Gas Detection Through the Ages
By Jeremy Davalle
By Jeremy Davalle
We all know how gas detection works for us today, but how many of you understand how it has evolved over time?
Today, there are sensor technologies designed to detect almost any gas to which we might be exposed. Some of these technologies include, but are not limited to, infrared and photo-ionization detection. Some companies now are even using the Internet to test your detector and ensure everything is working correctly.
To understand just how far we’ve come in gas detection, you should know its history and evolution over time. The very first methods of detecting gases might astound you as they did me. When gas detection was first needed, there was no Internet or microprocessors — even the light bulb hadn’t yet been invented.
With the beginning of the Industrial Revolution, fuel became very important. The fossil fuel used during the Industrial Revolution that still is vital to us even in the present day is coal. Coal had to be mined from the ground, and since mining was primitive, it required lots of manual labor. People working in these areas ranged from very young boys to much older men. The miners wore flame lights on their helmets so they could see in the tunnels, and used hand tools to drill the coal out of the linings of the tunnel.
Several things make mining dangerous, chief among them the possible exposure to methane. This gas especially is dangerous because it cannot be seen or smelled, and appears naturally from the ground. When miners began to realize how dangerous methane was, they started exploring ways to detect it.
CANARIES IN A COAL MINE
The first method involved using humans, as that seemed to be the only solution. Before the shift started, everyone was removed from the mine. A person would wear a wet blanket over his shoulders and head and carried a long wick with its end lit on fire. This brave person entered the mine and began to move the flame of the wick along the walls of the mine. When the man would hit a small pocket of methane gas, it would ignite, but the miner remained fairly safe under the dampened blanket. Every once in a while, the intrepid miner would hit a huge pocket of this highly explosive gas, which would ignite the entire area around him.
Before gas detection became such an integral part of worksite safety, the general feeling was that it was better to lose one man than to lose an entire group of workers. Furthermore, losing only one person meant that the work could continue.
Once people realized the dangers of detecting methane in mines using this method, they began to look for other means. The next method of detection was to take a canary into the mine. Canaries were used because they have an extremely loud chirp. Additionally, the canary has the closest resemblance to the part of our nervous system that controls breathing.
The miners would go to the area where their canaries were housed and look for the canary that appeared to be not doing well. The miner would then carry the bird in its cage into the mine. It was said that when a canary was about to die, it would start to shake the cage. If the canary did this, the miners knew to exit the mine. If the canary wasn’t making any noise, they knew to make an even more urgent exit as something had caused the canary to die.
The next type of gas detection used was the flame light. One benefit of using a flame light, of course, was that it provided light, which enabled the miners to see in the mine. The flame was encapsulated in a flame-arrestor shell so that there was no way the flame could ignite the outside atmosphere. On the outside of the flame light was a glass piece that had three incisions running horizontally along the glass. Whenever a miner was using the flame light, he always started the flame in the middle line while in a fresh air environment. If the miners noticed that the flame was lowering down to the bottom line, they knew they were in an oxygen-deficient environment. The flame would drop to the bottom line because fire loves oxygen and if oxygen was scarce, the flame would start to extinguish itself.
If miners noticed the flame rising to the top line, they knew the atmosphere either was beginning to have methane current or an oxygen-enriched environment. To this day, the flame light still is used to ensure an environment is a safe place to work. Some people have even learned what types of gas are present when the flame flickers different colors.
However, the flame light still poses a threat to miners. If the light accidentally is dropped, and the glass breaks while the flame is lit, the flame can ignite the atmosphere if methane is present.
MODERN GAS DETECTION
Soon after gas detection became a part of the mining industry, other industries followed suit. Some applications included wastewater treatment plants, oil refineries, chemical processes, bleaching of metals and refrigeration. Since not all of these industries could use a detection method such as the flame light to measure the gases that were present in their specific atmospheres, the gas monitor was introduced.
The first gas monitor was a device with a valve that analytically showed how much methane was present in the atmosphere. The methane was detected through a sensor called the catalytic diffusion sensor. This sensor would burn the gas inside it, but never allowed the burning process to occur outside of the sensor. In this way, the instrument was able to accurately give a reading of how much gas was present. The problem with this type of meter was that each time you wanted to see how much methane was present, you had to manually press a button on the monitor.
Today, gas detectors have batteries, which enable the instrument to run for long periods of time without having to be turned off. Also, modern-day monitors not only measure oxygen and methane, but can measure several gases simultaneously.
As you can see, at one time, the death of a man was seen as a necessity to prevent the death of an entire team working in an area. We can be pleased that any death in the workplace today is considered unacceptable.
Among the many technologies that now exist to prevent workplace injuries and deaths are sophisticated gas detectors. As these technologies continue to evolve over time, we can be hopeful that death in workplace will not exist by the end of this century.
It is important for people to know how to use gas detectors, and it is critical that each person working in potentially hazardous environments understands just how important gas detection is. By spreading this knowledge, I hope to contribute to ending death in the workplace.
Jeremy DaValle is a training team lead for gas detection with Industrial Scientific Corporation.