Weather Proofing Your Secondary Containment System

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Storing hazardous substances outside

Across many industries, there is often the requirement to store the hazardous substances that they use, outdoors. This might be due to a lack of space indoors, the need to segregate non-compatible substances, or because the regulations determine that larger containers, e.g. 200L drums or 1,000L IBC’s, cannot be stored within a building.

Depending on the hazard class of the substance(s), in many situations these products will need to be on or within some form of secondary containment, or what is referred to sometimes as ‘bunding’. This is to contain any hazardous substances in the event of a leak or spill, and to prevent them from entering the stormwater system and causing major harm to the environment.  Solutions take the form of concrete block walls, lined berms or most commonly, relocatable spill containment pallets – see our range here.

The level of secondary containment necessary will vary depending on the class and quantity in question – contact our team for more information.

The challenges faced when storing outdoors

One of the key challenges faced when storing hazardous substances on secondary containment systems, is how to keep the rainwater out.  Allowing rainwater to enter the bund causes a number of problems:

  1. It takes up the secondary containment space, reducing the capacity of the system to hold the hazardous substance, therefore impacting site compliance
  2. Also, if chemicals have got into the bund, there is now the challenge of draining the rainwater without accidentally releasing a hazardous substance into the environment

Solutions to these challenges

There are a number of solutions to these challenges.

One: Build a lean-to or shelter over the secondary containment system
This can be a simple fix, but it does limit the flexibility of the system as the site, and its requirements, change.  You need to look ahead in these instances as you don’t want to build a structure, only for it to be modified or removed/rebuilt elsewhere a year or two down the track. The cost to construct such a structure needs to be factored in also, particularly if there are consent costs involved.

Two: Cover the drums/IBC’s with PVC covers

Another option is to cover the drums/IBC with PVC covers, which come part way down the spill pallet, allowing rainwater to shed off.  While this is often the least expensive option if there are only a few containers, it can create operational issues, particularly if they are accessed frequently. The PVC covers should be UV-protected but even these break down over time, so will have a relatively limited life-span.

Three: Covered Spill Pallets

The most common method in use today are covered spill pallets, sometimes referred to as “Roll Tops”. These unique units are typically constructed from polyethylene – resistant to corrosion - and completely cover the container(s). They have the required spill capacity in the base (sump), and feature swing open doors and a roller style roof, which makes the substances inside very easy to access.  Being easy to relocate, they provide a user full flexibility as and when their site changes. They are also lockable, which provides full security against unauthorised access.                                                                                          

Having the right weatherproof secondary containment when storing drums or IBC’s outdoors is crucial to keeping you, the public and the environment safe from harm. Our range of outdoor containment helps keep your drums and IBC’s safe for the weather, secure and compliant with secondary containment regulations. View the full range here

Creating safer working environments

At Hazero our mission is zero hazards. Our extensive range of quality products will help you store, contain and control and clean-up dangerous goods and hazardous substances.

View our full range of Outdoor Containment here.

Need help creating a safer working environment? Contact our team today on 0800 688 844 or email us at Our team are also available for on-site assessments across New Zealand, click here to request a site visit.

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