Aerosol storage and sprinkler Tech Bulletin TB216

[kurnal]

Please can anyone cast any light on the wording of TB216 para 5.4. I cant get my head round it at all and I wonder if what it says is correct.

I Quote
"Aerosols shall be classified as either alcohol or hydrocarbon based, with the base product and not the propellant as the basis for the classification....."

Examples are given- alcohol hased aerosols  include hair spray, antiseptics, anaesthetics, Hydrocarbon based include paints, lubricants and oil based anti perspirants.

The commentary goes on to say " Fire tests have shown that the base product of an aerosol makes the major fire load contribution, and it is therefore recommended that the base product forms the basis for any hazard assessment."

Now I always thought it was the propellant that caused all the problems - indeed in bulk storage it is the combined mass of the propellant that determines whether the site needs to be registered under COMAH regs.

It appears to me that the classification must therfore be based on the propellant and not the base product and not as stated in the TB?

[Mike Buckley]

It sounds to me that the classification is working open the nature of the base product. The propellant would be a gas under pressure and would obviously expand as the temperature increases this would apply to both alcohol based products and oil based products. However alcohols tend to have a lower boiling point so when the container bursts the alcohol is more likely to BLEVE than the oil based product.

[kurnal]

Thats true Mike but of course the usual propellant in  hydrocarbon based  aerosols is butane. The sprinkler system density of discharge for hydrocarbon based aerosols is double that for alcohol, and I can understand that.

But what I cant see is the link between the base product and the classification, and the statement that  fire tests that show the product as creating a greater fire loading than the propellant. Take a tin of wd40- does the 100ml of  oil or the 100ml butane create the greater fire loading?

[John Webb]

kurnal,
Having seen one of my former colleagues experimenting some years ago with an 'aerosol mortar' I can see why you consider the propellant as the major risk. But if aerosols burst propellant will burn off very quickly. If the remains of the aerosol are contained within a building at least part of the base liquid will be left, presumeably to contribute to a pool fire of some sort. I assume it is this that the sprinkler system has to be designed to cope with.

I haven't seen the latest edition of TB216 - it's not a risk I'm likely to have to deal with in my now limited area of interest! Perhaps a call (01923 664100) or e-mail to LPCB  (enquiries@brecertification.co.uk) might be useful?