Determining long-term chipper usage, productivity and fuel consumption

Abstract The Authors surveyed 6 industrial chipping operations for a whole work year, collecting data about machine usage, product output, fuel consumption and chipper knife wear. Despite the challenging work conditions offered by mountain operations, industrial chipping contractors manage to achieve a high machine use, ranging from 500 to over 2,500 h year −1 . Product output varies between 18,000 and over 120,000 m 3 loose chips per year. In order to acquire enough jobs, operators may travel between 1,500 to over 20,000 km in a year. Industrial chipping contractors adopt different operational strategies to achieve their production targets, and they equip accordingly. Some operators prefer to tap smaller local areas and opt for smaller tractor-powered chippers, which are less powerful and productive than larger independent-engine units, but cheaper and capable of negotiating low-standard forest roads. Others prefer to explore larger areas and achieve higher product outputs, and they opt for larger independent-engine chippers, often mounted on trucks. Long term productivity varies with machine type: tractor-powered units produce between 40 and 50 m 3 loose chips per hour, whereas larger independent-engine chippers produce between 60 and 90 m 3 loose chips per hour. Specific fuel consumption is about 0.5 L diesel per m 3 loose chips, regardless of chipper type. A sharp knife set can process between 200 and 1,500 m 3 loose chips before getting dull. Disposable knives last longer and are cheaper to manage than standard re-usable knives.