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Liquid Chemicals in Snow and Ice Control. 3/29/2014 DistrictLCCLiquidowSalt Brine 10912.321,110,033.00 240,729.600363,056.00 316,449.370381,580.00 494,488.0001,827,784.00.

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Presentation on theme: "Liquid Chemicals in Snow and Ice Control. 3/29/2014 DistrictLCCLiquidowSalt Brine 10912.321,110,033.00 240,729.600363,056.00 316,449.370381,580.00 494,488.0001,827,784.00."— Presentation transcript:

1 Liquid Chemicals in Snow and Ice Control

2 3/29/2014 DistrictLCCLiquidowSalt Brine ,110, , , , , , ,827, , , , , , , , , , , , , , , Total353,1529,0186,697,066

3 3/29/2014 Chemicals: How do they work? Depress the freezing point of water, turning ice or snow into liquid or slush Solid salts dissolve to form brine solution

4 3/29/2014 Chemical Terms Concentration % by weight of chemical in solution Eutectic Temperature Lowest Temp solution will melt ice Endothermic Requires heat when going into solution Exothermic Gives off heat when going into solution Hygroscopic Draws water from the air

5 3/29/2014 Liquid Chemical Uses Anti-icing FHWA Manual Pre-treatment Plan Pre-wetting solids Lower temperatures Less bounce and scatter

6 3/29/2014 Anti-icing Creating a chemical layer ahead of the event to: Prevent freeze bond Prevent frost or black ice formation Increase needed response time Anti-icing chemicals Liquids Pre-wetted solids

7 3/29/2014 Resource for All Snow & Ice Winter Maintenance Need FHWAs Manual of Practice for an Effective Anti-Icing Program FHWAs Manual of Practice for an Effective Anti-Icing Program

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9 Anti-icing Rules of Thumb Less is Best Applied in controlled amounts to leave surface merely damp Does not result in the flow of liquid across the pavement Monitor Pavement Temperatures Quick re-freeze occurs at lower temperatures Monitor Humidity Higher humidity can cause slickness issues Does not replace de-icing techniques

10 3/29/2014 Pre-wetting Solids Improves effectiveness at lower temperatures Reduces bounce and scatter Application at auger (not spinner) is most effective Rule of Thumb – It is always more efficient to pre-wet solids

11 3/29/2014 Typical Liquid Products Natural Occurring Salts Sodium Chloride – 23% solution Calcium Chloride – 32% solution Magnesium Chloride – 28% solution Potassium Chloride Other Chemicals Urea Calcium Magnesium Acetate Agricultural Products – Both by-products and engineered products Various Additives

12 3/29/2014 Phase Diagrams

13 3/29/2014 Evaluating Snow & Ice Control Chemicals Product Performance Use Criteria Infrastructure Impacts Environmental Impacts Availability Cost

14 3/29/2014 Evaluating Snow & Ice Control Chemicals Performance (deicing mechanics) Effective temperature range Speed Quantity needed Duration of melting action

15 3/29/2014 Evaluating Snow & Ice Control Chemicals Use Criteria Equipment requirements Storage & handling needs Application versatility Safety & hygiene considerations

16 3/29/2014 Evaluating Snow & Ice Control Chemicals Infrastructure Impacts Structures (bridges, buildings) Roadway pavement & structure Vehicles & equipment

17 3/29/2014 Evaluating Snow & Ice Control Chemicals Environmental Impacts Soil Animals Vegetation Water Air Human Health

18 3/29/2014 Evaluating Snow & Ice Control Chemicals Availability Cost Availability Alternatives Performance Use Criteria Infrastructure Impact Environmental Impact $$

19 3/29/2014 Other Natural Salts Calcium Chloride Natural State - Liquid Magnesium Chloride Natural State - Liquid Potassium Chloride Natural State - Solid Common Use: Prewetting Anti-icing

20 3/29/2014 Other Natural Salts Calcium Chloride Exothermic: gives off heat Hygroscopic: attracts moisture Eutectic Temp: -60 o F 30-33% concentration in solution Magnesium Chloride Exothermic: gives off heat Hygroscopic: attracts moisture Eutectic Temp: -28 o F 22-26% concentration in solution

21 3/29/2014 CMA (Calcium Magnesium Acetate) FHWA originally identified CMA as a possible replacement for salt in CMA manufactured by reacting dolomitic lime with acetic acid.

22 3/29/2014 CMA Use Bridge Structures Parking Garages Environmentally Sensitive Areas

23 3/29/2014 Corrosion More corrosive –Calcium Chloride –Sodium Chloride –Magnesium Chloride –CMA –Urea Less Corrosive

24 3/29/2014 Chemicals Specifications Material Safety Data Sheet (MSDS) Sample and test (certification) Talk to other users: effectiveness, concerns, problems Storage Issues – some chemicals require circulation

25 3/29/2014 Material Handling Safe Chemical Handling Labels MSDS (Material Safety Data Sheet) Personal Protective Equipment Common Sense & the Right Attitude!

26 3/29/2014 MSDS Material Safety Data Sheets Manufacturers Data Product ID Major Components Hazardous Ingredients Physical Data Fire & Explosion Data Reactivity Data Health Hazard Info Emergency & First Aid Procedures Personal Protection Equipment Spill, Leak & Disposal Procedures

27 3/29/2014 Chemical Handling Toxicity vs. Hazard Hazard = toxicity + exposure Toxicity: LD 50 & LC 50 Just how toxic are snow and ice control chemicals to human health?

