Dangerous Goods Placarding Explained

February 23, 2022

Storage of hazardous chemicals (hazchem) and dangerous goods comes with innate risk, so it’s vitally important that these substances are stored and labelled in line with workplace health and safety regulations. Placards are critical to ensure the safe storage of dangerous goods both in facilities and in transit. Read on to better understand why placards are necessary, and how to properly interpret them.

What are placards?

Also known as Emergency Information Panels (EIP), placards are used as indicators of high-risk chemicals being stored in a certain area. This includes manufacturing and storage facilities, and goods transport vehicles. Placards must be visible adjacent to the bulk or packaged storage unit, as well as outside the entrance to any workplace containing hazardous goods.

Any vehicle transporting bulk hazardous chemicals must have a visible dangerous goods placard
Any vehicle transporting bulk hazardous chemicals must have a visible dangerous goods placard

Placards and EIPs also are vital for ensuring that any emergency situations are dealt with safely and effectively. In case of a fire or chemical accident, emergency services must know what class of dangerous good is involved so that they can respond appropriately and without exacerbating the situation. 

One of the key benefits to placards is that they are universally recognisable, thanks to the Globally Harmonised System of Classification and Labelling of Chemicals (GHS). Interpreting them correctly only requires an understanding of pictograms and key words such as DANGER. While most of the information represented on placards is consistent around the world, there are slight differences when it comes to additional information such as colour coding, emergency contact details, or hazchem numbers (which are only used in Australia, Malaysia, New Zealand, India, and the United Kingdom).

How do you read a placard?

A regulation hazchem placard in Australia will contain the following features: a 4-digit UN substance number, a substance name, a 2 to 3-digit hazchem code, and a dangerous goods code class label according to the designations below:

  • Class 1: Explosives
  • Class 2: Gases
  • Class 3: Flammable liquids
  • Class 4: Flammable solids; substances liable to spontaneous combustion; substances which, on contact with water, emit flammable gases
  • Class 5: Oxidising substances and organic peroxides
  • Class 6: Toxic and infectious substances
  • Class 7: Radioactive material
  • Class 8: Corrosive substances
  • Class 9: Miscellaneous dangerous substances and articles, including environmentally hazardous substances

Classes 1, 2, 4, 5, and 6 have subclasses which further specify the hazard presented. These code classes are now a standard amongst chemists and allied industries, based on the United Nations’ system.

Dangerous goods class label diamonds vary in colour and pictogram, in order to be easily readable

There are additional placards for other categories of dangerous goods, such as mixed class dangerous goods, substances kept at a high temperature (greater than 100oC for liquids or 240oC for solids), or for environmentally hazardous substances. Some chemicals are too hazardous to even move from one location to another. These have their own class label, stating “unstable goods, too dangerous to transport”, as well as any other applicable labels.

Dangerous goods can be further organised into packing groups, where packing group I is for high danger substances and packing groups II and III are for substances that present medium and low risk. The packing group determines the kind of packaging required for chemical storage and transport. 

Europe’s ADR treaty mandates a similar system to Australia, closely based on the UN model regulations. The United States’ National Fire Protection Association uses an additional optional label known as the NFPA 704. This indicates levels of health hazard, fire hazard, and reactivity from 0 (minimal hazard) to 4 (severe hazard), and shows any specific hazard if applicable (such as an acid or an oxidising agent). 

Usage and restrictions

Placards and dangerous goods class labels need to adhere to visibility requirements. Placards must have a white or silver background to maximise readability. Any building containing hazardous chemicals must have a “HAZCHEM” placard, with lettering in red and at least 100mm in height. A dangerous goods code class label must be oriented in a diamond, the sides of which must measure at least 250mm. If there are multiple relevant class labels, these all need to be visible and must measure no less than 100mm.

Hazardous chemicals are divided into two storage categories: packaged and bulk chemicals. In Australia, hazardous chemicals classified as packaged means the storage capacity must not exceed 500L or a net mass not exceeding 500kg. Any amount greater than this is classified as a bulk quantity. Internationally, this bulk classification amount varies between 400 and 500kg (or L).

Packaged and bulk hazardous chemicals have stringent packaging and labelling requirements
Packaged and bulk hazardous chemicals have stringent packaging and labelling requirements

Version 7.7 of the Australian Code for the Transport of Dangerous Goods by Road & Rail outlines minimum quantities of goods which require placarding for transport. See the table below.

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