Dispense gas known as beer gas, keg gas, cellar gas or pub gas is used in bars and restaurants as well as the leisure and hospitality industry. Using dispense gas in the process of dispensing beer and soft drinks is common practice worldwide. Carbon dioxide (CO2) or a mix of CO2 and nitrogen (N2) is used as a way of delivering a beverage to the ‘tap’. CO2 as a keg gas helps to keep the contents sterile and at the right composition aiding dispensing.
Even when the beverage is ready to deliver, gas-related hazards remain. Those arise in any activity at premises that contain compressed gas cylinders, due to the risk of damage during their movement or replacement. Additionally, once released there is a risk of increased carbon dioxide levels or depleted oxygen levels (due to higher levels of nitrogen or carbon dioxide).
CO2 occurs naturally in the atmosphere (0.04%) and is colourless and odourless. It is heavier than air and if it escapes, will tend to sink to the floor. CO2 collects in cellars and at the bottom of containers and confined spaces such as tanks and silos. CO2 is generated in large amounts during fermentation. It is also injected into beverages during carbonation – to add the bubbles. Early symptoms of exposure to high levels of carbon dioxide include dizziness, headaches, and confusion, followed by loss of consciousness. Accidents and fatalities can occur in extreme cases where a significant amount of carbon dioxide leaks into an enclosed or poorly ventilated volume. Without proper detection methods and processes in place, everyone entering that volume could be at risk. Additionally, personnel within surrounding volumes could suffer from the early symptoms listed above.
Nitrogen (N2) is often used in the dispensing of beer, particularly stouts, pale ales and porters, it also as well as preventing oxidisation or pollution of beer with harsh flavours. Nitrogen helps push the liquid from one tank to another, as well as offer the potential to be injected into kegs or barrels, pressurising them ready for storage and shipment. This gas is not toxic, but does displace oxygen in the atmosphere, which can be a danger if there is a gas leak which is why accurate gas detection is critical.
As nitrogen can deplete oxygen levels, oxygen sensors should be used in environments where any of these potential risks exist. When locating oxygen sensors, consideration needs to be given to the density of the diluting gas and the “breathing” zone (nose level). Ventilation patterns must also be considered when locating sensors. For example, if the diluting gas is nitrogen, then placing the detection at shoulder height is reasonable, however if the diluting gas is carbon dioxide, then the detectors should be placed at knee height.
The Importance of Gas Detection in Drinks Dispense Systems
Unfortunately, accidents and fatalities do occur in the drinks industry due to gas hazards. As a result, in the UK, safe workplace exposure limits are codified by the Health and Safety Executive (HSE) in documentation for the Control of Substances Hazardous to Health (COSHH). Carbon dioxide has an 8-hour exposure limit of 0.5% and a 15-minute exposure limit of 1.5% by volume. Gas detection systems help to mitigate gas risks and allow for drinks manufacturers, bottling plants and bar/pub cellar owners, to ensure the safety of personnel and demonstrate compliance to legislative limits or approved codes of practice.
The normal concentration of oxygen in the atmosphere is approximately 20.9% volume. Oxygen levels can be dangerous if they are too low (oxygen depletion). In the absence of adequate ventilation, the level of oxygen can be reduced surprisingly quickly by breathing and combustion processes.
Oxygen levels may also be depleted due to dilution by other gases such as carbon dioxide (also a toxic gas), nitrogen or helium, and chemical absorption by corrosion processes and similar reactions. Oxygen sensors should be used in environments where any of these potential risks exist. When locating oxygen sensors, consideration needs to be given to the density of the diluting gas and the “breathing” zone (nose level). Oxygen monitors usually provide a first-level alarm when the oxygen concentration has dropped to 19% volume. Most people will begin to behave abnormally when the level reaches 17%, and hence a second alarm is usually set at this threshold. Exposure to atmospheres containing between 10% and 13% oxygen can bring about unconsciousness very rapidly; death comes very quickly if the oxygen level drops below 6% volume.
Gas detection can be provided in the form of both fixed and portable detectors. Installation of a fixed gas detector can benefit a larger space such as cellars or plant rooms to provide continuous area and staff protection 24 hours a day. However, for worker safety in and around cylinder storage area and in spaces designated as a confined space, a portable detector can be more suited. This is especially true for pubs and beverage dispensing outlets for the safety of workers and those who are unfamiliar in the environment such as delivery drivers, sales teams or equipment technicians. The portable unit can easily be clipped to clothing and will detect pockets of CO2 using alarms and visual signals, indicating that the user should immediately vacate the area.
For more information about gas detection in drink dispense systems, contact our team.