28 3/29/2014 Toxicity Classification CategoryOral LD 50 (Rat, mg/KG body wt) Probable Human Lethal Dose Extremely Toxic<1<1Taste Highly Toxic1-5Teaspoon Moderately Toxic50-500Ounce Slightly Toxic500-5,000Pint Practically Nontoxic5,000-15,000Quart Relatively Harmless>15,000>1 Quart

29 3/29/2014 Toxicity Comparison *LD 50 (rat, mg/KG body wt.) highest toxicity first Material Nicotine Caffeine Calcium Chloride Aspirin Salt (Sodium Chloride) Calcium Magnesium Acetate Magnesium Chloride Vitamin C *LD 50 < Human Category Extremely Toxic Moderately Toxic Slightly Toxic Practically Nontoxic

30 3/29/2014 Snow & Ice Chemicals Common Potential Problems Eye Irritant Skin Irritant Breathing Irritant - Dust or Mist Inhalation Good Personal Hygiene & Personal Protective Equipment

31 3/29/2014 Chemical Handling Gloves Shoes & Boots Eye Protection Dust Mask Attitude

32 3/29/2014 Choosing a New Chemical A big opportunity (as you shift to liquids) What do you need the chemical to do? What constraints do you have on how the chemical will perform? Approach is based on the Guide for Selecting Anti-Icing Chemicals Copy included on reference disk

33 3/29/2014 Purpose of the guide Differentiate between different chemicals on the basis of performance acknowledge that different agencies have different needs allow factors to be weighted

34 3/29/2014 Categories Used Freezing point depression Consistency Viscosity Specific gravity Environmental Impact Heavy metals BOD/COD Toxicity Stability Corrosion Handling Documentation Unspecified content Completeness

35 3/29/2014 Most Important Ones Depends on your needs Is corrosion a big issue for you? What about the environment? Definitely freezing point depression Consistency Complete documentation

36 3/29/2014 Why Freezing Point Depression? Tells whether its suitable for your climate Tells when you should stop using it because its too cold Tells how much youll need to fight a typical storm

37 3/29/2014 How Freezing Point Depression? Based on the eutectic curve BUT, not just the eutectic point Its more an indicator of melting action Need to know two temperatures At half the concentration of the EP At quarter of that concentration

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39 How does NaCl do? The half point is about 15 F Typically represents lower end of the useful range of salt use The quarter point is 26 F Illustrates impact of dilution

40 3/29/2014 Chemical Comparison NaCl (salt) sodium chloride CaCl calcium chloride MgCl magnesium chloride KCl potassium chloride KAc potassium acetate CMA calcium magnesium acetate Urea ChemicalEutectic Temp Conc. o C o F % by weight

41 3/29/2014 Chemical Comparison Eutectic vs Effective Temp NaCl (salt) sodium chloride CaCl calcium chloride MgCl magnesium chloride KCl potassium chloride KAc potassium acetate CMA calcium magnesium acetate Urea ChemicalEutectic Effective* o C o F o C o F

42 3/29/2014 What about Consistency? The addition of organic chemicals and by-products makes some new liquid products much more variable than traditional chemicals You MUST know that the product you use this week performs the same as what you used last week

43 3/29/2014 How do we Measure Consistency? Have to use index tests Viscosity and specific gravity are easy to do and will quickly tell you if something isnt right The only long term answer is good quality program with suppliers

44 3/29/2014 Why Documentation? You cant compare products if you dont have enough information Any worthwhile product will come with documentation, test results and so forth Provide a critical input for your choice

45 3/29/2014 How Documentation? Two factors How much of the product is termed other in the chemical analysis? Do the suppliers give you all the info you need?

46 3/29/2014 Another factor for Consistency and Documentation Legal issues You HAVE to know what youve put on the road If you dont, you are very vulnerable during the deposition/trial process

47 3/29/2014 So how do we rate different products? Set levels within each category Weight the categories according to which matter to you Then grade the chemicals (multiply their category level by their weight to get a grade point score) See the guide for more details

48 3/29/2014 Pacific Northwest Snowfighters pns/ pns/ Evaluate and establish specifications for materials used in winter maintenance Approved product list

49 3/29/2014 Salt Institute Salt Institute Salt Institutes Winter Maintenance Material: What are you Using? Salt Institutes Are You Using the Right Amount of Ice Control Chemical? (based upon findings of NCHRP 6-13) Copies included on reference disk

50 3/29/2014 SICOP Website Snow and Ice Pooled Fund Cooperative Program, SICOP Snow and Ice List Serve _list-serve.htm _list-serve.htm

51 3/29/2014 Reference Materials FHWA Manual of Practice for an Effective Anti-Icing Program Appendices A and B eapcov.htm eapcov.htm Nixons Guide for Selecting Anti-icing Chemicals (on reference disk) NCHRP 6-13 Guidelines for Snow and Ice Control Materials and Methods Chapter 6 Hard copy provided Chemical Recommendation Tool Worksheet On reference disk

52 3/29/2014 Reference Materials (continued) NCHRP 526 Snow and Ice Control: Guidelines for Materials and methods Table A-6 Equivalent rates (on reference disk) NCHRP Synthesis 344 Winter Highway Operations Table 4, Chemicals used by various agencies (on reference disk)

53 3/29/2014 Material Details Specifications (on reference disk) Liquid Calcium Chloride (32%) Corrosion Inhibited Liquid Calcium Chloride Rock Salt Contract Product Literature SBA-2 and Caliber by Syntech Corp. De-Ice 55 and De-Ice S by Road Solutions Magnesium Chloride products by SWI Ice BGone by Sears Ecological

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55 Website Development odot_snow_and_ice_program.htmhttp://www.dot.state.oh.us/maintadmin/ odot_snow_and_ice_program.htm

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