Finding and calculating a cylinder or tank capacity

Background

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:

1. Use the formula Volume of Cylinder = πr² x Length
   Note: For a vertical tank, the length is replaced by the height in centimetres
2. Measure the radius (half of the diameter) of the cylinder in centimetres, this value is 'r' in the formula.
3. 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.

Formulas

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

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.