Xtralis VESDA VLS - Page 173

ASPIRE Software
VESDA Student Workbook 7-29
Adding unions to angle pipe into airflow
• Unions must be used to angle the
holes for proper airflow
– This ensures the pressure will be
the same at the pipe regardless if
the grille is running
Sampling methods - return air grille
Standoffpost
100 to 200mm long
(4 in to 8in)
Sampling
pipe
Self tapping
screws
AHU
Sampling point
angled to obtain
best airsample
AHUvent
Path of
return
airstream
Area of neutral pressure at 20-45°
to the airflow
✓ Using multiple pipes for multiple AHU units protection
x Using single pipe for multiple AHU units protection