Heat Pack Study

[BeanAnimal]

BeakerBob,

Can you work out the average caloric content of the typical sized heat packs? If we knew that we could possibly come up woth a cheap and reliable system, similar to what hahn mentioned. Though I am not sure how shippers would feel about having heaters in sealed boxes. Actually I would imagine they don't like the heat packs anyway... The ValueJet crash was blamed on a similar reaction (though it was cardox or a similar substance that superheated due to pure oxygen being present). Not that a heat pack has enough reactant to generate that kind of heat... but anyway.

 

[flyyyguy]

Good info.

here is soemthing I do that you may or may not even want to throw into the equation, but I can confidently ship in weather that is 10-20 degrees. as mos tknow it s fine line sometimes in getting things too hot and too hot is worse than too cold, so what i do (in thick walled nice coolers of course) is the usual pack inside taped to the lid at least a copuple inches from any bags, and then I throw two more packs OUTSIDE the cooler and underneath with 5-10 layers of newspaper in between ad I dotn want to cook those bags on the bottom

I can get the water in the bags there in this 10-20 degrtee weather holding steady 74-78 degrees.

just a point to ponder and it works for me

 

[johnlewis]

Great data Bob. I will let you know what I find on my next shipment. It sounds like a larger box and more O2 is the way to go. If you have to much o2 exchange from outside of the box you will be letting more cold thatn the heat pack can warm I imagine.

 

[johnlewis]

I received a shipment this morning. I did a check of 2 bags as soon as I opened the box. I picked random bags
one was 63.3 F and the other was 63.6 F as measure from my AC3. The outside was approximately 32.

 

[BeakerBob]

How many hours were the packages in transit?

This temperature matches my findings at 18 hours of time.

 

[johnlewis]

Bob,

You are right on 17hrs 40m. That is very accurate. This was a large box also 24" x 18" x 14". 15 bags

 

[BeakerBob]

Johnlewis,
Isn't it amazing that the corals stay alive at 60 degree temps? It seems that they don't tolerate high temps (>90F), but can tolerate low temps (<60F).

 

[NanoCube-boy]

good info.

 

[wld1783]

Great thread thanks for the info.

Bill

 

[wld1783]

<a href=showthread.php?s=&postid=11942010#post11942010 target=_blank>Originally posted</a> by billsreef
That's because dry ice is hazardous to handle if not done right. They want to know so that the people handling the package are aware should something happen to the package causing the dry ice to be exposed

BTW, beware of putting too many heat packs in a container. To many will use up the O2 and cause them to cool down early. In a small box you are better off with one heat pack, not two.

As an airline pilot we are given the exact amount of dry ice in our Acft. Its not hazardous unless you believe Al Gore. But too much melting in a closed vessel may become a problem so the FAA has guidelines on how much can be carried at any given time. This also accounts for the puppies in cages in our cargo hold. Even so I worry more about Geese than frozen CO2.

As far as ventilation most aircraft have more fresh air than office buildings. Our outflow valves are the size of grape fruits and this is at 8 PSI.

Bill