Tolerances - Down Content Analysis
Multiple tests from a single down and feather product often give very different results.
How can test results be so different?
- Down and feather material is not homogenous.
- Testing down and feather is very tedious and difficult. The composition test requires decisions on
thousands of small fibers, down clusters and feathers.
If test results are different – which test report is correct?
- Test reports from the most experienced analyst or laboratory are usually more correct.
- The most accurate result is the AVERAGE of ALL test results.
What is a normal testing variance for tests of the same material?
The International Down & Feather Bureau (IDFB) allows a ± 2-3% testing tolerance when certifying laboratories around the world. This means that if a sample has 80% down, a laboratory test of 77% down or 83% down would be in the acceptable testing range.
High fiber samples are very time-consuming and difficult to test. Therefore, high fiber samples may have a testing tolerance of up to ±5%. Extremely high fiber or couché samples may require an even higher testing tolerance of up to ±5-10%.
More reasons for differences in Test Results
- Down & Feather testing is very labor intensive. A single test can take 3-6 man-hours.
- The testing requires very experienced staff. Results can vary from person to person. Even the
same person testing the same sample twice will get slightly different results.
- Test results can be strongly influenced very subtly and indirectly by pressure from other testing
staff, laboratory managers, sales staff and outside clients. IDFL will NOT be influenced by outside
sources to change test results.
- After bulk or raw down is tested, it can be re-mixed and resorted to provide a completely different
How can accuracy of Content Testing be improved?
- The single best way of improving test accuracy is double testing by different analysts.
- Sending samples to an experienced laboratory that does large volume of testing is important. IDFL
has 30 years of experiences and tests 10,000 samples per year.
- Participation in external multi-lab round robin such as IDFB is important.
- An organized, well-thought out training program for new staff should be developed
- Careful record keeping and statistical analysis of each person must be maintained.
- Adherence to the exact testing method is critical. IDFL has discovered that many labs around the world do NOT follow the official IDFB or EN test methods to save money by testing less than required or by not completing a double test.
IDFL feels confident that IDFL Test Results are the most accurate in the world.