A 200# Mullen rating withstands 200 pounds per square inch applied directly to the carton face [S3][S1]. It does not establish the maximum suggested contents for a single-wall box.
Single-wall, double-wall, and triple-wall cartons use different Mullen-to-ECT equivalents, with recommended maximum loads ranging from 20 lb to 300 lb [S2].
What a 200# Mullen Rating Measures
The Mullen Burst Test applies increasing pressure to the face of corrugated board until the board ruptures, and the result is reported as pounds per square inch or the conventional # rating [S5]. A 200# result therefore identifies 200 psi of face-burst strength; it does not mean that the finished carton can carry 200 lb [S3][S4].
Mullen testing is relevant where rough handling, sharp products, uneven loads, collisions, or impacts can puncture a carton wall [S1][S5]. A higher rating generally provides greater resistance to rupture, but it must still be matched to board construction, box dimensions, and distribution conditions rather than treated as an allowable product weight [S1].
ECT Versus Mullen for Load Selection
Edge Crush Test compresses a board segment edgewise between rigid plates until a peak load is established, with the result expressed in pounds per lineal inch and commonly reported as a value such as 32 ECT [S2]. Unlike Mullen, ECT directly measures the edgewise property used to estimate compression and stacking performance [S2][S5].
ECT is generally the more suitable specification for palletized or stacked shipments, while Mullen provides the more relevant indicator for sharp, irregular or severely handled products [S1][S5]. For maximum protection, specifying both properties can be justified [S1].
Single-Wall Rating Equivalents
Single-wall corrugated boxes can be specified with separate Mullen and ECT ratings because the tests measure different material properties [S2]. The listed equivalents do not include a 200# Mullen-to-32 ECT pairing [S1][S2].
Maximum suggested contents and the load bands associated with a 200# Mullen specification should be confirmed for the selected single-wall construction [S1][S2].
The broader engineering comparison is documented in ECT vs BCT vs Mullen for Corrugated Carton Specification, which places the three carton-strength methods in one selection framework.
Double-Wall and Triple-Wall Options
A double-wall Mullen-to-ECT equivalence table and its corresponding suggested loads are not provided in the sources.
Triple-wall boxes likewise require separate Mullen, ECT and load requirements, with maximum suggested loads treated as guidance rather than certified container capacities, so box dimensions still require engineering review.
Common Mullen values include 200#, 275# and 350# [S7]. The choice between double-wall corrugated boxes and heavier triple-wall construction should follow load, puncture exposure and material cost rather than board style alone.
Where Mullen Ratings Fail
A Mullen rating does not measure the load that may be stacked on the carton, so it cannot substitute for ECT when a box will carry pallet or warehouse loads [S3][S4]. The test also does not reproduce the combined effects of box size, joint design, creases, moisture exposure, print coverage, pallet overhang, vibration or repeated handling [S1][S3].
ECT-rated boxes can use less board material than equivalent Mullen-rated boxes because the Mullen rating imposes a minimum base-paper weight, while ECT does not [S3]. Selecting by burst rating alone may therefore add material cost without improving edge compression performance [S3][S5].
Mullen ratings should not be treated as puncture resistance for every sharp object. Product geometry, sharp corners, retention restraint and internal padding can concentrate local loads that a uniform face-pressure test may not represent, so carton box design must be validated against the actual packing and distribution profile.
Procurement Specification and Verification
Specify the board construction, Mullen rating, ECT rating and maximum intended load as separate requirements, because one numeric rating cannot represent every handling risk [S1][S2]. Use the box maker's construction specifications to confirm the appropriate ratings and suggested-load limits for the intended application.
A burst rating cannot be treated as a free-form strength estimate independent of board construction, because paper content and board construction affect the relationship between a stated Mullen rating and the finished material.
For final acceptance, request the box maker's board specification, confirm the grade against the intended packing and distribution environment, and verify that the selected Mullen and ECT values address separate failure modes. The edge crush test should govern compression design, while the Mullen rating governs face-burst and puncture exposure [S2][S3].
The sources explain that ECT is important for stacking boxes and that 32 ECT is the most commonly used corrugated material, but they do not establish a specific 200# Mullen–32 ECT pairing for a 65 lb load band.