Finding and calculating a cylinder or tank capacity
This guidance provides information on how to determine the capacity of cylinders (pressure receptacles) and tanks used to store liquid refrigerants.
This guidance material has been prepared using the best information available to WorkSafe, and should be used for general use only. Any information about legislative obligations or responsibilities included in this material is only applicable to the circumstances described in the material. You should always check the legislation referred to in this material and make your own judgement about what action you may need to take to ensure you have complied with the law. Accordingly, WorkSafe cannot be held responsible and extends no warranties as to the suitability of the information for your specific circumstances; or actions taken by third parties as a result of information contained in the guidance material.
Occupiers of sites where dangerous goods are stored and handled must determine the quantity of dangerous goods for placarding, notification, manifest and fire protection purposes, under the Dangerous Goods (Storage and Handling) Regulations 2022.
Finding the capacity
Cylinders and tanks (liquid receivers) containing gases under pressure are required to have the total capacity which means the internal capacity (in litres) recorded. This can often be found marked as water capacity (WC) in kg or litres:
- on the cylinder collar or label
- on the compliance plate or
- printed on the liquid receiver
When you cannot find the capacity
Tanks and cylinders must be clearly marked and occupiers should contact their supplier or maintenance provider if the markings or information are not available, accessible, visible or legible.
Calculating the water capacity
If you cannot find the plate, records or information listing the capacity, then it can be calculated.
The following outlines how to calculate the cylinder or liquid receiver capacity in Litres:
- Use the formula Volume of Cylinder = πr² x Length
Note: For a vertical tank, the length is replaced by the height in centimetres
- Measure the radius (half of the diameter) of the cylinder in centimetres, this value is 'r' in the formula.
- Measure the length of the cylinder, or height of the vertical cylinder, in centimetres, this value is 'Length' in the formula.
Using the measurements in the example above, length (320cm) and radius (50cm), to calculate the volume of litres using the formula below.
Volume of liquid receiver (cylinder)=πr² x Length
Litres water capacity=πr² (cm)x Length(cm)/1000
3.142 (π) x (radius) x (length) x (radius) / 1000 (conversion to Litres) = Litres Water Capacity
Example of formula
(3.142) x (50cm) x (320cm) x (50cm) / 1000 = 2,514 Litres Water Capacity
In this example, the receiver is a bulk quantity of Class 2.3 Dangerous Good, the quantity of 2,514 Litres is reportable on the manifest.
Refrigeration liquid receiver capacity included in a Dangerous Goods Notification
Anhydrous ammonia is a class 2.3 Toxic Gas sub-risk 8 Dangerous Good, commonly used in workplaces with ammonia refrigeration systems (industrial refrigeration systems). It is acutely toxic if inhaled or ingested, corrosive and flammable and can cause severe and catastrophic burns to persons at the workplace and in surrounding areas if an uncontrolled release occurs.
The quantity of anhydrous ammonia on site should be calculated and reported as Class 2.3 dangerous goods in the notification and the site manifest.
Duty to notify of dangerous goods storage and handling
The Dangerous Goods (Storage and Handling) Regulations 2022 (the Regulations) regulate the safe storage and handling of dangerous goods, by setting out the legal duties for manufacturers, suppliers, and occupiers of workplaces where dangerous goods are stored or handled. As a site occupier, you must identify all dangerous goods stored and handled at your workplace, including any gases and anhydrous ammonia in the liquid receiver of the ammonia refrigeration system.
Occupiers must notify WorkSafe when the quantities of dangerous goods stored and handled at your workplace exceed the manifest quantities specified in Schedule 2 of the Regulations.