Vehicle Standard (Australian Design Rule 38/01 – Trailer Brake Systems) 2006
I, JAMES ERIC LLOYD, Minister for Local Government, Territories and Roads, determine this vehicle standard under subsection 7 (1) of the Motor Vehicle Standards Act 1989.
Dated 3 September 2006
James Eric Lloyd
Minister for Local Government, Territories and Roads
A. legislative provisions............................................................................ 3
B. Function and SCOPE................................................................................. 3
C. APPLICABILITY................................................................................................ 3
D. Applicability Table................................................................................... 4
38.1. DEFINITIONS.................................................................................................... 4
38.2. Design REQUIREMENTS............................................................................... 4
38.3. PERFORMANCE TEST REQUIREMENTS....................................................... 9
38.4. PERFORMANCE CALCULATION REQUIREMENTS.................................. 18
38.5. ALTERNATIVE STANDARDS........................................................................ 22
APPENDIX 1.................................................................................................................. 23
A. legislative provisions
A.1. NAME OF STANDARD
A.1.1. This Standard is the Vehicle Standard (Australian Design Rule 38/01 – Trailer Brake Systems) 2006.
A.1.2. This Standard may also be cited as Australian Design Rule 38/01 — Trailer Brake Systems.
A.2.1. This Standard commences on the day after it is registered.
A.3.1. This Standard repeals each vehicle standard with the name Australian Design Rule 38/01 — Trailer Brake Systems that is:
(a) made under section 7 of the Motor Vehicle Standards Act 1989; and
(b) in force at the commencement of this Standard.
A.3.2. This Standard also repeals each instrument made under section 7 of the Motor Vehicle Standards Act 1989 that creates a vehicle standard with the name Australian Design Rule 38/01 — Trailer Brake Systems, if there are no other vehicle standards created by that instrument, or amendments to vehicle standards made by that instrument, that are still in force at the commencement of this Standard.
B. Function and SCOPE
B.1. The function of this Australian Design Rule is to specify requirements for braking under both normal and emergency conditions.
B.2. Compliance is to be demonstrated by means of procedures outlined in the Rule for road testing and/or calculations based on data for ‘Approved’ components.
C.1. This ADR applies to the design and construction of vehicles as set out in the table hereunder (except those trailers having an ‘Aggregate Trailer Mass’ over 4.5 tonnes and designed for use behind a drawing vehicle with a maximum speed less than 50 km/h or trailers which are otherwise specially exempted by the ‘Administrator’).
C.2. ADR 38/00 is an acceptable prior rule except for trailers designed for use in ‘B-Doubles’ which are fitted with ‘Antilock’ brake system.
D. Applicability Table
ADR Category Code *
UNECE Category Code *
Manufactured on or After
Acceptable Prior Rules
Moped 2 wheels
Moped 3 wheels
Motor cycle and sidecar
Forward-control passenger vehicle
Off-road passenger vehicle
up to 3.5 tonnes ‘GVM’ and up to 12 seats
up to 3.5 tonnes ‘GVM’ and more than 12 seats
over 3.5 tonnes and up to 4.5 tonnes ‘GVM’
over 4.5 tonnes and up to 5 tonnes ‘GVM’
Light goods vehicle
Medium goods vehicle
over 3.5 tonnes up to 4.5 tonnes ‘GVM’
over 4.5 tonnes up to 12 tonnes ‘GVM’
Heavy goods vehicle
Very light trailer
1 July 1995
1 July 1995
1 July 1995
38.1.1. Refer to Vehicle Standard (Australian Design Rule Definitions and Vehicle Categories) 2005.
38.2. Design REQUIREMENTS
38.2.0 ‘Brake Systems’ for trailers with an ‘Aggregate Trailer Mass’ of up to 4.5 tonnes.
18.104.22.168 Every trailer shall be equipped with an efficient ‘Brake System’ which, with the exception of trailers equipped with over-run ‘Brakes’, shall be so designed as to be applied by the driver of the drawing vehicle from the driver’s ‘Seat’ and, in the case of trailers with an ‘Aggregate Trailer Mass’ of greater than 2 tonne, operates on all wheels.
22.214.171.124 The ‘Brake System’ on trailers with a ‘Gross Trailer Mass’ up to 2 tonnes may be actuated for both ‘Service Brake System’ and ‘Secondary Brake System’ by the over-run of the trailer.
126.96.36.199 Every trailer having a ‘Gross Trailer Mass’ over 2 tonnes and every ‘Semi-trailer’ shall be equipped with an ‘Emergency Brake System’ which will cause immediate automatic application of its ‘Brakes’ in the event of the trailer or ‘Semi-trailer’ accidentally becoming disconnected from the drawing vehicle. ‘Brakes’ so applied shall remain applied for at least 15 minutes and shall have the performance prescribed for emergency brakes as prescribed in the Rule.
188.8.131.52 Trailers with an ‘Aggregate Trailer Mass’ of up to 4.5 tonnes are not required to comply with other Sections of this Rule.
38.2.1. ‘Brake System’
184.108.40.206. A ‘Service Brake System’ shall be fitted to all trailer wheels and be in accordance with the requirements of clause 38.2.2 (‘Service Brake System’).
220.127.116.11. The trailer ‘Brake System’ shall be capable of being actuated from the towing vehicle by means of a connection between the trailer and towing vehicle with a performance not less than that specified for the ‘Emergency Brake System’ in clause 38.2.3 after any one failure in a ‘Brake Device’ in the trailer ‘Brake System’.
18.104.22.168. A ‘Parking Brake System 38/00’ shall be fitted and shall meet the requirements of clause 38.2.4.
22.214.171.124. The trailer ‘Brake System’ must restrain the trailer automatically, in the event of a trailer break-away with a performance not less than that specified for the ‘Emergency Brake System’ specified in clause 38.2.3.
126.96.36.199. A ‘Brake System’ which utilises ‘Stored Energy’ to actuate the ‘Service Brake System’ shall be designed so that when the ‘Supply Line’ energy level is reduced at a rate of not less than 0.15 ‘E’/sec (100 kPa/sec) the following conditions are met.
(a) the ‘Brake System’ shall not start to automatically apply the ‘Brakes’ at a ‘Supply Line’ energy level of more than 0.65 ‘E’ (420 kPa) AND,
(b) the ‘Brake System’ shall start to automatically apply the ‘Brakes’ at a ‘Supply Line’ energy level of not less than
(i) 0.31 ‘E’ (200 kPa) where the maximum braking effectiveness of the ‘Brakes’ so applied is dependent on ‘Stored Fluid Energy’ OR,
(ii) 0.24 ‘E’ (155 kPa) where the maximum braking effectiveness of the ‘Brakes’ so applied is not dependent on ‘Stored Fluid Energy’, AND
(c) with the ‘Supply Line’ energy level at 0.0 ‘E’ the braking effectiveness shall be at least that specified for the ‘Emergency Brake System’ in clause 188.8.131.52 (‘Emergency Brake System’).
