Windshield Wiper Systems - Trucks, Buses, and Multipurpose Vehicles
This SAE Recommended Practice establishes for left-hand steer on-road trucks, buses, and multipurpose passenger vehicles with GVW of 4500 kg (10 000 lb) or greater:
a. Minimum performance requirements for windshield wiping systems.
b. Uniform test procedures that include those tests that can be conducted on uniform test equipment by commercially available laboratory facilities.
c. Uniform terminology of windshield wiper system characteristics and phenomena consistent with those found in guides for the use of engineering layout studies to evaluate system performance.
d. Guides for the design and location of components of the systems for function, servicing of the system, etc.
The test procedures and minimum performance requirements, outlined in this document, are based on currently available engineering data.
It is the intent that all portions of the document will be periodically reviewed and revised as additional data regarding windshield wiping system performance are developed.
Rationale: The requirements in the previous version of this standard established wiper durability based on the GVW of the vehicle with a cut-off at 11 800 kg (26 000 lb) GVW. The intention was to prescribe a greater durability requirement for over-the-road (OTR) trucks that have long life expectancy. This, however, meant that some low-mileage vocations such as recreational vehicles, fire apparatus, school buses, etc. would be held to the higher durability standard simply because of their GVW. Other vocations below 11 800 kg (26 000 lb) GVW would not require the higher durability even though their mileage life expectancy may be high. The standard has therefore been revised to recommend wiper durability based on the life expectancy of the vocation (in miles) rather than the GVW.