What is the Bund of a Chemical Storage Cabinet?

Are you searching for bunded storage? You may be asking yourself about the bund requirements in a chemical storage cabinet? Perhaps you’re not sure what function a bund performs or why it’s needed in chemical storage. In this post, we’ll be looking at chemical storage cabinet bunds, and explaining what makes a compliant solution – and why it’s necessary in your organisation.

But first, let’s look at bunding in general to understand why we need it in a workplace.

What are the Bunding Applications?

A bund is a physical barrier, typically a wall, embankment, or dike, constructed to contain or control the flow of liquids. Bunds are commonly used in industrial and environmental settings for various purposes, including:

• Containment of Spills: Bunds are used to contain accidental spills of hazardous or non-hazardous liquids in handling or storage areas of the workplace. Bunds can be temporary measures, fixed or incorporated into storage areas and equipment.
• Flood Protection: In areas prone to flooding, bunds can be built to protect property and infrastructure by directing or holding back floodwaters.
• Agricultural Use: Bunds can be employed in agriculture to manage water resources, improve irrigation efficiency, and prevent soil erosion.
• Mining and Construction: Bunds are used in mining and construction sites to manage water runoff, control sediment, and prevent contamination of surrounding areas.

In this blog, we’ll be looking specifically at bunds in chemical cabinets – otherwise known as safety cabinets – and how you can ensure that your storage is compliant with spill containment requirements.

What Makes a Compliant Bund in Chemical Storage?

The design and construction of a bund depend on the specific application, the type of liquid being contained, and the environmental conditions of the site. Key considerations include the height, width, and materials used to ensure the bund is effective and durable.

When discussing compliant bunding for indoor chemical storage, Australia has standards that dictate how the bund is made and the capacity of the bund.

The bund capacity of a chemical storage cabinet is the volume of liquid that the containment area (bund) can hold in the event of a spill. It is an essential safety feature designed to prevent the spread of hazardous chemicals in case of a leak or accidental spill.

Keeping your cabinet compliant includes making sure the bund is not used for storage, and that it's monitored for any leaks and spills.

Key Considerations for Bund Capacity:

• Regulatory Requirements: Different regions have specific regulations and guidelines that dictate the required bund capacity for chemical storage cabinets. These regulations often require the bund to hold a certain percentage of the total volume of the chemicals stored. For instance, in some regions, the bund capacity must be at least 110% of the largest container's volume or 25% of the total volume of all containers stored, whichever is greater.
• Type of Chemicals: The nature of the chemicals stored can influence the required bund capacity. Hazardous chemicals, flammable liquids, and corrosive substances might have stricter containment requirements.
• Storage Configuration: The total volume of chemicals stored and the sizes of individual containers need to be considered. The bund must be capable of containing spills from the largest container stored in the cabinet.

REMEMBER: Generally speaking, bunds should be able to hold at least 110% capacity of the largest container stored or 25% of the total packages stored, whatever’s greater. However, you must refer to the requirements to determine specific capacities for your operations, as these vary.

Australian Requirements for Safety Cabinet Spill Containment

As we’ve mentioned earlier, there are standards that provide guidance on the construction of safety cabinets – including their spill containment bunds.

This is to ensure that the bund is adequate for the type and quantity of chemical stored, and that it does not create further hazards (such as incompatible substances meeting in the same bunding system).

The bund requirements include:

• The inner base of the cabinet should form a liquid-tight compound
• This must be a minimum of 150mm deep
• Any leaks must be directed into the lower spill compound
• The bund must not be used for storage

For Class 3 larger cabinets exceeding 250L, the bund must be capable of holding:

• At least 25% of the design capacity of the cabinet or the volume of the largest package able to be stored in the cabinet, whichever is the greater.

Bunds and spill containment systems are designed to prevent spillage from entering the workplace. However, it’s important to practice good housekeeping with your cabinets, ensuring all lids are on containers, chemicals are stacked and loaded safely, and any chemical residue is wiped off before the product is placed back into storage.

You can access the spill containment bund my removing the bottom shelf of the safety cabinet.

Bund Capacities

If you’re choosing not to use a Safety Cabinet to store your dangerous goods, there are specific requirements that apply to the spill containment system in regard to capacity. These are more complex and can be different when dealing with various classes of dangerous goods.

Some commonly used dangerous goods, including flammable liquids, toxic substances and corrosive substances have specific capacity requirements. These include:

Class 3 Flammable Liquids:

The capacity of the spillage containment compound shall be at least 100% of the volume of the largest package plus 25% of the storage capacity up to 10 000 L, together with 10% of  the storage capacity between 10 000 L and 100 000 L, and 5% above 100 000 L. 

Class 6 Toxic Substances:

The net capacity of any compound shall be— 

• For Packing Group I liquids, 100% of the aggregate volume of liquids kept. 
• For Packing Group II and III liquids, 25% of the aggregate volume of liquids kept

In any case, the net capacity of any compound shall be at least the capacity of the largest container kept. 

Class 8 Corrosive Substances:

(a) Stores, other than those for closed lead-acid batteries, shall be provided with a means of  either containing a spill or of diverting it to a compound within the boundaries of the  premises. The net capacity of any compound shall be not less than whichever is the greater  of— 

• 25% of the aggregate volume of liquids kept; or 
• the capacity of the largest container kept; 

but need not exceed 5000 l where only packages are kept. 

It’s also important to note that corrosive substances, due to their ability to destroy metal and other materials, must have a bund that is impervious to corrosion. Storemasta Corrosive Cabinets are equipped with PVC drip trays and sump tray , to stop corrosive chemicals from eating away at these sheet metal storage cabinets.

REMEMBER: There are many requirements that apply to bunding. To learn more, read our blog to find out more about bunding regulations.

Bunded Storage and Spill Containment

All operators and workplaces have an obligation to protect people, place and property from chemical hazards. This includes preventing chemical spills from entering the workplace.

Spill containment, as well as spill clean-ups and emergency procedures, are all necessary to prevent incidents such as environmental contamination, chemical burns and inhalation exposure, and the destruction of property. To learn more about protecting your workplace from leaks and spills, you can access our free eBook. This guide details a range of bunding options that are suitable for all types of operations. Grab your free copy today to learn more.