Toxic load: detecting hazards

Ensuring worker safety is a concern all employers share.

However, you need only look at the Health and Safety Executive’s (HSE) daily bulletin to discover that many firms still commit safety failings.

One of the biggest issues, and one which gas detection specialist Crowcon says is a frequent offender, is the use of inadequate gas detection technology.

Crowcon product manager Nick Dajda says engineers working in systems such as sewers are often most at risk.

Bump testing is a quick and safe way of checking that each of your gas channels are working and reacting as they should be

Crowcon product manager Nick Dajda

Fortunately, there are means of mitigating these risks.

“Portable gas detectors, for instance, form a protection that alerts engineers well in advance of life threatening situations that arise from working in close proximity to toxic gases such as hydrogen sulphide and methane, as well as risks associated with oxygen depletion and flammable hazards,” Dajda says.

Portable systems can often be of more use than their fixed detector counterparts as they are able to give an accurate record of a worker’s personalised gas exposure throughout the day.

“Portable gas detectors stay with the user,” Dajda says.

“They are clipped onto a worker’s pocket near the breathing zone so they can record what they are breathing throughout their shift. Essentially, they are much more localised to the user so if the user walks into a gas cloud, the portable detector will pick it up.”

Portable gas detectors, however, do have one obvious shortcoming, Dajda says.

To work effectively, they must create a positive voltage or a current in the presence of the gas that they are trying to detect.

“In the case of toxic gas sensors, you use an electrochemical cell which has a finite lifetime. As the sensor ages and as its capacity get absorbed, that reduces its lifetime by small amounts,” Dajda says.

“It’s similar to a battery wearing down over time.”

In order to check whether a gas detector is working correctly or not, Dajda says engineers will often turn to bump testing.

Bump testing is the process by which a gas detector is exposed to a known concentration of target gases – predominantly methane, carbon monoxide, hydrogen sulphide and oxygen.

“Bump testing is a quick and safe way of checking that each of your gas channels are working and reacting as they should be,” Dajda says.

Engineers working in hazardous environments - such as those in the oil and gas industry - should consider using a combination of gas detection and self-contained breathing apparatus (SCBA), says Christian Vieille, product manager respiratory, Honeywell Safety Products EMEA.

“Gas detection systems allow workers to identify and understand existing gas risks while SCBAs (including working sets – autonomous and airline systems – and escape sets) protect them from inhaling toxic gases,” he says.

“Both technologies combined allow, on one hand, to prevent general risks and, on the other, to protect the workers’ vital functions in case of gas release,” Vielle adds.

Gas is not the only hazard a process engineer needs to be aware of, however.

Increasingly, noise – and noise-induced hearing loss - is becoming a major issue for employers.

Alan McArthur, technical services specialist at personal protection equipment firm 3M, says it’s an area where insurance firms in particular are becoming increasingly concerned and increasingly active – particularly when a company is found to have inadequate noise detection and noise reduction protocols.

Insurance claims made as a direct result of noise-induced hearing loss have risen sharply in the last few years, McArthur says.

However, he says the legal framework regarding noise concerns in the workplace is well established in the UK and that there are mandatory limits for exposure, making noise-related issues a matter of inadequate protection or lack of compliance.

McArthur advises that companies try to better understand their noise issues and eliminate them via targeted measurement in the workplace, or wherever the issues are occurring.

“You don’t just want to issue the highest level of hearing protection to a worker because you usually need to balance the levels,” McArthur says.

“If you give someone too much hearing protection, then they cease to be able to communicate or hear alarms properly,” he says.

McArthur says the issue of over-attenuation can cause serious problems within industry.

“You need to attenuate the sound to get it below harmful levels…for 3M, it’s about balancing the equipment with the environment.

You should always try to eliminate the hazard but if that can’t be done, you have to look at what can be changed in the process to make it less hazardous.”