Hidden assassins05 October 2012

Every year, thousands of people in Great Britain develop occupational asthma or die of lung diseases, because of airborne contaminants they inhale at work. Brian Wall reports

No organisation wants to see the health of its employees jeopardised, and most take their obligations very seriously, ensuring high standards of health and safety across their plants. Yet some aspects of employee protection may be more evident than others. With airborne contaminants, the enemy is often invisible and can slip through the proverbial net.

For example? Where your plant produces dust, mist (such as paint mist from spraying), fumes (from welding), gas (carbon monoxide from furnaces) or vapour (solvents from painting). All of these pose a level of risk to health, so it's vital that employees are given the highest levels of protection.

This is where local exhaust ventilation (LEV) systems come in. Properly designed LEV collects and removes contaminated air, cleans it (where necessary) and gets rid of the contaminants safely.

So how marked is the problem? Within the UK alone, an estimated 3,000 people develop occupational asthma every year through exposure to dangerous substances at work, while around half of sufferers find their pre-existing asthma is aggravated by conditions at work, according to Asthma UK.

The World Health Organisation (WHO) recommends that the highest concentration of airborne particles (PM10) should be 50µg/m3 (0.05 mg/m3) over a 24-hour period. "Actual levels in warehouses, factories and on shopfloors are, on average, between 200—500µg/m3, so it is advisable for any company undertaking dusty processes to carry out initial assessments and establish whether people are at risk," advises Louise Harris, UK brand manager, Zehnder Clean Air Solutions.

"Before any products are installed, it is important to first measure the dust contamination levels over a week-long or shift/production pattern period, in order to ensure a comprehensive understanding of the airborne concentrations in a typical working week. This helps pinpoint whether the problem is occurring throughout the day or only at specific times – and will dictate which control measures are used," she adds.

High concentrations of dust etc can then be simply and quickly removed by installing air filtration units at the correct locations on site. Modern low-noise and low-energy equipment works like a continuous vacuum cleaner, reducing the concentration of airborne particles by 60—80%.

No panacea

However, LEVs are not an instant cure-all. According to the HSE, many employers who buy equipment later discover it doesn't work properly. Why? Because they purchase the wrong type or they're not properly installed, used or maintained. So it's imperative to make sure your solution is fit for purpose.

Gary Keene, project director at Nederman, which supplies industrial air filtration, agrees. "Unless a plant has specialists in-house, they will need to seek professional advice when designing, commissioning and testing cost-effective LEV. Despite all good intentions, it is still difficult to keep on top of all the legislation and best practice advice."

Nederman recommends that plant managers work with dust and fume experts – and in collaboration with unions and employee representatives – to provide, maintain and use effective LEV and to reduce exposure to inhaled hazardous substances.

"Rather than picking and choosing individual products," adds Keene, "the key is to look at the dust and fume extraction as a system and create a bespoke solution designed to match a plant's industrial processes. Often a slightly bigger initial investment can be a better long-term solution, rather than purchasing individual pieces of apparatus."

Covering all the bases

The law (the Control of Substances Hazardous to Health (COSHH) regulations) states that you must control risks from airborne contaminants. But while installing local exhaust ventilation (LEV) may help, you should consider other options first, says the HSE. These include:

Eliminate the source/reduce its size

Substitute the material being used with something safer

Modify the process to reduce the duration or frequency of emission

Decrease the number of employees involved with a process

Apply simple controls, such as fitting lids to equipment

For more information, see HSE's COSHH website: www.hse.gov.uk/coshh

Brian Wall

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Nederman Ltd
Zehnder Group UK Ltd

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