Spray Suppression

Fitment Regulation 64 Road Vehicles (Construction and Use) Regulations 1986 states that suitable spray suppression equipment (to British Standard or EC 91/226) should be fitted on each axle. There are exceptions to these requirements with a full breakdown of what vehicles spray suppression is applied to, and the exempt vehicles – see below.

Maintenance of spray suppression devices

Regulation 65 Road Vehicles (Construction and Use) Regulations 1986, states that every part of every spray suppression device, which a vehicle is required to be fitted with, by the provisions of regulation 64 shall at all times, when the vehicle is on a road, be maintained free from any obvious defect which would be likely to affect adversely the effectiveness of the device.

Vehicle Types Affected

Spray suppression and containment equipment must be fitted to many vehicles. Apart from certain exemptions, the vehicles affected are as follows:

• motor vehicles over 12 tonnes maximum gross weight, first used on or after 1 April 1986
• trailers over 3.5 tonnes maximum gross weight, manufactured on or after 1 May 1985
• trailers over 16 tonnes maximum gross weight with two or more axles

Spray Suppression Equipment, must be fitted in relation to the wheels on each axle and must meet the British Standard specification for spray reducing devices for heavy goods vehicles (BS AU200).

Alternatively, vehicles may be fitted with spray suppression devices type approved to the EU standard in Directive 91/226. This performance standard is marginally higher than the British Standard.

BS AU200 stresses three aspects of design as follows.

• containment around the wheels in the form of wheel guards, valances and wheel flaps;
• fitting suppression devices;
• paying due regard to vehicle aerodynamics

Three categories of suppression and containment systems are covered by the standard, which are that:

• a conventional type of wheel guard with a valance and wheel flap;
• longitudinal strips and a flap of suppressant material;
• an air/water separator

The equipment must at all times – when the vehicle is on a road – be maintained free from any obvious defect likely to limit its effectiveness.

The Department for Transport have obtained legal opinion that wheel flaps must be, at least, as wide as the tyre(s) and not just the tyre tread.

Vehicle Types Exempt

There are two areas of concession and exemption. Any spray suppression device fitted before I January 1985 is considered satisfactory if it conforms substantially to BS AU200, with the following vehicles being exempt from these requirements:

• works trucks and trailers;
• broken down vehicles;
• motor vehicles incapable of exceeding 30mph on the level when laden;
• vehicles designed for carriage and mixing of concrete;
• agricultural motor vehicles, agricultural trailers, agricultural trailed appliances and agricultural trailed appliance conveyors;
• engineering plant;
• fire engines;
• vehicles constructed so that they can be unloaded by part being tipped sideways or rearwards (tractive units towing tipper semi-trailers are not covered by this exemption);
• military vehicles;
• vehicles with no bodywork proceeding to a body builder or vehicle dealer/distributor or being checked by a manufacturer or dealer/distributor;
• street cleansing vehicles, cesspool and gulley emptiers and refuse vehicles including skip carrying vehicles, ejection trailers and walking floor trailers;
• trailers constructed to carry timber beams or girders of exceptional length;
• trailers imported for less than 12 months;
• four wheel drive vehicles and other vehicles with drive capability on front and rear axles at the same time;
• vehicles with ground clearance on centre underside portion of more than 400mm (this covers many vehicles designed for off-road operations);
• vehicles proceeding to a place where spray suppression or containment equipment is to be fitted

Source: https://www.legislation.gov.uk/uksi/1986/1078/regulation/64/made