📌 Key Takeaways

Pilots fail when acceptance criteria are vague, turning validation into negotiation rather than verification.

• Three Gates Lock In Confidence: Evidence documentation, runnability at target speed, and performance metrics must all pass before scale-up—skipping any gate creates downstream risk.
  
• Method Names Prevent Disputes: Certificates of analysis must specify ISO, TAPPI, or ASTM test methods by number, not just list values, because different procedures yield different results for the same board.
  
• Moisture Windows Trump Absolutes: Defining and enforcing a target moisture range with documented conditioning methods prevents the warping and curl issues that sink most pilots after threading.
  
• ECT Doesn’t Equal BCT: Edge crush test results correlate with stacking strength but cannot predict box compression performance without accounting for box design, dimensions, and environmental factors.
  
• Output Beats Clock Time: Measuring pilot success by production volume—rolls completed or shift output—reveals stability better than arbitrary time durations that may not capture real operating conditions.

Clear gates eliminate guesswork. Approved criteria = confident decisions.

QA managers, production leaders, and procurement teams evaluating containerboard suppliers will find this framework essential, preparing them for the detailed three-gate system and documentation requirements that follow.

The corrugator is threaded. Your team watches the first boxes come off the line. Everything looks acceptable until the second shift reports chronic warping. By day three, the supplier insists their board “meets spec,” but your production manager refuses to scale. Without clear acceptance criteria, pilots become expensive debates rather than confident decisions.

For QA and operations leaders evaluating containerboard suppliers, the challenge isn’t running a pilot—it’s knowing what evidence to demand before approving scale-up. You need measurable gates that separate a genuine pass from a marginal result that will create problems at volume. This article provides a three-gate framework (Evidence, Runnability, Metrics) with explicit pass/fail thresholds and documentation requirements, so you can approve pilots with confidence or reject them with justification.

Why Pilots Fail Without Clear Criteria

A pilot run reveals whether a supplier’s containerboard will perform in your specific converting environment. The problem is that “performance” means different things to different stakeholders. Production cares about runnability at target speed. QA focuses on whether the board’s properties match the certificate of analysis. Sales worries about box integrity in the field.

Without explicit acceptance criteria, these concerns create friction. The supplier points to their COA (Certificate of Analysis)  showing the board is within spec. Your corrugator operator counters that the moisture profile causes edge-curl no matter how carefully they adjust tension. Both parties are correct within their frame of reference, but neither has the evidence needed to resolve the dispute.

Typical failure modes include evidence gaps where COAs lack method names or recent dates, uncontrolled material inputs without defined moisture windows, and metric mismatches where teams equate Edge Crush Test (ECT) results directly to Box Compression Test (BCT) without factoring in box design and environmental conditions. Clear acceptance criteria prevent this stalemate by defining what “pass” means before the pilot begins. You establish measurable thresholds for material evidence, converting stability, and performance metrics. When everyone agrees on the gates upfront, the pilot becomes a verification exercise rather than a negotiation.

The Pilot “PASS” Framework: Three Non-Negotiable Gates

A successful pilot must clear three sequential gates. Each gate serves a specific purpose, and skipping any of them creates risk during scale-up.

Gate 1: Evidence & Setup

Before threading the first roll, verify that the supplier has provided complete documentation. This gate ensures you’re piloting material that matches what you’ll receive at volume.

Required evidence:

• Method-named certificates of analysis (COAs). The COA must specify which test method was used for each property—not just list numbers. For containerboard pilots, relevant methods include ECT measured per ISO 13821 (which replaces the older ISO 3037) or TAPPI T 811 for corrugated board, Short-span Compression Test (SCT) per ISO 9895 or TAPPI T 826, Ring Crush Test (RCT) per TAPPI T 822, and moisture content per ISO 287 or TAPPI T 412. A COA stating “ECT: 44 lb/in” without the method is insufficient because different methods can yield different results for the same board. Set method-named tolerances and attach results at the quote stage to avoid ambiguity.
  
• Recent laboratory certificates. The COA should reflect recent production, ideally from the same mill and machine that will supply your volume orders. A certificate from six months ago or from a different facility doesn’t verify current capability.
  
• Sealed sample retention with chain-of-custody. The supplier must retain sealed samples from the pilot lot under a defined chain-of-custody protocol. If a dispute arises during scale-up, these samples allow independent testing to confirm whether the material changed.
  
• Moisture window and conditioning parameters. Define your acceptable moisture range (measured per ISO 287 or TAPPI T 412) and the standard atmosphere for conditioning (typically ISO 187 or TAPPI T 402). Agreement on these parameters before the pilot prevents disputes about whether moisture was “in spec.”

