17.7.5* Smoke Detectors for Control of Smoke Spread
- Rigid mounting within the duct
- Rigid mounting to the wall of the duct with the sensing element protruding into the duct
- Installation outside the duct with rigidly mounted sampling tubes protruding into the duct
- Installation through the duct with projected light beam
If the depth of wall section above the door is 24 in. (610 mm) or less, one ceiling-mounted smoke detector shall be required on one side of the doorway only, or two wall-mounted detectors shall be required, one on each side of the doorway. Figure 220.127.116.11.5.1(A), part A or B, shall apply.