Do chips in packaging affect pressure differential in a sealed bag test?

[Danfishman]

Hello,

I hope this is the right area to post this question. We are having a debate at my workplace and was hoping there was someone more qualified to settle the debate.

We are a packaging company and have setup an experiment to test the pressure differnential from sealiong at 1800m vs. Sea Level. We would like to see if the packaging can with stand the external pressure at sea level. We have calculated this diffence to roughly .2 bar (~3PSI), set up an experiment by placing the sealed packs in pressure chamber, and add the 3psi of air to the tank.

The debate came about as to wether adding chips (the product) would effect the result. Ie decreasing the amount of air (chips are displacing the air) would help offset the external air pressure being applied.

One side is saying that the smaller volume of air will result in less external pressure as there is less air trying to equalise. The otherside believes it makes no difference, as the pressure is being applied externally and the amount of air is inside makes no difference, as long it is at the same pressure in both instances.

Would having chips in the packaging affect the result?

Cheers!

 

[Lnewqban]

Welcome, @Danfishman !

Could you describe the package?

 

[Danfishman]

Sure,

It is a cardboard/ paperboard can, like a pringles can.

 

[256bits]

One side is saying that the smaller volume of air will result in less external pressure as there is less air trying to equalise

That argument doesn't make sense.
The external pressure is established by the elevation.

 

[Baluncore]

It is a cardboard/ paperboard can, like a pringles can.

If the lid is clipped on, the can will probably breathe out when taken to a higher altitude, where the external air pressure will be less. If taken to a lower altitude, the increased pressure may seal the lid and so provide a positive external pressure.

I expect the aim should be to avoid the inward flow of air that could introduce spores or contaminants to the product.

The details of the lid seal will be critical to determining the pressure differential during transport.

 

[sophiecentaur]

A breather, coupled to an internal balloon with a volume big enough to absorb the pressure differential will avoid stressing the package (that's one extreme). A rigid (like a submarine) package will maintain the internal pressure whatever your altitude. Which do you actually need?
My coffee packs have a breather valve which works one way, to let air out at altitude and the pack is always a bit wrinkled when the aircraft lands. This pack gives no physical protection to excess pressure (the coffee beans don't care) but avoids contaminated air entry.