Hi I am a new user of the Bloodbank Talk too. We are in the process of validating our Igloo coolers. We were using the same method as NedB was using, two frozen and one refrigerated gel pack (the ones with hard container and blue ice in it), and I was able to cary four units for 6 hours at 3-3.5 C. I wasn't able to carry on for long time due to shortness of time. This was with opennig cooler every 15 minutes, because I was taking temps every 15 min. I wasn't sure how often we should be taking temps. Does enyone has written procedure or protocol for validation of coolers to share ? That will be greately appriciated. Thanks Mini Me