184.108.40.206. The ‘Brake System’ shall be designed so that no single failure in a ‘Brake Device’ in the ‘Service Brake System, except of a ‘Supply Line’ or ‘Control Line’, shall cause the ‘Brakes’ to apply on more than one axle.
220.127.116.11. Manual devices for the isolation of faulty devices or brake circuits may be included in the ‘Brake System’ but automatic devices of the type that normally remain passive and whose function cannot readily be checked during normal operation of the trailer are not permitted. For the purposes of this clause normal operation also includes the activity of coupling and uncoupling the trailer connections.
18.104.22.168. Where a trailer is fitted with an auxiliary park brake release device, enabling stored energy actuation or release of any part of the ‘Brake System’ to be cut out, the device must be such that the ‘Brake System’ is restored to normal no later than on the resumption of the supply of ‘Stored Energy’ to the trailer from the towing vehicle.
22.214.171.124.1. Notwithstanding clause 126.96.36.199 above, at the option of the ‘Manufacturer’, the ‘Administrator’ may permit other safety related devices in the ‘Parking Brake System, when such fitment would lead to increased safety in operation or to meet other specified mandatory requirements.
188.8.131.52. All components and devices in the ‘Brake System’ shall meet or exceed at least one appropriate and recognised international, national or association standard, where such standards exist, or the relevant parts thereof. “Recognised” can be taken as meaning SAA, SAE, BS, JIS and DIN standards in addition to other standards recognised by the ‘Administrator’.
184.108.40.206. Brake line couplings shall not be interchangeable.
220.127.116.11.1. Couplings shall be polarised in accordance with AS D8 - 1971, “Hose Couplings for use with Vacuum and Air-pressure Braking Systems on Prime-movers, Trailers and Semi-trailers” where applicable. i.e. Vacuum systems, ‘Supply Line’, female connector; Compressed air systems, ‘Supply Line’, male connector; or palm type with inboard interference lug.
18.104.22.168. Each air reservoir in a compressed air ‘Brake System’ shall be fitted with an automatic or manual condensate drain valve at the lowest point. Where an automatic condensate valve is fitted, it shall have provision for manual operation.
22.214.171.124. Each ‘Brake System’ shall incorporate devices which compensate for any increased movement of its components arising from wear. Such devices shall themselves contain provision for securing them throughout their working range in any position in which they may be adjusted to or to which they may themselves automatically adjust.
126.96.36.199. Each ‘Brake System’ shall, when applied, produce a resultant braking force acting along the longitudinal centre line of the vehicle.
188.8.131.52. The first call on the ‘Stored Energy’ shall be that of the ‘Brake System’. Any other demand for ‘Stored Energy’ shall be disconnected automatically if the ‘Stored Energy’ level available becomes depleted to two-thirds of ‘Normal Minimum Energy Level’.
184.108.40.206. Where separate methods of actuation are provided for any of the functions of the ‘Brake System’, the actuation of one function shall not cause the operation of another function.
220.127.116.11. ‘Stored Energy’ devices shall be safeguarded to prevent depletion of the ‘Stored Fluid Energy’ through failure of any part of the supplying system.
38.2.2. ‘Service Brake System’
18.104.22.168. The ‘Service Brake System’ shall be designed so that the braking force can be progressively increased and decreased by means of the ‘Control Signal’ from the towing vehicle.
22.214.171.124. The combined total energy capacity of energy storage devices incorporated into the ‘Service Brake System’ shall be not less than 8 times the combined maximum energy capacity of the service brakes actuating devices. In the case of compressed air ‘Braking Systems’, the ratio of air reservoir volume to actuator volume will be taken as being the ratio of energy capacity.
126.96.36.199. The elapsed time, as measured in accordance with the procedure specified in clause 38.3.11 for measuring brake actuation time response shall not exceed in the case of:
(a) any brake actuator of any ‘Axle Group’ on the trailer, 0.35 seconds; and
(b) any trailer or dolly rear service coupling for towed trailers, 0.25 seconds.
188.8.131.52. The elapsed time, as measured in accordance with the procedure specified in clause 38.3.11 for measuring brake release time, shall not exceed in the case of:
184.108.40.206.1. the brake actuator on any trailer, 0.65 seconds; and
220.127.116.11.2. any, trailer or dolly, rear service coupling for towed trailers, 0.55 seconds.
18.104.22.168. Each ‘Axle’ in the ‘Service Brake System’ shall have an individual ‘GALR’ not less than
‘Total Trailer Axle’ Load at ‘GTM’ ´ Brake torque rating of individual ‘Axle’
Total brake torque rating of all ‘Axles’
‘Axle’ torque rating shall be determined according to clause 38.3.3 (Service Brake Effectiveness) and the fade performance according to clause 38.3.4 (Service Brake Fade Effectiveness).
22.214.171.124. The ‘Established Retardation Coefficient’s’ of the ‘Service Brake System’ shall be between the upper and lower bounds of Figure 1 (Service Brake Effectiveness Requirement) when tested according to clause 38.3.3 (Service Brake Effectiveness).
126.96.36.199. Where a trailer is fitted with a ‘Variable Proportioning Brake System’ it shall meet the requirements of clause 188.8.131.52 with the brake proportioning device/s set in the ‘LTM’ position.
184.108.40.206. Notwithstanding clause 220.127.116.11 where a trailer is fitted with an ‘Antilock System’, the ‘ERCs’ need only exceed the lower bound described in Figure 1.
38.2.3. ‘Emergency Brake System’
18.104.22.168. The ‘Emergency Brake System’ may utilise parts of the ‘Service Brake System’ on the condition that any one failure of a ‘Brake Device’ in the ‘Service Brake System’ does not prevent the ‘Emergency Brake System’ from achieving its performance requirement. For the purpose of this clause, the ‘Brakes’ and any mechanical linkage connected directly thereto, shall be considered as not subject to failure.
22.214.171.124. The ‘Established Retardation Co-efficient’ of the ‘Emergency Brake System’ shall be shown to be not less than 0.18 according to the requirements and limitations of clause 38.3.5. (‘Emergency Brake System’). The ‘Brakes’ force required to obtain an ‘ERC’ of 0.18 shall be able to be sustained for a period not less than 15 minutes.
