Testing and Verification Procedure
Irreversible Temperature Indicator Labels
Linkam TP92 temperature measurement stage (or similar Linkam model) with current calibration certificate traceable to UKAS (united Kingdom Accreditation Services).
Overall accuracy of the measurement system is ± 0.1ºC
- The test strip is applied to the block
- The temperature of the block is raised rapidly to 5ºC below the lower rating and then warmed at 2 degrees centigrade per minute through the range until all the papers have melted and their melting ranges recorded.
- The start of the melt is recorded as the temperature at which dark grey spots begin to appear on the segment of paper.
- The end of the melt is when at least 90% of the surface coated has melted.
- The temperatures are recorded.
- The mid-point of the chemical is calculated from the start and finish of melt using the following formula
ºC MID = (ºC END OF MELT + ºC Start Melt) / 2
Accuracy readings for irreversible strips
- Accuracy to 99ºC is +/- 1ºC
- Accuracy to 100ºC is +/- 1.5ºC
- Accuracy to 160ºC to 280ºC is +/- (1% + 1ºC)