In brief
An alarm system is useless if it cannot be heard in every corner of the workplace, if people do not know what it means when they hear it, and if it is unclear who will say what afterwards. The Regulation on the Fire Protection of Buildings requires the audible warning to be at least 15 dBA above ambient noise; in very noisy production areas this can only be achieved by supplementing it with a visual warning. The evacuation announcement should be made from a short pre-written text by a designated person on every shift.
Emergency alarm system: answering three questions
One of the most common sentences heard in drills is "we didn't hear the alarm". The operator in the middle of the press line, the maintenance technician in the compressor room, the forklift driver in the cold store or the person working in the office with headphones learns that the alarm has sounded minutes after everyone else. An emergency alarm system must give a clear answer to three questions:
- Does everyone hear or see it? In every department, on every shift, even while wearing hearing protection.
- Does everyone know what it means? Can the evacuation alarm be distinguished from the break bell, forklift warnings and machine alerts?
- What will be said after the alarm? Who will make the announcement, from which microphone and with what text?
The legislation addresses these three questions in different regulations. Art. 10 of the Regulation on Emergencies in Workplaces requires warning, evacuation and communication methods to be determined and put in writing. Arts. 76 and 81 of the Regulation on the Fire Protection of Buildings (BYKHY) set the technical requirements for audible and visual warning devices and announcement systems. The Regulation on Health and Safety Signs sets the minimum rules on how illuminated signs, acoustic signals and verbal communication are used to signal danger and for emergency evacuation.
Alarm audibility: measurement and site test
Art. 81/5 of the BYKHY defines alarm audibility in figures:
| Rule | Value |
|---|---|
| Measurement point | Everywhere in the building, 150 cm above the floor |
| General areas | At least 15 dBA above the average ambient sound level |
| Sleeping areas, bathrooms and showers | At least 75 dBA |
| The device itself | Must be able to produce at least 75 dBA and at most 120 dBA at 3 m |
| Distinguishability | The fire warning sound must be distinguishable from other audible devices used in the building for other purposes (Art. 81/6) |
Annex 7 of the Regulation on Health and Safety Signs states the same approach in words: the acoustic signal must be at a level considerably higher than the ambient noise, but not excessively loud or harmful, and must be clearly distinguishable from other sounds. The same annex requires the evacuation signal to be continuous.
The way to verify these values on paper on site is an audibility test:
- Take the department-by-department values from the noise measurement report; if there is no measurement, plan one with an authorised laboratory. For details see our article on workplace noise measurement.
- Sound the alarm while production is at full capacity; one person in each department notes whether they heard the alarm and how clearly.
- Do not forget enclosed rooms: toilets, changing rooms, compressor and boiler rooms, archives, cold stores, the roof and the outdoor yard.
- In departments where hearing protection is worn, carry out the test with protection on.
- Mark the results on a layout plan; plan additional sirens or visual warnings for points where the alarm is not heard.
Audible and visual warnings in noisy production areas
The "15 dBA above ambient" rule becomes difficult in noisy departments. In a forging or press department with ambient noise of 95 dB(A), the alarm would need to reach 110 dB(A); this is both difficult and undesirable for workers' hearing. Annex 1 of the Regulation on Health and Safety Signs anticipates this situation: acoustic signals are not used where there is too much ambient noise. In these areas the alarm is carried by a visual warning.
Art. 81/3 of the BYKHY also requires evacuation warnings, as a rule, to be both audible and visual; visual warnings are not mandatory in areas where people with hearing impairments are unlikely to be present. However, a worker wearing hearing protection in a noisy production area is effectively hearing-impaired as far as the alarm is concerned. When planning visual warnings, pay attention to the following:
- Line of sight: The beacon must be in the direction in which the worker at the machine is looking; it must not be hidden behind a machine.
- Coding: Under Annex 6 of the Regulation, if a flashing light signal is used together with an acoustic signal, the same code is used; flashing lights that signal serious danger are kept under observation and a spare lamp is kept.
- Confusion: Machine fault lamps, forklift warning lights and the evacuation beacon must not have the same colour and rhythm.
- Reducing machine noise: Where possible, the alarm is designed to trigger the shutdown of noisy machines; this makes both audibility and safe evacuation easier.
| Area | Recommended warning |
|---|---|
| Office, canteen, meeting room | Siren or announcement loudspeaker; beacon if there is a hearing-impaired employee |
| Moderately noisy production | Siren + beacon |
| Very noisy production (hearing protection mandatory) | Beacon as primary, siren as support; machine shutdown |
| Remote points where people work alone | Beacon + radio or personal pager |
Vibrating pagers for hearing-impaired employees and designating a colleague to accompany them during evacuation are also part of the plan; Art. 10/4 of the Regulation on Emergencies requires employees with disabilities to be accompanied during evacuation. See adapting work for employees with disabilities.