This evidence forms a “passport” for the material. Build a comprehensive RFQ evidence pack that travels with the pilot shipment, so your QA team can verify documentation before production time is committed. Additionally, establish sampling plans with appropriate AQL levels so both parties understand which defect categories trigger retest or rejection decisions.

Gate 1 pass condition: Complete, method-named COAs; documented sampling plan; defined moisture window with conditioning method specified; sealed samples under chain-of-custody; line plan approved by both parties.

Gate 2: Runnability & Stability at Target Speed

Material properties on paper don’t guarantee converting success. The second gate verifies that the board runs cleanly through your corrugator at your target line speed with acceptable waste levels.

Stability criteria:

The pilot must demonstrate a stable run for a duration that represents real production conditions. Rather than focusing solely on time, many operations use output-based criteria—such as a defined number of rolls or a full shift’s production volume—that better capture stability for their specific corrugator and grade. Choose metrics that reveal whether the board can sustain performance beyond initial setup adjustments.

Target speed achievement: The board must run at your standard production speed, not a reduced “safe” speed. If your line normally runs at 500 feet per minute, the pilot needs to demonstrate stability at that speed. Running slower might mask tension-control issues or moisture-related defects that will surface at volume.

Waste band compliance: Establish an acceptable waste percentage before the pilot. If your typical linerboard waste is 4%, a pilot generating 7% waste signals a problem even if the board “runs.” The specific threshold is plant- and grade-dependent; the critical element is agreement and measurement before threading.

Moisture and profile control: Before threading, verify that incoming board falls within your plant’s acceptable moisture range. Understanding why moisture windows matter more than absolute values prevents many pilot failures. During the run, monitor that on-machine moisture remains stable and that cross-direction profile doesn’t trigger chronic warping, curling, or edge defects.

Defect assessment: Document any chronic defects during the run. Occasional edge imperfections might be acceptable, but persistent warping, curling, or delamination indicates the board won’t scale successfully. The key distinction is between random defects (which occur even with proven suppliers) and systematic problems that appear consistently.

Gate 2 pass condition: Target speed achieved and sustained; waste within agreed band; no chronic paper-driven defects; pilot log documenting speed, waste, downtime, and adjustments completed.

Gate 3: Performance Metrics & Integrity

The final gate confirms that the board delivers the structural performance your boxes require. This is where many pilots fail due to misunderstanding the relationship between material tests and box performance.

Appropriate metric selection and interpretation:

Edge Crush Test (ECT), Ring Crush Test (RCT), and Short-span Compression Test (SCT) each measure different aspects of board strength. ECT, measured per ISO 13821 or TAPPI T 811, assesses the edgewise crush resistance of corrugated board and correlates reasonably well with stacking strength. However, it’s not a direct predictor of Box Compression Test (BCT) results—which are measured per ASTM D642—without accounting for box design, dimensions, perimeter, flute type, and environmental conditions during storage or shipping.

If your application requires specific BCT values, don’t assume that meeting an ECT threshold automatically guarantees box performance. Containerboard strength indicators like SCT (ISO 9895 or TAPPI T 826) and RCT (TAPPI T 822) inform expected board behavior, but results must be combined with corrugator conditions and design context. For guidance on translating material properties into box-level performance, consult resources like the Fibre Box Association’s Fibre Box Handbook, which provides engineering context for packaging design.

Conditioning consistency: Ensure all comparative tests use the same standard atmosphere—typically ISO 187—and the same moisture measurement method to avoid inconsistent results. Testing one sample at 50% relative humidity and another at 65% RH produces incomparable data.

Integrity verification: Beyond compression values, verify that the board maintains integrity during typical converting operations. Scoring should produce clean creases without cracking. Adhesive should bond properly to the liner surface. Any requirement for special handling or process adjustments during the pilot suggests the board may not be a good fit for volume production.

Gate 3 pass condition: All quoted metrics meet or exceed COA targets by the named methods under the agreed conditioning; no integrity issues during converting operations.

The PASS/RETEST/FAIL Rubric

With three gates established, you need a decision framework that translates pilot results into action.

PASS: All three gates met without qualification. Material evidence is complete and matches pilot performance. The board ran stably at target speed with waste within your acceptable band. Performance metrics meet or exceed requirements by the specified test methods. Documentary trail complete. Proceed to scale-up.

RETEST: One or two gates showed limited misses that can be corrected with specific actions. Perhaps moisture was slightly outside the agreed window, requiring acclimatization under ISO 187 conditioning before a second pilot. Or waste exceeded your band by a small margin due to a correctable tension-control issue that can be documented and addressed. Chronic warping observed despite meeting target ECT might warrant reconditioning and a focused re-run at the agreed moisture setpoint.

