Dust Explosion Risk Calculator

Work out dust explosion risk instantly with clear inputs, formula shown and shareable results.

About Dust Explosion Risk Calculator

A dust explosion needs a cloud above the minimum explosible concentration, typically 20 to 60 g/m³, plus an ignition source and confinement. Severity is graded by the Kst index. The larger danger is usually secondary: a primary event disturbs settled dust, and a layer of just one millimetre across a room provides enough fuel to destroy the building.

Formulas

Explosibility

Concentration ratio = airborne concentration / minimum explosible concentration

Severity class

St 1 up to Kst 200, St 2 to 300, St 3 above 300 bar·m/s

Worked example

With the default values below, Dust Explosion Risk Calculator returns Concentration as multiple of the MEC of 2.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Airborne dust concentrationminimum 0 g/m³: 60 g/m³
Minimum explosible concentrationminimum 1 g/m³: 30 g/m³
Dust explosion index Kstminimum 1 bar·m/s: 150 bar·m/s
Dust layer thickness on surfacesminimum 0 mm: 1 mm

Results

Concentration as multiple of the MEC: 2.000
Explosion severity class: St 1 — weak explosion, Kst up to 200
Dust layer assessment: Layer at or above 1 mm — sufficient fuel for a secondary explosion, housekeeping required
Overall risk: High — explosible cloud and secondary fuel both present

Step by step

1Values used
2Explosibility
3Severity class
4Concentration as multiple of the MEC= 2.000
5Explosion severity class= St 1 — weak explosion, Kst up to 200
6Dust layer assessment= Layer at or above 1 mm — sufficient fuel for a secondary explosion, housekeeping required
7Overall risk= High — explosible cloud and secondary fuel both present

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Preliminary estimate only. Dust explosion risk assessment, area classification and explosion protection must be carried out by a specialist to the applicable standards.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Dust explosion risk assessment, area classification and explosion protection must be carried out by a specialist to the applicable standards.

Frequently Asked Questions

How is the Dust Explosion Risk figure worked out?

Concentration ratio = airborne concentration / minimum explosible concentration. A dust explosion needs a cloud above the minimum explosible concentration, typically 20 to 60 g/m³, plus an ignition source and confinement.

Why is one millimetre of dust significant?

Dispersed through the room volume, a one millimetre layer over the floor produces a cloud well above the minimum explosible concentration. It is the standard housekeeping threshold for that reason.

What values do I need to enter?

This calculator takes 4 inputs: Airborne dust concentration, Minimum explosible concentration, Dust explosion index Kst, Dust layer thickness on surfaces. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.