Công cụ tính mức âm còi báo cháy

How this is calculated#

The tool finds the sound level a fire alarm sounder must reach. The point is the bed head or the room. It reads NZS 4512:2010 Clause 406.

1. Residual level. You enter the ambient level in dB. Cl 406.3 uses it as the base.
2. Margin. The tool adds the margin that Cl 406.3 sets for the room. The margin depends on the system type and on sleeping accommodation.
3. Lower limit. It reads the floor that applies, such as the floor for sleeping areas. The result is not lower than that floor.
4. Upper limit. It reads the ceiling level. The result is not higher than that ceiling.
5. Visual device. Cl 406.4 sets a trigger level. Above it, a visual alerting device is also needed.
6. Measurement height. The tool gives the height for the reading, from Cl 406.3.

The result is in dB LAFmax.

Worked example#

• Office at 50 dB ambient, tone sounder. The margin is 5 dB. The required level is 65 dB LAFmax. The 65 dB floor sets it. A visual alerting device is not required.

Limits#

The tool does not count devices. Check Cl 406.6 for that. It does not give the measurement method. A care area has its own rules in Cl 406.7. The tool reads NZS 4512:2010. NZS 4512:2021 supersedes it, so check the current edition.

The result is a design target. Measure the level on site with the method the standard gives, then record it. A tone sounder and a voice sounder can need different levels. Check the entry you pick against the clause.

See also: Detector spacing calculator, Fire alarm cabling and Fire alarm battery.