Type B/240
3
OVERPRESSURE PROTECTION
The recommended maximum allowable pressures are
stamped on the regulator nameplate.
If actual version hasn’t a built-in safety shut-off device, some
type of overpressure protection is needed if the actual outlet
pressure exceeds the actual maximum operating outlet
pressure rating.
Overpressure protection should also be provided if the
regulator inlet pressure is greater than the maximum
operating inlet pressure. Downstream side pressure after
possible built-in SSD’s intervention shall stay within the
actual maximum operating set-up range to avoid anomalous
back pressures that can damage the SSD’s pilot.
Downstream overpressure protection shall be also provided
if the SSD outlet pressure can be greater than the PS of the
SSD pilot (differential strength type).
Regulator operation below the maximum pressure limitations
does not preclude the possibility of damage from external
sources or debris in the line.
The regulator should be inspected for damage after any
overpressure condition.
TRANSPORT AND HANDLING
Established transport and handling procedures shall be
followed to avoid any damage on the pressure containing
parts by shocks or anomalous stresses.
Built-up sensing lines and pressure accessories shall to be
protected by shocks or anomalous stresses.
ATEX REQUIREMENTS
If the provisions of EN 12186 & EN 12279, national regula-
tions, if any, and specic manufacturer recommendations are
not put into practice before installation and if purge by inert
gas is not carried out before equipment’s start-up and shut-
down operations, a potential external and internal explosive
atmosphere can be present in equipment & gas pressure
regulating/measuring stations/installations.
If a presence of foreign material in the pipelines is foreseen
and purge by inert gas is not carried out, the following
procedure is recommended to avoid any possible external
ignition source inside the equipment due to mechanical
generated sparks :
• drainage to safe area via drain lines of foreign materials, if
any, by inow of fuel gas with low velocity in the pipe-work
( 5m/sec)
In any case,
• provisions of Directive 1999/92/EC and 89/655/EC shall
be enforced by gas pressure regulating/measuring station/
installation’s end user
• with a view to preventing and providing protection against
explosions, technical and/or organizational measures
appropriate to the nature of the operation shall be taken
(e.g. : lling/exhausting of fuel gas of internal volume
of the isolated part/entire installation with vent lines
to safe area - 7.5.2 of EN 12186 & 7.4 of EN 12279 ;
monitoring of settings with further exhaust of fuel gas to
safe area ; connection of isolated part/entire installation to
downstream pipeline; ….)
• provision in 9.3 of EN 12186 & 12279 shall be enforced by
pressure regulating/measuring station/installation’s end user
• external tightness test shall be carried out after each
reassembly at installation site using testing pressure in
accordance with national rules
• in case of selfop regulators diaphragm’s incidental failure
the amount of maximum ow to be vented can be calcu-
lated using the universal gas sizing equation, assuming
inlet pressure = regulator’s set-point, outlet pressure =
atmospheric pressure and venting hole DN on the regula-
tor’s upper cover = 16 mm (Cg = 280).
• periodical check/maintenance for surveillance shall be
carried out complying with national regulations, if any, and
specic manufacturer recommendations.
SLAM-SHUT CONTROLLER
The following controllers are used with B/240 series
regulator with built-in slam-shut:
• OS/66 Series spring loaded controllers
Figure 3. OS/66 Slam-Shut Controller
Table 2. OS/66 Characteristics
MODEL
BODY
RESISTANCE
bar
OVERPRESSURE
SET RANGE
W
do
bar
UNDERPRESSURE
SET RANGE
W
du
bar
Min. Max. Min. Max.
OS/66 6 0.022 0.6 0.007 0.45
OS/66-AP 6 0.2 5 0.1 2.5
Materials
Body: Aluminium
Cover: Steel
Diaphragm: NBR rubber
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