Hochiki FIRElink-400CM - Manual (Page 29)

FIRElink-400 Air Sampling System – Installation Manual Page 29 of 58
© 2010 Hochiki Europe (UK) Ltd 9-5-0-346/ISS4/OCT10
c. Maximum recommended total sampling pipe length is 200 metres. In order for the installation to
conform to EN54-20, pipes must conform at least to EN61386-1 Class 1131
NOTE: This is 4 lengths of 50 metres, 3 lengths of 70 metres or 2 lengths of 100 metres.
d. Sampling pipes must have capped ends. The end cap should be drilled with a sampling hole
normally between 4 or 5mm diameter and free from burrs. Sampling holes should normally
be 3-4mm diameter or as calculated by FIRElink PipeCAD and free from burrs. Each pipe
run should not have more than 25 holes. Pipe transit time must not exceed 120 seconds and
an approved type of pipe must be used for installations conforming to LPCB requirements.
When drilling holes in the sample pipes, or cutting off lengths of pipe, ensure that all swarf
and debris is removed from the pipe.
This guide holds true for average sampling pipe lengths, but if using long pipes (typically
more than 60 metres total), performance may be improved by making the sampling holes
near the ends slightly larger than those nearer the detector.
Although by no means essential, it must be recommended that if in doubt, FIRElink
PipeCAD® be used to ensure that transit times, balance of suction and individual sampling
point sensitivity are within desired limits.