IEEE 515-2004 pdf free download – IEEE Standard for the Testing, Design, Installation, and Maintenance of Electrical Resistance Heat Tracing for Industrial Applications.
4.1.6 Thermal performance benchmark One of the following tests shall be used to verify power output stability for all parallel heating devices.
4.1.6.1 Primary test Three randomly selected samples representing the maximum output of all cables or surface heating devices under evaluation shall be tested. If the type of cable or surface heating device has different levels of rated voltages and wattages, then three samples each shall be selected that represent the following:
a) The lowest rated voltage level and the maximum rated output
b) The maximum rated voltage and the minimum rated output Samples shall be terminated according to the manufacturer’s specifications, such that a heating length of at least 600 mm or representative surface heating device dimensions are provided. The aging temperature of the test shall be the maximum declared maintain temperature of the heating device. The samples shall be conditioned, while energized, at the aging temperature for 120 h ± 24 h. The initial output of the samples is then to be determined by one of the three methods given in 4.1.11, with the exceptions of sample length and number of test temperature points for the procedure in item c) in 4.1.11. For this case, the samples shall be evaluated at rated voltage and at the manufacturer’s stated reference temperature for the rated output.
The output shall be within the manufacturer’s stated output range. The samples shall be attached to a fixture or suitable heat sink as described in itemc) in 4.1.11 and insulated accordingly. The pipe or heat sink temperature shall be set to the specified aging temperature and maintained with ± 3 °C plus 1% of the temperature reading in degrees Celsius. Circulating fluid or external heating may be used to raise the fixture to the aging temperature. The samples shall be operated at rated voltage. The power supply shall be attached to a 15 min cycle timer such that the samples are energized for 12 min and de-energized for 3 min.
The samples shall be exposed to this conditioning for 32 weeks (5376 h). For heating devices with an intermittent temperature exposure rating, the samples are exposed to the same conditioning for 32 weeks, except for an 8 h excursion once each week. At the beginning of the 8 h, the samples shall be disengaged from the cycle timer. The pipe or heat sink temperature shall be increased to a temperature equal to the manufacturer’s stated intermittent exposure temperature.
The time allowed to increase the temperature should be no greater than 1 h. After 7 h from the beginning of the excursion, the pipe or heat sink temperature shall be decreased back to the aging temperature, again allowing no more than 1 h for the operation. Where the intermittent temperature rating is based on the heating device being energized, then the heating device shall be continuously energized during this temperature excursion, except during cool down back to the maximum maintain temperature.
Where the intermittent temperature rating is based on the heating device being de-energized, the exposure cycle is conducted in a de-energized condition. At the end of the 8 h excursion, the samples shall be reengaged to the cycle timer. The excursions should occur on the same day each week. At the end of the 32 weeks of operation at the continuous rated temperature, the output of the samples shall be determined by the same procedure as utilized for the initial readings. The heating device samples shall maintain a power level within plus 20% or minus 25% of the initial measured output.IEEE 515 pdf download.