5
Classification and control
In accordance with the Pressure Equipment Directive and
national usage monitoring regulations in the European Union
the protection devices for these machines are classified as
follows:
Safety
device
(1)
Device for damage
limitation in the event
of an external fire
(2)
Refrigerant Side
High pressure safety loop
(3)
X
External relief valve
(4)
X
Rupture disk
X
Heat transfer fuid side
External relief valve
(5)
(5)
(1) Classified for protection in normal service situations.
(2) Classified for protection in abnormal service situations. These accessories are
sized for fires with a thermal flow of 10kW/m². No combustible matter should be
placed within 6.5m of the unit.
(3) High pressure safety loop = SRMCR as described in component section of this
manual and in electrical diagram.
(4) The instantaneous overpressure limitation of 10% of the operating pressure
does not apply to this abnormal service situation.
The control pressure can be higher than the service pressure. In this case, either
the design temperature or the high pressure switch ensures that the service
pressure is not exceeded in normal service situations.
(5) The selection of these relief valves must be made by the personnel responsible
for completing the hydraulic installation.
In compliance with the European Pressure Equipment
Directive (PED) and national regulations relating to design:
-
These valves are not safety devices but accessories
which limit damage in the event of a fire,
-
The safety device is the high pressure safety loop
described in section 11.3.1
Do not remove these valves even if the fire risk is under
control for a particular installation. There is no guarantee that
the accessories are re-installed if the installation is changed
or for transport with a gas charge.
When the unit is subjected to fire, safety devices prevent
rupture due to over-pressure by releasing the refrigerant.
The fluid may then be decomposed into toxic residues when
subjected to the flame:
-
Stay away from the unit.
-
Set up warnings and recommendations for personnel in
charge to stop the fire.
-
Fire extinguishers appropriate to the system and the
refrigerant type must be easily accessible
NOTE : Pressure equipment for the hydraulic side (optional) are
delivered as separate items. Their integration in the complete
hydraulic installation remain under the user’s responsibility.
All factory-installed relief valves are lead-sealed to prevent any
calibration change. If the relief valves are installed on a
change-over valve, this is equipped with a relief valve on each
of the two outlets. Only one of the two relief valves is in
operation, the other one is isolated. Never leave the change-
over valve in the intermediate position, i.e. with both ways
open (Bring the actuator in abutment, front or back according
to the outlet to isolate).
If a relief valve is removed for checking or replacement please
ensure that there is always an active relief valve on each of
the change-over valves installed in the unit.
The external relief valves must always be connected to drain
pipes for units installed in a closed room. Refer to the
installation regulations, for example those of European
standard EN 378 and EN 13136.
These pipes must be installed in a way that ensures that
people and property are not exposed to refrigerant leaks. As
the fluids can be diffused in the air, ensure that the outlet is
far away from any building air intake, or that they are
discharged in a quantity that is appropriate for a suitably
absorbing environment (note that R1234ze(E) refrigerant is
heavier than air).
Periodic check of the relief valves: See chapter 1.3 -
“Maintenance safety considerations”.
Provide a drain in the drain pipe, close to each relief valve,
to avoid an accumulation of condensate or rain water.
It is recommended to install an indicating device to check
whether any refrigerant has leaked from the relief valve.
The presence of oil at the outlet orifice is a useful indicator
that refrigerant has leaked. Keep this orifice clean to ensure
that any leaks are obvious. The calibration of a valve that has
leaked is generally lower than its original calibration. The new
calibration may affect the operating range. To avoid nuisance
tripping or leaks, replace or re-calibrate the valve.
All precautions concerning handling of refrigerant must be
observed in accordance with local regulations.
Ensure good ventilation, as accumulation of refrigerant in an
enclosed space can displace oxygen and cause asphyxiation
or explosions.
Inhalation of high concentrations of vapour is harmful and
may cause heart irregularities, unconsciousness, or death.
Vapour is heavier than air and reduces the amount of oxygen
available for breathing. These products cause eye and skin
irritation. Decomposition products are hazardous.
1.2 -
Equipment and components under
pressure
These products incorporate equipment or components under
pressure, manufactured by Carrier or other manufacturers. We
recommend that you consult your appropriate national trade
association or the owner of the equipment or components under
pressure (declaration, re-qualification, retesting, etc.). The
characteristics of this equipment/these components are given on
the nameplate or in the required documentation, supplied with the
products.
These units comply with the European Pressure Equipment
Directive.
These units are intended to be stored and operated in an
environment where the ambient temperature must be not less
than the lowest allowable temperature indicated on the nameplate.
Do not introduce significant static or dynamic pressure with regard
to the operating pressures used during operation or for tests in
the refrigerant circuit or in the heat exchange circuits.
See section “10.2 - Pressure vessels”.
1.3 - Maintenance safety considerations
If the unit is running, hearing protection is required for any
intervention in its vicinity.
Carrier recommends the following drafting for a logbook (the table
below should not be considered as reference and does not involve
Carrier responsibility):
Intervention
Name of the
commissioning
engineer
Applicable
national
regulations
Verification
Organism
Date
Nature
(1)
(1) Maintenance, repairs, regular verifications (EN 378), leakage, etc.
Engineers working on the electric or refrigeration components
must be authorized, trained and fully qualified to do so.
All refrigerant circuit repairs must be carried out by a trained
person, fully qualified to work on these units. He must have been
trained and be familiar with the equipment and the installation. All
welding operations must be carried out by qualified specialists.
1 - INTRODUCTION
