Storage of flammable liquids in safety cupboards
General regulatory requirements and definitions
The following definition applies for the storage of hazardous substances:
Hazardous substances must be kept or stored in a way that ensures they do not endanger human health or the environment. Misuse or abuse must be prevented. The storage of hazardous substances in containers for foodstuffs is prohibited. Storage means keeping hazardous substances for later use or distribution to others.
This includes their provision e.g. for transport or unloading, if this does not occur within 24 hours of starting these activities or by the following working day. If this working day is a Saturday, the period ends at the end of the next working day.
Storage in safety cabinets and explosion protection measures
The advantages of using type 90 safety cabinets made in accordance with EN 14470-1 for the storage of flammable liquids in workrooms are obvious:
- Fulfilment of elementary requirements for fire and explosion protection
- Fast and effective storage of hazardous substances in the safety cabinets when work ends
- Minimisation of unsafe storage of hazardous substances at the workplace
- Reduction of the in-house transport of hazardous substances and the associated risks
- Flexibility of storage locations
- Storage spaces can be exploited more effectively
Note: safety cabinets can also be installed and set up in corridors following consultation with the local fire fighting services as long as this does not limit the width of the escape route.
Safety cabinets with and without forced ventilation
Safety cabinets should, by principle, be equipped with forced ventilation. This can be put into practice using one of the following methods:
- Connection to an existing ventilation system
- A separate fan with a corresponding exhaust pipe
- A ventilation kit installed on the safety cabinet with a corresponding exhaust pipe
- Connection of a recirculating air filtration module (AFM) that operates using the adsorption principle
In these cases, a classification of the cabinet surroundings into ex-zones is not required.
Air filtration module
When air filtration modules are used, practical studies have demonstrated that fires in the adsorption filters – as are familiar from large industrial plants – cannot occur when operating safety cabinets when the air filtration module fitted on a safety cabinet is equipped with a continuously acting protective device. If the use of forced ventilation is not possible, a safety cabinet can also be operated without forced ventilation. In this case, different zones must be demarcated.
Safety cupboards in accordance with DIN EN 14470-1
DIN EN 14470-1 – key requirements
- Minimise the risk of fire associated with the storage of flammable substances and protect the contents of the cabinet in the event of fire for a specific (tested) period of time.
- Minimise vapours emitted into the working environment.
- Containment of potential leaks within the cabinet.
- For the first time, firefighters are also defined as requiring explicit protection. The standard defines that personnel have sufficient time to leave the workplace and firefighters have sufficient time to enter the building before an uncontrolled fire breaks out due to the flammable substances kept in storage.
- Test in a suitable fire chamber as an individual, free-standing cabinet.
- The entire cabinet must be exposed to uniform heat conditions.
- Burn test in accordance with the temperature-time curve EN 1363-1 (5.1.1).
- The increase in temperature is measured in the cabinet (13 measuring points on the surfaces and the air).
- The cabinet is then classified as type 15, 30, 60 or 90.
- They must close fully from any position (closing time max. 20 seconds).
- Integrated arrest systems must release doors fixed in place at a temperature of 50 (+0/–10) °C.
- Air intake and exhaust openings are mandatory.
- The ventilation openings must close automatically at a temperature of 70 °C (±10 °C).
Shelves and drawers
- The shelves and drawers must be able to bear the max. load specified by the manufacturer for the duration of the fire.
Base sump tray
- The base sump tray must retain its functionality after the duration of the fire.
- Visual inspection (filling the base sump tray with water).
Information to be included
- Operating instructions with information on the max. load of shelves or drawers in the cabinet, the capacity of the base sump tray, recommendations for inspection and maintenance, manufacturer's declaration of conformity or certificates of conformity from an authorised materials testing institute.
Marking and labelling
- Sign: Keep doors closed after use.
- Warning symbols “Caution: Risk of fire” and “Fire: Open flames and smoking prohibited” in accordance with ISO 3864.
- The fire resistance in minutes in accordance with EN 14470-1.
- Name and/or trademark of the manufacturer.
- Model number and year of manufacture.