A thesis that treats industrial scrap as a starting material — 247 metres of decommissioned seat belt, taken from pre-consumer waste and reengineered into two finished products, proven with lab testing.
Graded 1.0 — sehr gut. The top mark, on a thesis that took industrial scrap and pulled it to failure against the automotive belt standard.
HAW Hamburg · B.Eng. · 2025Cross-tack seams failed at a mean of 642 N
A billion metres of waste.
Every car carries about fifteen metres of seat-belt webbing. Globally that is over 1.4 billion metres a year; in Germany alone more than 1,600 tonnes — roughly 28,000 km — is discarded annually.
The material came straight from that stream: 247 metres of belt, donated by a former employee of Autoliv — one of the largest automotive safety suppliers — after the Elmshorn plant closed. Fabric-new, never used, headed for incineration.
- Origin
- Autoliv · Elmshorn
- Reclaimed
- 247 m belt
- Stream
- Pre-consumer waste
A technical textile, not a scrap.
100% high-tenacity polyester, woven in a 2/2 twill to industrial standard — warp yarns of 1,200–1,500 dtex, filaments just 15–25 µm across. Rated −30 °C to 100 °C, UV- and colour-stable.
The brief refused to hide where it came from — the belt stays inside the car, but carries a new function instead of a safety one.
- Fibre
- 100% HT polyester
- Weave
- 2/2 twill
- Warp
- 1,200–1,500 dtex
- Range
- −30 to 100 °C
Three boards, three directions
Nothing gets drawn before the world it belongs to is on one sheet. Each product started here — the register of colours, surfaces and situations it had to hold up in. The upcycling board set the tone for all of them; the other two narrowed it to a specific object.
Cut with heat, not blades.
A mechanical cut frays the belt and destroys its cohesion. So I built the tool for it — a self-built, modified hot cutter. Above the polyester melt range, 255–265 °C, the filaments fuse into a permanently sealed edge.
The window is narrow and mapped by hand: under-heat frays, the optimum gives a homogeneous edge, over-heat chars the belt.
- Tool
- Self-built hot cutter
- Temp.
- 255–265 °C
- Result
- Fused, non-fray edge
Tested to failure.
Seam strength was measured to breaking point with the HAW Department of Mechanical Engineering — coupons pulled against UN/ECE R16 (min. belt break force 1,470 daN).
Across five cross-tack coupons the seam failed at a mean of 642 N — lowest 563, highest 692, standard deviation 49. Straight stitching managed only a third. The seam, not the belt, is the limit.
Locked, woven, joined.
Load paths dictate the stitch — X-box bar tacks at handles and high-stress points, Z-box tacks across the net grid. A first prototype was woven seamlessly by hand, to read the belt before a single cut.
- Handles
- X-box bar tack
- Grid
- Z-box bar tack
- Prototype 1
- Hand-woven
- Edges
- Thermally sealed
Two products, one material.
A modular Storage Net — Z-box tacks, stainless O-rings, thermally sealed ends — and a Belt Bag for the boot: butt-joined panels, six adjustable handles, an integrated phone strap, X-box tacks at every load point.
Both return to the vehicle interior they came from. The examiner cited technical drawings “of a high professional standard”.
- Products
- Storage Net · Belt Bag
- Hardware
- Stainless O-rings · buckles
- Grade
- 1.0 (sehr gut)
07 — Documentation. Both products drawn to industry standard — technical flats, dimensioning details and colourways, sheet by sheet.
The belt stays in the car — not as safety, but as a new function that never leaves its origin.