Monitoring gas and air
September 1st 2003

As there is no one simple way to specifically detect all gases, a variety of techniques are usually required to ensure a complete monitoring programme. Here Draeger highlights some options The manufacturing process, the materials used, the cleaning methods and airflow can all affect the quality of air in workplace environments. In particular, the creation of gases and vapours can turn a previously safe atmosphere into a toxic and possibly lethal workplace area. In addition, the need to monitor oxygen levels for deficiency can be as important as the need to monitor and control potentially explosive or flammable environments. In accordance with CoSHH as well as European legislation, employers must ensure that any hazardous substances that are used in or created by workplace activities are both monitored and controlled. To ensure absolute safety, employees should also perform a risk assessment to ascertain the hazards that may be present and then continue to monitor the workplace area before entering a potential hazardous environment. A typical example can be found in the brewing industry where increased levels of nitrogen (used to make a more effervescent beer) could lead to oxygen depletion and, as a result, asphyxiation. In steelworks, leaks of carbon monoxide, which is used as a process gas, can create a potentially hazardous environment. Even those working in the food industry can suffer from the effects of disinfectants containing hydrogen peroxide or, in refrigeration and cold storage areas, unhealthy levels of ammonia. It is also possible that the toxic and/or flammable gases and vapours that are created during previous work might still be present upon re-entry at a later date. In addition, an atmosphere containing less than 21 per cent oxygen is known as being oxygen deficient and can be life-threatening. Regular air sampling will ensure that effective control measures are introduced as and when necessary to eliminate risks to health and safety for all employees. However, as there is no one simple way to specifically detect all gases, a variety of techniques are usually required to ensure a complete monitoring programme. Short Term Tubes Short term tubes provide on the spot gas measurement and are suitable for monitoring personal exposure, spot check measurements, leak checks and confined space investigation. Ideal for risk assessment in line with CoSHH, the Draeger-Tube range enables fast, accurate measurement of over 500 different types of gases and vapours. Spot measurements can also be easily carried out with the Draeger Chip Measurement System (CMS), a portable, Multi-gas Detection System that requires minimal user training and that provides an immediate, true digital readout without the need for further evaluation. Short Term Pumps Used in conjunction with the tubes, hand bellow pumps enable rapid measurements to be taken and provide optimum volume and flow specifications. Incorporating automatic stroke counters and a clear end of stroke indicator, pumps require no special tools and give accurate and reproducible results. Diffusion Tubes Providing up to eight hours of use, diffusion tubes give an accurate indication of exposure by allowing contaminant molecules to move into the tube without the aid of a pump. Sampling Tubes Requiring laboratory analysis, passive sampling tubes provide short and long term collection of toxic substances. Available in activated charcoal and silica-gel versions, they are often worn on the breast pocket. Personal Single Gas Monitors Simple to use, these handheld instruments can monitor a broad range of gases. Offering an immediate visual display of gas concentrations, they also provide audible and visual alarms when danger levels are reached. The fast response, pocket-sized Draeger microPac Single Gas Monitor, for instance, incorporates electromechanical sensor .technology and is suited to the monitoring of carbon monoxide, oxygen and hydrogen sulphide. Multi-Gas Measurement: These high performance instruments can be used to measure a wide variety of gases in virtually any application such as indoor air quality for confined space entry or the monitoring of landfill gas. The more modern units feature individually adjustable visual and acoustic alarms. For example, the handheld Draeger MiniWarn portable Multi-gas Monitor can detect up to 40 different gases, with up to four of these (usually oxygen, one flammable and two toxic gases) being detected simultaneously. Fixed Gas Detection Systems Fixed gas detection systems provide round-the-clock protection and can be used to monitor remote areas and multiple sites. The Draeger range of transmitters is designed for use under the toughest conditions. With a broad variety of environmental specifications, overall protection against RFI, and high vibration, shock resistance and corrosion resistant enclosures, the range is suitable for all kinds of applications CoSHH News Under recent CoSHH legislation any organisation with more than 5 employees should now be carrying out a workplace risk assessment if they are using asphyxiant gases. As some of these asphyxiants, such as nitrogen, helium and argon for instance, are colourless and odourless, it is difficult to prevent or adequately control exposure without measuring the oxygen content of air. Designed to continuously monitor toxic gas or oxygen concentrations within the workplace environment, the new Draeger Polytron C gas detector can help to solve the problem. Specific training courses on gas detection equipment are now available from Draeger and, as part of its ongoing gas detection and protection support programme, Draeger also offers free advice on the selection and use of air sampling methods.

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