Ducts Application Note
VESDA-E
35424_02
3
Figure 4: Top view of the inlet tubes positions, including duct mounting
bracket for a small ventilation duct.
These sampling points should be located in the middle of the duct width at least 50 mm (2 inches) from the
side walls.
Note!
Nominal sampling point spacing is 0.2 m (0.66 ft.).
Sampling Pipe Configuration in Large Ducts
1.2.1 VESDA-E VEP-1P
Large ducts are defined as those with widths of 1 to 2 m (3.28 to 6.56 ft). For these ventilation ducts, it is
recommended that the inlet pipe of the smoke detector be in two branches. The figure below (Figure 5) shows
a side view of a duct section with the relative insertion points for the inlet and exhaust pipes. The two inlet
branches are located at a quarter of the height (H) of the duct with the exhaust pipe inserted mid-height
approximately 0.5 m (1.64 ft) downstream of the inlet pipes.
Figure 5: Side view of the inlet and exhaust
pipe positions for a large duct.
The following figure (Figure 6) shows a cross-section view of the same duct with the positions of the inlet
branches and exhaust pipe indicated. The number of inlet pipe sampling holes, recommended hole size and
spacing are presented in Table 2.
