Pavement Preservation Journal - Summer 2015 - (Page 39)

New Cold Milling Rules will Reduce Respirable Silica By Tom Kuennen IMAGE CREDIT: TOM KuENNEN  A t World of Asphalt/AGG1 2015 in March in Baltimore, the road maintenance and pavement preservation community celebrated the release of new industry cold milling guidelines that will provide a reduction in airborne silica particles in the work zone, while forestalling onerous industry regulations. The new guidelines, released in March - Best Practice Engineering Control Guidelines to Control Worker Exposure to Respirable Crystalline Silica during Asphalt Pavement Milling - are the result of a collaboration between federal worker safety agencies, national associations and labor unions, and cold milling equipment manufacturers. Available as DHHS (NIOSH) Publication No. 2015-105, the document represents more than 10 years of collaborative research by labor, industry and government to reduce respirable crystalline silica exposure during asphalt pavement milling in highway construction. The collaborative research began when the Silica/Asphalt Milling Machine Partnership was formed at the 2003 National Asphalt Pavement Association annual meeting, and studies on milling machine dust controls began later that year. At World of Asphalt/AGG1 2015 observance, National Asphalt Pavement Association president Mike Acott recounts the challenges - and public/ private collaboration - involved in developing new manufacturer guidelines to reduce respirable crystalline silica in asphalt cold milling operations NIOSH recommends the use of ventilation controls to control worker exposures to respirable crystalline silica during asphalt pavement milling in highway construction. The ventilation controls used in combination with water-sprays that cool the cutting teeth can consistently reduce exposures below the NIOSH recommended exposure limit of 0.05 mg/m3. The partnership conducted considerable research to develop best practice recommendations for water-spray dust suppression on asphalt milling machines. NIOSH recommends using best practice water-spray systems on asphalt milling machines that do not have ventilation controls. Two effective dust control methods utilizing water sprays that are readily applicable to asphalt pavement milling operations are dust prevention and suppression techniques, the guidelines say. First, dust prevention is achieved by spraying water onto the pavement being milled in order to prevent dust from being liberated or generated and becoming airborne. The second method, dust suppression, involves knocking down airborne dust by spraying the dust cloud and causing the particles to collide, agglomerate, and fall from the air. A common and effective practice is to use a combination of both of these wet methods in the overall dust control plan. As water is used on all asphalt pavement-milling machines to cool the cutter bits, it is logical to also use this water for respirable dust control. The complete report and associated spreadsheet are available for download. Visit http:/ / docs/2015-105/ for your copies. Summer 2015 pavement preservation journal 39

Table of Contents for the Digital Edition of Pavement Preservation Journal - Summer 2015

President’s Message
Pavement Preservation World Convenes at PPRS Paris 2015
PPRS Paris: ARRA, AEMA and ISSA Meet at Same Venue
Superior Program Earns FP2 Award for Charleston County
Focus on Preservation at NCAT Pavement Test Track Meeting
Preservation Paramount at Record World of Asphalt
Under Traffic, Rejuvenating Fog Seal Preserves I-475
New Cold Milling Rules will Reduce Respirable Silica
Revised Recycling Manual Now Available from ARRA
San Diego County Preservation Work Wins ISSA’s Top Award
Report: Enhancer Provides Antistrip Performance in Adverse Conditions
Index of Advertisers

Pavement Preservation Journal - Summer 2015