Radar19:
Been having a little back and forth between some mates of mine regarding those hazardous diamonds you see on that ferry trailers. Now, they say you’re supposed to remove them as soon as you get the trailer because the powers that be can do you for carrying hazardous goods without displaying your ADR boards. I’ve always left them because they are only for sea going rules, not ADR rules.
Hi Radar19,
There’s so much that people have half remembered here that it’s difficult to know where to begin, but here goes…

It’s helpful to sort out our language first. 
“those hazardous diamonds” are called placards [250mm X 250mm]
“ADR boards” are called orange coloured plates [400mm X 300mm (or 300mm X 120mm due to vehicle construction)]
ADR is the name of the Regulations that govern the carriage of dangerous goods by road
IMDG is the name of the Regulations that govern the carriage of dangerous goods by sea
Now we can get to the questions.
The rules for ISO containers are easy… ADR and IMDG both require an ISO container to be placarded on all four sides when it contains any amount of dangerous goods. (There are only a few very minor exceptions to this.)
Now we can consider collecting/delivering an ISO container to/from a port by road…
Normal ADR rules apply to the road leg of the journey, so the dangerous goods are either being carried using the LQ or small load exemptions OR the load is packaged in a normal way, so the 20, 333 or 1,000 ADR threshold limits apply to decide whether orange coloured plates are required to be displayed on the carrying vehicle. This doesn’t alter the blue writing above.
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For a complete vehicle carrying dangerous goods which is itself going to be carried on a ferry, IMDG requires the blue writing above to be followed EXCEPT that a placard is NOT needed on the front of a complete vehicle.
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For a vehicle which is going to drop off/collect a trailer for onward/incoming shipment to/from a ferry, IMDG requires the blue writing above to be followed as for ISO containers EXCEPT that it should be remembered that placards are allowed (but NOT required) by ADR during the road leg of the journey. For all UN Classes, except Classes 1 and 7, it is perfectly OK to place or remove placards on/from unaccompanied trailers at the port.
Dave’s IMDG tips:
- If the ‘thing’ carrying dangerous goods going on a boat hasn’t got a windscreen, it needs four placards.
- If the ‘thing’ carrying dangerous goods going on a boat has a windscreen, it needs three placards.
- IMDG does not recognise ADR orange coloured plates, they ONLY use placards.
- IMDG allows that ADR orange coloured plates may be left in place during a ferry crossing.
Radar19:
The reason this came about was because I passed a college when I had a full load of soft drinks on whilst still having the Class 3 diamond from earlier in the day still on the trailer. He questioned me about it in the yard later, asking why I didn’t have my ADR boards out. I replied that I didn’t need to remove them as I consider them only for when the trailer on a ship.
So, who is correct in this?
As has already been (correctly) mentioned, you must remove (or cover) placards/orange coloured plates when there are no dangerous goods on board a vehicle or ISO container.
Sorry mate, but you risked a prohibition for not doing so.
Your mate is incorrect with a blanket statement that you need orange coloured plates when carrying dangerous goods, because ADR has a quite a number of exemptions to that rule.
Orange coloured plates are not need when carrying:
- LQs (Package type exemption, usually for retail goods)
- EQs (Package type exemption, usually for small samples)
- Dangerous goods (packaged in normal ways) being carried subject to ADR Transport Category vehicle load threshold exemption
- Dangerous goods being carried by use of some of the ADR Special Provisions
I hope this helps you. 
And your mate. 