MONITORING FOR HEALTH HAZARDS IN THE WORKPLACE
When you see deaths in the news caused by workplace incidents it is normally down to safety related issues such as falls from height. But deaths from health related issues arising out of the workplace far exceed those from safety failings, with UK estimates that 13,000 people die every year from work related ill health.1
data you are getting is valid and accurate. We can now look at types of exposure and look at the pros and cons of different instrumentation to make measurements.
Dust and aerosols Figure 1 - An air sampling pump
The cost of ill health to businesses is becoming increasingly understood. In the UK construction industry work related ill health costs £848 million per year.2
This is the cost to the employer alone and excludes the cost to society and the individual.
Monitoring for issues that can effect ill health in the workplace is therefore increasing. There are many monitoring technologies available for measuring hazards that can cause long latency health effects and monitoring forms part of the risk assessment. There are many ways in exposure can be estimated from existing data, such as Hand Arm Vibration (HAV) from tool manufacturers data, but often this is not enough to consider real world factors, such as tool wear which might increase exposure levels with time.
Understanding monitoring technology is key so you know the Gases and Vapours
There are similar parallels here to dust exposure, there is generally a pump method and often a real- time alternative. Pumps for sampling gases and vapours are generally smaller than those for dust as they don’t need to draw air at such a high flow rate, and the air is typically sampled onto a adsorbent tube filled with for example, charcoal. The pump is again the most accurate way of assessing exposure, but you must know what you’re sampling for and select the right tube, flow rate and ensure the lab selected
IET September / October 2019
www.envirotech-online.com
Dusts can cause significant health effects, both acute and chronic. There are two types of ways to measure exposure, the most common being an air sampling pump (Figure 1). Pumps are generally bodily worn devices which sample the dust onto a filter, via a sampling head worn in the breathing zone. The filter can be sent off to a laboratory for analysis. It seems almost archaic in the modern world that we need to do this, that there isn’t an instant result. Well of course, there is with a real time dust monitor. A pump and filter method is the most accurate way of assessing exposure, but you have to wait for the lab results, so a real time instrument is appealing. Real time monitors (Figure 2) generally use light scatter to measure dust level, and can provide a level of dust straight away. But as light interacts with different types of dust in different ways it cannot give a true level of dust, but gives an indicative level. So air sampling pumps can give as near a true level of exposure and real-time instruments can then tell you when the exposure occurred. Real time instruments can tell you if something has changed, if control measures such as LEV are effective, and provide a training tool to educate employees of how there actions may be effective exposure, such as using a brush to sweep dust rather than the recommended vacuum cleaner. Remember it is the dust you cant see that you breath in because it is too small, that is harmful, so being able to show this with a real time monitor is very helpful.
can analyse what you want to measure. There are also real time equivalents such as a Photo-ionisation detector for vapours, and the gas detectors. Gas detectors are of course a monitoring technology that most health and safety professionals are familiar with, being used for safety to stop people being hurt in the here and now, but they can also be used to monitor exposure. The pump sampling through a tube with allow calculation fo the 8 hour exposure to compare to Workplace Exposure (WEL) limits, but gas detectors can tell you when exposure is occurring, which can then point to the place exposure is occurring and therefore look at where control measures need to be put in place. Gas detectors and PIDs have different sensitivities to different gases or vapours so care must be taken to know exactly what is present in the air to make the correct assessment, and sensor cells can suffer from cross sensitivity to other gases. Know what you are measuring, and ensure any real time instrument is calibrated. For an accurate analysis of exposure, use the methods described in legislation such as the UKs Methods for Determination of Hazardous Substances (MDHS) available from the HSE.
Figure 2 - A real time dust monitor
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