SubscribeThe Düsseldorf Airport fire underlines the need for a state of the art fire safety and smoke extraction system, to avert fires and resulting disasters and the new T2 at Munich Airport was no exception.
It was an implicit, that it also needed to meet the currently applicable standards and measures for safe operation, however the new EN 61508 standard has not yet been adopted, so there were challenges, if a modern hardware and software based system was to be used and meet the requirements of EN61508, then how should this be achieved?
For this reason, Honeywell installed a control and management system based on LonWorks®, which was inspected by TÜV in August 2005. The inspection certified that the smoke extraction concept implemented by Honeywell conforms to the AK3 requirements in compliance with DIN V 19250 or DIN V 19251.
The scope of the installed hardware and software components indicates the size and the enormity of the task:
- 524 smoke extraction coordinators and valve coordinators
- 6200 valve modules for fire safety valves and ventilation valves
- 809 I/O modules for system control and recording alarms
- 20 Fire Department control panels
- 404 smart routers with ring and equipment monitoring
- 134 CBL LON-LWL routers for connection to the ring-shaped LWL backbone, which extends across the entire terminal
- Around 1 million logic functions programmed
- Control of numerous external devices, such as air vents, awnings, sunscreen, emergency exits and fire doors.
However compared with a simple Lon system for control, there are considerable additional requirements regarding operating security and monitoring to consider. The mechanisms for secure data transmission still missing from the Lonworks protocol and were added by using additional hardware and software measures.
Duplicate ring networks, where the location of a break is identified, reported and managed, identified faulty equipment is separated from the bus without repercussions and in the event of short circuits, any failure is restricted to a single LON device.
The equipment is also monitored continually to identify and report functional or communication problems. Regular automatic tests by a test program independent of ventilation control cover any faults that are not identified through device monitoring, e.g. mechanical faults in valves.
Automatic smoke extraction
When the fire alarm system is triggered, automatically an alarm is sent from the fire alarm sub centre to the corresponding extraction coordinator. The extraction coordinator activates the relevant extraction groups using the stored logic table and transmits this information to the valve coordinators via the LON network.
Using the allocations to the activated extraction group, the valve coordinators determine which valves or external systems need to be commandeered. Fire safety valves are closed and ventilation systems deactivated to seal off areas that may have filled with smoke together with neighbouring areas to prevent smoke from spreading.
Extraction valves and curtain valves are opened to release the extracted smoke. Fire ventilators are activated to vent the smoke rapidly. Commands to back-end systems ensure that fire doors are closed and emergency exits are disengaged.
Manual triggering of extraction by the Fire Department
In addition to automatic control, the Fire Department can use the panel keypads to manually control extraction or override the automated system at its discretion. Alarms from the activated table deactivators are sent via the backbone to the corresponding extraction coordinator, the panels are instructed to indicate the alarm via indicator light displays. Otherwise, manual extraction control operates in the same way as automatic extraction control.
This project shows that safety-related systems can be implemented, even before approval of the new EN61508 standard, using open protocol product like LonWorks®. The requirements class can be achieved for safe operation and can be mapped with minimal adaptations to a SIL (Safety Integrity Level) for airports requiring the new 61508 standard.