VESDA VESDA VLF-500-UL 7Ed Product Guide
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3.2 Branched Pipe Network
The table below shows the appropriate hole sizes for pre-engineered designs for a branched pipe set up.
Branched Pipe Network –
(2 branches)
max. length 90 ft. (30 m)
max. distance from detector to branch 15 ft. (5 m)
Sampling
Holes per
Branch
pipe
IPS ¾ in. Pipe ID 21 mm Pipe
Open Hole
3/8 inch
Capillary* with
1/8 inch hole
Open Hole
5.2 mm
Capillary* with 5
mm hole
Hole Size (in.) Length (ft.) Hole Size (mm) Length (m)
3 0 – 12 3.5 – 5.5 0 – 2.0
4 0 – 12 3.0 – 5.0 0 – 3.0
5 0 – 12 3.0 – 4.0 0 – 3.0
6 0 – 12 3.0 – 4.0 0.2 – 3.0
7-12* Use ASPIRE to calculate hole sizes in this range*
Table 3-2: Branched pipe hole numbers and sizes
*For code-specific information, refer to Codes and Standards Information for Air Sampling Smoke Detection on
page iii.
The set up below shows a branched pipe arrangement with 5 sampling holes per branch and fitted end caps
without sampling holes.
Legend
A Smoke Detector B Sampling Hole C End cap (no hole)
Figure 3-3: Open hole, branched pipe
The set up below shows a branched pipe arrangement with 3 capillary drop pipes per branch and fitted end
caps without sampling holes.
Legend
A Smoke Detector B Capillary Tube C End cap (no hole)
Figure 3-4: Capillary pipes, branched pipe