Hazard perception for gas safety

Paul Boughton

Louise Early reveals an end-to-end strategy for gas safety. The first step in securing gas safety in a steel manufacturing or processing plant is to identify which gas or mix of gases is present

According to the World Steel Association’s 2014 safety audit, gas or asphyxiation are among the most common causes of injury in the steel industry. So it is even more surprising that the same audit found that 27% of the 11,400 hazards that related to gas or asphyxiation were considered ‘not under control'.

Although these statistics make uncomfortable reading, they are perhaps understandable in an industry that has so many visible dangers. Identifying the risks posed by obvious hazards, such as moving machinery or molten steel, is much easier than assessing the risks posed by one or more gases. It is also relevant that, even when gas detectors are deployed, maintaining a high level of ongoing protection for every employee can also be a challenge.

The first step in securing gas safety in a steel manufacturing or processing plant is to identify which gas or mix of gases is present. A gas detection specialist with specific knowledge of the steel industry should be able to identify the risks that are specific to each site during a risk assessment. The most common gases found throughout the steel industry are carbon monoxide, ammonia, sulphur compounds, hydrogen, argon, benzene and nitrogen, or a mix of two or more of these gases. The levels of oxygen also need to be considered because environments that are deficient in oxygen can lead to asphyxiation, and oxygen-enriched environments can allow materials to ignite more easily and burn more fiercely.

The next step

The next stage in implementing a gas safety strategy is to match the different detector technologies to the hazards found in each site. Just as cars may be powered by engines that are based on different technology, so gas detectors also use different technologies to detect the same gas. Take, for example, carbon monoxide (CO) detectors. Electrochemical sensors are used to detect CO, however the presence of hydrogen (a common gas in the industry) is known to affect these sensors. In the steel industry, therefore, it is common that hydrogen-filtered CO sensors are used. Using a carbon monoxide sensor with a standard filter could introduce failures related to inhibited or masked readings, reducing the safety of the operator.

Other safety failures may include using a detector that does not have an extra removable filter cover. The ferrous dust that is present throughout the steel industry can easily block the sensors and prevent the target gas from reaching one or more of them. A filter cover fits over the gas inlets, preventing dust from blocking the sensors. However, the filters in the cover can also become blocked with use. It is therefore important that the filter cover can be easily removed and replaced with a clean one.

Other crucial factors in deciding which personal gas detector to use are the physical size of the detector and its ease of use. These are particularly important when an operator has to use crawl spaces, service hatches and inspection points, or work in other confined spaces. In these situations, a bulky detector, or one that is difficult to read, can make the work less comfortable for the operator and can also mean that the task takes longer to complete.

Assuming that all of the gas hazards have been identified correctly and that the appropriate detectors have been deployed, the challenge then becomes one of ensuring that the equipment continues to be used correctly. A comprehensive end-to-end gas strategy will include guidelines and training for the operators who use and/or service the equipment, for line and fleet managers and for the site safety manager.

Among the more important safety procedures is for the operator to carry out regular function checks to ensure the correct operation of equipment, so bump-testing and calibration checks should be carried out at the specified intervals. Some detectors are fitted with a useful indication advising the operator and other members of the work team when a test is due or overdue. Some test units can also output a log of test times and results that provide information for safety or line managers to highlight non-conformance to site requirements as well as non-alarm events that could contribute to improved safety.

A strong approach to reviewing and managing test data is as crucial as managing scheduled maintenance or end-of-life replacement of detectors that operate on a fixed life-cycle. For the safety manager, this information can be used to ensure safe working conditions as well as to prove compliance to safety regulations.

The expertise exists to identify the gas hazards that are specific to each site within the steel industry. There is also a wide choice of technologies, both conventional and new, that can be used to warn and protect operators from unsafe working conditions. If these skills and technologies are correctly deployed, and the steel industry takes an end-to-end approach to gas safety, perhaps the World Steel Association’s 2016 safety audit will find that all 11,400 gas or asphyxiation hazards are no longer ‘not under control'. 

Louise Early is strategic industry manager at Crowcon