Site visits are a great way to get a real appreciation for different work environments. In manufacturing and fabricating shops, one often notices a certain nuisance in the air. A manifestation of this nuisance could be in the form of floating dust particles, a thick haze of welding fumes, or even an odour from raw materials (see images below).
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Sawdust in woodworking |
Haze from weld fumes at a fabricating shop |
Push-pull system for odour control |
Eliminating the expulsion of these contaminants can be achieved through process modification or substitution, but that is not always an option. Many times, instituting control mechanisms is more feasible. The question arises as to why? Why should you, as an owner or a member of management, bother?
Well, for one thing, if you plan on attracting great talent and retaining it, it is easy to recognize that having a clean work environment is a significant contributing factor. It’s a necessity. These process contaminants (dusts / fumes / odours), while airborne, pose a respiratory hazard to your employees. Uncontrolled, it will adversely affect their health. If the problem persists, the employee will have to consider a change in environment which might even force them to leave the organization altogether. A significant number of resources are invested by organizations to train and assimilate employees into their workspace. So, it’s in their best interest to reduce turnover, which in this case can be attributed to poor indoor air quality due to process emissions.
Aside from respiratory illnesses, airborne dust travels with the air current and eventually settles and accumulates on various surfaces. Accumulation can occur on electrical and mechanical equipment, which can be detrimental to the longevity of such mechanisms. Sensors obstructed by dust can lead to production inaccuracies. I wish I could say that is the end of it, but unfortunately, there is another less well-known insidious hazard, and this has to do with combustibility.
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You see, depending on the type of dust we are dealing with, given the right conditions, it will combust. Take a log and try to ignite it, it will take some effort. Break it into smaller pieces, thereby increasing the exposed surface area, and it becomes a lot easier to ignite. Think of the fire triangle. An oxidant, sufficient ignition source, and sufficient fuel…we get a fire. In this case, the fuel is the dust. |
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Fire Triangle |
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Matters get even more serious when a combustion event occurs in a confined space. Combustion events are accompanied by a spike in pressure. In a confined space (this could be the inside of a facility, or a process vessel), in the absence of any relief mechanisms, this pressure continues to build up. If this pressure is allowed to exceed the yield strength of the structure, the net result is an explosion which can lead to loss of property, life or both. The destructive nature of explosions does not always stay localized…it could impact the neighbouring properties as well. |
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Dust Explosion Pentagon |
The good news is that we have a good understanding of what is required to operate safely, and we have many resources to guide us along the way. To get there, we need to apply the principles of capture and transport of contaminants best explained in the American Conference of Governmental Industrial Hygienist handbook.
Implementing systems that help maintain indoor air quality in industrial and manufacturing settings pays dividends. It provides a safe environment for your employees, reduces turnover, which facilitates productivity, and preserves the investment in property and infrastructure.