Compression Set and Sofa Recovery Measure Different Things
Distinguish a laboratory foam compression-set report from the shape and height recovery of a packed sofa after an actual storage trial.
Compression set measures residual deformation of a foam specimen after a specified compression and recovery procedure. The assembled sofa introduces seams, layers, folds and cover tension. Qualify the material and the packed furniture separately before promising a recovery time. ISO 1856
Read the report as a test condition
Check the foam identifier, test edition, specimen dimensions, degree of compression, temperature, dwell time and the interval before measurement. A supplier may quote a percentage from an old report while delivering a new grade. Link the report to the purchasing code and lot reference. Use the standard’s stated calculation for that test. A simple percentage of original height is a different shop-floor indicator.
Run a finished-product check
Measure the relaxed seat centre and both front corners, then pack the item with the production bag and carton. Reopen after your planned storage exposure. In an illustrative inspection, a corner originally 300 mm high measures 288 mm after the agreed rest. Its height recovery is 96%, while another corner may have reached 100%. Record both locations instead of averaging them into an uninformative single number.
Investigate the mismatch
If material coupons perform as expected but one covered corner stays low, inspect the fold direction, seam, local adhesive and cover orientation before changing the foam grade. If the same loss appears in several uncovered samples from one lot, widen the material investigation. Save the physical sample until buyer and supplier have agreed on the failure mode and disposition.
| Item | Reading |
|---|---|
| Original height | 300 mm |
| Recovered height | 288 mm |
| Height recovery | 96% at that point |
What should happen if the reference height drifts?
Remeasure the unstressed reference under the same conditions, check instrument placement and document both readings. If the baseline has changed beyond repeatability, repeat the comparison with a reliable reference. A percentage calculated to several decimals cannot correct a badly located starting point.
What to request from the supplier
Ask for the foam test report and a separately labelled finished-sofa recovery record including location, elapsed time and photographs.
Download: Sofa recovery logSources and further reading
Put it into practice with Hongkong Yonghua
