Flammable liquids are volatile substances that can easily ignite and cause harm to people property and the environment of your organisation. To help reduce the many risk that flammable liquids pose upon the people in your workplace, it is very important to store flammable liquids in a safe and compliant manner. Without any knowledge of the Australian Standards, it can be hard to determine what a safe and compliant flammable liquids storage facility looks like. Below we will discuss the design requirements for two flammable liquids storage facilities that are commonly used today.
Requirements for safe flammable liquids storage
The requirements for the safe storage of flammable liquids is outlined in the Australian Standard AS1940-2017 - The storage and handling of flammable and combustible liquids. Australian Standards are comprehensive documents that set out specifications, guidelines and procedures to ensure that products, services and systems are consistent, reliable and safe.
AS1940-2017 outlines a number of different facilities that can be used to store flammable liquids in a safe and compliant manner. Even though the design specifications of each of these storage facilities differ, they all provide adequate protection against the risk associated with flammable liquids. Some of the different flammable liquids storage facilities include:
- A detached store, being a store with or without a roof, or walls other than a bund
- An attached fire-separated store, being a store attached to a building with outside entry and no communication to the associated building.
- An attached store, sharing a wall or walls with the associated building and with a communicating fire door between the store and the associated building
- An internal store, being a store wholly within a building, not sharing a common wall with the building and communicating with the associated building
- Fire-separated stores, being grouped stores with no communication between adjacent storages.
- A storage cabinet located within a building or located outside a building as an outdoor storage.
- Facilities for the holding of materials awaiting use in a process, machine or the like.
- A detached store, being a freight container complying with the requirements of clause 4.8 of AS1940-2017
Even though AS1940-2017 outlines a number of compliant storage facilities that can be used for the storage of flammable liquids, there are two types of storage facilities that most organisations use because of their safe and practical design. These two types of store include:
- Safety cabinets for the storage of flammable liquids indoors
- Relocatable detached store for the storage of flammable liquids outdoors.
We will now discuss the design requirements for these flammable liquids storage facilities according to AS1940-2017.
Indoor flammable liquids storage cabinet
For indoor flammable liquids storage cabinets to adequately protect people, property and the environment from the risks associated with flammable liquids, the cabinet must have a safe and sturdy construction. Section 4.9.2 of AS1940-2017 sets out the construction requirements for indoor flammable liquid storage cabinets. These requirements include;
- The walls, floor, doors and roof of the flammable cabinet must be constructed from a double walled sheet steel construction. The gap between these walls must be no less than 40mm and can be left empty or filled with a fire resistant insulation.
- The gaps around the doors and the walls of the flammable storage cabinet shall be sealed to prevent heat radiation and the spread of flames in the event of a fire.
- The base of the cabinet shall form a liquid tight sump of at least 150mm deep. This sump must be designed in such a way that packages are prevented from being stored in the sump. This sump will contain any spills that may occur inside the cabinet.
- The shelves inside the cabinet must be perforated to allow for free air movement inside the cabinet. The shelves should also be sturdy and capable of carrying the maximum possible load.
- The inside of the cabinet including the shelves shall be designed in such a way that any spills are directed into the sump in the base of the cabinet.
- The doors of the cabinet shall be self-closing, close-fitting and held shut automatically by catches at two or more points.
- If the doors are equipped with a device to hold the doors permanently open when the cabinet is being loaded, the doors must automatically close when the temperature exceeds 80 degrees celsius.
- Materials that are critical to the structural integrity of the cabinet must not melt at temperatures below 850 degrees celsius. Seals and gaskets are an exemption to this requirement.
All these features are mandatory requirements for the construction of flammable storage cabinets. For cabinets that have a storage capacity that exceeds 250L, extra features must be added to the construction of the cabinet to ensure that it adequately protects the workplace from the risk of storing greater quantities of flammable liquids. These extra requirements include:
- The height of the cabinet shall not exceed 2 meters
- The external surfaces of the cabinet shall be constructed from sheet steel of at least 1 mm thick.
- The spill containment sump in the base of the cabinet shall be capable of containing at least 25% of the aggregate capacity of the cabinet or the capacity of the largest container being stored in the cabinet, whichever is greater.
