Bosch D296 - Page 11

Long-range beam smoke detectors Installation considerations | en 11
Bosch Security Systems, Inc. Installation manual 2017.03 | 7.0 | F.01U.068.899
Figure3.2: Smoke Densty and Obscuration Graph
1 Smoke density 3 UL maximum sensitiivity
2 UL minimum sensitivity 4 Distance between transmitter and
receiver
Determine the total obscuration needed for an alarm and select the sensitivity setting needed
according to the following table.
Total Obscuration at Alarm Sensitivity Switch Setting
20% 2
30% 0 or 3
40% 4
50% 5
60% 1 or 6
70% 7
The D296 and D297 can be set for quick response (5sec) or normal response (30sec). Some
burning materials release hazardous gases along with the smoke. Set the sensitivity for a
shorter response times to minimize exposure to the dangerous vapors. Denser smokes
allowed to collect for too long, can produce near total obscuration of the detector. This