BYKHY Article 81: Audible and Visual Alarm Devices

All the numerical rules on alarm devices in the Turkish Regulation on Fire Protection of Buildings (BYKHY) sit in one clause: Article 81. Sound level, measuring height, device output, the buildings that need a voice alarm system, when pre-alarm is allowed and when evacuation alarms may be phased rather than building-wide are all there. This article goes through its eight paragraphs and puts the numbers in one table.

81/1: call points mean alarms

People in every occupied part of the building are warned of a fire or similar emergency by audible and visual alarm devices. Wherever manual call points are mandatory, an alarm system is mandatory too. Call points are required under Article 75/2 (non-residential buildings of 2–4 storeys with a storey area above 400 m²; non-residential buildings with more than four storeys; all high-rise buildings); see the Article 75 article. The Guide adds a note: once the audible and visual devices operate, the building's emergency teams take the steps needed to evacuate people to a safe area, whatever the emergency (p. 131).

81/2: when pre-alarm is allowed and when it is not

A pre-alarm system that allows the signal to be investigated is permitted, provided the alarm reaches the response teams and staff trained in firefighting without delay. In other words, pre-alarm may briefly hold the general evacuation alarm; it may not hold the alert to the team. In industrial buildings where hazardous materials are kept or processed, and in storage buildings, any detection starts the evacuation alarm automatically and pre-alarm is not allowed. The Regulation sets no time for the pre-alarm; the time and the verification method are defined in the design and approved by the authority.

81/3: audible and visual, with two exceptions

Evacuation alarms are, as a rule, both audible and visual. The exceptions:

• a) visual alarm devices are not mandatory in areas where people with hearing impairment are unlikely to be present;
• b) in healthcare buildings, visual-only alarms may be used where so planned.

Exception (a) asks for a judgement of likelihood. As the users of a public building cannot be known in advance, bear in mind that it is usually defensible only in technical rooms with restricted access; the decision rests with the authority.

81/4: whole building or phased?

Evacuation alarms operate, as a rule, throughout the building. There are two exceptions:

• a) Phased evacuation: in buildings that by their nature cannot be evacuated all at once, alarms start only in the zones affected or about to be affected, and are installed to extend to the other zones in stages for an orderly evacuation.
• b) Staff alarm: in buildings with people who cannot leave on their own because of age or physical or mental impairment, the alarm may be given only to the staff responsible for their care and evacuation.

The Guide asks for (b) to be taken into account when fire compartments are planned in hospitals, care homes for the elderly and rehabilitation centres (p. 131). Phased alarm zones should be drawn together with the fire compartments; see hospital fire protection in Turkey.

81/5–81/6: sound levels

Sounders are placed so that the level measured 150 cm above the floor anywhere in the building is at least 15 dBA above the average ambient level. In sleeping areas, bathrooms and showers the level is at least 75 dBA. The device itself must be capable of at least 75 dBA and at most 120 dBA at 3 m. Rooms with voice alarm loudspeakers do not need separate sirens (81/5). Fire alarm sounds must be distinguishable from other sounders used in the building (81/6).

The Regulation gives no light output, coverage or mounting height for visual alarm devices, and no spacing for sounders. That detail is in the EN 54 series and in NFPA 72. The Regulation's numbers define the result: the design must show that the level at 150 cm meets this table everywhere. In noisy rooms such as plant rooms and production areas, the 15 dBA margin becomes the criterion that sets the number of devices.

81/7: where a voice alarm system is mandatory

A voice system that evacuates or relocates occupants with automatically broadcast messages and live microphone messages from the fire control centre is mandatory in:

In (b) the two criteria are joined by "or"; either is enough. The criterion is "construction area", which is not the same wording as the "total enclosed floor area" of Annex 7; agree with the authority which area applies. The Guide asks for the supply cable to the voice alarm central unit and the loudspeaker cables to be fire-resistant (p. 132); Article 83/1-a also requires signal and supply cables from the panel to voice evacuation amplifiers and loudspeakers to withstand fire for at least 60 minutes. Cable rules are in the Articles 82–83 article.

81/8: devices for emergencies only

Audible and visual alarm devices are used only for fire and other emergency alarms. Voice systems may also serve other purposes such as general announcements and background music, provided fire and emergency messages take priority and automatically override other uses. The Guide also stresses that the system must be operated for its intended purpose and kept continuously available (p. 132).

Design checklist

• Are call points mandatory? Then so is an alarm system (81/1).
• Industrial or storage building with hazardous materials? No pre-alarm (81/2).
• Where are visual alarms needed; is an exception defensible? (81/3)
• Evacuation strategy: whole building, phased or staff only? (81/4)
• Ambient + 15 dBA at 150 cm everywhere; 75 dBA in bedrooms, bathrooms and showers (81/5)
• Do beds, area, occupants or height exceed a voice alarm threshold? (81/7)
• If the voice system is shared, is emergency priority automatic? (81/8)

The fire detection and alarm requirement checker gives the call point, detection, alarm and voice alarm requirements with clause references. How the alarm reaches the panel and the fire brigade is in the Articles 76–77 article.

Frequently Asked Questions

What sound level must fire alarm sounders reach under the Turkish regulation?

Under Article 81/5, the level measured 150 cm above the floor must be at least 15 dBA above the average ambient level, and at least 75 dBA in sleeping areas, bathrooms and showers. The device must deliver at least 75 and at most 120 dBA at 3 m.

Which buildings need a voice alarm system?

Under Article 81/7: hotels, motels and dormitories with more than 200 beds; public buildings, shopping centres, supermarkets, industrial plants and similar with a construction area above 5000 m² or more than 1000 occupants; and every building with a structure height above 51.50 m.

Can a factory use a pre-alarm (delayed alarm)?

Not in industrial buildings where hazardous materials are kept or processed, nor in storage buildings; any detection starts the evacuation alarm automatically (81/2). Elsewhere pre-alarm is allowed if the alarm reaches the response teams without delay.

Are visual alarms alone enough in a hospital?

Article 81/3-b allows visual-only alarms in healthcare buildings where so planned. Article 81/4-b allows the alarm to be given only to the staff responsible for evacuation in buildings with people who cannot leave on their own.

Is a siren needed where there are voice alarm loudspeakers?

No. Under Article 81/5 rooms with voice alarm loudspeakers need no separate siren. If the voice system is also used for other purposes, emergency messages must take priority and override other uses automatically (81/8).

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