Mid-2026 Corrugated Buyers Push Written Flute and ECT Holds

Mid-2026 export RFQs for corrugated packaging are arriving with a clearer instruction: state the flute letter and the ECT method in writing, rather than leaving either item to a sample or a supplier’s standard construction.

Buyers say the change follows repeat claims where a quoted ECT figure was technically valid but measured under a different conditioning or test method than the destination pack-out team expected.

Anhui Zhandelao Packaging–class sheet suppliers and peers report that early method locks make it easier to reserve the right medium, liner combination, and corrugator slot for export programs.

The requirement is spreading from PackTrades Corrugated Board & Sheets sourcing into Cartons RFQs, where converters need the board construction fixed before they can confirm die-cut, print, and stacking performance.

A flute letter alone is no longer enough for many buyers. They are asking whether ECT is stated as a minimum, which standard or internal method applies, and whether the value is tested on finished board after conditioning.

Suppliers say written holds also reduce late requests to substitute B for C flute, or to move to a lower board grade after artwork and freight dates have already been approved.

Why buyers care: a carton can match its print proof and dimensions yet still fail pallet compression or transit protection when the flute and ECT basis were never aligned.

Buyer takeaways

Put flute letter, minimum ECT, conditioning basis, and test method directly on every RFQ and PO.

Ask Corrugated Board & Sheets suppliers on PackTrades to confirm the construction before releasing carton artwork.

Keep any approved board or flute substitution subject to written buyer sign-off and a refreshed performance check.