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?

Can Electrostatic Discharge (ESD) from Non-Conductive Bags act as an Ignition Source?

Hope you are enjoying the posts and able to gain some insights from the blog.

Now for this week blog, I am touching on a more sensitive question, which people have asked me in almost all Electrostatic Hazard Seminars. "Can Non-Conductive Bag act as an ignition source?"

A non-conductive bag, being an insulator can act as a source of Brush Discharge which has approximate energy of up to 3-4 mJ associated with it. Depending on the type of flammable atmosphere, brush discharge from the non-conductive bag may/ may not act as an ignition source.

Based on the equivalent energy of brush discharges, it must be assumed that most potentially explosive gas/air mixtures, solvent vapor/air mixtures and hybrid mixtures (vapor/gas and dust with air) can be ignited by brush discharges.