SAMPLES NEEDED
1 or more, depending on your needs
TYPICAL TURNAROUND
1-2 days
You probably need this if
You make or buy fiberboard boxes for UN certification and need Cobb results
Your packaging is exposed to humidity, condensation or wet handling
You’re evaluating a coating, sizing or water-resistant board
A specification sets a maximum Cobb value for your board
What the test involves
01
Conditioning
Specimens are conditioned in the standard atmosphere for paper and board testing (TAPPI T402) before testing.
02
Water exposure
A measured area of the specimen is exposed to water for a set time, such as 2 minutes, or 30 minutes for UN fiberboard.
03
Weighing
The specimen is blotted and weighed. The gain in mass is the water absorbed.
04
Reporting
Results are reported in grams of water absorbed per square meter (g/m²).
What to send us
Flat sheets of the board or finished boxes. We’ll confirm how many.
Design drawings or a packaging specification, if you have them.
Ship to 9708 Industrial Drive, Bridgeview, Illinois 60455.
Not sure the count is right for your configuration? We confirm it with you before you ship anything.
Related standards
Common questions
What is a Cobb test?
It measures water absorptiveness: the weight of water a board takes up per square meter over a fixed time. Lower values mean better water resistance.
Why does UN certification need a Cobb test?
Federal rules for UN fiberboard boxes (49 CFR 178.516) require the outer surface to absorb no more than 155 grams of water per square meter in a 30-minute Cobb test.
Can you run Cobb testing with my UN certification?
Yes. Gaynes runs Cobb testing as part of UN fiberboard box certification or as a standalone test.
Not certain Cobb testing is the right test?
Send us an email, give us a call, or schedule time to chat. We can answer your questions and let you know which standard applies for your situation.
