Frequently asked questions
- Do I have to fit airflow indicators to all the hoods in the LEV system?
- How do I know that LEV hood airflow is adequate?
- Do I have to fit airflow indicators now?
- Are airflow indicators the best way to check airflow for all types of hood?
- What sort of airflow indicator should be fitted?
- Wouldn’t airflow ‘tell-tales’ be good enough?
- Do examiners have to label LEV systems they test?
- Do examiners have to label all LEV hoods tested?
- Do examiners have to put red labels on all LEV hoods that have failed?
- Is there an alternative to labels?
I’m an employer
- I have been told that I need my LEV thoroughly examined and tested, what does this mean?
- What is the purpose of a thorough examination and test?
- Who can undertake the thorough examination and test and what responsibility does that person have?
- What information does the examiner need?
- What should be in the LEV examination?
- How should I choose my examiner?
Answers to above
1 – Do I have to fit airflow indicators to all the hoods in the LEV system?
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.
2 -How do I know that LEV hood airflow is adequate?
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.
3 – Do I have to fit airflow indicators now?
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.
4 – Are airflow indicators the best way to check airflow for all types of hood?
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.
5 – What sort of airflow indicator should be fitted?
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.
Example of a simple airflow indicator display
Green – Adequate airflow
Red – Inadequate airflow
6 – Wouldn’t airflow ‘tell-tales’ be good enough?
‘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.
7 – Do examiners have to label LEV systems they test?
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.
8 – Do examiners have to label all LEV hoods tested?
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.
9 – Do examiners have to put red labels on all LEV hoods that have failed?
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.
10 – Is there an alternative to labels?
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.
I’m an employer
1 – I have been told that I need my LEV thoroughly examined and tested, what does this mean?
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.
2 – What is the purpose of a thorough examination and test?
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. (For examples see http://www.coshh-essentials.org.uk/). If none of this is available, you could consider getting someone competent to advise you.
3 – Who can undertake the thorough examination and test and what responsibility does that person have?
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 http://www.hse.gov.uk/lev/faqs.htm#q11). 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.
4 – What information does the examiner need?
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.
5 – What should be in the LEV examination?
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.
6 – How should I choose my examiner?
The person who undertakes your thorough examination and test must be competent to do so. See http://www.hse.gov.uk/lev/faqs.htm#q12 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.
You can find more information at: http://www.hse.gov.uk/pubns/indg408.pdf