S9074-AR-GIB-010/278
8.9.3 Installing Thermocouples. Thermocouple wires shall be electrically insulated except at their hot junctions. In order to avoid erroneous readings, thermocouples shall be so arranged that flames do not impinge on the junctions of the wires themselves. When the electrical resistance heating method is used, the thermocouple provided control the operation shall be covered by a protective wrapping to prevent direct radiation of the heating elements on its hot junction. Thermocouples shall be attached to the weldment by a method which ensures that the thermal junction is held firmly. 8.9.4 Pyrometrically controlled furnaces. For furnace stress relief of weldments, when a recording pyrometric control furnace has been calibrated and it is verified that the temperature variation within the furnace is within the stress-relieving temperature range for the materials involved, the furnace control thermocouples may be used as the indication of the temperature of the part being treated in lieu of thermocouples attached to the component. between them. For flange to pipe joints, one thermocouple shall be attached to the flange side of the joint.
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