Neglecting functional safety can have serious consequences in food and beverage processing plants
03 July 2017
In 2014, in the UK, a large food manufacturer had to pay an £800,000 fine after a serious industrial accident. An engineer was trapped by the machinery while examining a conveyor belt and suffered major injury and ongoing nerve damage. Accidents such as this are widely reported, but many people are unaware of the number of hazardous areas found in food and beverage processing plants.
Across the globe, there are a variety of different regulations for food processing plants. In particular, North America and Europe have strict regulations for safety in these potentially dangerous environments. This also applies to the safety of employees in the processing plants and employers who fail to make adequate safety considerations can face large fines. Not only can these authorities enforce these in the case of accidents, they can also be enforced during regular inspections.
In Europe, the Machinery Directive 2006/42/EC requires machinery to be designed and built so that it can be used safely. In food processing plants, there are many dangerous machines for which plant managers should follow safety regulations, or the plants may face closure or high fines. Machines such as decanters exhibit high centrifugal forces during operation and it is not unknown for the machine's g-forces to reach more than 2000 times gravitational force. This is clearly a dangerous environment for employees to work in, however as these machines are essential for use, the key concept is the management of risk.
In the 1970s, the increase in heavy machinery such as the creation of the steel press led to increased safety guards. Since then, many safety conscious companies undertake a risk analysis in the initial stages of machine development. In the case of decanters, it is not possible to remove the risk, but it is possible to mitigate the risk to an acceptable level by putting safety guards such as enclosures or emergency stops into place.
The hazardous nature of a food processing plant is especially affected by the need for hygiene, the continuous working of the plant and the high turnover of staff. To comply with hygiene regulations, plants need to be constantly washed down, meaning that despite safety guards, equipment needs to be accessible, which adds additional risk.
Due to the high demand on food and beverage production facilities, plants often run 24 hours a day. Continuous operation means there is little time for downtime and repairs to be carried out. In the food industry, it is during breakdowns when injuries occur. Workers, faced by high targets and strict deadlines, will attempt to repair equipment themselves. They may override safety guards to reach into machines and risk injury in the process. It is therefore vital that despite high production targets, employees are well educated in the company’s safety policies.
Despite overall labour turnover falling in Britain over the last five years, there is a notoriously high turnover of staff in food and beverage processing plants. This presents an additional complication to the hazardous areas. Employers are often reluctant to spend much time training staff on safety procedures, but run the risk of having employees who are not sufficiently up to speed.
The UK’s food processing industry employs 117,000 migrant workers from the EU, which supplies the sector with the necessary labour. However, language barriers and a high turnover of staff can indirectly create safety hazards. It is vital that plant managers communicate safety measures more effectively to reduce the risk to non-English speaking employees. This can be done by using visual displays or by placing new staff members alongside more experienced employees.
Hazardous areas exist in plants across the food processing industry. Safety guards need to put in place from the very start of the food chain, such as in the milking process. In milking parlours, exposed platform rollers must be guarded to avoid any clothing or employee becoming trapped. Hazards are present throughout the plant, from the handling of the raw material, to production — where industrial ovens can often reach very high temperatures— to the final packaging of the product.
Breweries are a particularly strong example of the hazards present in the food processing industry. The dust generated in the conveying, sieving and milling of malt grains, can form flammable dust clouds. This creates a potentially explosive environment, officially classifying the environment as a hazardous area. This means that ATEX ratings must be observed on all equipment used in this environment.
Later down the line, carbon dioxide, a dangerous by-product of the fermentation process, can be fatal if inhaled. Workers have died while trying to perform repairs or checking fermentation tanks, becoming overwhelmed by CO2 almost immediately. This means that companies should use suitable sensors and locks to separate workers from the tanks, while also educating workers on the dangers of the tanks.
In the beverage industry, particularly in breweries, packaging and filling is the most dangerous place in the food processing chain. The speed of operation and high quantity of goods being moved increase the risk of things going wrong.
In the beverage industry, glass bottles are commonly filled at high speeds and at high pressure, meaning the glass bottles could explode if the machines are incorrectly programmed. As these beverage plants are operating under high time pressures, it is not possible to completely stop the production line for receptacles to be changed. Instead, the filler operates at a slow speed, allowing the operator to change the bottle or can. It is vital that companies use sensors to monitor the speed of the machine and have emergency stops in place, in case of a breakdown.
Often, companies find it too difficult to manage the complex world of safety regulations and procedures alone. In this case, it is always better to consult a professional rather than fail to comply with the regulations, as this will work out to be a costly mistake. ABB’s experts can provide specific advice on regulations in specific countries, which also takes into account the needs of food processing plants.
As companies become more knowledgeable about regulations and regulations become more stringent, the need for retrofitting old equipment with additional safety measures will rise. Although it may seem instinctive, where there is a dangerous moving machine, the safest answer is not always to shut it away behind an enclosure or barrier.
In the food processing industry, companies should consult with functional safety experts who have experience in the sector. The experts will, for example, suggest equipment such as a light grid, which performs a local controlled safe stop when the light grid is actuated. These devices are more appropriate for the food processing sector than using physical guards or barriers as they allow easier access for maintenance and washdown, which is essential for hygiene in food processing plants.
Functional safety experts are also able to advise on the use of safety programmable logic controllers (PLCs), rather than traditional PLCs. Safety PLCs are designed to help companies comply with functional safety regulations such as IEC61508 and IEC61511. Safety devices can be connected directly to the PLC, which monitors equipment such as light curtains. By using the PLCs, companies can meet the rigorous standards required in the food industry.
Managers of food processing plants in all countries, regardless of the country’s regulations, should prioritise plant safety. Not only must plant managers comply with regulations to avoid the plant being closed by authorities, they also have a duty to protect their employees.
Plant managers are aware that they manage very hazardous areas and the risks cannot be completely avoided. By working with specialist safety consultants, plant managers should be aware of what they can do to mitigate risks, all the while considering the specific needs of the food and beverage industry.
About the author
Jörgen Saxeryd is safety products and functional safety advisor to ABB’s food and beverage program.