This is an update on the post originally published on 12 May (‘Is a dangerous goods placard required for an ambulance?‘). Although I’ve changed my mind about the correct answer, I’ll leave that post ‘online’ so the history of this discussion can be seen. I write this update because of the useful discussion that has followed that original post that has given me more relevant facts and guidance.

First let me say I stand by my original conclusion, if the ambulance is carrying more than 1000 litres of compressed oxygen then placarding is required.

The complexity is how you calculate the relevant volume. It also shows, as explained in my original post, that the regulator’s official publications may not reflect the actual law.

The capacity of a cylinder is defined to mean ‘the total internal volume of a form of packaging at a temperature of 15° Celsius, expressed in litres or cubic metres’. The capacity so defined is not however equivalent to the volume of gas in the cylinder – ie a cube that is 1m x 1m x 1m has a volume of 1m^{3 }(or 1 cubic metre) but that tells you nothing about how much compressed oxygen can be put into that cube.

In the original post I said:

According to BOC Healthcare UK, a “D” size oxygen cylinder is 340 litres and a “C” size is 170 litres (http://www.bochealthcare.co.uk/internet.lh.lh.gbr/en/images/cylinder_data_med309965_2011409_54065.pdf). I assume that is also true in Australia. Assuming all the oxygen bottles are full, an ambulance with 2 D and 3 C bottles is carrying 1190 litres of compressed oxygen.

A number of people have told me that the assumption (that an Australian gas cylinder has the same capacity as a UK gas bottle) is incorrect. I have been told that in Australia

- D cylinders are 1200 litres or 1600 litres and
- C cylinders are 400 litres or 630 litres.

Given they are both bigger numbers than my original assumption, it must follow that the ambulance is carrying much more than 1000 litres of oxygen.

So then the issue is – is it the capacity of the cylinders (as defined), or the amount of compressed oxygen that is relevant?

The definition of aggregate quantity:

… in relation to a load containing dangerous goods, means the total of:

(a) the number of kilograms of:

(i) solid dangerous goods, and

(ii) articles (including aerosols),

in the load, and

(b) the number of litres or kilograms, being whichever is used in the transport documentation for the load to describe the goods, of liquid dangerous goods in the load, and

(c) the total capacity in litres of receptacles in the load containing dangerous goods of UN Class 2 (except aerosols).

Let us assume that compressed oxygen is not a ‘solid’ dangerous good so (a)(i)=0. ‘Articles’ is not defined so let us assume that is five (ie there are five bottles). Let us also assume that oxygen is not a ‘liquid dangerous good’ so (b) = 0. Oxygen is a class 2 dangerous good so the total capacity in litres would seem to refer back to the definition of capacity already given. I’m told a D cylinder has a ‘capacity’ of about 10 litres of water, and a C cylinder about 3 litres. That would mean the capacity, in litres, of 2 D and 3 C cylinders would be 29 litres.

Clause 5 says the* Dangerous Goods (Road and Rail Transport) Regulation 2014 *(NSW) does not apply where:

- the load does not contain (i) dangerous goods in a receptacle with a capacity of more than 500 litres

and

- the aggregate quantity of the dangerous goods in the load is less than 25% of a placard load.

The D and C cylinders do not have a ‘capacity’ in excess of 500 litres so (a) applies. If the relevant amount for placarding is the ‘aggregate quantity’ which is the volume in litres of the cylinders then the aggregate quantity is 29 litres which is much less than 25% of the placard load amount (1000 litres).

So what about my comment on believing the regulator? The EPA website says that a placard is required where ‘there are more than 1,000 L/kg of dangerous goods in a load’ (http://www.epa.nsw.gov.au/dangerousgoods/FS2placardloads.htm). That’s talking about the actual quantify of the dangerous goods (which is clearly well over 1000 litres) not the water holding capacity of the containers in which the gas is stored.

So to further clarify the matter I’ve gone back to the EPA and they have refined their advice. They say:

The load limits on which a placard load is determined is based on the aggregate quantity of dangerous goods being transported. The Australian Code for the Transport of Dangerous Goods defines aggregate quantity as:

1.2.1.2.1 Aggregate quantity – (Regulation 1.2.1)

The aggregate quantity of dangerous goods means the total of:

(a) the number of kilograms of:

(i) solid dangerous goods; and

(ii) articles (including aerosols); and

(b) the number of litres or kilograms, whichever is used in the transport documentation to describe the goods, of liquid dangerous goods; and

(c) the total capacity in litres of receptacles containing dangerous goods of Class 2 (except aerosols);

The aggregate quantity of Class 2.2 dangerous goods that would require placarding is more than 1000 litres so the load carried by an ambulance, as listed below, is well below that amount. In most instances vehicles transporting less than a placard load are still required to carry transport documents however because of the small quantities involved there is an exemption in the Dangerous Goods Regulations that would be applicable:

5 Exempt transport

(2) This Regulation does not apply to the transport by a person of a load that contains dangerous goods if:

(a) the load does not contain:

(i) dangerous goods in a receptacle with a capacity of more than 500 litres, or

(ii) more than 500 kilograms of dangerous goods in a receptacle, and

(b) the goods are not, and do not include, designated dangerous goods, and

(c) the aggregate quantity of the dangerous goods in the load is less than 25% of a placard load, and

(d) the goods are not being transported by the person in the course of a business of transporting goods by road, and

(e) in relation to transport by rail—the goods are not being transported by the person on a passenger train.

The ambulances are carrying less than 25% of a placard load and are not in the business of transporting goods and so are exempt from the provisions of the Regulations.

**Conclusion**

So the extra information that has been provided causes me to rethink my answer. The conclusion is that if compressed medical oxygen is being carried in a container or containers with a capacity of more than 1000 litres of water, then a placard is required.

If, as I am told, the aggregate capacity in litres of 2 D and 3 cylinders is somewhere around 30 litres (even though you can fit in more than 1000 litres of oxygen) then there is no need for a placard. A placard would only be required if the vehicle was transporting more than 100 D cylinders.

That would explain why ambulances do not need dangerous goods placards which does accord with the intuitive answer.

I also stand by my original starting point: I thought the answer to this question would be easy to find but this has turned out to be one of the most complex answers I have ever had to wade through.