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Section K – Cabin Modifications (Seats, Seatbelts, Conversions)

Section K of VSB6 covers all modifications to the cabin of heavy vehicles – from adding or removing seats and seatbelts to full cabin conversions and wheelchair or child restraint installations. At Autocert, we are accredited to assess and certify modifications under all K-series codes (K1, K2, K3, K5, K6).

What Modifications Are Covered?

Section K includes:

✅ K1 — Seating Capacity Alteration

  • Adding or removing seats and seatbelts
  • Installing ADR-compliant seat and seatbelt anchorages
  • Replacing or altering seat configurations

✅ K2 — Certification of Anchorages

  • Engineering certification of custom seat or seatbelt anchor points (typically precedes K1)
  • Suitable for custom cabins, aftermarket seats or when ADR anchorages are not pre-approved

✅ K3 — Cabin Conversion

  • Full replacement or structural modification of a cabin
  • Changes to the roof, steering column, gear selector or cabin dimensions
  • Requires validation to UNECE R29 (if applicable)

✅ K5 — Wheelchair Occupant Restraints

  • Installation of restraint systems complying with AS/NZS 10542.1
  • Applicable to disability access vehicles and transport fleets

✅ K6 — Child Restraint Anchorage Installation

  • Install anchor points or CRA bars to carry approved child seats
  • Includes twin cab devices, universal frames, vertical posts, and parcel shelf anchors

ADR Compliance

All modifications must comply with relevant Australian Design Rules (ADRs) including but not limited to:

  • ADR 3/.. – Seats
  • ADR 4/.. – Seatbelts
  • ADR 5/.. – Anchorages
  • ADR 34/.. – Child Restraint Anchorages
  • ADR 42/.. – General Safety
  • AS/NZS 10542.1 – Disability Restraint Systems

We ensure all changes are designed, tested and certified in accordance with these standards.

When is Section K Required?

Section K certification is mandatory for:

  • Upgrading or reducing seating capacity
  • Fitting aftermarket seats or belts in heavy vehicles
  • Installing child restraint anchorages in a truck or van
  • Replacing or converting cabins
  • Adding wheelchair occupant restraints
  • Repositioning cabin controls like steering or pedals

Safety & Design Notes

✅ Advanced Braking Systems
Extra care is needed when modifying vehicles fitted with ESC, EBS, RSC or similar systems. We ensure modifications don’t interfere with sensor operation or system performance.

✅ Structural Integrity
We assess the structure for rust or fatigue and ensure all components are strong enough to handle ADR-specified crash loads.

✅ Enclosures for Cargo Area Seats
Seats fitted in tray-back or cargo areas must be enclosed by a certified barrier, not a canopy or cage unless roll-rated.

✅ Seating Removal
If seats are permanently removed, SRS systems must still function correctly. The seating capacity must be updated and certified.

✅ Wheelchair Restraints
Anchorages must be welded to strong chassis or cross-member sections using certified hardware. Weak floor sections (e.g. wood or aluminium) are not acceptable without full structural reinforcement.

✅ Child Restraints
We install only ADR-compliant hardware. Anchorages are positioned and reinforced per the restraint manufacturer's instructions. For vehicles without parcel shelves, CRA bars or vertical posts are used.

Certification Process

Each modification under Section K follows a structured process:

  1. Assessment
    We confirm if the mod is within manufacturer specs or if engineering certification is required.
  2. Engineering & AVE Consultation
    For anchorages and complex alterations, we provide or validate K2 certification drawings and calculations.
  3. Modification
    All work must be done to spec using correct fasteners, mounting techniques and materials.
  4. Inspection & Sign-Off
    An Accredited Vehicle Examiner (AVE) performs a physical inspection, completes the checklist, and certifies the vehicle.
  5. Issue Certificate & Mod Plate
    We affix a modification plate and submit the certification paperwork to the relevant authority.

Our Cabin Certification Services

At Autocert, we provide:

  • ADR-compliant seat and seatbelt installations
  • Custom child restraint anchorage certification
  • Engineering designs for anchorages (K2)
  • Cabin conversions and repowering support
  • Disability access (wheelchair restraint) compliance
  • Professional consultation with RPEQ and AVE support
  • Full documentation and mod plate issue