Rel-Tek - Model 501B - Section Alarm - Brochure

This alarm unit was developed for use in hazardous areas of the coal mines for alerting workers of possible hazardous conditions. Previously, the large, nonpermissible alarm units had to be sited in fresh air areas – often hundreds of feet away from the hazardous conditions where persons were working. Consequently, for these old alarm units to be affective, they needed powerful strobetype flashers and loud horns with sufficient volume to transmit the alarm signals to the work places.