Method 2: Explosion Suppression System; Isolation Device - Nederman E-PAK 150 DX Manual De Instrucciones

explosion, the resulting flame and pressure escape through the explosion relief
panel which is to be directed towards a safe area without any people. This area
is referred to as the 'risk area'.
The risk area is to be clearly marked, for example with a fence, warning lines
and signs, and entry is prohibited when the filter is in operation. The area is to
be free of any flammable or combustible material or other objects which may
be damaged by the flames and explosion pressure.
The general size of the risk area is shown in Figure 6. The following
dimensions apply:
• A=8 m (26.2 ft)
• B=2 m (6.6 ft)
• C=3.5 m (11.5 ft) or ground level, if elevated
• D=4 m (13.1 ft)
NOTE!
The risk area may extend beyond the values given above. The
final risk area is to be evaluated with regards to affecting factors found in
Standard EN 14491.
In some cases, it is necessary to use a duct on the explosion relief panel to vent
the flame and pressure to a proper safe area. Such a duct is to be at least 0.1 m
(0.33 ft) larger than the relief panel outer dimensions, and be able to withstand
an overpressure of at least 0.4 bar (5.8 PSI).
NOTE!
The maximum length (L) of the explosion relief panel duct depends
on the characteristics (Kst value) of the collected material. Figure 7 shows a
diagram indicating the maximum length of the duct for a specific Kst value.
4.1.2

Method 2: Explosion suppression system

With an explosion suppression system, the early stage of an explosion is
detected with optical and/or pressure-sensitive devices, and an extinguishing
agent is quickly dispersed into the filter. The suppression of the explosion
is initiated an extremely short time after detection of the explosion (in
milliseconds), and stops the pressure rising and extinguishes (suppresses) the
flames of the explosion.
This ensures that the filter is not stressed to a dangerous level by the explosion.
The key components of the explosion suppression system are the following:
• An explosion detection device (optical/pressure-sensitive).
• A computer-operated control unit.
• Action elements such as pressure cylinders containing an extinguish agent
with an extra fast opening valve.
Detailed information regarding system installation, function, operation and
maintenance can be found in the suppression system manual.
4.1.3

Isolation device

An isolation device, see Figure 8, item 5, is to be installed to prevent a filter
explosion from propagating back into the plant through the connected duct.
The duct, see Figure 8, item 8, between the unit and the isolation device is to
be pressure-resistant to an overpressure of at least 0.5 bar (7.2 PSI) and have a
minimum length (Figure 8, item A) as specified in the manual of the isolation
device. This is normally 4 meters for ST2 and 2 meters for ST1.
E-PAK 150 DX/300 DX/500 DX EN
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