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Aerosol dispensers (aerosols) use pressure from a liquefied or permanent gas (propellant) to provide the driving force to dispense product in the form of a mist, and have been in commercial production for around fifty years.

Chlorofluorocarbons (CFC’s) were in common use as non-flammable propellants, but since the Montreal Protocol in 1989 they have been replaced by Liquefied gasses typically propane, butane and dimethylether (DME). Nitrous oxide and carbon dioxide are used as propellants for foodstuffs, whilst medical aerosols typically use hydrofluoroalkenes.

The internal pressure from the propellant means that aerosols store a significant amount of energy which, if suddenly released (i.e. a bursting can), would have the potential to give rise to high velocity missiles (can fragments).  In addition the liquefied gas propellants commonly used are highly flammable. If these propellants are released either due to a leak from a can, or due to a can bursting, they may pose fire and explosion hazards.

Product preparation can involve flammable liquids, combustible powders or chemical reaction, all of which pose significant hazards during the preparation process.

All aerosols are required to pass a leak-proofness test to confirm that when they are stored, transported and sold to the public there is minimal risk of them causing injuries or property damage.  In regulatory terms this means complying with EU transport regulations for dangerous goods (ADR 2011) and the amended EC Aerosol Dispensers Directive (75/324/EEC).

Historically the water bath test has been used as a test of leak-proofness, and it may function in two ways:

  1. To heat the aerosol dispenser and by total immersion permit the visual detection of leaks in any part of it.
  2.  To heat the aerosol dispenser (less than total immersion) but with a separate leak detection process by other means. Note it is not enough to ‘partially’ immerse the dispensers with no associated leak test.

Tests carried out in the 1980’s showed that at line speeds in excess of around 80 aerosols per minute, visual leak detection was ineffective. ADR 2011 allows alternatives to water bath testing to be used subject to approval by the competent authority. The water bath alternative does away with the need to heat the aerosols for the purpose of testing and visual inspection in return for stringent quality control on containers and components to guard against the risk of bursting.

Handling of bulk flammable Liquefied gasses is highly hazardous.   Many aerosol facilities and warehouses fall under the COMAH regulations due to the aggregated quantities of hazardous materials on site.  Commonly as a result of ingredients or propellants the processes are within the scope of  DSEAR.

HSD have extensive experience with aerosol manufacture, having worked with the British Aerosol Manufacturers Association (BAMA) for many years, and have been closely involved with the alternative to water bath testing. We can help in many ways, to find out more call us today.