Attachment 8 - traffix-sentry_water-freezing-prevention.pdf
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- Attached to
- FASTC Barrier Replacement
- Solicitation number
- 19AQMM26R0459
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This document is a technical specification section addressing water freezing prevention requirements for SLED (work zone) modules. The guidance applies when ambient temperatures are expected to reach or fall below 32°F (0°C), recommending the use of additives to prevent water solidification within the modules.
Five freeze-prevention additive options are detailed with specific formulation ratios, protective temperature ranges, environmental impacts, and cost considerations. Salt (Sodium Chloride) at 20% by weight provides protection to 0°F at low cost but poses corrosion risks to inadequately protected steel and environmental hazards. Calcium Chloride at 35% by weight protects to 20°F with medium cost but creates corrosion and environmental concerns. Ethylene/Propylene Glycol at 50% by volume protects to 0°F at high cost while presenting dangerous environmental impacts. Liquid CMA (Calcium Magnesium Acetate) at 25% by volume and Liquid Potassium Acetate at 60% by volume both protect to 0°F and 20°F respectively, feature non-toxic environmental profiles, and carry high costs. The document emphasizes pre-mixing additives before filling, preventing spillage in environmentally sensitive areas, and draining solutions in acceptable locations. A comparison table synthesizes these parameters to facilitate additive selection based on temperature requirements, environmental considerations, and budget constraints.
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Revision C (Dated DRAFT) 14
Water Freezing Prevention
In freezing weather conditions, do not allow the water in the SLED modules to freeze to a solid mass of ice. If the temperature at the SLED site is expected to be at or below the freezing point of water 32° F [ 0°C ], it is recommended that an additive be used to prevent the water in the SLED modules from freezing. See Table 1 on pg 17.
-Common additives used to prevent water freezing currently used in work zone devices under the same category as the SLED Modules.
SALT (Sodium Chloride) 20% mixture by weight Reduces freezing down to 0° F [-18° C].
Corrosive to inadequately protected steel components (Galvanizing adequately prevents corrosion) Recommended - premix before filling Prevent spilling since solution is harmful to vegetation, soils, and wildlife. Draining should be done in an acceptable area.
CALCIUM CHLORIDE
35% mixture by weight Reduces Freezing down to 20° F [ -6.6 °C ].
Corrosive to thin zinc plated components Corrosive to inadequately protected steel components (Galvanizing adequately prevents corrosion) High tendency to stay on road surface resulting in slick road surface.
High level of heat created when mixing. It is recommended that pre-mixing is done before filling.
Prevent spilling since solution is harmful to vegetation, soils, and wildlife. Draining should be done in an acceptable area.
ETHYLENE/PROPYLENE GLYCOL
50% mixture by volume Reduces water freezing to 0° F [-18° C].
High tendency to stay on road surface resulting in slick road surface.
Prevent spilling since solution is harmful to vegetation, soils, and wildlife. Draining should be done in an acceptable area.
LIQUID CMA (Calcium Magnesium Acetate) 25% mixture by volume Reduces water freezing to 0° F [-18° C].
Has a low environmental impact.
LIQUID POTASSIUM ACETATE
60% mixture by volume Reduces water freezing to 20° F [-6.6° C] Low corrosive characteristics and has a low environmental impact.
Revision C (Dated DRAFT) 15
Additive Environmental
Impact Cost Rating Protection Temp Mix Solution Ratio
Salt (Sodium Chloride) Harmful Low 0 °F [-18 ° C] 20% by weight
Calcium Chloride Harmful Medium 20 °F [-6.6 ° C] 35% by weight
Ethylene/Propylene Glycol Dangerous High 0 °F [-18 ° C] 50% by volume
Liquid CMA Non-Toxic High 0 °F [-18 ° C] 25% by volume
Liquid Potassium Acetate Non-Toxic High 20 °F [-6.6 ° C] 60% by volume
Table 1- Recommended water freezing prevention chart solution comparison.
File details come from the government source that posted it. Updated .