Phase 24 Packs (brand name of some Phase packs is Cryopak) are very versatile phase-change material packs that can be used in different ways depending on what you need them to do.
Ph24 packs try to stabilize the shipment at temps between 68°F to 75°F (or approx 24°C, hence the name Phase24). At 72°F, the pack is in a gel-like state (think slushy texture), but when it is below 72°F, it becomes solid and opaque white, and when warmed above 72°F, it becomes clear and liquid.
Over time, a Ph24 will work to regain and maintain its gel-like state at 72°F. When used warm, a Ph24 will try to release heat to get back down to 72°F, and when used in its solid state, it will try to absorb heat to get back up to 72°F. When used at room temperature or in its gel-like state, it will help reduce temperature changes within your box and helps to keep the internal temperature of your shipment closer to 72° than without it.
Using a Phase 24 pack when shipping from warm to cold:
They can act as a buffer when used in conjunction with a heat pack, such as for shipments where temps are too warm for normal heat pack use at the origin but you still need a heat pack on the receiving end. While this is a tricky situation, as long as you use a bigger box (~12x9x6 or larger) and your temps are not too hot, placing a solid Ph24 in between the heat pack and the animal will allow the Ph24 to absorb much of the heat on your end where you do not want active heating, while still allowing the heat pack to fulfill its purpose on the receiving end.
● You can chill a Ph24 by popping it in the fridge (not the freezer) until it becomes solid and opaque.
Using a Phase 24 pack when shipping from cold to warm:
They can be used warm (clear and liquid) to act as a warming element for when you're shipping from cooler temps to hotter temps where the use of a heat pack on the receiving end would be too dangerous.
● To warm a Ph24, place it in a bowl of warm (not boiling) water until it becomes liquid and clear
Using a Phase 24 pack as a stabilizer:
When used at room temp (~72°F) and the Ph24 is in its slushy form, you can include it by itself in your shipment to generally help keep the temps in the box stable--since reptiles are cold blooded, they absorb any heat change in the box. The pack will then act as an extra thermal mass (basically an extra 'body') so that any heat change can be absorbed across multiple 'bodies' rather than just the reptile by itself.
Tips and Tricks:
● Once your Ph24 is solid or liquid, depending, that is enough - there is no benefit to making it “colder” or “hotter” and you risk damaging the pack with extreme temperatures.
● Ph24 packs are quite safe and can be placed anywhere in the box, but should be secured in place in the box wherever you put them - you can even put them below, on top of, or right next to the animal or its container.
● Multiple packs can be used in a single shipment, and they are generally more effective when used in multiples in larger boxes.
● Over time and as the Ph24 changes phases, small microtears can happen in the plastic as the solid state packs can have hard and sharp edges - seal your pack in a zip top baggie before putting them in your box to avoid any leaks in transit!
Pros and Cons of Phase 24 packs:
PROS:
● Safe for use with all shipments.
● Helps maintain steady, stable internal temperatures.
● No shelf-life or expiration date.
● They are reusable.
● They can make the difference between being able to ship or not when dealing with trickier temps. ● They are really hard to mess up.
CONS:
● They work best if more than one is used. The more used, the more stable the temps. If you only have a few on hand, using a smaller box will help keep the pack more effective.
● They are not a fix-all and can only help to a limit; more extreme temperatures may simply be too hard to mitigate.
● They are roughly the size and weight of a 72-hour heat pack and will add weight to your shipment.
Reach out with any questions or concerns!