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Liquids

Discussion in 'Ice Management' started by wthistle, Nov 17, 2006.

  1. wthistle

    wthistle Junior Member
    Messages: 1

    Are any of you using liquid deicers. If so, are you using any for pre-treatment (anti-icing) on walks or lots especially.
     
  2. Rampart Ranger

    Rampart Ranger Senior Member
    Messages: 165

    I have applied several million gallons of liquid on interstate highways.

    Pretreatment only works to the point of dilution - 1" of dry powder in most cases (40-60 gal per lane mile). If you can afford to scrape/retreat, if the moisture content of the snow is not too high, if the temperatures do not drop too low - it can work.

    We quickly learned that anti-icing is NOT cost effective for highway use in most cases. Liquid DE-icing can be effective with good operators and large reserves available. You have to be able to scape hard, and apply enough chemical (60-80 GPLM) to deal with accumulation before the next pass. Breaking heavy pack (3" hardpack) often requires application through high pressure pencil nozzles at rates up to 200 GPLM - but when she breaks she breaks RIGHT NOW! This is more effective than mounting the ice cutter blades on the grader and following up with regular plows as we used to do.

    Your mileage may vary - but remember when the MagCL reaches dilution point freezing may occur instantaniously @ or above 33 degrees F!

    The only advantage of pretreatment that I have seen is that it aids in preventing bond of ice to surface. Snowpack will still occur if enough falls, but it will be easier to scrape off when temperatures rise.
     
    Last edited: Nov 17, 2006
  3. Rampart Ranger

    Rampart Ranger Senior Member
    Messages: 165

    I'm sorry, used to dealing in lane miles. These numbers should work for standard concentrations of magnesium chloride in light to moderate snow and temperatures to 18 degrees F.

    EXAMPLE ONLY! FOLLOW RECOMENDATIONS OF YOUR CHEMICAL SUPPLIER!

    1 lane mile = 12' x 5280' = 63360 SqFt

    PRETREAT - 60 GLM = approx 1 gal per 1000 SqFt
    MAINTAIN - 90 GLM = approx 1.5 gal per 1000 SqFt
     
  4. SnowGuy73

    SnowGuy73 PlowSite Fanatic
    Messages: 24,867

    How well do they work as a pre-treater?
     
  5. Rampart Ranger

    Rampart Ranger Senior Member
    Messages: 165

    Pretreat works well until enough snow falls to dilute the solution - usually 1-2 inches depending on moisture content. Scrape and reapply at maintenance rate. Always remove as much snow/slush as possible before reapplication - this extends time interval before next treatment is necessary.

    Liquid anti/deicers fail when they reach dilution point (enough snow has melted to dilute the solution at the given temperature). High moisture content snow and falling temperatures will speed this process.

    Even if you do not reapply, the pretreat will aid in preventing ice bond to surface, making removal at later time easier.

    If you want to use liquids to maintain wet conditions, it is important to keep an eye on temperatures, accumulation, and moisture content. Maintaining wet condition will require much more chemical repeatedly applied at appropriate times.

    In my opinion, the best use of liquid for the small operation is to pretreat critical areas. Plow with the storm, using no liquid. As weather clears out, reapply to prevent refreezing thawed areas.

    At CDOT we often had storms that even our ability to apply massive amounts of liquid did not allow us to maintain wet conditions. We then switched to aggregates for traction. Resumed liquids at cleanup.