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Before operation, the refrigerant leaked in the room is not allowed.
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The area of the room in which maintenance is made shall be in line with the nameplate.
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Continuous ventilation shall be maintained during maintenance.
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Open fire or high-temperature heat source higher than 548 degree which can easily give birth to open fire is
not allowed inside the room within the maintenance area.
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During maintenance, the phones and the radioactive electronics of all the operators inside the room must be
powered off.
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One dry powder or carbon dioxide extinguisher shall be equipped inside the maintenance area, and the
extinguisher must be under available state.
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The maintenance site shall be provided with favorable ventilation and must be flat. Arrangement of the
maintenance site inside the basement is not allowed.
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Welding zone and non-welding zone shall be divided at the maintenance site, and shall be clearly marked. A
certain safety distance must be guaranteed between the two zones.
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Ventilators shall be installed at the maintenance site, and exhaust fans, fans, ceiling fans, floor fans and
dedicated exhaust duct can be arranged, to meet the requirements of ventilation volume and uniform exhaust, and
to avoid accumulation of refrigerant gas.
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Leak detection equipment for flammable refrigerant shall be equipped, with relevant management system
being established. Whether the leak detection equipment is under available state shall be confirmed before
maintenance.
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Sufficient dedicated vacuum pumps of flammable refrigerant and refrigerant charging equipment shall be
equipped, with relevant management system for maintenance equipment being established. It shall be guaranteed
that the maintenance equipment can only be used for vacuumizing and charging of one type of flammable
refrigerant, and mixed usage is not allowed.
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The master power switch shall be arranged outside the maintenance site, with protective (anti-explosive)
device being equipped.
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Nitrogen cylinders, acetylene cylinders and oxygen cylinders shall be placed separately. The distance
between the gas cylinders above and the working area involved in open fire shall be at least 6m. The anti-backfire
valve shall be installed for the acetylene cylinders. The color of the acetylene cylinders and oxygen cylinders
installed shall meet the international requirements.
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The warning sign of "No Fire" shall be arranged inside the maintenance area.
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Fire control device suitable for electric appliance such as the dry powder extinguisher or carbon dioxide
extinguisher shall be equipped, and shall always be under the available state.
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The ventilator and other electrical equipment at the maintenance site shall be relatively fixed, with
standardized pipe routing. Temporary wires and sockets at the maintenance site are not allowed.
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The environment in which the refrigerant leakage is checked shall be free from potential ignition source.
Leak detection with halogen probes (or any other detector with open fire) shall be avoided.
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For the system containing flammable refrigerant, leak detection may be realized with electronic leak
detection equipment. During leak detection, the environment in which the leak detection equipment is calibrated
shall be free from refrigerant. It shall be guaranteed that the leak detection equipment will not become potential
ignition source, and is applicable to the refrigerant to be detected. Leak detection equipment shall be set at a
percentage of the LFL of the refrigerant and shall be calibrated to the refrigerant employed, and the appropriate
percentage of gas (25 % maximum) is confirmed.
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The fluid used for leak detection shall be applicable to most of the refrigerant. The use of chlorine-
containing solvent shall be avoided, to avoid chemical reaction between chlorine and refrigerant and corrosion to
copper pipelines.
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In case leakage is suspected, the open fire at the site shall be evacuated or be put out.
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In case welding is required at the leakage position, all the refrigerants shall be recovered, or be isolated at a
position far from the leak point with a stop valve. Before and during welding, the whole system shall be purified
with OFN.
Inspection on Maintenance Environment
Maintenance Site Requirements
Leak Detection Methods
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