Doc: G1-4200 Guide-0709
TQ Environmental plc.
Infra Red Gas Detection.
Page 3 of 3
regular intervals, similar to cable installations. Avoid unsupported loops and sags that can
cause damage to pipework and personnel.
When running lines out of cold rooms, avoid passing through freezer compartments as this
can cause blockages due to condensation freezing in the sample lines. Also avoid long runs
inside freezer compartments, as condensation will freeze in the line. When sampling these
areas it is best to drop a short length of tubing through the ceiling to the sample point.
End of Line filters.
P Clip
30mm
40mm
15mm
Filter
Element
Although the control panel is fitted with internal filters, to avoid problems internally it is
recommended that End of Line filters are fitted. These can be of a disposable bonded fibre
type or a stainless steel element that can be cleaned and replaced. When positioning these end
of line points, again avoid areas where they could become damaged or crushed. In cold
storage rooms, position the filter in a clear air space, not in a position where it will become
closely packed by stored items. Also avoid areas that are prone to freezing (ice formed by
drips or leaks ) as filters will become blocked by frozen condensation.
When monitoring from plant rooms and machinery, avoid locations where oil or water
splashes can be sucked into the sample line, machinery drip trays for example. If monitoring
from external areas keep End of Line filters out of water or rain or splashes and avoid
condensation running down the sample lines to the filter. For ease of identification it is a good
idea to mark each end of a sample run with the sample line or channel number. This will help
when pinpointing potential refrigerant leaks and future problem solving. Sample lines can be
identified using suitable cable marking systems.
Zero point.
The zero point, connected to the “0” line, is the reference for zero gas. It should be positioned
in clean air and the end point has a charcoal filter fitted to filter out any unwanted gas from
this reference point. It is usual to have this mounted next to the control panel as this is usually
also in a clear air space. It is not necessary to run the zero line outside. Positioning it next to
an air vent is usually sufficient and again avoid sucking water into the zero line.
