Introduction

In general, the most commonly used gases in the brewing process are Carbon Dioxide (CO₂), oxygen (O₂), and nitrogen. As CO₂ is a mild asphyxiate, it can be dangerous for personnel operating around the process machinery. The worst outcome of exposure to CO₂ is suffocation. Breweries of all sizes need to be aware of the dangers of CO2 and have a fixed gas leak detection system installed.

How does CO2 provide a danger to people?

At ordinary levels, CO₂ is one of the safest chemicals you’re likely to ever encounter. It is a normal component of air and so safe it is added to beverages to carbonate them. However, CO₂ could have a detrimental health effect from exposure at high concentrations – a real possibility within the brewing process.

In breweries, CO₂ is used in large volumes and can result in over-pressurisation within storage and process vessels posing the threat of rupture. In the event of a gas leak, personnel operating around the process machinery are faced with the real threat of CO₂ poisoning.

The properties of CO₂ are colourless, odourless, and tasteless making it difficult for a human being to sense it until overexposure. Even a low concentration of CO₂ such as 0.5% (5000 ppm) may be sufficient to become unwell.

The first noticeable effects of inhaling CO₂ at high concentrations will be dizziness, poor respiration and eye and throat irritation.

This could develop with severe headaches and could eventually cause you to black out. A CO₂ rich environment of 5% provides an increased risk of asphyxiation and eventually suffocation.

Where does CO₂ provide a danger?

In addition to fermentation, storage and dispensing, CO₂ is also used in breweries to carbonate beer and to purge tanks, bottles, kegs, and/or cans before being filled with beer.

Certain areas within the brewing process have been identified as having (or potentially having) elevated levels of CO₂.

Fermentation

During the fermentation process, yeast consumes oxygen and expels large amounts of CO₂. As it has a density that is heavier than air, it collects in small toxic pockets low on the floor and can build up in poor ventilated, confined spaces in and around the process.

If the cellar (or wherever fermentation vessels are located) does not have adequate ventilation there is a risk of CO₂ build up.

Compressed Gas Storage

All compressed gases must be properly labelled and stored and might require specific PPE when changing tanks.

Gas Cylinder Storage

Portable gas cylinders such as CO₂, nitrogen, and oxygen should be properly chained up in a cool, dry, ventilated area with their valves closed if not in use.

CO₂ Leaks

CO₂ leaks can be detected using CO₂ detectors. Alarms can be put in place to warn employees that there is a risk of CO₂ exposure. Also, small personal CO₂ detectors can be worn by employees in areas where a high CO₂ release could occur.

A Case Study: CO2 in Breweries

a1-cbiss have been supplying and installing gas detection systems to medium and large breweries across the UK for the past 15 years. a1-cbiss are relied upon for their gas detection experience working with breweries thanks to their ability to design and build a system specifically for the clients’ needs.

Due to the physical size and complexity of breweries, a1-cbiss always carry out a survey to fully determine how the process works, identify the location of gas hazards, where and how to initiate control measures, create an installation plan and to discuss project outcomes with the client.

The CHALLENGE

To adhere to the Control of Substances Hazardous to Health Regulations 2002, the EH40 guideline presents the workplace exposure levels. It is the responsibility of the brewery to comply within these WEL limits to ensure the safety of personnel.

The SOLUTION

In general, there are two proven solutions for CO₂ gas detection to create a safe work environment:

1. The installation of fixed CO₂ and O₂ A fixed gas detection system consisting of a gas transmitting head with a gas sensor connected to a control panel. The fixed sensor is mounted in the room where CO₂ could be present, and the control panel installed in another room which is guaranteed safe and CO₂ free.
2. The use of a portable and personal CO₂ gas detector. These should be worn by people when entering the room where CO₂ could be present.

Whilst the primary detection gas is CO₂, oxygen deficiency should also be measured in the brewery.

Fixed Gas Detection System

To ensure a safe workplace, a fixed gas detection system needs to be installed to provide visual/audible warnings, communication to extraction or ventilation systems, and integration to data acquisition and reporting software.

Alarms

Gas leak sensors should be installed near to potential leak areas. In the event of a leak, an alarm provides a warning to people entering or working in the area.

a1-cbiss supply either Oldham or Crowcon gas detectors. CTX-300 gas sensors are installed in some of the UK’s largest breweries. These are positioned within the hazardous zones in and around the process. As CO₂ is denser than air, these sensors are mounted as knee height. The gas sensors are cabled back to a central gas detection control panel.

Typically, each gas sensor is configured to respond to two alarm levels in relation to the EH40 guidelines (5,000ppm & 15,000ppm).

Depending on the requirements of the health and safety team at the brewery, the sensors provide internal alarm notifications (inside the hazardous zone) as well a visual alarm at each entrance to the detection zone (safe zone). Beacons on site are mostly the traffic light variety. They illuminate green when healthy/no alarm, amber on low-level alarm and red on upper-level alarm.

Activate Extraction or Ventilation Systems

In addition to alarms, the gas detection control panel also provides outputs to interface with extraction or ventilation systems.

Data Acquisition and Reporting Software

We recommend the integration of CDAS data acquisition & reporting software onto a local PC or into SCADA.

Health & safety teams commonly use a PC screen which is configured to show a complete graphical view of each zone, including traffic light coded indication of status and alarms. This setup generates a quick response in the event of a gas leak.

Personal Gas Detectors

Fixed gas detectors are hugely important in breweries but unless the detectors provide coverage of every inch of the space, there could be a risk of personnel being exposed to gas beyond a fixed gas detector.

Therefore, it is recommended that people wear personal gas detectors. Small personal CO₂ and O₂ detectors can be worn by employees in areas where a high CO₂ release could potentially occur. These detectors provide a visual and sounding alarm primarily to notify the wearer of imminent danger. More advanced gas detectors communicate with the health and safety team to provide a complete picture of what’s happening in the field.

a1-cbiss

a1-cbiss are flexible in supporting breweries in line with their capital budget requirements.

a1-cbiss are ISO accredited which means the installation teamwork to a good standard, and more importantly, Health & Safety standards are adhered to at all times.