Combustible Dust Assessment

This assessment is one step in a larger programme. Using it for work that belongs to a neighbouring template produces records that are hard to report on later.

ISO 45001 cl.6.1.2 requires the hazard identified and the risk assessed before controls are relied on; for dust that means confirming explosibility and accumulation before the residual band is scored.

Combustible dust sits under different instruments depending on where the site operates, and the record needs to answer whichever one applies.

The fields are straightforward to fill in. What decides whether the finished record would survive scrutiny is a smaller set of judgement calls the form itself cannot make.

The same gaps recur across sites running this assessment, most visible from the record itself without visiting the floor.

A flour handling line passed its combustible dust assessment with a 'Low' residual band. Every field pointed the same way: assessor competent, dust test data on file, housekeeping adequate, surfaces clean. The overhead cable tray running the mixing room, three metres up, was scored 'Light' on Accumulation On Overhead Surfaces on the strength of a glance from the floor rather than an inspection above it.

The layer on that tray had been building for close to a year. Nothing forced a closer look, because 'Light' is a valid answer with no defined threshold, and the form had no way to flag a mismatch between a floor-level glance and an actual inspection overhead. The gap sat unresolved until the next cycle, not because a field was answered dishonestly, but because the judgement behind 'Light' was never made explicit enough to challenge.

The form is the easy part. Keeping it current, routing it to the right owner and holding the evidence together is the work that actually slips.

KnowSafe

Holds the combustible dust assessment against the site register, flags when a material or process change should trigger an early review, and keeps scored fields consistent with the linked zoning record.

KnowMaintain

Tracks the cleaning method, vacuum suitability and overhead access this assessment depends on, so a housekeeping schedule change doesn't quietly invalidate a residual band nobody re-scores.

KnowEnviro

Owns the DSEAR zoning record (ENV-050) this assessment links to, and flags when it goes overdue so the dust assessment isn't left resting on a stale classification.

Ella

Coordinates the crew, rolls completion and exceptions into one view, and holds every write for your approval before it touches a record.

Minimum ignition energy (MIE)

The smallest energy, typically a spark or static discharge, needed to ignite a dust cloud of a given material. A low MIE means ordinary sources most sites tolerate, like static from plastic scoops, can trigger ignition.

Kst value

A measure of how violently a specific dust deflagrates once ignited, used to size explosion relief and rate protection equipment. It is material and particle-size specific, so one supplier's flour value doesn't transfer to another's.

DSEAR

The Dangerous Substances and Explosive Atmospheres Regulations 2002, the UK instrument requiring risk assessment and zoning of areas where an explosive atmosphere can occur.

Secondary explosion

An explosion where a smaller, often survivable primary event dislodges accumulated dust into the air, creating a much larger cloud that then ignites. Most fatal dust incidents are secondary, not primary.

Zoning (hazardous area classification)

Dividing an area into zones by how likely and how long an explosive atmosphere is present, which dictates what equipment rating is permitted in each zone.