Archive for the ‘Testing and Specifications’ Category

Can ECT board be used for UN tested cartons

October 28, 2019

Randy asks,

I asked this question a number of years ago but I was wondering if ECT Board can be used for UN Tested cartons or is Mullen tested board still the only thing that can be used?

That’s probably a yes and no answer. ECT is allowed as long as the packaging can pass an UL testing protocol and the liner weights do not vary by more than 5%. A wider 10% range has been approved and included in the most recent version of the 49CFR.

Don’t forget about the maximum Cobb test.

—Ralph

Is Burst and Puncture Testing Performed on Triplewall?

August 30, 2019

Bobs asks,

Is burst testing and puncture testing done on triple-wall boards? I’m having trouble interpreting the minimum fiberboard requirements issued by NMFC Item 22 and UFC Rule 41. Specifically 1100 triple-wall, does the 1100 represent minimum burst strength of 1100 lbs. per square inch? Or does 1100 represent a puncture test value?

That’s a really good question. It is Mullen burst and not a Beach puncture. It is really based on the additive Mullen values of the liners. So if you were experimenting with low Mullen yet high SCT liner and strong mediums, it would be better to go to an ECT standard.

— Ralph

UPDATE

Miranda comments,

TAPPI T810 Section 1.2 states mullen burst is not applicable to triplewall board. If the test is being performed on triplewall it would not be clear what the results would mean.

Pin Adhesion Test (PAT)

August 30, 2019

Sam asks,

Do you have any formal reference of what the ideal pin adhesion test result should be.   For agro boxes (vegetables) we currently use values of 55 to 60  (pound/inch) and in industrial 40 and higher.

We have a particular customer that has experienced some delamination failures. The PAT test value is 27 (pound/inch) which we believe to be too low. However, we are lacking established information to back up our opinion.

I could not agree with you more.  I prefer a minimum, not average, of 45 for industrial application.  My technical associates at TAPPI like this 45 value while I would rather have 55 on all corrugated bonds.  It is most important to know where the failure is occurring: linerboard, medium, or in the starch itself.  Under ideal conditions we want 100% liner failure. As you can see in these photos a very low PAT value can have disastrous results. There is very little liner pull and very little glue with a poor bond.

A good reference for the PAT is the most recent version of TAPPI document TM 821 (TM 821-0M 17 at this writing), Pin adhesion of corrugated board by selective separation.

— Ralph

Pin Adhesion Test sample Pin Adhesion Test sample Pin Adhesion Test sample

Insulating Properties of Corrugated

August 15, 2019

Rich asks,

I have a question about the insulating properties of corrugated and the impact of vent holes in dairy applications. I have a dairy customer who is looking to pack sour cream in cartons. It is filled at 100 degrees F and put into 35 degree refrigeration. What is the difference in how long it will take to get down to 40 degrees if there are no vent or hand holes in an RSC against if there are some? Is there a formula that exists for the cooling time? This would be an ECT48 DW RSC. Thank you as always for your guidance.

Here is a link to a research paper (Overall Effective Thermal Resistance of Corrugated Fiberboard Containers) complied by the US Dept. of Agriculture and the Forest Products Laboratory. Pages 4 – 6 of this report contain information regarding the affect of vent holes.

The location and area of the vent holes as well as the velocity of the circulating air will also have an affect on the thermal transition time.

Would it be possible to perform an experiment using a grill or meat type thermometer to determine when the core of a loaded box with vents and a loaded box without vents reached the desired 40 degrees F?

— Ralph