OECD TAD/CA/T(2009)3 - DRAFT PROPOSAL TO REVISE THE LIMITS FOR TECHNICAL EXTENSION FOR MODIFIED MODELS OF PROTECTIVE STRUCTURE IN OECD CODES FOR TESTING OF PROTECTIVE STRUCTURES (CODES 3, 4, 6, 7, 8, 9 and 10)

Since 2007 protective structures Codes (Code 3, 4, 6, 7 and 8, 9 and 10) include the possibility for the manufactures of protective structures to apply for a "Technical extension reports" when technical modification occur on the tractor, on the protective structure or on the method of attachment of the protective structure to the tractor. Manufacturers modify protective structures already having OECD approval for different reasons: mainly to have the possibility to fit the protective structure on different models of tractors or on model of tractors having higher mass (more than 5% increasing). Other technical reasons exist but it is difficult to foresee. Some modification on the protective structure could be minimal (e.g. weld attachment of the mounting plate of an accessory in a non-critical location on the structure, addition of seats with different SRP location in the protective structure) and not affecting the results of the test on the original tests. On the other hand other modifications on the protective structure (e.g. modification of structural components, modification of the method of attachment of the protective structure to the tractor) may affect the results of the original test, without calling into question the acceptability of the protective structure. In this case the testing station can carry out a validation test. The validation test results have to be included in the technical extension report. When a validation test is carried out all the acceptance conditions of the Code have to be fulfilled and the force and the deflection measured when the required energy level has been reached in the various horizontal load tests does not deviate from the force and the deflection measured when the required energy has been reached in the original test by more than ± 7%. The testing, after having checked the fulfilment of all these conditions can issue the technical extension report. The +/- 7% of the deflection/force reached in the original test limit has been introduced into the Codes to reduce the possibility for manufacturers to use the extension procedure as a "shortcut" to have under the same model and OECD approval number protective structures significantly different. No more than 5 technical extensions can be submitted for approval to the Co-ordinating Centre without a validation test has been carried out. More than one modification on protective structure may be included in a single extension report, when these modifications are different options of the same protective structure, but only one validation test can be accepted in a single extension report. The options not tested have to be described in a specific section of the extension report