Heavy Vehicle (Vehicle Standards) National Regulation

The outlet of the exhaust system fitted to a heavy motor vehicle must extend—

behind the back seat; and

at least 40mm beyond the outermost joint of the floorpan that is not continuously welded or permanently sealed; and

to the edge of the vehicle, if—

the vehicle’s body is permanently enclosed; and

the vehicle is not fitted with a vertical exhaust system; and

no further than the edge of the vehicle at its widest point.

The outlet mentioned in subsection (1) must discharge the main exhaust flow to the air—

if the vehicle is fitted with a vertical exhaust system—

at least 150mm above the cab of the vehicle; and

if the outlet discharges the main exhaust flow straight up—

at an angle above the horizontal; and

towards the rear, or to the right, of the vehicle; and

if the outlet does not discharge the main exhaust flow straight up—towards the rear of the vehicle and upwards at an angle within 0º to 45º of the longitudinal axis of the vehicle; or

in any other case—

less than 750mm above ground level; and

horizontally or downwards at an angle within 0º to 45º of the longitudinal axis of the vehicle; and

towards the rear, or to the right, of the vehicle.

Subsections (1) and (2) do not apply to a heavy motor vehicle—

that is a bus; or

that is primarily designed for the carriage of goods with a GVM not exceeding 12t.

An exposed section of a vertical exhaust system fitted to a heavy motor vehicle, other than a bus, must be positioned or shielded to prevent injury to any person.

An outlet of the exhaust system fitted to a heavy vehicle that is a bus must—

be as near as practicable to the rear of the bus; and

extend no further than the edge of the bus at its widest point.

The outlet mentioned in subsection (5) must discharge the main exhaust flow to the air—

if the bus is fitted with a vertical exhaust system—

behind the passenger compartment; and

if the outlet discharges the main exhaust flow straight up—

at an angle above the horizontal; and

towards the rear, or to the left or right, of the bus; and

if the outlet does not discharge the main exhaust flow straight up—towards the rear of the bus and upwards at an angle within 0º to 45º of the longitudinal axis of the bus; or

in any other case—

horizontally or downwards at an angle within 0º to 45º of the longitudinal axis of the bus; and

towards the rear, or to the right, of the bus.

If a rain cap is fitted to the outlet of a vertical exhaust system fitted to a heavy motor vehicle, the rain cap must be installed so the hinge of the cap is at an angle of 90º (plus or minus 10º) to the longitudinal axis of the vehicle when viewed from above.

In this section—vertical exhaust system means an exhaust system that emits exhaust gases in an upward direction above or near the top of a vehicle to which it is fitted. sch 2 s 99 amd 2015 SL No. 188 s 37