Initiated by: Administrator, Motor Vehicle Standards Date of Issue: May 1992
Replaces Bulletin 7 Part A, Issued December 1991 Date of Effect: Immediate
National Code of Practice
Design Parameters Necessary for Compliance with ADR 59/00 Omnibus Rollover Strength.
THIS CODE OF PRACTICE SETS DOWN A SIMPLE SET OF RULES FOR CONSTRUCTION OF A LIMITED RANGE OF BUS STRUCTURES, WHICH ALLOW SUCH STRUCTURES TO BE DEEMED TO COMPLY WITH AUSTRALIAN DESIGN RULE 59/00 “OMNIBUS ROLLOVER STRENGHT”.
PART B, being issued separately, provides a more complex set of rules to allow a larger range of structures deemed to comply with ADR 59/00.
The Vehicle Standards Bulletin provides information for those associated with the design, manufacture, sale, maintenance or repairs of motor vehicles and trailers.
The series is a major channel for communication from the Vehicle Safety Standards Branch in the case of matters relating to new vehicles, and from the Australian Transport Advisory Council and its committees in the case of vehicles in service.
ADR 59/00 comes into force on 1 July 1992 for category ME buses, having a GVM of in excess of 5 tonnes. It requires that manufacturers shall demonstrate that buses have sufficient strength to withstand a specified sideways rollover, without deforming to the extent that a specified "residual space" is intruded upon by any part of the bus structure or fittings. The Design Rule offers four possible ways in which compliance may be demonstrated, viz
Test by rolling a complete bus.
Test by rolling a section or sections.
Test by imposing a pendulum load to a section or section Verify by an approved calculation method
To assist bus manufacturers, and in particular the smaller manufacturers, the Federal Office of Road Safety (FORS) agreed in discussion with the Australian Bus and Coach Manufacturers Association (ABCA), to undertake a programme of investigation and testing, aimed at developing a National Code of Practice. It was agreed that manufacturers who could demonstrate that they had followed the code of practice in the construction of particular buses, would have such vehicles accepted by FORS as complying with the requirements of ADR 59/00, without the need for further testing or analysis as outlined above.
A sub-committee of ABCA was formed to provide guidance to FORS on omnibus construction. At its first meeting it was agreed that, to form a basis for the code, FORS would carry out the following:
Build a generic two axle, approximately 9 tonne tare mass, bus having a frame that included a rollover protection cage, generally in a manner (outlined by FORS) as having been found satisfactory in the United Kingdom.
Carry out a computer analysis of the test bus frame, using a suitable programme.
Roll the test bus in accordance with ADR 59/00.
Compare the observed results of the roll test with those predicted by computer analysis, so that the application of the proposed code could be made sufficiently wide to be suitable for a reasonably wide range of buses.
Clearly it was unlikely that one configuration of bus could be made to truly represent all the possibilities in category ME buses. However, it was decided that the configuration chosen represents a significant proportion of the 50 to 58 seating position buses that are used for:
Local and district route runs in suburbs and country towns. Charter and tourist work other than long distance work.
Some city route runs.
The sub committee has considered the proposed frame drawings submitted to them and accepted them as a reasonable basis for the construction of buses to withstand service requirements.
A bus body frame of the type outlined above has now been built and roll tested. The bus met the requirements of ADR 59/00 successfully; an initial computer analysis of the frame is in progress at December 1991. Comparisons will be drawn with the measured results of the test.
Because of time constraints, it has been decided to issue the code in two parts:-
Part A, which is this document, sets down rules for construction, based on a fairly narrow interpretation of the results so far of testing and analysis. The rules set down in this document are closely based on the structure of the test bus and are therefore prescriptive. However, Part A requires almost no design testing and, as bus structures built to it will be deemed to comply with ADR 59/00, it provides an easy method by which manufacturers can attain compliance of the buses they build.
Part B. This part of the code allows for the wider application of the code to different bus shapes, sizes and configurations. Part B of the code, also allows for manufacturers to make suitable, relatively inexpensive tests, in order to validate such variants of the roll cage beyond those defined in Part A, for acceptance as complying with ADR 59/00.
It will be appreciated that this part A of the code, is directed primarily at the design and construction requirements of a bus that will be acceptable under ADR 59/00.
Manufacturers will need to take care in construction, for example, of joints in the roll cage which may be subject also to fluctuating stress conditions in ordinary service loading.
Manufacturers intending to meet ADR59/00 by means of the Part A Code of Practice will be subject to Conformity of Production assessment for Quality Assurance. The Code outlines the procedures necessary to meet Quality Assurance requirements.