126.96.36.199. In the case of ‘Semi-Trailers’, when disconnected from the ‘Prime-Mover’, the failure of any structure designed to support the front of the trailer shall not reduce the effectiveness of the ‘Emergency Brake System’ to less than half that required by clause 188.8.131.52.
184.108.40.206. ‘Emergency Brake Systems’ that employ ‘Stored Fluid Energy’ to hold them in the release position shall be provided with an auxiliary release mechanism that is not dependent on fluid energy provided by the tow vehicle. The auxiliary device, control or tool shall be attached to the trailer chassis rail, or equivalent structure, in an inconspicuous position forward of the forward most ‘Axle’ on the rear ‘Axle Group’ on the right hand side of the trailer.
38.2.4. ‘Parking Brake System 38/00’
220.127.116.11. The ‘Parking Brake System 38/00’ shall be independent of the ‘Service Brake System’ except that the brakes and any mechanical system attached directly thereto may be common.
18.104.22.168. The ‘Parking Brake System 38/00’ shall be able to be applied by means of a single ‘Control’ and once applied, shall be able to be held in position by purely mechanical means. It shall not be possible to release the ‘Parking Brake’ unless a means of immediately reapplying it is available. If the parking brake is held in the released position by ‘Stored Fluid Energy’ the provisions of clause 22.214.171.124 shall apply. Additional parking brake facilities are permitted provided that the requirements of this clause are met.
126.96.36.199. The ‘Parking Brake System 38/00’ shall be shown to be capable of holding the trailer stationary on an 18 per cent gradient in either direction, according to the requirements of clause 38.3.6 (Parking Brake Effectiveness).
38.2.5. ‘Antilock Systems’
188.8.131.52. ‘Antilock Systems’ when fitted to trailers designed for ‘B-Doubles’ must comply with the requirements of Appendix 1 - ‘ANTILOCK SYSTEM’ FOR TRAILERS DESIGNED FOR USE IN ‘B-DOUBLES’.
38.3. PERFORMANCE TEST REQUIREMENTS
184.108.40.206. The trailer ‘Brake System’ shall be capable of meeting the requirements of:
(a) clause 38.3.3 - Service Brake Effectiveness
(b) clause 38.3.4 - Service Brake Fade Effectiveness
(c) clause 38.3.5 - ‘Emergency Brake System’
(d) clause 38.3.6 - Parking Brake Effectiveness
(e) clause 38.3.11 - Time Response.
220.127.116.11. Each ‘Unique’ ‘Brake System’ fitted to each trailer type shall be shown to comply with clause 18.104.22.168. A trailer will be considered as being of the same type where it has the same number of ‘Axles’ and ‘Gross Trailer Mass’, and where no substantial change has been made to either trailer length, height, tyre size or suspension.
Trailers complying with ECE 13/05 shall be taken as meeting the requirements of this Rule so long as any ‘Variable Proportioning Brake Systems’ fitted are able to be held in the ‘LTM’ position and adjacent to the Trailer ‘Control Line’ connectors having the words: “Ensure Load Proportioning Brake System on Trailer is HELD in LOADED POSITION if Tow Vehicle NOT Fitted with Load Proportioning”.
22.214.171.124. Where minor changes have been made and compliance with clause 126.96.36.199 (test requirements) must be shown, compliance in relation to an ‘Approved Brake System’ for a trailer type may be demonstrated by supplying the evidence needed to justify the maintenance of performance standards in the areas affected by the changes.
188.8.131.52.1. For example:
(a) if an ‘Approved Brake System’ were fitted to a substantially shorter ‘Semi-trailer’ the suitability of a ‘Brake System’ having the same service brake effectiveness would have to be supported.
(b) if trailer length were substantially increased, time response data might be required.
(c) if an auxiliary ‘Parking Brake System 38/00’ control were fitted, evidence would need to be provided to show that the ‘Approved’ Brake System’ performance aspects had not been degraded.
184.108.40.206.2. Where ‘Axle’ types are to be substituted for one another, the comparison for service brake effectiveness should be on the basis of ‘Established Retardation Coefficient’. In the case of air ‘Brake Systems’ having service brake effectiveness specified as ARC, ERC may be determined by calculating K2 in the equation below.
S is stopping distance from initial movement of the ‘Control’ in metres.
V is the initial velocity, in km/h
K1 is a constant related to time delay where at a value of 0.09 is equal to a time delay of 0.32 second
K2 is a constant related to established retardation and at a value of 115 is equivalent to 0.45 g (4.4 m/s2).
220.127.116.11.3. In the case of ‘Brakes’ friction materials, the substitute material would have to be identical in regard to its SAE J 866a - “Friction Identification System for Brake Linings and Brake Blocks for Motor Vehicles” (September 1966) and to meet or exceed the requirements of SAE J 840c - “Test Procedures for Brake Shoe and Lining Adhesives and Bonds’ (May 1971), and SAE J 998 “Minimum Requirements for Motor Vehicle Brake Linings” (January 1968), or other international standards.
18.104.22.168.4. Submissions for compliance approval based in part on a previously approved trailer shall be in relation to an approval based on a complete submission of either test or calculation data.
38.3.2. General Test Conditions - Road Tests
22.214.171.124. The ambient temperature at the test site shall be greater than 0 and less than 40o C.
126.96.36.199. All road tests shall be conducted with tyres fitted of the size specified by the ‘Manufacturer’ as original equipment and shall be inflated to pressures not less than those recommended by the ‘Manufacturer’.
188.8.131.52. Braking tests shall be carried out on approximately level surfaces. Where the levels are unsurveyed, the test shall be completed in both directions, the brakes being applied over the same section, and the two results averaged to determine the final result. Where the difference in start and finish elevations for a brake test, expressed as a percentage of the stopping distance, is shown, the brake test need only be completed in one direction and the result corrected for any difference in elevation exceeding 1 percent.
184.108.40.206. The wind speed difference between two tests in opposite directions, or against the direction of travel in the case of a single brake test, shall not exceed 15 km/h.
220.127.116.11. The towing vehicle used to facilitate the tests shall be of a type normally employed to tow the particular trailer under test and shall have enough power to attain the initial speed required for the specified braking tests.
18.104.22.168. All road tests shall be conducted with the trailer loaded to ‘MLTM’ and energy storage devices charged to ‘Normal Minimum Energy Level’, unless otherwise required by this Rule.
22.214.171.124. The test surface shall be either concrete or bitumen pavement and shall be free from loose material.
126.96.36.199. No towing vehicle braking system or other contrived means shall contribute to braking effort, and the towing vehicle engine shall be declutched or neutral engaged, during the braking tests required by this Rule.
188.8.131.52. The ‘Brakes’ shall be burnished before conducting any effectiveness tests according to the brake manufacturer’s recommended procedures.
