Xtralis VESDA VLC-400, Руководство по эксплуатации продукта

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VESDA by Xtralis VESDA VLC-400 Product Guide
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5 Pipe Network
This document does not cover the design and installation of Aspirating pipe work in detail. For complex or
customized designs please contact an approved Xtralis agent who can use the ASPIRE2 pipe work modeling
program to verify non-standard designs.
Notes:
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These standard designs are provided for ease of installation in the majority of applications. The
limitations specified are conservative and the VLC-400 is fully capable of being successfully applied
beyond the limits stated when the design and installation of the pipe work is directed by an approved
Xtralis agent.
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The following standard designs are Class C under EN54-20 when used with the default alarm threshold
of 0.2% obscuration/m.
5.1 Primary Sampling (of Air Handling Unit return grilles)
VESDA VLC-400 detectors are ideally suited to protecting large areas (up to 800m²) with high airflows by
arranging sampling pipe across the return grille of Air Handling Units.
Up to 2 identical Air Handling Units may be covered as long as they are not independently controlled or
unusually large (e.g. > 30kW or >10,000m3/hr).
Pipe work across the grille should be arranged to ensure that the flow into the grille is adequately sampled.
Generally, Xtralis recommends a maximum coverage of 0.2m² per sampling hole. For example a grille
measuring 1.5m x 0.8m would need 6 sampling holes (refer to Figure 5-2). When sampling across a grille the
sampling holes should generally face into the flow, as such slight rotations of the pipe during commissioning
may improve performance. Consideration should be given to any maintenance requirements for the Air
Handling Unit. For example, it may be necessary to allow for convenient removal of the VESDA pipe work to
allow easy access to filters in the AHU.
Figure 5-1: Sampling an AHU
5.2 Secondary Sampling (room or void protection)
VESDA VLC-400 detectors may be used to protect open areas up to 800m². This is generally achieved by
positioning sampling holes according to the standards relating to conventional point detectors.
The pre-engineered pipework solutions presented in the following section may be used without verifying their
performance using the ASPIRE2 pipe modelling software. These pre-engineered solutions are compliant with
the European standards and achieve a transport time of less than 90 seconds and sensitivity performance
significantly better than 4.5% obs/m and so the systems are Class B under VESDA approvals to EN 54-20
and sensitivity performance is significantly better that the requirements of EN54-7 (or EN 54-20 Class C)
where the sensitivity of individual sampling points must be better than 10%obscuration/m. However, where