Hazchem

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A sample Hazchem plate

Hazchem is a warning plate system used in Australia, New Zealand and the United Kingdom for vehicles transporting hazardous substances, and on storage facilities housing such substances. Part of the Hazchem plate describes how an emergency service should deal with an incident pertaining to the vehicle or facility.

Hazchem is not the ADR Hazard Identification Number (HIN), also known as the Kemler Code, as this is a different warning plate carried by vehicles in the rest of the EU. The main difference is the HIN details the nature of the hazard presented by the goods as opposed to the actions to be taken when dealing with them.

The top-left section of the plate gives the Emergency Action Code (EAC) telling the fire brigade what actions to take if there's an accident. The middle-left section gives the UN Substance Identification Number describing the chemical. The lower-left section gives the telephone number that should be called if special advice is needed. The warning symbol at top-right indicates what danger the chemical presents. The bottom-right of the plate carries a company logo (the flower is a sample logo).

There is also a standard null Hazchem plate to indicate the transport of non-hazardous substances. The null plate does not include an EAC or substance identification.

The National Chemical Emergency Centre provides a glossary in which you can find most terms associated with Hazchem.

[edit] Emergency Action Code

The EAC consists of a digit followed by one or two letters.

digit	fire suppressant
1	coarse water spray (jets)
2	fine water spray (fog)
3	foam
4	dry agent (powder)

The digit indicates what type of fire suppressant should be used to extinguish a fire involving the chemical:

Any higher number may be used, but no lower number. For example, a fire involving a substance with a recommended extinction agent of 2 (fine water spray) could also be tackled with 3 or 4 (foam or a dry agent).
The digit 4 (dry agent) is used for chemicals that react adversely with water and so must not be allowed contact with it.

letter	V?	kit	spillage
P	V	LTS	dilute
R	-	LTS	dilute
S	V	BA	dilute
T	-	BA	dilute
W	V	LTS	contain
X	-	LTS	contain
Y	V	BA	contain
Z	-	BA	contain

The first letter of the EAC is selected from eight possibilities, giving three items of information regarding how to handle an accident:

The first item V indicates that the substance can react violently.

The second item indicates what type of kit firefighters must wear: BA means that breathing apparatus is required, whereas LTS means that a liquid-tight chemical-protective suit must be used in addition to breathing apparatus. (S, T, Y and Z can also be reversed, that is an orange letter on a black square, signifying that breathing apparatus is only required in the case of fire.)

The third item indicates how to handle a spillage: dilute means that the chemical may be washed into drains with lots of water, whereas contain means that the chemical must be prevented from entering drains or watercourses.

The optional second letter of the EAC is E, which indicates that an accident poses a public hazard beyond the immediate vicinity. In an accident involving such a chemical, the nearby populace may need to be evacuated, and if not should be warned to stay indoors with doors and windows closed.

A very commonly seen example is 3YE on petrol tankers. This means that a fire must be fought using foam, that it can react violently, that fire fighters need only wear BA and not a full containment suit, and that the run-off needs to be contained. It also indicates to the incident controller that evacuation of the surrounding area may be necessary.