Application Note: Avoiding Dust Explosions

Dust poses a range of dangers from a simple nuisance to a potential explosion hazard. A combustible dust explosion hazard may exist in a variety of industries, including food (e.g., sugar, starch, flour, feed), plastics, wood, rubber, textiles, pesticides, pharmaceuticals, metals, and fossil fuel power generation. Most natural and synthetic organic materials, as well as some metals, can form a combustible dust.

A systematic approach to identify and minimize the risk of explosion hazards is needed in order to avoid potential dangers.

An essential first step is to characterize the fire and explosion properties of the powder to be processed. The Minimum Ignition Energy (MIE) of the powder is used to evaluate the sensitivity of the product to electrostatic discharge. The Minimum Ignition Temperature (MIT) is used to evaluate the sensitivity of the powder to hot surfaces.

The maximum explosion pressure (Pmax) is required if containment is to be part of the basis of equipment safety. The explosion severity index (Kst) is required if venting is to be part of the basis of equipment safety. The limiting oxygen concentration (LOC) is required if inerting is to be part of the basis of equipment safety. Characterizing the properties of the powder is normally done by a test laboratory.