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What Do the Signs on Lorries Mean?

By: Kevin Watson MSc - Updated: 24 Sep 2019 | comments*Discuss
What Do The Signs On Lorries Mean?

Anyone who has driven behind a lorry, especially a tanker, may have wondered what the signs on it mean. Some of these signs can seem obscure unless the onlooker can translate the codes and symbols.

Hazardous Chemicals

Hazchem Emergency Action Code (EAC) signs on lorries are orange. They warn of hazardous chemicals in transit, and display a range of information. The signs have been compulsory since 1979, although a voluntary scheme ran before this. London Fire Brigade first proposed the signs' use.

In the top left corner of the sign is the emergency action code (EAC). This is a number followed by a series of letters. The number indicates what the fire brigade should use if the chemical on the lorry ignites. If the fire brigade need to employ a coarse spray, the number is "1". For a fine spray, the number is "2". "3" refers to foam. And "4" means the fire fighters must use a dry agent to combat the flames.


The letter following the number refers to any safety precautions that apply. "P" and "R" mean that firefighters should wear chemical suits and breathing apparatus. "S" and "T" advise firefighters to use breathing apparatus and fire kit. All four of these letters apply to chemicals the fire brigade must dilute with lots of water.

The letters "W" and "X" refer to chemical suits and breathing apparatus, and "Y" and "Z" mean firefighters should wear fire kit and breathing apparatus. These four letters, however, apply to different types of chemicals than those covered by "P", "R", "S" and "T". With "W", "X", "Y" and "Z", the fire brigade must try to contain any spillage so it doesn't enter watercourses or drains.

The letter "V" may also appear. This shows the chemical on board the lorry is explosive, or reacts dangerously when spilled.

The EAC may have one final letter, an "E". This indicates the chemical is potentially hazardous to public safety.


A sign may have an EAC of 4YE, for example. If so, in the event of a chemical spill, the fire brigade must use a dry agent to treat it, wear breathing apparatus and fire kit, and try to contain the spillage. The chemical also poses a safety hazard to the public.

Chemical Identification

Below the EAC is a number that identifies the chemical. The number comes from a list drawn up by the United Nations.

Phone Number and Other Markings

A further number on the sign is for phone calls. The fire brigade can ring to receive advice about the chemical in transit.

The final markings on the sign are the name or logo of the company transporting the chemical, and a warning. The latter indicates whether the chemical is flammable or radioactive.

Diamond Warning Signs

Separate warnings may accompany a Hazchem EAC sign. They have a diamond shape and give the classification of the chemical in transit.

There are nine such classifications, and some have sub-categories. The signs appear in a range of colours and may be striped. They cover warnings such as environmentally hazardous, corrosive, likely to spontaneously combust, and toxic.

International Journeys

Many UK lorries make regular trips abroad. UK roads also have lorries from the continent transporting goods and chemicals.

All such lorries should have an orange warning sign with a hazard identification number (HIN). This is unlike the number on the domestic Hazchem EAC sign. The HIN explains the nature of the hazard rather than the action the fire brigade must take when an accident occurs.

A HIN has two or three figures. The number "2" refers to possible gas emission because of chemical reaction or pressure. Flammable liquids have a "3". A "4" appears when a lorry carries a flammable solid or self-heating liquid. "5" is for a chemical that is able to increase the ferocity of a fire. "6" refers to a toxic substance or one that spreads infection. Radioactive substances have a "7". Corrosive liquids have an "8". And where there is a risk of a spontaneous violent reaction, there is a "9".

A number may appear twice on some HIN signs. This indicates an enhanced risk of danger. A "33", for example, refers to a particularly flammable liquid.

If an "X" appears before the number or numbers, the lorry is carrying a chemical or substance that reacts dangerously with water. "X88", for example, indicates a highly corrosive chemical that doesn't mix well with water.

Standard chemicals on lorries have a single number followed by "0". But the HIN system also uses certain combinations of numbers to highlight specific potential problems.

"623", for example, indicates a toxic chemical capable of releasing flammable gases when in contact with water. And "333" refers to a chemical that may ignite spontaneously when exposed to the air.

As with Hazchem EAC signs, a HIN has a UN number beneath it to identify the chemical in transit.

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The company I work for have recently put on the road some new trucks . The dealership in the UK was asked to put on the front of the truck a flooding board same as an adr board but it is white with a capital A on it can you tell me what loads this indicates / covers please ?
K - 24-Sep-19 @ 9:39 AM
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