What does the AICC hazmat guide say about tolerances on basis weight? Customer says they must run: “We must run the 31-31-35 hazmat board combo” but the corrugator no longer runs that combo.
The DOT has relaxed the “49 CFR 178.516 – Standards for fiberboard boxes” from +/- 5% to now allow +/- 10 percent basis weight tolerance in the linerboards.
Per the Legal Information Institute “UN4G combination packaging with outer fiberboard boxes and with inner fiberboard components that have individual containerboard or paper wall basis weights that vary by not more than plus or minus 10% from the nominal basis weight reported in the initial design qualification test report.” Click on this link to learn more at the Legal Information Institute.
How did your customer arrive at the 31-31-35 combination? Is it from a previous requirement? As long as they the meet the strength requirements for the content it should be acceptable to use another combination. The +/-10% relates to the base weight of the liner used and may not mean that you could directly substitute a 28lb for a 31lb. If a 28lb liner is used then the tolerance would be +/-10% of the 28.
So I think it would be important to first see if you can provide a combination that meets their strength requirements WHILE remaining while remaining within the +/-10% tolerance.