184.108.40.206. The ‘Brake System’ shall be adjusted in accordance with the brake manufacturer’s recommendations before performance tests are conducted.
220.127.116.11. The performance requirements shall be met with no deviation of the vehicle from its course greater than 300 millimetres.
38.3.3. Service Brake Effectiveness
18.104.22.168. Each ‘Unique’ trailer ‘Service Brake System’ shall be either tested in accordance with clause 38.3.2 (general test conditions) and clause 22.214.171.124 (service brake effectiveness test) or be shown by calculation, based on data for approved components, as detailed in clause 38.4.1 (service brake effectiveness calculation), to meet the requirements of clause 126.96.36.199 (refers to Figure 1).
188.8.131.52. Service Brake Effectiveness Test.
184.108.40.206.1. The initial speed at the point where trailer braking commences shall be:
(1) for trailers having a ‘Aggregate Trailer Mass’ less than 45 tonnes and not being restricted by design speed limitations, 58 to 64 km/h.
(2) for trailers having a ‘Aggregate Trailer Mass’ greater than 45 tonnes, or special trailers having a design speed less than 58 km/h, not less than the ‘Manufacturer’s’ nominated design speed.
220.127.116.11.2. The trailer shall be laden to ‘LTM’ and braked to a stop from initial speed starting with a ‘Control Signal’ of 0.2 ‘E’ and in increasing increments of not greater than 0.2 ‘E’ for subsequent stops until an ‘Established Retardation Co-efficient’ of not less than 0.45 is achieved.
18.104.22.168.3. In the case of a compressed air ‘Brake System’ the ‘Control Signal’, applied to the ‘Control Line’ at the front of the trailer, shall reach 65 per cent of the final value in less than 0.22 second. Where the available ‘Control Signal’ is slower than 0.22 second the additional time will be allowed for entirely in clause 22.214.171.124.5 by adjusting the K1 or K3 term. The response of a vehicle control system should be determined by using an 800 millilitres vessel to simulate the trailer, with the pressure being measured at the point most remote from that of air entry.
126.96.36.199.4. Either stopping distance or time from the point where the trailer brake control commences actuation from the off position, to the point where the trailer comes to a stop, may be used to calculate the ‘ERC’ according to the equations in clause 188.8.131.52.5. A calibrated decelerometer and chart recorder may also be used.
184.108.40.206.5. The ‘Service Brake System’ Established Retardation Coefficient shall be determined according to the following as required:
V is the initial speed km/h
S is the ‘Stopping Distance’ metres
T is the ‘Stopping Time’ seconds
‘Total Combination Mass’ tonnes
‘Total Trailer Axle Load’ tonnes
K1 is the time delay constant referred to in clause 220.127.116.11 and should be set at 0.09 for air ‘Brake Systems’ unless it is shown that an alternative value should be used.
K3 is the effective time delay of 0.32 seconds referred to in clause 18.104.22.168 for air ‘Brake System’s’ and this value should be used unless a more appropriate value can be demonstrated.
22.214.171.124.6. The computed ‘Established Retardation Coefficients’ determined from clause 126.96.36.199.5 shall comply with clause 188.8.131.52 (service effectiveness).
184.108.40.206.7. No part of the ‘Brake System’ shall exceed 100oC immediately prior to the commencement of a brake test sequence.
220.127.116.11. No trailer wheels shall remain locked, except below approximately 10 km/h, during completion of the braking tests required by the sections of clause 18.104.22.168.
22.214.171.124. In the case of ‘Dog Trailers’ at least one front ‘Axle’ shall skid before at least one rear ‘Axle’ at an ‘ERC’ greater than:
(a) 0.3 in the case of two ‘Axle’ ‘Dog Trailers’;
(b) 0.15 in the case of ‘Dog Trailers’ with three or more ‘Axles’.
126.96.36.199.1. The test shall be conducted generally in accordance with clause 188.8.131.52 (service brake effectiveness) with the ‘Control Signal’ and surface type selected to demonstrate the requirement of clause 184.108.40.206 above.
The initial speed requirement of clause 220.127.116.11.1 does not apply.
18.104.22.168. Computer simulation of the requirements of clause 38.3.3 is allowed where the simulation is sufficiently sophisticated and has been approved by the ‘Administrator’ on the basis of an adequate back to back comparison with physical test results.
38.3.4. Service Brake Fade Effectiveness
22.214.171.124. Each ‘Unique’ trailer ‘Service Brake System’ shall be shown by either test in accordance with clause 38.3.2 (general test conditions) and clause 126.96.36.199 (service brake fade effectiveness test) or by the calculation based on data for ‘Approved’ components in clause 38.4.2 (service brake fade calculation), to meet the requirements of clause 188.8.131.52.1 (degree of fade) and clause 184.108.40.206 (distribution of fade resistance).
220.127.116.11. Service Brake Fade Effectiveness Test
18.104.22.168.1. The ‘Service Brake System’ shall, on the next application after not less than 20 successive applications, each not more than 60 seconds after the preceding one, of the trailer ‘Brakes’ from an initial speed of 60 km/h to a final speed as calculated by clause 22.214.171.124.2, achieve a calculated ‘Established Retardation Coefficient’, when tested in accordance with clause 126.96.36.199, (service brake effectiveness test), of not less than 60 per cent of the value obtained for the service brake effectiveness test required by clause 188.8.131.52 nor less than 80 per cent of the value specified by the lower bound of Figure 1.
184.108.40.206.2. The final speed to which the trailer has to be successively braked as part of the brake fade conditioning procedure shall be determined from the equation
V1 is the initial speed in km/h
V2 is the final speed in km/h
Masses and Loads in tonnes
220.127.116.11.3. The temperature (100o C) requirement of clause 18.104.22.168.7 shall not apply to the test required by clause 22.214.171.124.1.
38.3.5. ‘Emergency Brake System’
126.96.36.199. Each ‘Unique’ trailer ‘Emergency Brake System’ shall be shown by either test in accordance with clause 38.3.2 (general test conditions) and clause 188.8.131.52 (Emergency Brake System’ test) or by the calculation based on data for ‘Approved’ components in clause 38.4.3 (‘Emergency Brake System’ calculation), to meet the requirements of clause 184.108.40.206 (‘Emergency Brake System’ retardation).
220.127.116.11. The ‘Established Retardation Coefficient’, as determined by clause 18.104.22.168.5, shall be not less than 0.18 when the ‘Emergency Brake System’ is tested to the requirements of clause 22.214.171.124 (service brake effectiveness) except where clause 126.96.36.199 applies, and except that:
(a) The ‘Control Signal’ source shall be left in the “off” position with no ‘Control Signal’ being provided to the trailer control line; AND
(b) The energy level in the supply line shall be reduced to zero (in a 2-line compressed air system this will be the emergency line).
