Speed is important

Few people stop to consider not only does a sensor respond, but how fast does it respond? The average walking speed for humans is 5 km per hour or 83 m per minute. Some gas detectors can take up to a minute or more to respond, that’s 80-odd meters later if you are walking into a hazard at normal pace. If not walking, it is up to a minute lost to take evasive action. Time is of the essence and evasive action taken sooner can and will prevent disaster.

Recently safety alerts were issued in mining to warn people to be aware of the potential to walk into hazards whilst being distracted or awaiting for sensor response particularly to rapidly depleting oxygen. In this case on two reported occasions persons entered areas of depleted oxygen and were able to proceed into a potentially dangerous and depleted environment. The instruments were functioning normally and met the requirements of the relevant Standard. In one case the user was distracted by an already functioning alarm however in the other the operator was able to enter before the alarm initiated. These are real everyday situations.

Confined spaces add additional concerns. By definition these tend to be difficult to enter or leave, meaning it is even more critical. Forget walking, what if you have to climb through narrow passages in tight conditions!! The sooner you know of an impending issue the better.

Work in confined spaces, particularly hot work, presents another set of concerns. Hot work can produce toxins, deplete oxygen rapidly or leak combustible gas into the confined space. With typically restricted ventilation, a rapid response of a gas detector to warn takes even higher precedence.

Always remember a gas detector does not provide a means of protection. These only provide a warning for action. The sooner the warning, the quicker can be the action.

Critically everyone should be aware of sensor response times in gas detectors and should pay extra attention whether gas is expected or not. One of the critical outcomes of the safety notice was efforts should be made to revise the design of gas detectors to minimise response times. There is limited scope for this in standard products using traditional sensor technology. MSA Xcells are newly designed, new-technology sensors exclusive to MSA.

Xcells are MSA-designed sensors with a typical response time of less than 15 seconds for all sensors including oxygen, four times faster than the required response time (AS/NZS) and up to eight times faster compared to some industrial detectors. Fast sensors don’t alleviate the need for care and attention however they do add that extra confidence.

Speed is important.