Understanding Infrared Thermography Reading 7 Part 2 of 2.pdf

EPRI Licensed Material
Basic Elements of an In-House Program
6.2 Approvals – The required approvals to conduct a survey shall be coordinated with the IR
administrator. The control room should be notified both prior to the start of the survey
and at its end. If requested, the infrared thermographer will inform the control room prior
to opening equipment that presents a possible plant trip hazard.
6.3 Emergencies – In cases where requests for surveys are done on an emergency basis, the
infrared thermographer shall fulfill the duties of the IR administrator and provide the
necessary coordination.
7.0 CONDUCT OF THE SURVEY
7.1 The equipment survey matrix shall identify the equipment to be surveyed and the
frequency of the survey.
7.2 The sequence of the survey is not important unless specifically stated in the procedure or
requested by either Maintenance or Operations. All equipment on the matrix must be
surveyed unless it is not in operation or conditions dictate otherwise. The infrared
thermographer shall note any exceptions in the inspection report.
7.3 Standard practice is to videotape all surveys and to include an audio track for verbal
identification and discussion.
7.4 The thermal images must be of sufficient resolution to identify the components and any
problem areas.
7.5 When problems are identified, the thermographer shall reposition the imager and obtain
more than one view. This is done to eliminate the possibility of apparent problems being
caused by reflections from hot objects. The hard-copy images should be obtained from
the position that provides the best image.
7.6 All problems are to be photographed in the visible as well as in the infrared. This is to
allow proper and easy identification of the problem areas, which will facilitate
maintenance activities.
7.7 The problems shall be customarily reported as a temperature rise. This rise can be
calculated from ambient, thermal baseline data, or made by comparison in the cases
where similar equipment exists.
7.8 When absolute temperatures are requested or required, the infrared thermographer shall
determine and use the target's effective emissivity to assure accuracy. A standard table of
effective emissivities will be developed by measurement and will be maintained by the
infrared thermographer.
7.9 Important information relating to test conditions, such as load, flow, and pressure shall be
noted by the thermographer if it is available. This information will be used in component
trend analysis.
7.10 The components shall be inspected with the imager aimed along a line normal
(perpendicular) to the target surface whenever possible, to minimize the potential for
errors due to reflections.
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