Fire protection
Aspirating smoke detection, best known by the VESDA name, pulls air from the room through a network of small sampling pipes to a very sensitive detector. It can raise an alarm while smoke is still invisible, early enough to find an overheating UPS component or cable before a fire, and to shut equipment down before a suppression system is needed.
It is smoke detection that brings the air to the detector instead of waiting for smoke to reach a detector on the ceiling. Xtralis' specification for its VESDA-E VEP describes highly sensitive, short-wavelength laser-based detectors with aspirators connected to networks of sampling pipes. Each pipe has sampling holes along its length; the aspirator draws air from the protected area through them, and the sample passes through a filter into the detection chamber.
Because the samples are drawn continuously from chosen points, the pipe can follow the air: along the racks, at the cooling returns, above the UPS and battery cabinets.
Its sensitivity and its alarm levels. Xtralis calls the VESDA-E VEP very early warning smoke detection, with four output levels: Alert, Action, Fire 1 and Fire 2. Under EN 54-20, used in Europe, an aspirating system is configured to a sensitivity class, A, B or C; the VEP data sheet lists each class with its number of sampling holes.
Schneider Electric's guidance on monitoring physical threats recommends rack-level very early smoke detection in highly critical areas or areas without dedicated smoke sensors, and, where that exceeds the budget, very early detection at the input of each cooling unit as some degree of early warning.
| Level | What Xtralis gives as a possible use |
|---|---|
| Alert | A visual and audible alarm in the fire risk area |
| Action | Trip the electrical or electronic equipment shutdown relay, and alarm the security office |
| Fire 1 | An alarm at the fire alarm control panel to call the fire brigade and start all warnings |
| Fire 2 | Release a suppression system or other countermeasures |
Xtralis is clear that these are possible scenarios, to be set for each application and for the authority having jurisdiction. For a UPS room the Action level matters most: a shutdown relay can take an overheating piece of equipment out of service before it becomes a fire, and the first person called should be someone who knows the UPS. The remote UPS monitoring page covers how such alarms reach the right people.
By calculation, so that every hole draws its share of air and smoke reaches the detector quickly. Xtralis' specification asks that sampling holes be no further apart than the spacing allowed for conventional point detectors under local codes, and that, where there is a false ceiling, the pipe runs above it with capillary sampling points on the ceiling.
Transport time, the time smoke takes from the least favourable hole to the detector, is the key figure. Xtralis asks for under 60 seconds for open holes and under 90 seconds for capillary tubes where possible, and lists code limits in the Americas of 60 seconds under NFPA 76 and 120 seconds under NFPA 72. The detector monitors its own filter for contamination and reports when maintenance is needed.
Through the fire alarm panel and the suppression release. A clean-agent system should not discharge on one detector: Honeywell's FK-5-1-12 manual states that an automatic system should release only when two or more sensors detect the fire, after a time delay that lets people leave. Aspirating detection gives that logic more time. Alert and Action happen long before Fire 2, so staff can find the source, and equipment can be shut down, while the agent stays in its cylinders.
The suppression side is covered in the clean-agent systems guide; the room sensors that sit alongside the detector, such as temperature and leak, are in the server room monitoring guide.
Less than a field of point detectors, but not none. The VESDA-E VEP specification calls for a flow sensor in each pipe, with airflow faults set per pipe, so a blocked hole or a broken joint shows up as a fault rather than as silence. The detector monitors its filter and reports when it needs changing, and it stores smoke levels, alarm conditions, operator actions and faults, which gives the next visit a history to read.
A periodic check still walks the pipe network, confirms the holes are clear and the caps in place, and tests that each alarm level reaches the fire panel and, at the Action level, the equipment it is meant to shut down. In a UPS room that test is best run with the UPS team present, so nobody is surprised by what the shutdown relay does.
Where the heat and the airflow go. In a UPS and battery room, that usually means the return air path of the cooling units, above the UPS cabinets where hot air leaves them, and above the battery cabinets or racks. The pipe layout and hole positions come from the designer's calculation, and the authority having jurisdiction approves the result. Aspirating detection and its connection to the fire alarm panel are delivered through specialist fire protection subcontractors; for the UPS side, see UPS maintenance, repair and battery services.
A brand of aspirating smoke detection. Other makers build aspirating detectors too; the principle, sampling pipes drawing air to a sensitive detector, is the same.
It depends on the code applied by the authority having jurisdiction and on the owner's risk decisions. Xtralis cites transport time limits from NFPA 76 and NFPA 72 in the Americas.
It can be set to, typically at the highest level (Fire 2). Honeywell's manual calls for two or more sensors to detect the fire before automatic release, and a delay so people can leave.
Yes. The detector reports filter contamination and airflow faults, and the pipe network and its holes need periodic checks to the maker's schedule.
Sources, checked 2026-10-04:
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