8 replies to this topic

[David]

Under current regs anything with over 25% flashpowder per tube is now 1.1G (I think I've got that right.)

However, in "man on the street" terms, what does that mean.

Is the traditional "Airbomb" effect now 1.1G? IE a single tube that sends up a flash report?

[Mortartube]

If you mean what does the classification mean? It is a mass explosion hazard and a load in transport can be expected to explode en-masse in the same way that a lorry full of military shells or bombs might in the event of a fire. That is the 1.1 part.

The G is a device designed to produce an effect by sound, light, smoke or movement or any combination of these. If I recall correctly.

I assume that if you can prove this doesn't happen you can argue for a lower classification. When at Wells the owner set fire to a box of plastic bottle ground maroons in a UN box. They were surrounded by polystyrene packing chips. They went off individually at different times and did not explode en-masse. So the packing method is also important in determining the classification. Not just what the fireworks contain.

Edited by Mortartube, 14 April 2009 - 02:10 PM.

[BrightStar]

David, from what I have in front of me:

Single shot candle, <=30mm id, <= 25g NEQ, <=5% flash: 1.4G
Single shot candle, <=30mm id and >25g NEQ, or >5% and <=25% flash: 1.3G

For 1.1G you can look at big roman candles:

>=50mm id containing any flash, or <50mm id with >25% flash composition: 1.1G

I imagine this last category would include flash filled AirBombs...

[Spyrotechnics]

Under current regs anything with over 25% flashpowder per tube is now 1.1G (I think I've got that right.)

Yes, you have that right as thats what I just wrote in your bangers thread

To try and simplify the regulations that are followed or should I say interpreted, to classify a particular item and post on here for the "man on the street" wouldn't be something I would be willing to try and do.

Needless to say there are a number of the items characteristics that are taken into account (bore size, composition, fusing etc) when reaching a conclusion as to what an items default classification should be

Some that you will know/be interested in:

>5% flash* = 1.3G
>25% flash* = 1.1G

*or compounds that are "flashlike" in behaviour

Stu

[David]

Is this a new change, or was it current with the reg changes that came about in 2007?

Without meaning to sound thick, composition isn't my area of knowledge. I can tell from watching a firework if it uses flash or blackpowder for the burst, but I wouldn't have a clue as to percentages etc.

Edited by David, 14 April 2009 - 03:01 PM.

[Richard H]

The UN Model Regulations state:

Division 1.1 Substances and articles which have a mass explosion hazard (a mass
explosion is one which affects almost the entire load virtually
instantaneously);

Compatibility Group G:

Pyrotechnic substance, or article containing a pyrotechnic substance,
or article containing both an explosive substance and an illuminating,
incendiary, tear- or smoke-producing substance (other than a wateractivated
article or one containing white phosphorus, phosphides a
pyrophoric substance, a flammable liquid or gel, or hypergolic
liquids)

[Rick]

Every explosive requires classification and authorised by the HSE (UK’s Competent Authority) before they can be legally transported or stored.

There are several ways to gain classification for an explosive – but not to over complicate things lets just look at two common methods used for fireworks:

1) UN Testing

2) UN Default Scheme

The first method is to conduct a series of tests, the results from these provide evidence of how the explosive, (packaged for carriage) will behave if it ignited. Tests are made to set criteria; often costly to meet.

The second method for determining the hazard represented by a firework is simpler* and makes use of a default scheme, this is where the tables come into play <=5% flash etc – Information concerning the construction and chemistry of each firework is supplied to the HSE, a process of “its one of those with a bit of that in it” is applied and tables used to determine hazard division. Table hazard assignment has been made through generic tests.

The majority of firework classification applications are made using the default scheme – imagine the cost of series 6 testing every firework manufactured/imported – and what would be the point when results would show that a 3” Red peony has the same explosive effect as a 3” Green peony.

The default scheme is a cost effective way for a company to classify fireworks and if a company does not agree with the hazard division prescribed by the tables then there is the always the option of UN Series 6 testing.

Hazard Classification/Division Hazard Description

1.1 Mass Explosion
1.2 Non-Mass explosion, fragment producing
1.3 Mass fire, minor blast or fragment
1.4 Moderate fire, no blast or fragment
1.5 Explosive substance, very insensitive but with mass explosion hazard
1.6 Explosive article extremely insensitive

The suffix letter “G” is the compatibility group of the explosive. This is used to determine which explosives may be transported or stored together.

The group “G” definition

Pyrotechnic substance, or article containing a pyrotechnic substance, or article containing both an explosive substance and an illuminating-, incendiary-, tear-, smoke- producing substance (other than a water- activated article or one containing white phosphorus, phosphides, a pyrophoric substance, a flammable liquid or gel, or hypergolic liquids).

You can transport a “G” and a “G” together or a “G” and an “S” but not a “G” and a “K” etc

Not sure if this helps………or was even asked for.

*please do not go there

[pyrotrev]

Stuff that isn't catered for by the default system will also likely be classified as 1.1G unless specifically tested, regardless of it's potential for mass explosion!. The last re-jig of the default classifications left a few notable gaps in the default lists such as single shot comets >30mm calibre, hence the reason all such things incorporate some little stars so they can be called "comet mines"

Edited by pyrotrev, 15 April 2009 - 12:18 PM.

[Spyrotechnics]

hence the reason all such things incorporate some little stars so they can be called "comet mines" wink.gif

ha ha yes but they look better for it