A blue dye housed in a blister is held adjacent to a micro-porous membrane. Upon squeezing the activation button the liquid dye comes out of the blister and into contact with the membrane. If the temperature of the product is below the stated ‘STOP’ temperature, the blue dye changes state to solid form, and it is unable to move through the membrane. If the temperature rises to or above the threshold temperature, the dye changes to liquid form and moves at a precise rate through the membrane. Its progress is irreversible and the distance it travels through the viewing window indicates the cumulative time the indicator has been exposed to the threshold temperature or above.
Once activated, Timestrip® PLUS will keep monitoring temperature for days, weeks or months, depending on your needs. During that time it will record how long any temperature breaches last.
Here is an example. An 8°C Timestrip® PLUS was chosen to monitor a shipment which would take 3 weeks to arrive. When the shipment arrived, the indicator showed 4 hours of 8°C breach. This breach could have happened in one long event or from a series of shorter breach events across the 3 weeks. The 8°C Timestrip® PLUS could have indicated up to 8 hours of temperature breaches during that 3 weeks.