188.8.131.52. Where the actuation of the ‘Emergency Brake System’ depends on one or more sources of ‘Stored Energy’ that are common to the ‘Service Brake System’, for the purposes of testing for compliance with the requirements of clause 184.108.40.206, the trailer energy storage devices shall be charged to an energy level no greater than 0.05 ‘E’ above the supply level determined for clause 220.127.116.11, or the energy storage device level if higher, at which the ‘Emergency Brake System’ commences to activate the ‘Brakes’.
38.3.6. Parking Brake Effectiveness
18.104.22.168. Each ‘Unique’ trailer ‘Parking Brake System 38/00’ shall be shown by either test in accordance with clause 38.3.2 (general test conditions) or by the calculation based on data for ‘Approved’ components in clause 38.4.4, to meet the requirements of clause 22.214.171.124 (parking brake effectiveness), and shall be deemed satisfactory if clause 126.96.36.199.1 or clause 188.8.131.52.2 is met.
184.108.40.206.1. The ‘Parking Brake System 38/00’ shall be able to meet the requirements of clause 220.127.116.11 (18 per cent gradient) for a 5 minute period in each direction with the force required to actuate the parking brake not exceeding 685 N in the case of a foot operated brake and not exceeding 590 N in the case of a hand operated brake. The necessary longitudinal force will be considered to have been applied if the sum of the force applied to the trailer towing point and the force due to the effect of gravity on the laden trailer mass, in the direction parallel to the test surface and trailer longitudinal axis, is greater than 0.18 times the ‘Aggregate Trailer Mass’. Where the test involves a force depending on the slope of the test surface, the slope shall not be less than 10 percent. When the test involves the action of slope on the trailer or combination mass, and the towing vehicle remains connected, 1.5 per cent of the towing vehicle mass shall be subtracted from the other forces parallel to the test plane, to allow for rolling friction.
The test slope shall be specified in terms of unit vertical per unit horizontal distance.
18.104.22.168.2. The ‘Parking Brake System 38/00’ shall meet the requirements of clause 22.214.171.124 (‘Emergency Brake System’ performance) when the calculation of ‘ERC’ according to clause 126.96.36.199.5 is with an ‘Aggregate Trailer Mass’ instead of ‘Total Trailer Axle Load’ and the ‘Foundation Brakes’ geometry is such that a reversal of the required braking torque will not reduce the ability of the ‘Parking Brake System 38/00’ to generate the required braking torque.
38.3.7. Not used
38.3.8. Dynamometer Test Conditions
188.8.131.52 Where dynamometer testing is used in lieu or in support of the requirements of the road testing required by clauses 38.3.2 to 38.3.7, the requirements of this clause shall apply.
184.108.40.206. The dynamometer inertia for each wheel shall not be less than that determined from the expression:
I = MR2
I is the dynamometer inertia, in kg.m2
M is the mass supported by the wheel at the ’GALR in kg.
R is the ‘Static Loaded Tyre Radius’ of the tyre, as specified by the tyre manufacturer, in metres.
The ambient temperature shall be between 23.0 and 38.0oC
220.127.116.11. Ambient air shall be directed continuously over the brake drum or disc at a velocity of not more than 11.2 m/s.
18.104.22.168. The temperature of each brake shall be measured by a single plug-type thermocouple installed in the centre of the lining surface of the most heavily loaded shoe or pad. The thermocouple shall be outside any centre groove.
22.214.171.124. The rate of brake drum or disc rotation on a dynamometer corresponding to the rate of rotation on a vehicle at a given speed shall be calculated by assuming a tyre radius equal to the ‘Static Loaded Tyre Radius’ specified by the tyre manufacturer.
126.96.36.199. Burnishing, if conducted, shall consist of:
(1) not more than 200 stops such that any instantaneous deceleration does not exceed 3.1 m/s2 from a maximum speed of 65 km/h. The initial brake temperature for each stop shall be not less than 155 and not more than 200o C; and
(2) not more than 200 additional stops from a maximum speed of 65 km/h at a deceleration not exceeding 3.1 m/s2. The initial brake temperature for each stop shall not be less than 230 and not more than 290o C. After burnishing, the ‘Brakes’ will be adjusted in accordance with the ‘Manufacturer’s’ recommendations.
188.8.131.52. Brake temperature shall be increased to the
specified level by conducting one or more stops from not more than 65 km/h at a deceleration not exceeding 3.1 m/s2, or decreased to a specified level by rotating the drum or disc at a constant speed not exceeding 50 km/h.
184.108.40.206. Speeds, decelerations and time specified in clause 38.3.8 shall be achieved within the following tolerance limits:
Speeds. +5, -1 km/h
Decelerations: +0.25, -0.25 m/s2
Times: +5, -5 seconds.
38.3.9. Service Brake Effectiveness - Dynamometer Test
220.127.116.11. The service brake effectiveness test is to be conducted with an initial brake temperature of between 50 and 95o C by conducting a series of stops from 80 km/h whilst maintaining constant brake actuator air pressure. The average torque from the time the specified air pressure is reached until the brake stops is divided by the ‘Static Loaded Tyre Radius’ specified by the tyre manufacturer to determine the retardation force. The complete test procedure requires seven stops to be made, each from the specified initial temperature, with the first run pressure being 138 kPa and increasing an additional 69 kPa for each of the remaining stops.
18.104.22.168. If a comparison of ‘ERC’ determined under clause 22.214.171.124 is to be made with that obtained under the road test described in clause 38.3.3 of this Rule, due allowance must be made for the effect that test speed may have on the result. A direct comparison of dynamometer data from an initial speed of 60 km/h or that derived by interpolating between a high and lower speed is acceptable.
38.3.10. Service Brake Fade Performance Dynamometer Test
126.96.36.199. When mounted on an inertia dynamometer, each brake shall be capable of making 10 consecutive decelerations at an average rate of 2.75 m/s2 from 80 km/h to 24 km/h at equal intervals of 72 seconds, and shall be capable of decelerating to a stop from 32 km/h at an average deceleration rate of 4.25 m/s2 one minute after the 10th deceleration. The series of decelerations shall be conducted as follows.
188.8.131.52.1. With an initial brake temperature between 65 and 95 Celsius for the first brake application, and the drum or disc rotating at a speed equivalent to 80 km/h, apply the brake and decelerate at an average deceleration rate of 2.75 m/s2 to 24 km/h. Upon reaching 24 km/h accelerate to 80 km/h and apply the brake for a second time 72 seconds after the start of the first application. Repeat the cycle until 10 decelerations have been made. The service line air pressure shall not exceed 690 kPa during any deceleration.
