Choose the method according to the question
Not all qualitative tools answer the same question. Some help estimate risk considering existing controls; others indicate the control level that should be implemented. Technical Prevention Note 935 explains this difference.
Before choosing a spreadsheet, define whether the aim is to prioritise operations, select measures or demonstrate that exposure is controlled. Confusing these objectives may turn an initial recommendation into a conclusion the method cannot support.
Which data are needed
The COSHH Essentials model, described in Technical Prevention Note 936, uses hazard severity, quantity used and the substance’s tendency to enter the environment. For liquids, volatility and temperature matter; for solids, dust generation matters.
Start with the current safety data sheet and actual operation. The size of a stored container does not necessarily describe the quantity handled or how a person is exposed.
Interpret the control bands
In COSHH Essentials, existing measures are not an input variable: the result guides the control needed, ranging from ventilation to containment or specialist intervention. Obtaining a band does not demonstrate that a particular installation works correctly.
The selection must become a verifiable measure for the task. A recommendation for local exhaust ventilation requires appropriate design, correct use and checks of its operation; it is not satisfied by noting that the room has windows.
When measurements are needed
In Spain, Article 3 of Royal Decree 374/2001 establishes measurement as the general rule for assessing inhalation exposure, except where adequate prevention and protection are clearly demonstrated by other means.
Applying a simplified method therefore creates no general exemption. The decision must be technically justified. If data are missing, the scenario falls outside the method or control cannot be demonstrated, the assessment must be completed using the necessary procedure.
What a band does not resolve
The general COSHH Essentials model focuses on inhalation and has exclusions, such as gases and liquids handled above their boiling point. It should not simply be extrapolated to every substance or process.
Skin contact, fires, explosions, incompatible reactions and specific obligations for carcinogenic or reprotoxic agents require separate attention. A favourable inhalation result does not close those assessments.
Document and review the decision
A useful record identifies the task, products, method version, input data, uncertainties, outcome and agreed measures. It should also explain how effectiveness will be verified and who will resolve outstanding matters.
Changes in product, temperature, quantity or application method can alter the scenario. An earlier result should not automatically be reused for another operation merely because the same trade name is retained.
Hypothetical example: changing a mixture
A company wants to replace a powdered ingredient with a liquid formulation. It uses a qualitative method to compare the operation and identifies the need also to study the new product’s volatility.
The prevention service reviews the safety data sheet, controls and need for measurements before approving the change. A visible reduction in dust is not interpreted as proof of absent exposure.
