A pocket flap opens by lifting an edge. In a strap under tension, overlapping sections can pull against each other along the contact plane. Look for two different figures in the data sheet: peel for separation starting at an edge, and shear for sliding. A single assembly can see both loads.
Identify the direction of the force
In peel, separation advances from an edge and the hooks disengage progressively. In shear, the engaged surfaces are pulled parallel to one another. Mark the force direction and the free edge on your drawing. If a strap bends and lifts an edge, check peel even when the main pull is along the tape.
Read the units before comparing values
The VELCRO® Brand ONE-WRAP® data sheet for the HTH 888/Loop 3610 system lists typical averages of 0.5 PIW for peel and 23 PSI for shear. Here PIW means pounds-force per inch of width; PSI means pounds-force per square inch of area. Those are different bases. Compare peel with peel and shear with shear under matching methods, units and conditions. The manufacturer gives these values for reference for that system. They are neither design loads nor values for other items. Manufacturer data sheet.
Check the closure on a sample
Record the exact hook and loop pairing, width, actual overlap, attachment to the substrate and opening direction. Test with the material used in the product. Observe whether the edge lifts, the tapes shift and where failure starts. Record disengagement of the hooks and loops, adhesive backing separation and seam damage as distinct outcomes.
Agree what to check after repeated use
Set the number of cycles and conditions for the product, then define acceptance criteria before testing. ISO 22776 and ISO 22777 describe separate footwear fastener methods for shear and peel before and after repeated closing. They illustrate different methods; citing a standard does not establish that a particular tape was tested to it. ISO 22776 / ISO 22777.
What to send to DELIM
Include a sketch showing the force direction, contact dimensions, mounting method, conditions of use and expected number of cycles. If you need a self-engaging tape, see the separate Back-to-Back guide to identify the configuration.
VELCRO® fasteners in the DELIM catalogue · Back-to-Back guide