Danger in the air

How to protect warehouse staff from dust hazards

Dust in warehouses is bad for workers, for machinery and for business. Mark Nicholson highlights the dangers and the solutions, with advice from a leader in the dust-fighting field.

“Warehouses are typically quite clean compared to factories, where cleaners sometimes face thick layers or deep spills of material,” says Anh-Tai Vuong, President of industrial vacuum specialist DuroVac®. “Nevertheless, dust gathers on almost every surface – and none of it should be viewed as harmless.”

Where does dust come from and why is it a problem?

Dust, sand and grit, including dirt from the fields, blows in when dock doors are open. Tyre and brake pad materials wear away from lift truck wheels. Rubbing and cracking of hard materials like concrete releases minerals including silica – a known health hazard. Cutting, grinding and sanding tasks in warehouse construction and maintenance generate metal as well as mineral dusts. Most dust in a warehouse probably comes from the cardboard in boxes and the wood in crates and pallets.

Movement of forklift trucks, people and processes then stirs it into the air. Some companies even move dust around by using compressed air to clear it from equipment – a practice DuroVac says is particularly frowned upon in applications where combustible dusts exist.

The health of your employees – your greatest asset – should be your main dust-related concern, but there are other good reasons to keep your warehouse clean. Dirty and contaminated products or packaging give a bad impression and may be rejected. Dust may create slipping hazards for vehicles and personnel. It also damages warehouse machinery, including forklifts, by entering and abrading moving parts. This is worst for diesel and LPG trucks, where dust can contaminate their engines, the air they breathe and the oil that is meant to protect them. A manufacturer like Cat® Lift Trucks can fit a customised dustproofing kit for extra forklift protection, but are you protecting your workers?

The cost of dust in human lives and health

Anh-Tai Vuong summarises the most worrying effects of dust on human bodies. “Larger pieces of dust tend to be trapped by the nose or by the mucus that lines our airways, but finer particles can evade our body’s defences. They may become lodged in the lungs or even absorbed into the bloodstream. Long-term exposure often contributes to respiratory disorders, such as bronchitis, emphysema and other forms of chronic obstructive pulmonary disease (COPD), as well as cancers.”

COPD is a life-changing and debilitating disease, and one of the world’s biggest causes of death. The number of sufferers worldwide is hard to measure, but published estimates sometimes exceed 300 million – with many cases going undiagnosed. A worker with this condition will find breathing difficult and will be less productive. He or she will also regularly take time off, or be hospitalised, when symptoms are aggravated by colds or flu. Meanwhile, less serious dust effects, like dermatitis, allergic reactions and irritation of the eyes, nose and throat, can also cost work time.

Dust control solutions

Vacuum systems

For the largest buildings, DuroVac recommends installation of a heavy-duty central vacuum system. Pipework and flexible hoses radiate from a single suction unit to reach all areas, allowing simultaneous use by multiple staff. The most powerful systems can remove thousands of kilos of dust per hour. A variety of hose attachments can be fitted to reach and clean different surfaces. They include crevice, brush and pipe-cleaning tools, in different shapes, sizes and lengths.

“For smaller warehouse spaces, we have portable industrial vacuum systems which still deliver high suction power to remove large dust accumulations and pick up heavier grains,” the President adds. “The portable vacuum cleaner market offers a wide range of choices, but dust removal rates and capacities reduce with size. You need to choose one that’s cost-effective for your building dimensions but bear in mind that a higher-powered machine will save on cleaning time and labour costs. You should also look for continuous suction power, which means the cleaner doesn’t lose effectiveness as the bag and filter fill.”

Another vital consideration is the type of material you are tackling. “A system specifically designed to remove ultra-fine particles and heavy powders, for instance, is different from one dealing mainly with moderately dense or light materials. Particle size and nature also affect filter choice. Filters are graded according to their filtration efficiency, expressed as the percentage of particles of a specific size that they can trap. In many cases, a filtration efficiency of 99% down to 1.0 micron is enough. If the dust is known to contain toxins, we recommend a HEPA (high efficiency particulate air) filter, which removes 99.97% of particles down to 0.3 micron.”

Air cleaning systems

Extraction and filtration systems can be used to draw air into high-positioned units which trap airborne particles and then recirculate the cleaned air. “These systems, which our industry calls ‘dust collectors’, should be used alongside vacuum systems. While vacuum cleaners periodically remove dust clinging to surfaces, before it can be stirred up and breathed in, air cleaners run constantly to capture contamination already in the air. They also help to dilute the concentration of substances which may otherwise accumulate in a particular area.”

Filtration technologies for air cleaners can be selected according to the types of dust or other pollutants present. An alternative air cleaning approach is to use a ventilation system in which extractor fans pull air into ducts. Dust is then collected by bags or filters at the other end of the ducts and the extracted air is expelled outdoors. A variation on this, for processes which generate dust or fumes, is local exhaust ventilation (LEV), where extraction hoods draw pollution from its point of origin.

Fogging systems

Fogging systems emit a fine mist which combines with dust particles and makes them heavy enough to fall to the floor. This is achieved without soaking the warehouse and its goods. Although the method is highly effective, especially for premises with high concentrations of airborne dust, DuroVac believes it is not ideal for general use. “Except for rare cases where extremely combustible dusts are the problem, we would prefer to see more environmentally friendly solutions, as fogging consumes a lot of energy and water.”

Partitions

As part of an overall dust control strategy, partition walls or curtains can be used to stop its spread from one area to another. By confining a dusty material or process in this way, vacuum cleaning becomes more focused and efficient. There are many suppliers of permanent or temporary partitioning solutions. Anh-Tai Vuong notes: “Partition curtains are especially flexible, as they can be simply drawn closed when dust is being produced or if a contamination incident needs to be tackled. They can then be opened again when not needed.”

Other measures

He adds: “Where dangerous concentrations of dust are a risk, consider installing air monitoring sensors to track it and to sound an alarm if safe levels are exceeded. In some workplaces, dust is inevitable even after all reasonable measures have been taken to eliminate it. Employers must then provide workers with the necessary personal protective equipment (PPE) and clearly outline the dangers and safety protocols for all possible dust.”