The key to effective retests is specificity. Don’t accept a vague promise to “improve moisture control.” Require a defined corrective action: “We will recondition the next pilot lot per ISO 187 to achieve moisture between 7-8% as measured by ISO 287, and will provide timestamped documentation from our in-line moisture scanner.”

FAIL: Critical misses that indicate fundamental incompatibility. Auto-fail conditions typically include method-mismatched COAs (such as ECT claimed but measured by a non-equivalent procedure), chronic out-of-window moisture or profile causing persistent defects, runaway moisture variability during the pilot, systematic structural defects, or performance shortfalls below the quoted target when measured by the named method. A fail means this supplier or this specific board grade isn’t suitable for your operation. Document the specific failure mode so you can communicate the decision clearly and avoid repeating the pilot with material that won’t improve.

Documentation & Traceability

Pilot results are only valuable if they’re properly documented. Without clear records, you can’t verify that scaled-up material matches the pilot batch or defend your acceptance decision if problems arise later.

Essential documentation:

• COAs with method identifiers. File the complete certificate showing exactly which test methods—such as ISO 13821 or TAPPI T 811 for ECT, ISO 9895 or TAPPI T 826 for SCT, TAPPI T 822 for RCT—were used for each property, along with tolerances, units, dates, and lot identification.
  
• Conditioning and moisture records. Document the conditioning atmosphere used (such as ISO 187) and the moisture measurement method (ISO 287 or TAPPI T 412) for all tests to ensure comparability.
  
• Timestamped moisture and profile logs. Record moisture readings at multiple points during the run, not just at start-up. If your plant has in-line sensors, capture the data stream. If not, take manual readings every 30 minutes and log them.
  
• Sealed sample retention with chain-of-custody. Keep sealed samples from at least three points in the pilot run: beginning, middle, and end, maintained under a defined chain-of-custody protocol. This documents whether the board was consistent throughout the roll.
  
• Pilot run log. Maintain a timestamped record of line speed, waste percentage, downtime causes, and any adjustments made during the run. Note when the corrugator ran at stable target speed versus when operators reduced speed to address issues.

This documentation serves two purposes. First, it creates an objective record for scale-up decisions. Second, it establishes a baseline for verifying that volume shipments match the pilot material. When the first full production order arrives, you can compare its COA and performance against the pilot baseline to confirm consistency.

From Pilot to Scale-Up: Volume Ramp with Checkpoints

Approving a pilot doesn’t mean immediately jumping to full volume. A structured ramp protects against the risk that pilot-scale consistency doesn’t translate to production-scale reliability.

Initial volume checkpoint: After the pilot passes, start with a modest production order—perhaps one week’s worth of consumption rather than a full month’s inventory. Run this material through your normal production schedule and verify that it performs consistently with the pilot.

Document the baseline: Lock in the exact settings that produced the pass—line speed, temperatures, wrap angles, adhesives, moisture windows—so you have a reference point for troubleshooting if issues emerge.

Structured volume ramp: Increase volume in deliberate steps—for example, 20% of full volume, then 50%, then 100%—re-checking the same metrics at each step under the same conditioning protocols. This staged approach allows you to catch problems before committing to full-scale inventory.

Re-verification cadence: Even after successful scale-up, periodic re-verification prevents supplier drift. The supplier’s process can change over time due to equipment maintenance, raw material sourcing shifts, or operational adjustments. Agree when COAs will refresh (such as per production lot or monthly) and which tests continue in routine QA—for instance, periodic ECT by ISO 13821 or TAPPI T 811, periodic BCT by ASTM D642. Quarterly or semi-annual spot-checks where you pull random samples and compare their properties against the pilot baseline catch these changes before they become problems.

If you’re sourcing from multiple mills or the supplier is running your material on different machines, treat each new mill or machine as a distinct pilot scenario requiring its own verification. A pilot from Mill A doesn’t validate material from Mill B, even if both are owned by the same supplier.

Quick-Reference Checklist

Use this operational checklist during pilot evaluation. Adapt thresholds to your plant’s specific requirements.

