Improving efficiency and safety in Australian labs
Russell Urquhart, general manager of G3Lab, looks at how the European Standard EN 14470-1 compares to those governing storage cabinets in Australia and how Australian consultants are using a risk-based alternative approach to the storage of hazardous products in laboratories and other facilities.
In the Australian lab design code AS2982, it is recommended that no more than 30 L of class 3 flammable solvent be stored in a single underbench safety cabinet. The lab safety standard AS2243.10 recommends a minimum of 3 m between any class 3 safety cabinet and escape doors, and 10 m separation between aggregate dangerous goods of 250 L or more. The Australian flammables goods standard AS1940 recommends a maximum of 250 L of flammable goods in safety cabinets per 250 m2 in multilevel buildings.
What do these regulations all have in common? They refer to double skin metal cabinets manufactured according to AS1940, which require no formal testing of fire resistance properties. For this reason, managers of labs and other large facilities are increasingly turning to dangerous goods consultants to investigate a risk-based method of flammable storage to challenge these restraints and raise the level of safety in Australian labs. Often the specified solution is a central fire-rated store with integrated spill containment, ventilation, explosion-proof lighting, access control, etc — in effect a ‘concrete bunker’, which can be very expensive and creates a lot of inefficiencies for users.
Fortunately, this issue has been addressed well in other parts of the world, resulting in the development and regulation of cabinets with a guaranteed fire rating, such as those manufactured to EN14470 by asecos in Germany.
The advantages of a 90 minute fire-rated safety storage cabinet
Once a cabinet with a proven fire rating is considered, the consultant can look more objectively at the flammable goods workflow and often increase the amount of solvents stored within labs and work areas. If the EN approach is used as a guide, 90 minute fire-rated cabinets (type 90 cabinets) can be stored adjacent to each other, since they are wholly isolated from the fire and from each other for 90 minutes in a fire incident.
Efficiency is immediately improved, as time spent fetching flammable liquids from the central storage room to the workplace is minimised and all hazardous materials for daily use can be readily available, safely and conveniently, in the lab. An added benefit is the elimination of risks associated with moving flammable goods around the building through traffic areas such as corridors and lifts.
Safety cabinets in accordance with EN 14470-1 for flammable liquids provide a high degree of safety for personnel and the environment and give maximum protection to assets. They guarantee the highest fire protection available today, minimise the potential for explosions and prevent an existing fire from spreading. They will provide sufficient time for personnel to safely leave the building and for firefighters to rescue people from the building and extinguish a fire.
The primary function for which a safety storage cabinet is intended is to shield stored, hazardous materials from a temperature rise of more than 200°C in the event of fire for the defined period of time. Combustion may begin if the temperature rise inside the safety storage cabinet exceeds 200°C, as many common class 3 flammable liquids will reach their autoignition temperature around 220°C (a room temperature of 20°C plus a temperature rise of 200°C), which is when they explode.
Whether in Munich or Melbourne, a fire has the same properties and temperatures. A temperature curve shows that after only 5 minutes, a fire has reached a temperature of 576°C. After 30 minutes 842°C has been reached, and after 90 minutes the flames are at more than 1000°C. The contents of a double skin storage cabinet designed to AS1940 will follow much the same temperature curve.
A double-wall steel cabinet provides 3–10 minutes of protection before the interior has heated to 220°C. A type 90 safety storage cabinet provides 90 minutes of protection before the interior has heated to 220°C. That’s almost 10 times more safety in the event of fire compared with a double-wall steel cabinet designed to AS1940.
In the event of a fire, the cabinet must ensure that, over a period defined by the manufacturer, its contents do not present an additional risk that the fire will spread. The cabinet doors must close entirely, starting from any position (closing time max 20 seconds).
Air inlet and outlet openings
The cabinets must have openings for air inlet and outlet (for connection of the cabinet to an exhaust system). The ventilation openings must close automatically at a temperature of 70°C. Shelves and drawers must be able to support the loading specified by the manufacturer over the period of the test in the furnace. The internal equipment of the cabinet must include a spill containment sump and the spill containment sump must retain its ability to function after the fire resistance test. This is to be checked visually by filling the spill containment sump with water.
Each model must be independently verified by tests on a design sample. A fire-resistant cabinet is exposed to flames in a suitable furnace. The doors, walls and ceiling of the cabinet being tested must be exposed to the same heating conditions. Cabinets must be tested as free-standing single cabinets. The flame exposure is carried out in accordance with the standard temperature curve of EN 1363-1 (5.1.1). The temperature rise is measured inside the cabinet. The cabinet will then be classed as type 15, 30, 60 or 90, according to the time that has elapsed before the temperature rose by 200°C.
EN 14470-2 — the highest standard for gas cylinder cabinets
Australian labs and industry are also taking advantage of 90 minute fire-rated gas cylinder stores designed to EN14470-2, for safety in the storage, provision and handling of gas cylinders in indoor areas.
Due to the high pressure and the contents (corrosive, toxic, flammable, fire accelerating), gas cylinders represent a significant potential hazard compared to flammable liquids. It is therefore usually recommended to store gas cylinders in outdoor areas. In practice, this is often not possible or is associated with very high costs. With the publishing of the EN standard for gas cylinder cabinets, EN 14470-2, an economical and flexible option for the installation of gas cylinders in indoor areas is now available that offers a level of safety comparable to that of outdoor storage.
Fire resistance is classified into four classes, from G15 up to G90 (fire resistance of 15 up to 90 minutes).
Each type of cabinet and each cabinet size must to be type tested in a furnace. In case dimensional variation exceeds the tolerance, the cabinet must be retested again. Tests can only be executed by an authorised material testing institute.
EN 14470 parts 1-2 stipulates that the following documents are supplied with each fire-rated safety cabinet:
- A test report of an authorised material testing institute stating/proving the successfully passed fire test.
- A test certificate issued by an independent testing organisation.
This ensures compliance with regulations, safety for the user and clear identification of approval documents with the model of safety storage cabinet.
While the Australian standards mentioned above are a starting point for users looking for compliant solutions, EN 14470-1 and EN 14470-2 are providing some welcome and relevant guidance to Australian dangerous goods consultants and clients who are adopting a risk-based approach to dangerous goods storage to increase both efficiency and safety.
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