Safety in confined space with desiccant dehumidification

Due to the conditions of the environment and the operations performed within them, confined spaces present inherent dangers. Atul Bansal, Chief Operating Officer, Technical Drying Services, Pahwa Group, remarks that worker safety requires precautions, including air quality testing, ventilation, and dehumidification systems, to maintain optimal environmental conditions and minimise risks during maintenance and repair work.

Working in a confined space is inherently dangerous. The space features a fully or partially enclosed area where various risky operations occur. Depicting a hazardous setup, it encompasses vessels, tanks, containers, pits, bunds, chambers, cellars, columns, spheres, boilers, drums, chimneys, pipelines, cyclones, dust catchers, scrubbers, sulphur pits, ESP areas, kiln, and other similar spaces. Looking at the nature of the space and process, working in a confined space raises a lot of concern for the safety of the workers.

The enclosed area contains harmful gases, fumes, and vapours that are highly flammable and explosive. Even a little ignition could culminate in a fire explosion. The perils get exacerbated by excessively high temperatures. It creates a threatening environment when coupled with a lack of oxygen. In addition, the space is affected by poor air quality due to a lack of oxygen. It makes it difficult for the occupants to breathe. Owing to this, workers are highly susceptible to developing symptoms of rapid breathing, a jump in heart rate, clumsiness, and fatigue. It can emotionally take a toll on the person. In extreme cases, this can lead to nausea, vomiting, convulsions, collapse, and even account for coma and death of the person. 

Given the toxic nature of gases, they are responsible for giving rise to illness among the occupants while increasing their susceptibility to unconsciousness. Consequently, all the factors together increase the risks of accidents, harm or injury to the workers, making it difficult for them to carry out maintenance and repair work within the space. Moreover, processes such as welding, fabrication, riveting jobs, strip lining, nozzle replacement, and tray replacement, coupled with the presence of many people, account for the soaring temperature, reaching as high as 48-50° C in combination with high humidity.

Therefore, looking at the innate perils of space, working in confined spaces is generally plagued by the risk of fatalities. It necessitates conducting maintenance work with measures in place to ensure the safety of the workers while contributing to their productivity in the process. Working in such locations should be accompanied by mandatory emergency action devised beforehand to avoid any unforeseen situation.

Air quality testing should take place before starting the work. In addition, fresh air should be mediated to purge toxic gases while achieving the correct amount of air exchange. Maintaining oxygen levels within safe limits should be prioritised while monitoring the proper functioning of ventilation equipment. It is strictly advisable to keep the temperature within the 32-35° C range and maintain the relative humidity (RH) below 60 percent.

The industry generally shuts down the facility to cool the furnaces to achieve the said conditions. Resorting to natural ventilation is time-consuming and might be insufficient to achieve optimal air quality within the space. It can impact the completion of the project, which in turn can severely compromise the company’s productivity and revenue. Therefore, external dehumidification should be deployed to drive the desired outcome, which comes with engineered solutions to exercise temperature control, humidity control, drying, and ventilating the enclosed space.

As a result, the dehumidifiers, condensing units, blowers, and ducts are adept at achieving the required temperature and humidity levels. Accelerating the cooling process reduces the overall shutdown time. The technology works on the simple mechanism of forcing dehumidified, cool, conditioned air within the space to create a positive pressure that drives away the contaminated air. Introducing fresh, dry, cool air in the process invariably contributes to reaching the optimal temperature quickly. Eliminating the toxic gases, the desiccant dehumidifiers come in handy for absorbing excess moisture from the air by maintaining RH below 60 percent. The condensing units work in tandem at the same time, where they keep the temperature between 25-26° C.

Consequently, perceiving the processes’ complexity and the space’s hazardous condition necessitates regulating the environment to ensure the workers’ safety and productivity. Deploying mechanical ventilation and condensation systems helps avoid achieving optimal environmental conditions and helps complete the project in a timely manner.