Quality Control in Box Manufacturing: ECT vs Bursting Strength Explained

A technical comparison of Edge Crush Test (ECT) and Mullen Burst Test methods for corrugated board quality, including rating tables, test standards, and guidance on when to specify each test.

In This Article

• What Is the Edge Crush Test (ECT)?
• The Technical Standard
• ECT Rating Scale: Single-Wall Board
• ECT Rating Scale: Double-Wall Board
• What Is Bursting Strength (Mullen Test)?
• The Technical Standard
• Historical Context
• ECT vs. Mullen: Why There Is No Direct Conversion
• When to Specify ECT
• When to Specify Mullen (Bursting Strength)

Key Highlights

Two numbers dominate the specification sheet of every corrugated box: the Edge Crush Test (ECT) rating and the Bursting Strength (Mullen) rating. Both measure the strength of corrugated board, but they measure fundamentally different properties, predict different failure modes, and are appropriate for different shipping environments. Specifying the wrong test—or worse, assuming one number can substitute for the other—is one of the most common and costly errors in packaging procurement.This guide explains the technical basis, test methodology, rating scales, and practical application of both ECT and Bursting Strength, with the data tables and decision guidance that packaging professionals need to specify the right quality standard for their products.What Is the Edge Crush Test (ECT)?The Edge Crush Test measures the compressive strength of corrugated board when force is applied perpendicular to the flute tips—that is, in the same direction that a stacked box experiences load in a warehouse or transport vehicle. A small specimen of board (typically 2 inches wide by 2 inches tall, with flutes oriented vertically) is placed between two platens and compressed until the flutes collapse. The maximum force sustained before failure is reported in pounds per linear inch (lb/in) of specimen width.The Technical StandardECT is governed by TAPPI T 811 ("Edge Crush Test of Corrugated Board") and the equivalent ISO standard ISO 3037.

Topics Covered

This article covers: ECT vs burst test, box quality control, edge crush test, mullen burst test, packaging standards.

About This Article

Published on June 12, 2026 by JobaidaPack Team. Filed under Production. Estimated reading time: 10 min read minutes.