A waterproof fabric does not automatically create a waterproof bag. Leakage usually appears at seams, zipper ends, attachment points or closures. Buyers should therefore write the performance brief around the finished product.
Define the exposure
Light rain, repeated spray, temporary immersion and prolonged submersion are different conditions. State the expected duration, depth and load, and ask which test method will be used.
Review the construction system
- Fabric coating or laminate and abrasion requirement
- Sewn, taped or high-frequency welded seams
- Roll-top, water-resistant zipper or airtight zipper closure
- Reinforcement around handles, straps and hardware
- Drainage, internal organization and cleaning access
Ask for evidence at the right stages
Review the sample for dimensions, closure operation and leakage points. During production, confirm that seam settings, materials and accessories match the approved basis. Final checks should use the agreed loading and water-exposure condition.
Avoid absolute claims without a defined test
Terms such as “100% waterproof” or “IPX7” are only useful when the finished-product method, sample condition and acceptance criteria are recorded. Put that definition in the brief before the quotation is finalized.