Together with the buckle, the straps make up the harnessing system which is the most important part of a safety seat or also called a child restraint system, CRS.
According to UNECE R44/04, harness straps should have below features and went through stipulated tests before it can be approved:
- Minimum width of the strap for group 0, 0+ and I should be 25 mm.
- Minimum width of the strap for group II and III should be 38 mm.
- Not possible to pull complete strap through any adjusters, buckles or anchoring points.
- Samples should be tested for tensile strength to ensure breaking load is within permissible limit not below than: 3.6 kN for group 0, 0+ and I; 5 kN for group II; 7.2 kN for group III.
These tensile strength tests are done with different conditionings as below:
✍ Room conditioning – under normal room condition
✍ Light conditioning – strap is exposed to light until it fades to a certain shade.
✍ Cold conditioning – strap is exposed for a certain period of time in low-temperature chamber (-30 °C) and subjected to cold load on it.
✍ Heat conditioning – strap exposed to heating with temperature 60 °C.
✍ Exposure to water – strap is fully immersed in distilled water with a wetting agent.
✍ Abrasion conditioning – strap ran through cycles of load to simulate abrasion due to use.
As you can see above, extensive conditionings are done before the tensile strength of the straps are tested to simulate the abuse a CRS harness went through throughout its life cycle. For a CRS manufacturer/owner without R&D facilities, these tests may have been done at third-party facilities who supply them with the harnessing system. It is imperative that they look for a facility with integrity.
As the end users, we only hope that the brands manufacturing the CRS we use for our children really look into this matter seriously.
⚠️ Although the sample of the straps went through extensive conditions, we should always follow the usage and maintenance care the manufacturers have outlined in the CRS manual ⚠️