silentone fire and security alarms

  Fire and security alarms that alert humans without disturbing animals.

Manufactured to a high specification in the UK, easy to install in place of conventional sounding equipment allowing you to test your system or take appropriate action in an emergency without disturbing your animals or adversely affecting the study environment. 

The diagram shows the reported frequency ranges to which various species are known to respond and indicates the frequencies to which each is most sensitive.

For example, mice are insensitive to sounds below 1kHz. In rats the cochlear responses in both adults and infants to signals as low as 100Hz have been recorded but the threshold decreases rapidly below 1kHz, and their most sensitive frequency range is from 35-40kHz.

For humans, the noise created is intensely irritating, however mice and rats are not awakened or, if already awake, show no startle response, ear twitching or other indication of auditory disturbance. Rabbits and guinea pigs show little more than mild disturbance, and no observable response if the alarm is activated in the corridor of the animal house.

Silentone alarms generate a sound level of 97dB (measured at 450mm or greater peaks as measured in an anechoic chamber), at a frequency between 430 and 470Hz.

Operates from a continuous or pulsating direct current supply of nominally 24 volts. To ensure operation at the end of long supply lines, they are designed to operate down to 10 volts. Output of 5 watts with a 24 volt DC supply and a current of 450 Milliamperes.