Correct as at 19th April 2024. It may be superseded at any time.

Extract taken: from Vehicle Inspection Portal > VIRMs > Alternative fuel system certification > CNG inspection > Location and ground clearances

2-7 Location and ground clearances

Reasons for rejection

Mandatory equipment

1. An installation to NZS 5422: 1987, Part 2 does not meet all the requirements in the left-hand column of Table 2-7-1.

2. An installation to AS/NZS 2739: 2003 does not meet all the requirements in either:

a) the right-hand column of Table 2-7-1, or

b) the left-hand column of Table 2-7-1 of the requirements

Table 2-7-1. Location and ground clearance requirements

Requirements from NZS 5422: 1987: Part 2

Requirements from AS/NZS 2739: 2003

1. Cylinders, fittings and pipework must be mounted inside the perimeter of the vehicle.

2. Cylinder valves on externally mounted containers must be positioned no less than 200mm from the vehicle extremities.

3. A cylinder must not be fitted:

a) on the roof or above a passenger compartment

b) forward of the rear of the driver’s seat in its rearmost position without specific approval

c) in a position beneath the vehicle that decreases the effective ground clearance.

4. A cylinder located between or behind the axles must be within the zone limit shown in Figure 2-7-1.

1. A cylinder must lie within the ground clearance zone limits indicated by Table 2-7-2 and Figure 2-7-2 and Figure 2-7-3.

2. A cylinder must not be mounted outside the body contour to the front or sides of the vehicle.

3. A cylinder must not be mounted outside the body contour to the rear or top of the vehicle without specific approval.

4. A cylinder must be located such that its fittings are at least 100mm inside the outer body skin or tray of the vehicle.

Table 2-7-2. Ground clearance zone limits (requirements from AS/NZS 2739: 2003)

Vehicle mass1

Chassis ground clearance at rear of vehicle

Figure that shows ground clearance zone limits

Less than 3500kg

610mm or less

Figure 2-7-2

Less than 3500kg

More than 610mm

Figure 2-7-3

3500kg or more

610mm or less

Figure 2-7-2

3500kg or more

More than 610mm

Figure 2-7-3

1 Unladen mass with fuel, coolant and oil containers full.

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Figure 2-7-1. Zone limit for container location (requirements from NZS 5422: 1987, Part 2)

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Figure 2-7-2. Ground clearance zone limits for a small vehicle (requirements from AS/NZS 2739: 2003)

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Figure 2-7-3. Ground clearance zone limits for a large vehicle (requirements from AS/NZS 2739: 2003)

Summary of legislation

Applicable legislation
Mandatory equipment

1. Installations to NZS 5422: 1987, Part 2 must meet the requirements in the left-hand column of Table 2-7-1.

2. Installations to AS/NZS 2739: 2003 must meet the requirements in the right-hand column of Table 2-7-1, or if this is not practicable, the requirements in the left-hand column.