Shaun Evers explains the importance of cold store safety

The food and drink processing industry, worth £103 billion to the UK economy, relies heavily on cold storage technology to ensure its smooth operation. As a result, the sector remains the fourth highest industrial energy user in the UK. However the implementation of sophisticated refrigerant technologies can significantly cut down on electricity consumption and the associated costs. Refrigerant gases are crucial for powering cold storage and industrial refrigeration units across the food and drink sector, but if a leak occurs the impact can be extremely damaging both to the environment and a company’s bottom line.

According to research by the Carbon Trust, a leak of just 1kg of refrigerant gases can cause the same environmental damage as driving a van for 10,000 miles. The financial implications of failing to address leaks is also evident, with energy consumption in the refrigeration sector costing British industry approximately £300 million each year, and the average site energy bill for a cold store totalling £0.5 million.

Add to this the fact that an estimated 4.1 millions tones of food is wasted in the food and drink industry annually, largely due to the incorrect storage of perishable goods, and the financially repercussions of not addressing cold store gas leaks is obvious. In fact, this figure represents over half of the UK’s total yearly food waste.

Gas leaks occur for a number of reasons. Equipment failure, improper maintenance work, mechanical damage and accidental release during refrigerant replenishment can all cause a potentially dangerous leak. Reducing the amount of gas leaks, or spotting and stopping them as early as possible, not only improves energy efficiency and helps protect the environment, it can also ensure employee safety.

While refrigerants are essential for keeping industrial refrigeration systems in food processing premises running, exposure can cause a serious threat to workers. Symptoms can include, irritation of the throat, eyes and skin, frostbite, and chemical burns, as well as more severe ailments like lung and brain damage.

Despite increasingly stringent regulations placed on companies who use refrigerants, leaks are still common. In fact, the Carbon Trust has recorded an average annual leak rate of up to 20 per cent in UK refrigeration systems, meaning store operators remain on the lookout for ways to ensure their employees safety.

Refrigerant gases
Steps are already being taken to ensure the most damaging refrigerants are not in use. Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) gases have been banned in new refrigeration equipment, due to their Ozone depleting properties, and have been gradually replaced. Hydrofluorocarbons (HFC) refrigerants have become more popular as a like-forlike substitute. However, these gases are still not environmentally friendly.

While safer than HCFCs and CFCs, HFCs still carry a significant threat. In fact, research has revealed that when released in to the atmosphere HFCs have a global warming potential of over 3000 times that of CO2. This significant discovery has led to a call for urgent action to reduce gas leaks from refrigeration systems.

These figures paint an even starker picture when leaks are left unrepaired. A typical 300kW refrigeration system with a small but continuous leak, left unrepaired for three months, could incur an energy penalty of 10kW in electricity once the leak becomes critical. This means an increased energy cost of £1400, not including the repair costs, which will be higher than if immediately repaired, as more refrigerant will be required.

Given the fact that 60 per cent of gas escapes before an employee notices, it cannot be left to staff to spot potentially dangerous leaks. However, by installing new technologies action can be taken to ensure leaks are spotted immediately and promptly repaired. This not only minimises the amount of energy loss, but is also a legal requirement as part of the EU F-Gas Regulations. The solution is quite simple, the use of a high-tech gas detection system.

Gas leak detection
EU legislation states that any refrigeration system with 300kg or more of refrigerants must be fitted with a leak detector, with cold stores that have a charge of 3-30kg required to be tested for gas leaks once annually and those with a charge of 30kg or more needing to be tested twice a year.

Fitted gas detectors must have a sensitivity of 5g/year and should be checked after 25 hours of continuous use. This is particularly prevalent in the food and drink industry where cold stores are required to operate on a 24/7 basis to keep foods safe and prevent spoiled produce. They should also be calibrated with a 1,000ppm gas to air mix.

Gas detection systems can be programmed to detect a wide array of both toxic and non-toxic gases, including HFCs. Staff members are alerted to any sensed gas leak with an audio and visual alarm, while LED colours indicate the presence and status of each sensor. This ensures that any problem can be quickly rectified.

Shutting the door on energy loss
Although gas leaks are the foremost contributor to energy loss and health and safety risk in modern cold stores, equally detrimental to an industrial refrigeration system’s energy performance is leaving doors open. While it may seem like a minor error, leaving a cold store door open can force a system to work harder to stay cool, in turn using more energy and incurring higher energy costs.

An easy way to prevent doors being left open for an extended period is through the installation of a door open alarm. These wall mounted devices use flashing Xenon Beacon lights and 100dB sounders, which produce audible and visual warnings to alert staff of open doors. An adjustable delay of up to 30 minutes can be preset and the sounders can be independently disabled or adjusted to ensure maximum speaker volume.

The alarm provides the food industry with a simple, cost effective solution for preventing major problems and the costs associated with damaged merchandise and energy losses due to refrigeration doors being left open.

Temperature control
Running equipment at the incorrect temperature is another area where energy is wasted throughout the food and drink sector. In fact overcooling by just 1ºC can lead to a significant increase in energy consumption of up to three per cent with temperature differences of 5ºC proven to increase electricity consumption by ten to 20 per cent.

Efficient thermometers linked to audio and visual alarms that warn staffof variants are essential to both monitorthe temperature of the cold store and the temperature of its contents. At its most basic this could be a digital thermometer designed to be used with a thermistor probe across a range of plus or minus 50ºC that will constantly display the temperature. These probes can be wall mounted or hand-held and chosen for wash down areas.

While vital to the extending the shelf life of food and drink, cold stores and refrigerated warehouses can be hazardous working environments.However, with the installation of effective refrigeration systems a business can reduce energy costs, limit unnecessaryfood waste, cut carbon emissions, anddemonstrate corporate responsibility. With a payback period of less than two years, installing technologies to monitor gas leaks and energy waste incold storage offers a simple solution for businesses across the entire food and drink sector.

Shaun Evers is managing director of Stonegate Instruments. Stonegate Instruments designs, develops and manufactures electronic equipment for the refrigeration industry. The company’s products are proven in cold storage facilities for reducing energy, carbon emissions and the associated costs.

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