Do Supply and Exhaust Air Openings Close Automatically in the Event of a Fire?
Self-closing ventilation openings on safety storage cabinets – regulatory requirements and standards, trigger mechanisms and constructive implementation according to EN 14470-1
Summary
Yes – safety storage cabinets according to EN 14470-1 should be equipped with self-closing supply and exhaust air openings. Self-closing supply and exhaust air openings close automatically once the temperature reaches a trigger value defined by the manufacturer. This mechanism prevents the cabinet from acting as a channel for fire, heat and smoke in the event of a fire. DÜPERTHAL safety storage cabinets are equipped with this system as standard – tested according to EN 14470-1 in the burn chamber test following the standard time-temperature curve of EN 1363-1.
Regulatory Basis: Standards and Directives
What does EN 14470-1 require for ventilation openings in the event of a fire?
EN 14470-1 describes that all supply and exhaust air openings of a safety storage cabinet should close automatically in the event of a fire.
Why is automatic closing so important?
Open ventilation openings in the event of a fire would endanger the cabinet in both directions: flames and hot gases from an external fire could penetrate the cabinet and ignite the stored flammable liquids. Conversely, flammable vapours from inside the cabinet could escape through the openings and further fuel the external fire. The self-closing system interrupts both pathways.
Trigger Mechanism: How Does the Self-Closing System Work?
At what temperature do the ventilation openings close?
The supply and exhaust air openings on DÜPERTHAL safety storage cabinets close automatically at a trigger temperature of approx. 70 °C. The mechanism is designed to be passive-thermal – it functions without power, without electronics and without external control.
What technical principle is behind this?
The closing mechanism is based on a thermal trigger – typically a thermal fuse. Once the trigger temperature of approx. 70 °C is reached, the element changes shape or melts, releasing a pre-tensioned flap or gate valve that then closes the opening under spring force. This process is irreversible – after a fire or a thermal trigger event, the closing elements must be replaced.
What happens to the connected ventilation system?
The ventilation duct connecting the cabinet to the industrial exhaust air system is separated from the cabinet interior once the opening on the cabinet side closes. The ventilator continues to run in the event of a fire until it is switched off by the heat or until the AUV monitoring unit – which detects a drop in the air volume flow – triggers an alarm.
The Complete Fire Protection Closing System at a Glance
Which components close automatically in the event of a fire?
A safety storage cabinet according to EN 14470-1 has several automatic closing systems that trigger in stages:
| Component | Trigger temperature | Mechanism | Effect |
|---|---|---|---|
| Supply and exhaust air openings | approx. 70 °C | Thermal trigger | Prevents flame and hot gas penetration through the ventilation duct |
| Doors (door arrest system) | approx. 50 °C | Thermal trigger | Releases the arrest system; door closes independently |
| Doors (max. closing time) | – | Mechanical | Door must close within 20 seconds at the latest |
| Drawers and interior components | Fire heat | Intumescent seals | Seal joints under thermal expansion |
| Door joints | Fire heat | Intumescent fire protection seals | Seal the door gap and prevent the passage of smoke and flames |
Why do doors and ventilation openings trigger at different temperatures?
This staggered response is intentional by design. The door arrest system triggers at 50 °C, as an open door represents the largest opening area and must be closed as a priority. The ventilation openings close at 70 °C, as they are smaller and must remain open during normal operation for the required airflow – closing them too early could potentially impair regular operation
Key Facts: Self-Closing Ventilation Openings
- Standard: EN 14470-1 – mandatory for fire protection certification
- Trigger temperature, ventilation openings (DÜPERTHAL): approx. 70 °C
- Trigger temperature, door arrest system: approx. 50 °C
- Maximum door closing time: 20 seconds
- Mechanism: Passive-thermal – functions without power
- Trigger element: Thermocouple
- Irreversible: elements must be replaced after triggering in a fire or thermal event
- Door seals: Intumescent fire protection seals additionally seal joints
- Test verification: part of the burn chamber test according to EN 1363-1
- DÜPERTHAL: all Type 90 safety storage cabinets equipped with self-closing openings
What Happens if the Ventilation Openings Do Not Close?