184.108.40.206.2. One minute after the end of the last deceleration required by clause 220.127.116.11.1 and with the drum or disc rotating at a speed of 32 km/h decelerate to a stop at an average deceleration rate of 4.25 m/s2.
18.104.22.168. Starting 2 minutes after completing the tests required by clause 22.214.171.124 the brake shall be capable of making 20 consecutive stops from 48 km/h at an average deceleration rate of 3.65 m/s2 at equal intervals of one minute measured from the start of each brake application. The service line air pressure needed to attain a rate of 3.65 m/s2 shall be not more than 586 kPa and not less than 137 kPa for a brake not subject to the control of an ‘Antilock System’, or 82 kPa for a brake subject to the control of an ‘Antilock System’.
38.3.11. Time Response Measurement
126.96.36.199. Except where hydraulic brakes are used, each ‘Unique’ trailer ‘Brake System’ shall be shown to meet the requirements of clause 188.8.131.52 (actuation time) and clause 184.108.40.206 (release time) by testing in accordance with clause 220.127.116.11 or on the basis of a calculation in accordance with clause 38.4.5 (time response calculation).
18.104.22.168. A variant of a ‘Unique’ trailer ‘Brake System’ will be considered to be identical in regard to time response, when the only variation from the ‘Unique’ ‘Brake System’ is one or more of the following:
(a) Plumbing or energy transmission line lengths and number of fittings are reduced but other characteristics including diameter, material, type of connecting fittings and the characteristic transmission loss per unit length are not changed.
(b) Entire subsections of the ‘Brake System’ have been removed, as would be the case in converting a modular three ‘Axle’ system to a modular two ‘Axle’ system, such that the effect if any is to slightly increase the energy flow rate to and from the remaining brake sub-systems.
(c) The energy required to actuate the substitute brake actuators to their maximum design level is less.
22.214.171.124. Where a trailer ‘Brake System’ is required to be tested for compliance with clauses 126.96.36.199 and clause 188.8.131.52 in the case of compressed air ‘Brake System’, the test rig described in Figure 2 shall be calibrated in accordance with clause 184.108.40.206.2 and connected as described in Figure 3.
220.127.116.11.1. Where a rear service coupling for towed trailers is provided, time responses shall be measured with an 800 millilitres vessel attached to the rear service coupling as in Figure 3.
18.104.22.168.2. The test rig described in Figure 2 shall be calibrated by adjustment of the orifice (O) such that with the storage reservoir (R1) charged to 1.0 ‘E’ (650 kPa), the time between the initial pressure drop measured between the storage reservoir and the control valve (V), and the pressure at the end of the calibrating vessel (R2) increasing to 0.65 ‘E’ (420 kPa), is between 0.18 and 0.22 seconds.
22.214.171.124.3. The test rig and the trailer energy storage devices shall be charged to 1.0 ‘E’ (650 kPa) prior to the test being conducted and no additional energy shall be added to the storage vessel (R1) or the trailer ‘Supply Line’ during the period of the test.
126.96.36.199.4. The brake actuation time shall be taken from when the pressure level, measured between the storage reservoir and the control valve, initially drops to when the pressure in the least favoured brake actuator reaches 0.65 ‘E’ (420 kPa).
188.8.131.52.5. With an initial service brake application level of 1.0 ‘E’ (650 kPa) the brake release time shall be taken from when the pressure level, measured between the control valve and the orifice, initially drops to when the pressure in the least favoured brake actuator reaches 0.05 E (35.0kPa).
184.108.40.206.6. The brake control valve shall be of a configuration that permits energy to flow from the storage reservoir to the orifice (O) when in the “on” position and from the orifice to waste when in the “off” position. It shall not allow additional energy to flow into the test rig ‘Control Line’ by way of its own ‘Control Signal’. The brake control valve control shall be designed so that the manner of its operation shall have no effect on the output response of the test rig. The brake control valve may be arranged to provide a modulated test rig output signal for other brake development purposes but which for the purpose of measuring trailer ‘Brake System’ response in accordance with clause 220.127.116.11 will be rendered inoperative.
38.4. PERFORMANCE CALCULATION REQUIREMENTS
38.4.1. Service Brake Effectiveness Calculation
18.104.22.168. Service Brake Effectiveness will be considered satisfactory if it complies with all the requirements of clause 38.4.1.
22.214.171.124. The distribution of braking effort amongst the ‘Axle’s’ in an ‘Axle Group’ shall be a value, or be in the range of values, referred to in clause 126.96.36.199.4 (suspension behaviour).
188.8.131.52. In the case of ‘Dog Trailers’ at least one front ‘Axle’ shall have a higher friction utilisation than that of at least one rear ‘Axle’ at decelerations greater than:
(a) 0.3 g in the case of 2 ‘Axle’ ‘Dog Trailers’,
(b) 0.15 g in the case of ‘Dog Trailers’ with 3 or more ‘Axle’s’.
184.108.40.206.1. In the case of two-‘Axle’ ‘Dog Trailers’ the friction utilisation factors may be calculated according to
Friction Utilization Factor = Tangential Force at Wheel
Dynamic Load at Wheel
F Friction utilisation factor.
P1 front ‘Axle’ static load
P2 rear ‘Axle’ static load
P total static ‘Axle’ Load
h height of trailer and load centre of mass
L ’Wheel Base
z deceleration, as a proportion of acceleration due to gravity.
220.127.116.11.2. No friction utilisation factor (F) shall exceed 0.7 at z = 0.45.
This is taken as to mean that wheel lock would have occurred in the physical test otherwise required by clause 18.104.22.168.2 (service brake effectiveness).
22.214.171.124.3. For ‘Dog Trailers’ with more than two ‘Axle’s’ where it is not practical to calculate the friction utilisation factors, a skid test on a loose surface at ‘LTM’ to ensure that at least one front ‘Axle’ skids before a rear ‘Axle’ is sufficient evidence.
126.96.36.199. The braking ratio (Total brake force)
(‘Total Trailer Axle Load’)
of the trailer for various levels of input ‘Control Signal’ as determined on the basis of data provided under clause 188.8.131.52 for the ‘Control System’ and clause 184.108.40.206 for the ‘Foundation Brakes’, shall lie between the upper and lower bounds of Figure 1. e.g.
e (C1T1 + C2T2 + … etc
total brake force at e = R R .
‘Total Trailer Axle Load’ (P1 + P2 + … etc
e is values of ‘E’ in the range 0.2 - 1.0
C is the ratio of output to input signal strength for the ‘Control System’ for the ‘Axle’ concerned
T is the ‘Brakes’ output torque per unit input signal to the ‘Brakes’ actuator from the ‘Control System’ for the ‘Axle’ concerned
R is the rolling radius of the tyre on the wheel
P is the static load on the ‘Axle’ concerned
1,2, etc are subscripts referring to a particular ‘Axle’.
