to refer to information about expected performance for this type of equipment and use this in your report. Many design criteria are standard and should be known and used by competent examiners.

Where no information is available for non standard and multipoint LEV systems, then coming to a judgement on whether it meets its initial design and performance standards may be more difficult and in some cases not possible. In such cases, you should still undertake a thorough examination and test, which will provide information on the current performance of the system.

Paragraphs 176 and 177 of the Approved Code of Practice lay out the range of things to cover and ways of making an examination assessment. However, it is accepted that such a report may not fully meet the advice in the ACOP, which recommends reference to intended operating performance, and you should indicate this in your report. You should also suggest that the user assesses whether the performance you have reported is providing adequate control. Your examination should also identify any adjustments or repairs that you believe are needed.

Further guidance on the methods and techniques to use in conducting your examination can be found in the booklet ‘Controlling airborne contaminants at work’ HSG258.

Where you cannot make a professional judgement on the design performance standards of the LEV, or your assessment suggests that the exposure control may not be adequate, you should clearly indicate this in your report to the employer (client). The report should also clearly indicate where no information on intended performance was available.