Item B - Ice and Snow Policy - Laserfiche WebLink

Home Browse Search

Ice Slicer is a naturally occurring complex chloride ice-melter consisting of synergistic trace minerals plus magnesium, potassium, sodium, and calcium chlorides, and grit. The material is mined in Utah. Realite is only used in limited snow situations. It is a lightweight shale material that has been baked at 2000 degrees to make it harder, lighter and more porous. It is saturated in a calcium chloride solution. Since Realite is coated with a dust suppressant, and due to the durability of the product, the degradation is delayed and dust particles tend to bind together, keeping the fines from becoming airborne and contributing to the "brown cloud." However, DRCOG and the RAQC recommend the crystallized deicers that dissolve over any traction material that breaks down. Environmental Effects: Numerous studies have been done over the years by the federal and state governments, departments of transportation, and by the material vendors to determine the environmental impacts of the deicers and traction materials being used throughout the country. On an ongoing basis, city water quality staff has conducted water quality testing of the materials the city is using in its snow and ice control programs and have found no significant impacts to-date. Staff tries to stay current on the latest reports and makes its decisions on material use based on recommendations of DRCOG and RAQC as well as on recommendations and standards set by the industry and environmental groups. Attached is a matrix from a study showing the effects of magnesium chloride on vegetation, soils, water quality, aquatic life, and humans and mammals (Attachment 1). Levelton Engineering Ltd of Richmond, British Columbia did this matrix in 1998 as part of a report to the Insurance Corporation of British Columbia. Corrosion: The industry measures corrosion based on "PNSDOT" standards. Transportation agencies within the states of Washington, Oregon, Montana and Idaho and the province of British Columbia formed a committee several years ago to develop specifications for chemicals related to snow and ice control. The committee has evolved to become the Pacific Northwest Snowfighters (PNS) Association. The association has developed performance specifications for corrosion. Caliber MlO00 deicer passes the tests developed by the National Association of Corrosion Engineers Standard TM-02-69 as modified by the PNS. The specification set by the PNS is that materials must be 70 percent less corrosive than salt. Caliber MIO00 corrosion rate is 22 for metals (78 percent less corrosive than salt). For comparison, the corrosion rate for distilled water is zero and 100 for rock salt (sodium chloride). Staff could not find a PNS rating for the Ice Slicerwe have been using and the product does not show on the PNS approved materials list. (PNS does show a rating for a new enhanced Ice Slicer.) However, other non-PNS tests and standards (including the Utah Department of Transportation approved testing method - American Standard Testing Methodology) show a corrosion rate of 30. Corrosion tests on cold rolled steel, galvanized steel, and aluminum show the following penetration rates per year for Ice Slicer. Type of Metal Penetration/Year Converted to Inches/Year Cold Rolled Steel 4.643 millimeters .18"/year Galvanized Steel 25.44 microns .001 "/year Aluminum 18.55 microns .00073'/year