FIKE CORPORATION
Page 4 of 20 Fike Explosion Protection System FM 3020541
07/04 P/N E06-054 Rev. 1
4.0 INSTALLATION
4.1 INSTALLATION OVERVIEW
The effectiveness of active explosion protection
systems, such as explosion suppression and
explosion isolation, depends upon the
instantaneous reaction of the protection system
and is a direct function of its speed of response.
It is therefore, critical that all possible measures
are taken to reduce the individual system
components’ response times to an absolute
minimum.
An active explosion protection system basically
consists of three components: One or more
explosion detectors, an electronic system
controller, and one or more protective devices
such as explosion suppressors or isolation
valves. Instrumentation wiring interconnects
these components.
The system controller is microprocessor-based
and shall be installed in a location that maintains
the EPC’s temperature rating of -18°C to 43°C
(0°F to 110°F) when it is installed in an auxiliary
housing. For FM Approved installations the
housing shall be a lockable enclosure
conforming to the installed area requirements as
defined by NEMA 250 “Enclosures for Electrical
Equipment (1000 Volts Maximum).”
Besides its function as a fire controller it also
incorporates an event table and a self-checking
feature to continuously monitor the complete
system-loop for errors or system defects.
Electronic devices, microprocessors,
pyrotechnic initiators, and field wiring are
influenced by the electromagnetic “environment”
surrounding these components. The use of
cellular telephones, transmitters, induction
motors, welding equipment or the presence of
power cables and transformers can create
environments with high levels of electromagnetic
radiation, resulting in induced electrical “noise”
or voltage peaks.
Such effects are known to designers and
manufacturers of instrumentation and control
systems (PLC’s), used in industrial
environments and are handled through the use
of specially designed electronic filters. These
filters neutralize the unwanted noise and offer a
“clean” signal for further processing. The filters,
however, result in a delay in the processing of
signals, and can therefore only be applied with
great care in explosion protection systems
where the effectiveness depends on the overall
response time.
In active explosion protection systems, a
balance must be maintained: The system must
be extremely fast to achieve the required
effectiveness, but at the same time must be
stable and insensitive to surrounding sources of
noise.
The system controller will detect and report
major system troubles (such as ground faults,
wire disconnection, and unstable input or output
signals) and indicates the need for appropriate
action.
The system controller will also detect
unacceptable levels of electromagnetically
induced noise. If the magnitude of the noise is
such that this may result in a risk for
spontaneous system activation or affect the
system’s performance, the controller will revert
to its default error-mode.
It is essential to practice extreme caution when
selecting component location, cable
specifications, cable routes, and the
“cleanliness” of the offered power source. In
order to reduce the electromagnetic induced
noise to a level that will not affect the required
performance of the explosion protection system,
verify all earth connections. It is preferred to
have the enclosure and conduits connected to
Protective Earth (similar with other building
grounds) while the drain wires from the field
wiring and each module ground connected to a
separate Instrument Earth. This Instrument
Earth connection shall not have inductive or
capacitive loading such as motors, welders, or
other industrial equipment. Where a separate
earth connection is not available, the drain wires
and module ground connections should be
made to battery common. Complying with the
following recommendations will help minimize
the induced noise to acceptable levels.
4.2 POWER SPECIFICATIONS
The AC supply (commonly supplied to the
EPACO Power Supply Unit, PSU) shall be wired
through a dedicated circuit to a
1002/120/240VAC 15 or 16 Amp circuit breaker.
High voltage circuits may NOT be run in the
same conduit as low voltage circuits.
Cabling from transformer to PSU shall be
1.3 mm2(16AWG) minimum not to exceed
3 meters (10 feet).
2Not FM Approved for 100 VAC.
