VESDA by Xtralis
VESDA VLC-EX Product Guide
www.xtralis.com
17
5
Connecting the VESDA VLC-EX to the Sampling
Pipe Network
5.1
Inlet Pipes
The air inlet port is designed to fit a standard pipe of 25 mm (1 in) OD.
The air inlet port allows the pipe to be inserted up to 15 mm (0.60 in). To connect the detector to the pipe
network:
1. Ensure a minimum length of 500 mm (20 in) of straight pipe before terminating the pipe at the air inlet port
of the detector.
2. Square off and de-burr the end of the sampling air pipe, ensuring the pipe is free from debris.
3. Insert the pipe into the inlet port ensuring a firm fit. DO NOT glue the inlet pipes to the pipe inlet manifold.
Note:
It is recommended that metallic pipe is used, and that a metal inline filter (part number VSP-850-M)
is installed in the pipework, upstream of the detector, and earthed all together.
Caution:
The VLC-EX is intended for hazardous areas where there is little or no dust. Excessive or
unfavorable dust may lead to electrostatic charges occurring within the aspirator. While it is
very unlikely that such charges will lead to a high energy discharge it is recommended that little
or no dust be present. As a guide, if there is settled dust clearly visible on a surface that was
wiped clean a week earlier then further investigations may be necessary.
5.2
Air Exhaust Pipe
If necessary pipe the exhaust back to the relevant VESDA Zone. The maximum suggested length for the
exhaust pipe is 4 m (13 ft.).
1. The exhaust from the detector should be arranged to avoid the ingress of dust and water. Extraneous
dust is prevented from entering the enclosure due to the natural airflow that is exhausted from the
detector. However, high pressure water jets could enter the unit if the exhaust port is not protected by a
pipe with a series of suitable bends. A possible arrangement is shown in Figure 5-1.
2. The arrangement of the sampling pipes must also be considered with regard to ingress of dust and water.
The pipe runs should be arranged so that water entering the pipe network does not run towards the
detector. For example, for the exhaust pipe, use a bend arrangement as in Figure 5-1 below, or a water
trap. However, with regard to dust ingress the specific requirements of the application must be
thoroughly investigated particularly with regard to the location of sampling points.
Figure 5-1: A possible exhaust pipe arrangement to maintain an IP54 rating
Notes:
l
The pipe used to sample the air in the hazardous area must comply with all relevant codes and
standards. It is recommended that metallic pipe is used.
l
Even if the air is not to be returned to the sampling point, an exhaust pipe stub must be fitted to the VLC-
EX, so that the air sample is expelled from the case and the seal is maintained in the stainless steel
enclosure.
Summary of Contents for VESDA VLC-500-EX
Page 2: ......
