How Hazards Are Analysed and Controlled in Aerosol Manufacturing
Making an aerosol combines three hazards at once: a propellant that is usually flammable (LPG or DME), a container that works under pressure and the chemical raw materials of the formula. Hazard analysis assesses them stage by stage, from formulation to the warehouse, and controls them with ATEX zones, automated filling and a final test of every can.
What hazards does an aerosol plant face, and what to ask for on each?
Each hazard comes from a different component of the aerosol, so each is controlled at a different point on the line. The flammable propellant is the one that shapes the design of the whole plant.
| Hazard | Where it comes from | How it is controlled | What you ask for |
|---|---|---|---|
| Fire and explosion | LPG and DME propellants, solvents | ATEX zones, ventilation, gas detection | The zone classification of the gas room |
| Bursting or leaks | Pressurised can, faulty seal | Crimp control, final test | The crimp and final test record of a batch |
| Chemical exposure | Active ingredients, solvents | Safety data sheet, extraction, PPE | The safety data sheet of your product |
| Mechanical risk | Fillers and crimpers | Guards and line procedures | Nothing: it is the plant's own workplace safety |
A non-flammable propellant such as CO₂ removes the fire risk at gassing, but not the pressure risk: the can is still a pressure receptacle. If your formula uses LPG or DME, the gas room is the first thing you should see; with CO₂, focus on the crimp and the final test.
The risks at each stage, and the one you watch
The analysis is built on the real process, not on a generic list. Each stage has its critical point, the parameter that turns a good batch into a hazard when it drifts.
| Stage | Main risk | Control |
|---|---|---|
| Formulation | Solvent vapours, incompatible mixtures | Local extraction, order of addition |
| Concentrate filling | Spills and exposure | Automatic dosing, PPE |
| Valve crimping | Faulty seal that leaks | Crimp height and diameter checks |
| Gassing | Propellant leak, overpressure | ATEX room, controlled dosing |
| Final test | Can that deforms or leaks | Can rejected |
| Warehouse | Fire in finished goods | APQ rules, fire compartments |
Formula stability is a process hazard too. A concentrate that reacts with the can or the propellant can corrode it weeks after it leaves the plant, which is why compatibility is validated on the samples, before the first batch.
That is the stage that depends most on you. Before approving the first batch, ask for the result of the compatibility test of your samples with the can and the propellant. Then keep a few cans from each batch and check them after some weeks: a dripping valve or a change of smell or colour warns you before a customer complaint does.
What to check in the ATEX area on a visit
In Spain, Royal Decree 681/2003 requires employers to assess explosion risks, draw up an explosion protection document and classify into zones the areas where an explosive atmosphere can form. For gases, vapours and mists it defines three zones:
| Zone | Explosive atmosphere of gas, vapour or mist |
|---|---|
| Zone 0 | Present permanently, for long periods or often |
| Zone 1 | Likely to occur occasionally in normal operation |
| Zone 2 | Unlikely and, if it forms, short-lived |
In an aerosol plant, the gassing room and the area around the propellant tank are the main classified areas. There, equipment must be rated for its zone, ventilation keeps gas from building up and detectors trigger the alarm and emergency extraction. Hot work in those areas needs a specific permit.
On the visit, ask to see the explosion protection document and the zone plan, and check on the spot that the gas room has detectors and that its equipment carries the Ex marking. If the manufacturer cannot show you that document, do not go ahead with a flammable formula.
The final test: which values and which record to check
Royal Decree 1381/2009, which brings the European aerosol dispensers directive into Spanish law, sets the safety limits of the filled can and requires every unit to undergo a final test. The classic method is the hot water bath; Directive 2008/47/EC added alternative methods.
- Final test
- hot water bath or another method
- Pressure reference
- contents at 50 °C
- Maximum pressure, flammable gas
- 12 bar at 50 °C
- Liquid phase
- up to 90% of net capacity
- Metal container
- up to 1,000 ml
For your product, check two values on its technical sheet: that the pressure at 50 °C stays below the limit if the gas is flammable, and that the liquid phase does not exceed 90% of capacity. In the final test record, check that it states the method used and what happened to the rejected units.
The crimp has already been measured before that test. The height and diameter of the valve seal decide whether the can will leak, and they are recorded per batch so that any drift can be traced.
How Are Aerosols and Rejects Stored?
The warehouse holds the largest amount of flammable product in the plant. Royal Decree 656/2017 approves Spain's Regulation on the Storage of Chemical Products, and its technical instruction MIE APQ-10 covers storage in mobile containers, which is where aerosols fall. Quantities, fire compartments and fire protection are sized with it.
Cans rejected at the final test are not scrap: they still hold product and pressurised gas. They are kept apart from conforming stock and handed to an authorised waste manager.
💡 Audit tip: when you visit an aerosol manufacturer, ask to see the zone classification of the gas room and the final test record of a recent batch. Those two documents show whether hazard analysis is applied on the line.
When you have your brand made by a third party, the plant's hazard analysis is the manufacturer's responsibility, and what you receive is its result: a product that has passed the final test and arrives with its safety data sheet. Ilerspray prepares that safety data sheet, together with the product's technical sheet, as part of every aerosol contract manufacturing project.
