Effectiveness of agricultural tractors cabs for protection against hazardous substances in accordance with EN 15695 Part 1.

Tractors and self-propelled machine operators can be exposed to hazardous substances such as plant protection products, fertilizers and other toxic materials generated during soil tillage and harvesting. Cabs fitted on these machines can provide protection against these substances and can be used to reduce operator exposure to air contaminants. Recently available Standard EN 15695-1:2009 provides 2 test procedures to asses the protection cabs are able to assure to operators with regards to hazardous substances. First method consists in measuring the cab tightness using an artificial generated aerosol. A number of studies have conducted to develop this method and references reporting the results are available. The second method, called "blind filter test" in the Standard, consists in blocking the active filter area and measure the leakage flow through the filter seat. So far no details are available about this second method. Thus a blind filter test has been performed on a cab fitted on an agricultural tractor to asses the effectiveness of the method in measurement of tightness of the enclosure. The test has been performed on a 75 kW, four wheel drive orchard tractor fitted with a cab equipped with filtration system with carbon filters. Different combinations of adjustment of the engine and fan speeds, and air recycling and aperture for remote operation have been examined. During the investigation improper assembly of the filter housing has been detected. Therefore the investigation confirms that small cracks due to faults in filter assembly are the major source of penetration of hazardous materials into the cab enclosure. In accordance with result of the study the blind filter test seems to be an attracting method to verify the protection against hazardous materials of cabs fitted on agricultural machines. Furthermore it is simple, do no required special facilities or expensive instrumentation, and particularly skilled personnel. Nevertheless additional tests are necessary for a broader experience in different designed cabs to achieve the same knowledge existing for the alternative procedure to asses the tightness of cabs.