Housekeeping and Secondary Dust Explosions

Thanks for such brilliant response to my past blog on Relief Sizing. It really feels satisfying when it gives food for thought to people about their own plants. It is a much wider subject, hence all of us can hold different opinions on what is already there in terms of regulations and what is practically being done at the grass root level. In the end, my objective is simple and that is to make the community aware of some process safety aspects which can help them make their operations safer.

For this blog, I will be discussing the importance of housekeeping to prevent Dust Explosion or should I say Secondary Dust Explosions.

How many companies out there still utilise compressed air for cleaning of equipment surfaces and to blow off the settled dust from surface/ floor/ clothing?

How many of them still dry broom dust settled on the shop floor?

How many of you still don't know that the powder which is settled on equipment surface, shop floor, electrical fitting, etc., is combustible in nature and can result in fire/ explosion hazard in the plant?

How many of your plants have false ceilings and that hidden area is not being reviewed for any powder accumulation?

How many of you still use non-rated vacuum cleaners in plant areas to remove the spilt dust?



If we look at the West Pharmaceutical Explosion, which turned into a disaster because of accumulated dust above the false ceiling that got suspended and resulted in a major secondary explosion causing 6 deaths and 38 injuries.


























Also going back to the Imperial Sugar Explosion where accumulated sugar dust, fueled multiple secondary explosions and led to 14 deaths & injured 38.

Three major risks from dust layers are:

• A primary explosion can raise accumulated dust layers into clouds and produce a secondary explosion. 
• Dust layers may be ignited by the heat flux from layers resting on equipment. 
• A dust layer can be raised into a cloud and be ignited. 

Risks also depend on the properties of the dust and the thickness of layers which are affected by the level of housekeeping.

It is imperative for companies to ask themselves these questions:

• Do you know if there are open areas and overhead structures where dust may accumulate?
• Have you looked for "hidden" areas where dust may accumulate (e.g., behind false ceilings, inside ventilation or conveyor equipment, in ducts, on support beams, etc. )?
• Do you have a housekeeping program to regularly remove dust?
• Do you have a dust collection system in place? If yes, does your dust collection system is designed and working adequately conforming to requirements?
• Do you use dry brooming or compressed air for removing settled dust?
• Do you utilise vacuum cleaners that are not rated for flammable dust?

If any of these things are not covered in your housekeeping checklist and review checklist, then you might be facing a risk of a dust fire/ explosion.

Keep following the blog and write to me on himanshuchichra@gmail.com for any doubts and for any queries.