Gate 1 — Evidence & Setup

• ☐ COAs with method IDs attached (ISO/TAPPI/ASTM standards specified)
• ☐ Moisture window agreed; measurement method and conditioning standard named (e.g., ISO 287, ISO 187)
• ☐ Sampling plan and AQL levels documented
• ☐ Sealed samples labeled and stored under chain-of-custody
• ☐ RFQ “passport” complete and verified

Gate 2 — Runnability at Target Speed

• ☐ Target line speed achieved and sustained
• ☐ Waste percentage within agreed band
• ☐ No chronic paper-driven defects (warp, curl, edge issues)
• ☐ Pilot log completed (documenting speed, waste, downtime, adjustments)

Gate 3 — Performance & Integrity

• ☐ Board ECT meets target by named method (ISO 13821 or TAPPI T 811)
• ☐ BCT verified where required (ASTM D642)
• ☐ Containerboard strength properties confirmed as applicable (SCT, RCT)
• ☐ Same conditioning atmosphere used across all comparative tests (ISO 187)

Decision:

• ☐ PASS (approve scale-up)
• ☐ RETEST (with documented corrective actions)
• ☐ FAIL (document failure mode)

Finding Qualified Suppliers

When you’re ready to evaluate new containerboard sources, PaperIndex provides access to suppliers across categories. Find containerboard suppliers including kraft linerboard producers and fluting/corrugating medium manufacturers.

For suppliers, joining PaperIndex provides visibility to converters and box plants evaluating new sources. For buyers, submitting an RFQ connects you with potential suppliers who can meet your specifications.

Frequently Asked Questions

How long should a pilot run last?

Duration should be long enough to demonstrate stable running at target speed and to collect a representative picture of waste and defect patterns. Rather than focusing solely on time, many plants use output-based criteria—such as a defined number of rolls or a full shift’s production volume—that better capture stability for their specific corrugator and board grade. Choose metrics that reveal whether the board can sustain performance beyond initial setup and threading adjustments. If your typical production runs last a full shift, consider extending the pilot to match that duration to ensure the data represents real operating conditions.

How should ECT be used alongside BCT?

Use ECT (measured per ISO 13821 or TAPPI T 811) to validate board edgewise crush strength and BCT (ASTM D642) to validate box-level compression performance. These are distinct measurements serving different purposes. ECT does not automatically translate to BCT without accounting for box dimensions, style, perimeter-to-depth ratios, flute type, and environmental factors like humidity during storage and shipping. If you use predictive equations to estimate BCT from ECT, treat them as engineering estimates and verify the predictions with actual BCT testing on finished boxes representative of your application.

What moisture window should we demand before threading the corrugator?

Agree on a target moisture content with an acceptable tolerance range, measured using a specified method such as ISO 287 or TAPPI T 412 and stabilized under a standard conditioning atmosphere like ISO 187. While technical guides often cite common moisture ranges (such as 6-9%), these are not universal; the optimal target window is highly dependent on your specific corrugator design, local environment, and board grade. The precise numbers are plant- and grade-specific; what matters most is explicit agreement on the measurement method, the target range, and enforcement of that range before threading. Review historical data from your most successful suppliers to identify the moisture range where you experienced the fewest runnability issues, then specify that range as your requirement for new pilots.

Which defects force an automatic FAIL versus a RETEST?

Auto-fail conditions typically include method-mismatched COAs where claimed test results don’t align with the stated procedure, chronic out-of-window moisture or profile causing persistent defects that couldn’t be corrected during the pilot, or performance measurements below the quoted target when tested by the agreed method. Retest is appropriate for limited, correctable misses with defined actions—such as moisture slightly outside the window requiring reconditioning per ISO 187, waste marginally above the band due to an identifiable setup factor that can be corrected, or a single non-systematic defect that can be addressed through a specific corrective action. The distinction is whether the issue stems from a controllable variable with a documented fix versus a defect that appears intrinsic to the material itself.

What must be in the supplier’s COA packet to approve scale-up?

The COA packet must include method-named test results for all critical properties—such as ECT per ISO 13821 or TAPPI T 811, SCT per ISO 9895 or TAPPI T 826, RCT per TAPPI T 822—along with specified tolerances, units, measurement dates, and lot identification numbers. Include documentation of the moisture measurement method (ISO 287 or TAPPI T 412), the conditioning standard used (typically ISO 187), and identification of which mill and production machine supplied the material. The packet should also reference retained samples with chain-of-custody documentation and provide contact information for the supplier’s technical team if verification questions arise. The goal is completeness: your QA team should be able to verify full compliance without additional requests, and incomplete documentation often signals potential problems with the supplier’s quality systems.

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Disclaimer: This article provides general information about containerboard pilot acceptance criteria for educational purposes. Individual circumstances vary significantly based on factors like corrugator configuration and target line speed, board grade/flute and box design, moisture window and acclimatization, and plant environment. For personalized guidance tailored to your pilot approval process, consult a qualified professional.

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