220.127.116.11.1. The calculated ‘ERC’ corresponding to a ‘Control Signal’ of 1.0 ‘E’ shall be not less than 0.45. 18.104.22.168 The provisions of clause 22.214.171.124 (computer simulation allowed) also apply to clause 38.4.1 (service effectiveness calculation).
38.4.2. Service Brake Fade Calculation
The ‘Service Brake System’ shall be considered to have sufficient brake fade resistance to meet the requirements of this Rule if the fade resistance of the individual axles rated according to the dynamometer test in clause 38.3.8 and clause 38.3.10, or the road fade test in clause 38.3.2 and clause 38.3.4 is greater than the requirement of clause 126.96.36.199 (distribution of effort).
38.4.3. ‘Emergency Brake System’ Calculation.
The ‘ERC’ for the ‘Emergency Brake System’ shall be determined by computing the total braking force at the wheels to which emergency brakes are fitted and dividing by the ‘Total Trailer Axle Load’
188.8.131.52. The braking force at each ‘Axle’ shall be calculated according to
F is the tangential force at the braked wheels on the ‘Axle’ concerned
A is the input to the emergency brakes actuator
T is the ratio of output torque to input signal for the emergency brakes
R is the rolling radius of the tyre fitted to the wheel.
In most cases this will be the same as for the ‘Foundation Brakes’.
184.108.40.206.1. Where the actuating force is dependent on the stroke, as in the case of spring brakes, the force used in the equation above shall be that corresponding to the stroke determined from the data provided for the ‘Brake Device’ at the required actuating force. In the case of spring brakes the actuating force may be converted to an equivalent air pressure and actuator area so the units of the calculation are compatible.
220.127.116.11. The ratio of brake force to static ‘Axle Load’ at each ‘Axle’ must not exceed that specified in the data for the suspension as ‘Approved’ under the provision of clause 18.104.22.168. Higher values correspond to wheel skid and unrealised braking potential.
38.4.4. Parking Brake Calculation
22.214.171.124. The performance of the ‘Parking Brake System 38/00’ shall be determined on the basis of the characteristics of the ‘Foundation Brakes’ (where applicable) provided under clause 126.96.36.199 (‘Foundation Brakes’) and the control force available at the ‘Brakes’ actuator.
188.8.131.52. The provisions of clause 184.108.40.206.1 (spring brake force) shall apply.
220.127.116.11. When ‘Emergency Brake System’ performance data are used to demonstrate compliance of the ‘Parking Brake System 38/00’, the geometry of the ‘Brakes’ shall be such that brake effectiveness will be not less in the reverse direction.
38.4.5. Time Response
18.104.22.168. The time response of a ‘Brake System’ may be taken as complying with the requirements of this Rule if the ‘Brake System’ is installed in a manner identical to that prescribed in the documentation describing the ‘Approved’ ‘Control System’ used, except as allowed in clause 22.214.171.124 .
126.96.36.199. Actuator sizes and line lengths may be reduced to less than those specified in the ‘Approved’ ‘Control System’ documentation, but devices, fittings and other dimensions may not be changed without voiding approval of the ‘Control System’ in regard to time response.
38.4.6. Specification of ‘Brake System’ Components
Sub-assemblies of ‘Brake System’ components may be ‘Approved’ by the ‘Administrator’ as part of the ‘Brake System’ approval process where information has been supplied in accordance with the requirements of this clause.
188.8.131.52. ‘Control System’
184.108.40.206.1. The ‘Control System’ shall be characterised by comparing output and input signal strengths at not less than five points equally spaced over the range 0.2 ‘E’ to 1.0 ‘E’.
220.127.116.11.2. The input signal strength shall be the final value of the signal and shall be applied to the ‘Control System’ such that it rises from zero to 65 per cent of the final value in not more than 0.22 second.
In the case of air ‘Brake Systems’ the input ‘Control Signal’ strength (kPa) will be measured at the trailer ‘Control Line’ coupling.
18.104.22.168.3. The output signal strength shall be the final value of the signal generated for control of the ‘Brakes’ actuator and which shall be reached in not more than two seconds. The output signal strength (kPa) will be measured in the actuator attached to each output having a fundamentally different relation to the input.
In the case of air ‘Brake System’s’ a ‘Control Signal’ path having additional pressure limiters, relay valves or other active devices will be considered as being fundamentally different.
22.214.171.124.4. Time response shall be measured where necessary in accordance with clause 38.3.11 (time response measurement). Where the ‘Control System’ is not installed on an actual trailer, it shall be installed in an essentially identical manner, in the laboratory, with all bends, fittings and worst case line lengths and representative actuator volumes installed. Actuator displacement shall be the largest volume for which the ‘Control System’ is designed and it may be represented by an equivalent fixed volume.
126.96.36.199.5. All relevant test conditions pertaining to clause 38.3.2 (road test general conditions) shall be complied with.
188.8.131.52.6. The ‘Control System’ to be approved shall be fully documented and the logic of its operation described and assurances provided that the ‘Control System’ will meet the systems requirements of this Rule.
184.108.40.206. ‘Foundation Brakes’
220.127.116.11.1. The effectiveness of the ‘Foundation Brakes’ shall be characterised by comparing the ‘Control Signal’ provided to the ‘Brakes’ actuator against the output brake torque of the ‘Brakes’ device at not less than five points approximately equally spaced over the range 0.2 ‘E’ to 1.0 ‘E’.
Parameters relevant to the specification of the ‘Brakes’ actuator, and its stroke at each ‘Control Signal’ level, shall be recorded. In the case of ‘S-Cam’ air systems this will include the actuator size, slack adjuster length and any other special feature.
18.104.22.168.2. Measurements shall be taken under the conditions prescribed for the dynamometer test in clauses 38.3.8 and clause 38.3.9 or in accordance with the relevant conditions for the road test described in clause 38.3.2 and clause 38.3.3.
22.214.171.124.3. The ‘Brakes’ shall be burnished before conducting any effectiveness tests according to the brake manufacturer’s recommended procedures.
126.96.36.199.4. Specification of effectiveness for ‘Foundation Brakes’ shall be on the basis of ‘Axle’ performance with two brake assemblies rather than wheel performance.
188.8.131.52. Suspension Behaviour
184.108.40.206.1. Suspensions shall be classified by the ‘Administrator’ as ‘Brake Reactive Suspensions’ or non ‘Brake Reactive Suspensions’.