Evacuation announcement: who, when and with what text?
Art. 81/7 of the BYKHY makes it mandatory to install an announcement system capable of automatic voice messages and live microphone announcements in hotels and dormitories with more than 200 beds; in buildings open to the public with a construction area of more than 5000 m² or more than 1000 total occupants; in shopping centres, supermarkets, industrial facilities and similar buildings; and in buildings taller than 51.50 m. The announcement system can also be used for other purposes such as background music; however, emergency announcements always take priority and automatically override other uses (Art. 81/8).
Having the system installed is not enough; who will speak must also be written down. Designate an announcement lead and a deputy for each shift; this person is often the leader of the protection team, the shift supervisor or the security officer at the point where the fire control panel is located. In small workplaces without an announcement system, the same task is carried out with a hand-held megaphone.
Annex 8 of the Regulation on Health and Safety Signs requires verbal messages to be short, simple and clear, and requires the people communicating to know the language used. The evacuation announcement text is therefore not thought up in a crisis; it is written in advance and posted next to the microphone:
When writing the text, keep the following in mind: say what to do rather than giving details of the incident; name the assembly point; in workplaces where several languages are spoken, record the text in the other languages too. Our article on foreign national employees provides guidance on this. Scenarios that require a "shelter in place" or "stand by" announcement instead of evacuation are prepared with separate texts.
Faults, maintenance and testing
The alarm system is also a piece of work equipment. Annex III of the Regulation on Health and Safety Requirements for the Use of Work Equipment subjects fire detection and warning systems to periodic inspection once a year unless standards specify a shorter period; the inspection is carried out according to the criteria in the design and TSE CEN/TS 54-14. Between these annual inspections, do the following within the business:
- Carry out a short alarm test on a fixed day and time and announce it to employees in advance; the test bell sounding at the same time every week prevents confusion with a real alarm.
- Use the audible and visual warning devices only for emergencies; Art. 81/8 of the BYKHY requires this explicitly. Do not use the alarm siren as a shift or break bell.
- If there is a fault or a disabled zone on the panel, record it and limit its duration; when detectors are switched off for welding or maintenance, assign a fire watch to that zone.
- Check the condition of the uninterruptible power supply or batteries.
You can track inspection dates with the OHS calendar.
Testing the alarm and announcement in a drill
Under the Regulation on Emergencies, a drill is held at least once a year. The drill is the real test of the alarm and announcement design. Add these questions to the drill form: Was the alarm heard and seen in every department? How many seconds after the alarm did the announcement begin? Was the announcement understood, and did employees who speak a foreign language know what to do? Did the machines in noisy departments stop? For planning the drill see our article on how to carry out an emergency drill, and for the differences on the night shift see emergency teams on the night shift.
As part of our emergency plan service, we design your alarm, announcement and evacuation arrangements together with your workplace's layout plan and shift pattern.
Frequently Asked Questions
How loud should a fire alarm be?
Under the BYKHY, the audible warning, measured 150 cm above the floor, must be at least 15 dBA above the average ambient sound level; at least 75 dBA is required in sleeping areas and showers. The device must be able to produce at least 75 and at most 120 dBA at 3 m.
Is a beacon enough instead of a siren in a noisy factory?
In very noisy areas, visual warnings are used as the primary means instead of acoustic signals; the Regulation on Health and Safety Signs requires acoustic signals not to be used where there is too much ambient noise. The beacon must be visible from every work point and must not be confused with other warning lights.
Is an announcement system mandatory in every workplace?
The BYKHY makes announcement systems mandatory in certain buildings: hotels and dormitories with more than 200 beds; buildings open to the public with a construction area over 5000 m² or more than 1000 occupants, shopping centres, supermarkets, industrial facilities and similar buildings; and buildings taller than 51.50 m. Where it is not mandatory, the emergency plan must still state in writing who will give the evacuation instruction and how.
Who should make the evacuation announcement?
An announcement lead and deputy designated in advance for each shift; usually the leader of the protection team or the shift supervisor. The text is written in advance and kept next to the microphone.
An emergency plan that really works on site, with scenarios, support teams, evacuation diagrams and an annual drill.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.