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AXYS
ABF-260/100W PA6 V0 Low Profile Installation Manual Rev 1.1
®
3 . INSTALLATION GUIDE
PREPARING FOR INSTALLATION
It is assumed that the installation site (e .g . tunnel) has
been the subject of extensive acoustic analysis prior to the
actual installation . The analysis should have assessed the
acoustic conditions in the tunnel and defined the operating
scenarios (Local/All call, traffic speed, ventilation active/
inactive etc) for the PA/VA system . The minimum speech
intelligibility requirements must be met for each scenario .
The acoustic properties of the tunnel's interior surfaces
(acoustic absorption and scattering coefficients) and the
expected background noise levels due to the traffic and/
or ventilation system should also have been established .
More information regarding the acoustic design
procedure, including design guidelines, is available at
www .axystunnel .com .
Various acoustic modelling software applications are
available; for example CATT-Acoustic
when accurate predictions of the STI (Speech Intelligibility
Index) are necessary .
Nearly all tunnel installations will need to employ multiple
ABF-260 units to obtain satisfactory sound coverage .
The acoustic design procedure will have identified the
number of ABF-260s required and the optimum physical
location for each to accurately achieve the desired acoustic
coverage . In particular, the height above the roadway, and
any mechanical mounting angles will have been specified .
50 m linear spacing between units is typical, but two or
more units may be required at each position when the
overall tunnel width is more than 12 m .
The installer should confirm that he/she has all necessary
information relating to the location and physical
orientation of all ABF-260 units making up the system . It
is important to recognise that even small deviations from
the calculated positions can adversely affect the desired
acoustic coverage .
202103/ABFPA6VOLP_IM_1.1
modelling is suitable
®
MECHANICAL INSTALLATION
Location
The ideal mounting situation for the ABF-260 is with the upper
surface of the horn secured flush to the mounting surface (the
tunnel roof) . If the roof is curved, a totally flush fitment may
be unachievable; see "Fixing to a curved roof" in this section .
Tunnel infrastructure may also preclude a flush fitment; see
"Non-flush installation" at the end of this section .
The ABF-260 should be mounted so that the flare of the
horn faces the oncoming traffic . If it is found that tunnel
infrastructure items (lights, traffic signs, fans, etc .) are
within 5 m of the horn flare and in line with the horn,
an alternative mounting location should be found . In such
cases, the installer must contact the acoustic designer for
guidance before proceeding with the installation .
Do not mount the ABF-260 in the vicinity of
high pressure deluge / sprinkler system water
outlets . Any water outlets of the sprinkler
system should not spray directly into/onto the ABF-260 .
Fixings
Fixing is via the ten 9 mm mounting holes around the edge
of the upper surface . It is advised to use the 8 fixing points
located in pairs at a distance of respectively 75, 508, 782 and
947 mm from the front side of the unit as indicated in fig .2 .
M8 screws or bolts should be used, of a length appropriate to
the type of mounting employed (see below) .
The weight of the ABF-260 is 18 kg, and a safety
factor of 4 should be allowed when checking
the safe load capability of the mountings .
The diagram on the following page (fig .2) gives the
dimensions required for marking the mounting hole
locations on the roof . When marking out for the holes, take
care that the hole positions take into account any mounting
angle specified for the horn by the acoustic specification .
The roof mountings can be in the form of threaded inserts,
commercially available as "Rawlbolts", or similar . An alternative
approach is to inject a fire resistant chemical screw fixing
compound into the hole and fix the loudspeaker using 8 mm
diameter hex-head coach screws . The horn may need to be
supported during the compound's setting phase (curing time) .
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