Published 21.10.24
Does the smoke alarm work? Is the fire department automatically alerted? Does the overpressure ventilation still function if the doors to the stairwell are open? These are some of the questions that DBI's inspection department seek to answer.
What is an automatic fire alarm system worth if it doesn’t work on the very day that a fire breaks out? The obvious answer, of course, is: not much. That's why Lars Kayser, Paulius Giedraitis, and their 54 colleagues in DBI's inspection department work to ensure that fire safety systems function properly. While inspecting fire alarms and fire doors day in and day out might seem trivial and boring, it is, in fact, a job of tremendous importance. At the end of the day, spotting a faulty fire alarm or a malfunctioning door pump can mean the difference between life and death.
At first sight, Lars Kayser and Paulius Giedraitis don’t appear to be overly burdened by the heavy responsibility as they stand in the entrance of a 10-story apartment complex in Ørestad, Copenhagen. Paulius has opened the cabinet of the building’s fire control panel and is reviewing the electronic log of incidents since the last inspection.
“There seems to have been some issues with the transmission equipment,” he notes. The transmission equipment sends the alarm to the control center and, like many other components, is duplicated, with both a mobile data connection using a SIM card and a wired connection for transmitting alarms.
Today, the fire department has been informed that DBI is conducting an inspection, so Lars and Paulius’ many tests won't unintentionally trigger an emergency response. Lars follows the various test scenarios on a special app, monitoring how they appear at the alarm control center.
The upper floors of the building are more than 22 meters above ground, meaning there is a requirement for an automatic pressurization system (ATA) to keep the stairwell smoke-free in the event of a fire.
ATA systems have only become common since the introduction of the Danish building regulations of 2018 (BR18). In average, Lars and Paulius inspect a couple of them each month, typically located in new high-rise apartment buildings in Copenhagen’s Ørestad, Carlsberg Byen, and Nordhavn quarters.
After checking the key functions of the fire control panel and inspecting whether strollers and moving boxes are improperly stored in stairwells and apartment foyers, Lars grabs his suitcase of measuring equipment and heads to the basement shaft at the back of the building. If the fire control panel could be called the brain of an ATA system, the large fan, reminiscent of a jet engine, would be its heart. When a fire detector detects smoke on one of the floors, the fan creates overpressure in the stairwell. On the burning floor, a damper opens to a ‘chimney’ in the entryway, so that the overpressure keeps smoke from entering the stairwell, which serves as the escape route.
First, Lars checks that there’s a connection between the fire alarm system and the fan. The system performs a self-test every minute, briefly turning the fan on. Paulius observes that the system hasn’t been serviced since 2020, and DBI noted the lack of maintenance during last year’s inspection as well.
“That’s not good, because maintenance is crucial. An ATA system is only valuable if it works when a fire actually happens. That could be tomorrow, in 20 years, or never. However, the important thing is that the system is always operational,” says Lars.
Next on the list is checking the power supply. All fire safety systems have a redundant power supply from two different transformer stations so that a local electrical failure doesn’t jeopardize fire safety. But when Paulius presses the button to switch from one power source to the other, the result is not as expected. The constant hum of the control box's cooling fans stops, and all the displays go black. Now, neither the ATA system nor the elevator, which has the status of a special firefighter’s elevator due to its redundant power supply, has electricity.
“This is why the annual inspection is so important – especially when the maintenance hasn’t been done as required. This is a category A error, which means the system wouldn’t be functional in a real situation. That kind of error must be fixed immediately, and the system cannot pass an inspection before the issue is resolved,” Lars explains.
The serious error also means that the rest of the inspection will be a bit more random. Everything will have to be inspected again once the system has been serviced and the power supply issue has been resolved.
While Paulius stays by the fire control panel to test manual activation of the ATA system, Lars takes the elevator up to the 7th floor. First, he checks whether the door closer for the stairwell door works as intended and is not too tight. Then, he enters the hallway leading to the two apartments and holds a testing device up to the smoke detector to trigger the alarm. After a minute or so, the smoke detector activates the fire alarm system, and the sound of rushing air indicates that the overpressure ventilation in the stairwell has started as planned. At the same time, the damper to the chimney shaft in the hallway opens, so the overpressure from the stairwell would direct smoke that way if the door was opened.
The overpressure in the stairwell must be within specific limits. It shouldn’t be so high that it’s difficult to open the stairwell doors, but it must be strong enough to keep the fire smoke behind the door. Lars’ force gauge shows that it takes 76 Newtons to open the door – which is within the allowed maximum of 100 Newtons, equivalent to 10 kg of force. He then places a small propeller to measure airflow at various points in the doorway. The flow must be at least 0.75 m/s, and Lars’ average reading is 2.07 m/s – so everything is in order here, too. He then goes up a couple of floors and props open the doors to the 8th and 9th floors with wedges to test if it affects the pressure on the 7th floor. It doesn’t, and Lars records the measurements in his report. Afterward, he heads back up to the 8th and 9th floors to remove the wedges.
“It’s one of our perks: free exercise on the job. I probably walk up and down 30-40 floors on a typical day with ATA inspections,” Lars smiles as he removes the wedges from under the door.
Finally, Lars measures the pressure in the gap between the elevator and the elevator shaft to ensure that no smoke can enter the elevator. Meanwhile, Paulius has silenced all the alarms at the fire control panel, and the two inspectors can wrap up their visit with a trip to the roof.
The neighboring Royal Arena emerges from the mist, though the usual view of the airport, Øresund Bridge, and Sweden is obscured by fog. Paulius and Lars have climbed the ladder and exited through the skylight to check that the ventilation system for the apartments has started after the smoke detectors were activated. In principle, this could also have been done inside an apartment, but the stop button for the system happens to be located on the roof.
Back at the office, Lars and Paulius write an inspection report for the building owner. The 12 pages of measurements, data, and observations make it clear that the system is not approved and that the issues must be addressed. As the fault is in the most serious category, the county will also receive a copy.
“We request that the errors and deficiencies mentioned in the report be corrected. Please notify DBI in writing when this has been done, so a new inspection can be conducted,” as the standard phrasing succinctly states.
