Aspirating Smoke Detectors




The Hochiki America SZA-NA(FM) high sensitivity smoke detection system is capable of detecting minute particles of smoke. The SZA-NA(FM) is ideal for applications where response time is critical. It provides the earliest response to fires available. The SZA-NA(FM) provides a detection solution for rooms with high air flow, and rooms with large open spaces.


An aspirating smoke detection system continuously draws air from the monitored area into the sampling pipes. The air is drawn from the sampling pipes into the main sampling unit. In the main sampling unit, the air is analyzed by very sensitive laser detection components. The laser detection components constantly monitor for the presence of smoke particles.

If smoke particles are detected, the unit will activate the alarm output relays in accordance with the sensitivity selected and the alarm level reached. The SZA-NA(FM) High Sensitivity Smoke Detector is between 20 and 1000 times more sensitive than spot-type smoke detectors. The SZA-NA(FM) has three alarm stages. Alarm 1 is the lowest obscuration alarm (high sensitivity), activating when very small amounts of smoke are detected. The Orange Alarm 1 LED will light, and the Alarm 1 relay will activate. As the smoke density reaches alarm level 2, the Red Alarm 2 LED will light and Alarm 2 relay will activate. As the smoke density reaches alarm level 3, the Red Alarm 3 LED will flash and the Alarm 3 relay will activate.

The SZA-NA(FM) is ideal for use in areas such as computer server rooms, clean rooms, telecommunication equipment rooms, medical equipment/operating rooms, power generation plants, and many other applications. By continuously sampling the area, the SZA-NA(FM) can provide the earliest warning of the presence of smoke, even before the smoke is visible to the human eye.


• Detects very low density smoke
• 200 m2 detection area (2150 ft2)
• No filter necessary
• N/O or N/C alarm contacts form A, form B
• Automatic and manual laser tests
• Four selectable sensitivity ranges:
*Sensitivity 1: 0.005 to 0.1%/m (0.002 to 0.03%/ft)
*Sensitivity 2: 0.01 to 0.2%/m (0.003 to 0.06%/ft)
*Sensitivity 3: 0.025 to 0.5%/m (0.008 to 0.15%/ft)
*Sensitivity 4: 0.25 to 5.0%/m (0.08 to 1.55%/ft)
• 3 alarm levels:
*Alarm 1 (low)
*Alarm 2 (medium)
*Alarm 3 (high)