A tanker has rolled on the N3, there’s liquid on the road, and the first person on the scene has one source of information: the orange-and-white board on the back of the truck.
That board is the hazchem placard. In about a minute it tells a fire crew what’s in the tank, how dangerous it is, and who to call for help. If you drive, load, dispatch or manage dangerous goods vehicles, you should be able to read one just as fast.
What the Placard Is For
A placard has one job: to identify the danger in a load quickly, so the right people can find the right information during a spill or fire. In South Africa, the rules are set out in SANS 10232-1.
On vehicles over 3,500 kg GVM, the main placard measures 700 mm × 400 mm. It’s fitted to the left, right and rear of the vehicle, so it can be seen from behind and from either side of the road.
The Five Zones, One at a Time
1. The Hazard Class Diamond: What Kind of Danger
The large diamond (250 mm × 250 mm) shows the primary hazard class. Read the colour and symbol first, because they give you the type of danger before you’ve read a single number.
| Class | Hazard | Diamond |
|---|---|---|
| 1 | Explosives | Orange, exploding bomb |
| 2 | Gases | Red (flammable), green (non-flammable) or white (toxic) |
| 3 | Flammable liquids | Red, flame |
| 4 | Flammable solids | Red-and-white stripes, flame |
| 5 | Oxidisers and organic peroxides | Yellow, flame over circle |
| 6 | Toxic and infectious substances | White, skull and crossbones |
| 7 | Radioactive material | Yellow-and-white, trefoil |
| 8 | Corrosives | Black-and-white, liquid eating through hand and metal |
| 9 | Miscellaneous | White with black stripes |
Hazchemwize supplies all nine as hazard class diamonds.
2. Subsidiary Risk Diamonds: The Second Danger
Some substances are dangerous in more than one way. A liquid can be both flammable and toxic, for example. When the Dangerous Goods List shows a subsidiary risk, smaller 100 mm × 100 mm diamonds appear next to the main one.
3. The UN Number: Exactly What’s in the Load
The four-digit UN number identifies the specific substance. It’s the number responders look up in their emergency guides. A few you’ll see on South African roads:
- UN 1203: Petrol. It’s also used for diesel, paraffin and aviation fuel when carried together.
- UN 1075: LPG
- UN 1005: Anhydrous ammonia
- UN 1830: Sulphuric acid
The UN number changes with every load. That’s why fleets carrying different products use UN number overlays rather than ordering a new placard for every trip.
4. The Operator’s Number: Who Owns the Truck
This is where the vehicle operator or owner can be reached. Responders call it to find out what was loaded, where the truck was going and who’s in charge. Keep it current with operator advice number overlays.
5. The Specialist Advice Number: Who Knows the Chemical
This number reaches someone who can advise on the specific hazards of the cargo, usually the supplier, manufacturer or a spill response company. If the operator can give that advice, the two numbers can be the same. Supply them as specialist number overlays.
Rules for both numbers:
- Each zone has room for up to two numbers, and one of them must be a landline.
- Both must be answered 24 hours a day. An office line that rings out on a Saturday night fails the purpose of the placard.
Special Cases Worth Knowing
Mixed loads. When goods from different hazard classes travel together, the UN number is replaced with the words “MIXED LOAD” and a general “DANGEROUS” diamond is used. If the goods are mixed but from the same class, “MIXED LOAD” appears with that class’s diamond.
Bakkies and panel vans. Vehicles under 3,500 kg GVM use a half-size 350 mm × 200 mm placard. The class diamond shrinks to 100 mm, subsidiary diamonds aren’t required, and the orange danger warning diamond at the front drops to 100 mm × 100 mm.
Empty vehicles. Once the vehicle is completely offloaded, or a tanker has been certified clean, the placards must come off. A placard showing a load that isn’t there misleads responders just as badly as no placard at all.
Whose Job Is It?
Placarding isn’t only the driver’s problem:
- The consignor must supply the placards, or the information needed to placard correctly.
- The driver must check that the placards are in place before leaving.
- The dangerous goods loading supervisor must not let a wrongly placarded vehicle move.
- The operator carries responsibility as well, especially when collecting loads from several consignors on one trip.
The Placard Is Only One Piece
A correctly placarded truck still needs the rest of the kit: a tremcard in the cab, a valid dangerous goods permit, secure hazchem brackets, and the right safety equipment on board. Hazchemwize’s full vehicle compliance service covers all of it. If you’re not sure whether your load needs placards at all, check the exempted quantities first.
Reading a placard takes 60 seconds. Knowing what to do with that information takes training. Our dangerous goods training gives drivers, loaders and supervisors the knowledge to placard, load and respond correctly. The online Convey Dangerous Goods by Road course is a good place for drivers to start.
Need placards made up? Order hazchem placards in vinyl, chromadek, magnetic or PVC. Call 0861 429 243 or contact us.
FAQs
What does the UN number on a hazchem placard mean?
It’s a four-digit number that identifies the exact substance being transported, such as UN 1203 for petrol. Emergency responders use it to look up how to handle a spill or fire.
What is the difference between the operator number and the specialist advice number?
The operator number reaches the company that owns or runs the vehicle. The specialist advice number reaches someone who can advise on the chemical’s specific hazards, often the supplier or a spill response company. Both must be answered 24 hours a day.
What does “MIXED LOAD” mean on a placard?
It means the vehicle is carrying more than one dangerous substance. If the substances are from different hazard classes, a general “DANGEROUS” diamond is shown instead of a single class diamond.
What size hazchem placard does a bakkie need?
Vehicles under 3,500 kg GVM use a 350 mm × 200 mm placard. Vehicles over 3,500 kg need the full 700 mm × 400 mm size.
When must hazchem placards be removed?
Once the vehicle is completely offloaded or, for tankers, certified clean.