What is the consequence of a closing system failure?
If the ventilation openings do not close in the event of a fire, the cabinet cannot reliably maintain its Type 90 fire resistance. Heat, flames and smoke gases can penetrate the cabinet and ignite the stored substances. In the worst case, the cabinet itself becomes a source of fire, further fuelling the external fire through the release of flammable liquids. Failure of the closing system compromises the overall protective effect of the fire resistance test.
How can you tell whether the closing elements are intact?
As part of regular inspection and maintenance, the condition of the thermal trigger elements must also be checked. Thermocouples that have already been triggered or are damaged are no longer functional and must be replaced. DÜPERTHAL offers a comprehensive inspection and maintenance service for all safety storage cabinet models.
Frequently Asked Questions (FAQ)
Yes. The self-closing system is integrated into the cabinet and functions independently of whether the openings are used during normal operation. Even in non-ventilated cabinets, the openings must close in the event of a fire – and do so automatically via the thermal trigger.
EN 14470-1 does not explicitly require the ventilator to switch off in the event of a fire – but it does require the ventilation openings on the cabinet side to close. In practice, the AUV monitoring unit triggers an alarm upon detecting a fault. It is advisable to switch off the ventilator via a thermal switch or an external fire detection system, to prevent it from attempting to draw air through the already closed openings.
No. Thermal trigger elements are spent once triggered and must be replaced before the cabinet is returned to service. DÜPERTHAL recommends a complete inspection by customer service after every thermal trigger event.
Yes. As part of regular inspection and maintenance intervals, the closing system of the ventilation openings must also be checked. This involves verifying that the trigger elements are undamaged, that the flaps or gate valves function correctly, and whether replacement is required following a trigger event. An annual service inspection and professional maintenance ensure the reliable function of the safety features and sustainably minimise risk. DÜPERTHAL offers comprehensive services including inspection, maintenance and repair for all safety storage cabinet models.
The exhaust air duct between the cabinet and the exhaust air system is not part of the EN 14470-1 test. Penetrations through fire compartments must be secured with suitable fire dampers in accordance with applicable building regulations. Responsibility for the design and installation of the exhaust air ducting lies with the operator and the planner.
Expert Perspective
"The closing system of the ventilation openings is one of the most inconspicuous yet most critical safety functions of a hazardous substance cabinet. You don't see it during normal operation – but in the event of a fire, it determines whether the cabinet acts as a barrier or as a channel. That is why it must be consistently checked as part of regular maintenance."
— DÜPERTHAL Sicherheitstechnik GmbH & Co. KG, Hazardous Substance Storage Advisory
DÜPERTHAL: Fire Protection Construction in Detail
All DÜPERTHAL Type 90 safety storage cabinets combine the following fire protection functions in one tested system:
| Function | DÜPERTHAL Implementation |
|---|---|
| Self-closing ventilation openings | Thermal trigger, approx. 70 °C, on every storage level |
| Door arrest system | Thermal trigger, approx. 50 °C, max. 20 sec. closing time |
| Intumescent fire protection seals | Seal door joints and cabinet joints under fire heat |
| Fire resistance insulation | Between inner and outer casing, non-combustible material |
| Burn chamber test | Type-tested by TÜV Süd, iBMB Braunschweig, ift Rosenheim |
| Ventilation on every level | Supply and exhaust air on every storage level, not only top/bottom |
Standards and Regulatory References
| Document | Content | Status |
|---|---|---|
| EN 14470-1 | Safety storage cabinets for flammable liquids – classification, requirements, test methods | Current |
| EN 1363-1 | Fire resistance tests – general requirements (burn chamber test) | Current |
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