01 BARRIER-DATA GUIDE
OTR and WVTR: make barrier test results comparable
OTR describes oxygen transmission rate; WVTR describes water-vapour transmission rate. A value without its specimen identity, unit, method and test environment is an incomplete buying input—not a safe basis for saying two films are equivalent.
02 DECISION FRAME
Transmission-rate results belong to a defined test system
ASTM and ISO publish more than one method for permeation testing. Official method pages and instrument guidance show that the metric, detector or measurement approach, temperature, relative humidity and agreed test conditions matter. The enquiry should capture those details and leave the laboratory procedure to the current licensed standard.
- A barrier-film comparison using supplier data sheets or laboratory reports
- An RFQ that includes an oxygen or water-vapour target
- A trial where base-web, laminate and finished-package results must stay distinct
- That the same number means the same result when units or conditions differ
- That a base-film result predicts seals, seams, flexing or the finished package
- That OTR or WVTR alone proves shelf life or total package performance
03 COMPARISON MAP
Fields that make a barrier result usable
Ask for the laboratory report or data-sheet context behind every value. Keep requested conditions and actual tested conditions separate.
Swipe or scroll horizontally to review every evidence column.
| Report field | Why it matters | RFQ wording | Do not accept |
|---|---|---|---|
| Specimen identity | Base film, laminate and finished package answer different questions | Name the structure, thickness, grade, side and conversion stage | “Barrier film” without a traceable specimen |
| Metric and unit | OTR and WVTR measure different permeants and use different reporting units | State the requested metric and unit exactly | A number with no unit |
| Test method | Different standards and sensor approaches are not automatically interchangeable | Request the method designation and revision used by the reporting laboratory | “Standard method” with no identifier |
| Temperature | Permeation results change with the test environment | State requested and actual test temperature | A value reported without temperature |
| Relative humidity / gradient | Humidity can affect the material and defines the water-vapour driving condition | State humidity on the relevant sides or the laboratory’s reported gradient | “Ambient” without a controlled or recorded basis |
| Orientation | Multilayer and coated specimens may behave differently by exposed side | Identify which side faces the test gas or humidity source | A report that cannot identify specimen direction |
| Conditioning and sample history | Storage, flexing, conversion and preconditioning can alter the represented state | Record conditioning, conversion stage and relevant sample handling | A result detached from sample history |
| Reporting basis | Replicates, steady-state criteria and laboratory reporting rules affect interpretation | Request the report, individual or summary basis and any stated uncertainty | A rounded marketing value with no report context |
| Acceptance link | A laboratory result is useful only when tied to the pack decision | Name the target, tolerance, responsible approver and finished-pack validation | A barrier value treated as the sole shelf-life proof |
04 SELECTION SEQUENCE
Move from a broad comparison to an approvable decision.
Write the intended test basis
Specify the metric, specimen, unit, method and environment required for the sourcing decision. If conditions are open, say so explicitly.
Record what was actually tested
Do not silently relabel a supplier’s result. Capture the laboratory, method, specimen, conditions, date and report reference as supplied.
Reconnect the value to the pack
Use conversion and finished-package checks to address seals, seams, flexing and other factors that a flat-film result does not represent.
05 RFQ INPUTS
OTR / WVTR enquiry checklist
Use the checklist to request comparable data without reproducing a laboratory procedure.
Open the RFQ brief builder ↗- 01
Metric requested: OTR, WVTR or both, plus the exact reporting unit
- 02
Specimen identity: grade, full structure, thickness and base-web or converted stage
- 03
Test-method designation and the revision used by the laboratory
- 04
Requested temperature and the temperature actually reported
- 05
Requested relative humidity or gradient and the conditions actually reported
- 06
Specimen orientation, including the side facing the test gas or humidity source
- 07
Conditioning, storage, flexing, conversion and other relevant sample history
- 08
Laboratory report reference, test date and reporting or replicate basis
- 09
Target, tolerance, comparison control and person responsible for acceptance
- 10
Separate finished-package validation for seals, seams, closures and distribution damage
06 EVIDENCE BOUNDARY
Method summary only—use the licensed standard in the laboratory
This guide does not reproduce the procedural steps of ASTM D3985, ASTM F1249, ISO 15105-2 or ISO 2528. It explains which reporting fields a buyer should preserve. The testing laboratory must use the applicable current standard, calibrated equipment and its controlled procedure.
07 BUYER QUESTIONS
Resolve the assumptions that make quotes diverge.
01What is the difference between OTR and WVTR?+
OTR reports oxygen transmission rate, while WVTR reports water-vapour transmission rate. They address different permeants and must be stated with the applicable unit, method, specimen and test conditions.
02Why are temperature and relative humidity required?+
Permeation results are affected by the test environment, and humidity may also change material response. Values should be compared only after the requested and actual conditions are clear.
03Can a flat-film result predict the finished package?+
Not by itself. Seals, seams, closures, flex damage, conversion and package geometry can change finished-pack performance. Keep film data and whole-package validation as separate evidence.
04Which OTR or WVTR standard should an RFQ specify?+
Choose the method with the responsible laboratory or technical owner based on the specimen and decision. Record the exact current method designation rather than treating all OTR or WVTR methods as interchangeable.