An example of a safe and compliant flammable storage cabinet is shown below:
Outdoor relocatable detached stores
Outdoor relocatable detached stores are flammable liquid storage facilities that are used store flammable liquids outdoors. Storing flammable liquids indoors poses great risks upon the people and property of your organisation. To mitigate this risk, Standards Australia limited the capacity of indoor storage cabinets at 850L. This limitation forces organisations to store larger quantities of flammable liquids outdoors. Outdoor relocatable detached stores can range from 80L to 32,000L. The design requirement for outdoor relocatable detached stores according to AS1940-2017 are outlined below:
- Other than fire-rated structures, all outdoor flammable liquid storage facilities shall be constructed from masonry, concrete, or a structure sheeted with non-combustible material. Any skylights that might be necessary are not required to be constructed from non-combustible material.
- Floors on flammable liquid storage facilities that make up part of the spillage catchment system shall be impervious and not liable to degradation or incendive sparking.
All outdoor flammable liquid storage facilities shall have the provision to contain any leaks and spills. The spill containment system must be designed to prevent any flammable liquids from contaminating the soil in the surrounding area. The system shall also prevent flammable liquids from entering any drainage system or water course. All spillage containment systems installed on outdoor flammable liquids storage facilities shall comply with the following requirements.
- The spill containment compound must be impervious to retain spillage. The compound must also enable the recovery of the contents that have been spilled.
- Any pipework that is used to direct any spill contents to a remove spill containment tank must be fire resistant. Flashback protection must be provided between the outdoor flammable liquids storage facility and the remote spill containment tank.
- The capacity of the spill containment sump must be at least 100% of the volume of the largest package inside the store, plus 25% of the storage capacity up to 10 000L, together with 10% of the storage capacity between 10 000L and 100 000L, and 5% above 100 000L
- If a manual or automatic water-based fire suppression system is installed in the storage facility, the spill containment sump must be increased to a volume equal to the output of the fire suppression system over a 20 minute period.
- Any drainage system shall be capable of containing the output of the sprinkler system for the number of sprinklers operating at the required pressure outlined in AS 2118.1
- Drainage of any rainwater or fire water to outside the compound must be via a suitable interceptor or separator, or after sampling and testing the water.
- When more than one flammable liquids storage facility is connected to a common spill containment sump, the capacity of the sump must be equal to the capacity required for the largest package store, plus 25% of the capacity of the spill containment requirements for the other connected storage facilities.
Each outdoor flammable liquid storage facility must be provided with adequate natural or mechanical ventilation. This ventilation depends on the type of flammable liquids being stored. The ventilation system shall be sufficient to ensure that all vapours and fumes generated within the store are diluted and removed by air passing through the store. The workplace exposure standards, as published by Work Safe Australia, also apply when the type of flammable liquids being stored are listed in that standard.
A compliant natural ventilation system for an outdoor flammable liquids storage facility shall be one of the following configurations outlined below:
- A store with at least two walls completely open to the outside atmosphere.
- A wall of fixed louvers, lattice or wire mesh having at least 50% of its area as openings.
- One wall of the store being completely open to the outside atmosphere with no other vents in the store. In this case the distance to, and the length of, the opposite wall must not exceed the length of the open wall.
- Vents in one external wall, provided that the wall is at least 6m long and the opposite wall is no more than 5m away from the vented wall.
- One wall open to atmosphere and vents in one opposite or adjacent wall
- Vents in two opposing walls
In all cases vents should be located along the longest sides of the building and should be positioned to limit areas where there is no effective ventilation. With large stores, consideration should also be given to providing additional vents on adjacent walls and/or providing vents larger than 0.1 m2 or 0.15 m2.
An example of a safe outdoor relocatable flammable liquids storage facility that complies with the requirements outlined above is shown below:
As flammable liquids are volatile substances that can easily ignite and cause an immense amount of harm to people, property and the environment, it is very important that you store them in a safe and compliant manner. To learn more about how to reduce the risk associated with flammable liquids, download our FREE eBook with outlines our methodology for managing the risk of flammable liquids.