220.127.116.11.2. Suspensions being determined as brake reactive shall be further specified in accordance with the remainder of clause 18.104.22.168.
22.214.171.124.3. The ‘Skid Limit’ for each ‘Axle’ as determined by the need to provide service, emergency and parking ‘Brakes’ shall be determined. It is necessary to determine the ‘Skid Limit’ for each braked ‘Axle’ in a group of ‘Axles’ connected by a ‘Brake Reactive Suspension’ to ensure that brake induced ‘Axle’ Load changes do not lead to premature wheel lock-up. Note: Premature wheel skid could either be unsatisfactory in its own right (service brake effectiveness) or it could invalidate calculations based on no-skid performance (parking and emergency brake effectiveness).
126.96.36.199.4. For a ‘Service Brake System’ ‘Axle Group’ the ‘Skid Limit’ value, or a range of values, at a total retardation not less than 0.45 the ‘Axle Group’ load shall be determined.
The test result shall be reported as the value of the indicated retardation force for each ‘Axle’ divided by the greatest of the ‘Axle’ retardation forces.
In the case of ‘S-Cam air ‘Brake Systems’ the overall
effect of changing actuator and slack adjuster sizes can be
simulated by individually adjusting the air pressure to
188.8.131.52.5. For an ‘Emergency Brake System’ or a ‘Parking Brake System 38/00’ the ‘Skid Limit’ value shall be specified as the dimensionless ratio:
Indicated retardation force
Static ‘Axle Load’
The limit value should be determined by increasing the braking uniformly on all the wheels concerned until one wheel locks.
184.108.40.206.6. For the purpose of testing the suspension shall be installed in a typical trailer application, be fitted with ‘Axles’, wheels and tyres of a size appropriate to the mass rating of the suspension, and be fitted with identical calibrated ‘Brakes’ at each ‘Axle’.
“Calibrated” in this case means that the relationship between the input ‘Control Signal’ and the output torque for the ‘Brakes’ on each ‘Axle’ has been measured. ‘Skid limits’ may be determined either dynamically or at a low speed under drag conditions, in either case at a test mass not less than one half ‘GGALR’.
Note. Rigid ‘Drawbar’/chassis installations will not be considered as typical of installations on ‘Pig Trailers’ having a pivoted ‘Drawbar’.
38.5. ALTERNATIVE STANDARDS
(Refer to clause 220.127.116.11.)
‘ANTILOCK SYSTEM’ FOR TRAILERS DESIGNED FOR USE IN ‘B-DOUBLES’
A.1 PERFORMANCE REQUIREMENTS
A.1.1 Trailers designed for use in ‘B-Doubles’ which incorporate one or more ‘Antilock Systems’ must meet the following requirements:
A.1.1.1 The ‘Brake System’ of trailers must comply with the requirements of ADR 38/00 with the ‘Antilock Systems’ operational.
A.1.1.2 At speeds exceeding 15 km/h the wheels on the ‘Axle(s)’ specified in clause A.2.1 must remain unlocked when a ‘Control Signal’ of 1 ‘E’ (650 kPa) is suddenly applied from an initial speed of 40 km/h +5 to - 1 km/h and from an initial speed of at least 80 km/h on a road surface having approximately uniform surface friction on both sides of the vehicle.
A.18.104.22.168 This test is to be performed with the trailer laden to both ‘Lightly Laden Test Mass’ and ‘Maximum Loaded Test Mass’ and using the general test conditions from ADR 38/...
A.22.214.171.124 Brief periods of locking of the wheels are allowed, but stability must not be affected.
A.1.1.3 In the event of failure of an ‘Antilock System’, the braking performance of the ‘Service Brake System’ and ‘Emergency Brake System’ must be maintained.
A.1.1.4 The operation of an ‘Antilock System’ must not be adversely affected by magnetic or electric fields.
A.1.1.5 The ‘Control System’ equipped with an ‘Antilock System’ must be shown to meet the requirements of clause 126.96.36.199 (actuation time) and clause 188.8.131.52 (release time) by testing in accordance with clause 184.108.40.206.
A.2 INSTALLATION REQUIREMENTS
A.2.1 an ‘Antilock System’ complying with clause A.1.1 must be fitted to:
A.2.1.1 each ‘Single Axle’;
A.2.1.2 at least one ‘Axle’ in any ‘Tandem Axle Group’;
A.2.1.3 at least two ‘Axles’ in any ‘Triaxle Group’.
A.3 ’ANTILOCK SYSTEM’ ELECTRICAL SYSTEM.
A.3.1.1 ‘Antilock Systems’ must be powered by a 12V electrical supply system, through a connection to towing vehicle, using a connector conforming to DIN Standard 72570 configured for 12 volt operation.
A.3.1.2 The connector must be wired to have the following functions :
Pin 1 +ve high current trailer solenoid valve supply, 30 amps minimum rated capacity
Pin 2 +ve low current trailer electronic unit supply, 4 amps minimum rated capacity
Pin 3 -ve low current trailer electronic unit supply, 6 amps minimum rated capacity
Pin 4 -ve high current trailer solenoid valve supply, 30 amps minimum rated capacity
Pin 5 railer antilock failure, switched to -ve (e.g. pin 3 or pin 4) upon fault detection, 2 amps minimum rated capacity
A.3.1.3 Any break in the supply of electricity to an ‘Antilock System’ and any electrical failure of an ‘Antilock System’ other than a failure of one or all of the electrical conductors between pins 3, 4 and 5 on the electrical connector and the antilock control module must be signalled to the towing vehicle by connecting Pin 5 on the electrical connector to –ve (ie pin 3 or pin 4).
A.3.1.4 Each ‘Antilock System’ must connect pin 5 to -ve (e.g. pin 3 or pin 4) when initially energised and disconnect pin 5 from -ve at the latest when the trailer reaches a speed of 15 km/h and no defect is present.
NOMENCLATURE FOR FIGURES 2 AND 3
A = a supply connection with single check valve and regulator set at 650 kpa
CF = trailer brake actuator
L = coupling hose, 13 mm nominal bore and 2.5 metres long
M = Pressure gauge
O = orifice (see clause 16.4)
R1 = reservoir of not less than 30,000 mL
R2 = calibrating vessel of 800 ± 5 mL
RA = shut off valve
TA = coupling head - supply (emergency)
TC = coupling head - control (service)
TOA = transducer point for timing inlet to brake actuation time
TOR = transducer point for timing inlet to brake release time
T1 = transducer point for calibration at end of R2 reservoir
T2 = transducer point for testing rear tow coupling of trailer
T3 = transducer point for testing trailer
V = brake control valve
* The category code may also be in the format L1, LA etc.