Section 5: Recommendations for Use of Liquid Chemicals
Anchor: #i1000957Don’t Use During Ice Storms
The use of a liquid is not recommended during either a freezing rain or sleet storm because of the large quantity needed to retain an effective concentration. The application rates are the equivalent dry chemical rates suggested by the manufacturer.
Anchor: #i1000968Using for Snow Storms
For snowstorms, initial liquid applications can be made either as a pretreatment in advance of the storm or as an early-storm treatment, (i.e. soon after snowfall has begun and/or when the pavement temperature is dropping toward freezing).
Anchor: #i1000978Pretreatment
A pretreatment can be made prior to a storm, as long as the storm does not start out with above freezing temperatures and rain, washing the chemical away.
Benefits from liquid pretreatments can include higher friction and better pavement conditions early in a storm. These benefits are generally short-lived and should not be expected over a long period. Subsequent chemical applications should be made as soon as conditions begin to deteriorate. Pretreatments can be thought of as "buying time" in the early stages of a storm until subsequent chemical applications become effective.
Anchor: #i1000993Early-Storm Treatment
In the case of early-storm treatment, the application may be made onto dry, wet, light slush, or lightly snow covered pavement. Late applications onto pavements with more than a light covering of slush or snow can result in excessive dilution of the chemical, lowering its effectiveness.
Anchor: #i1001003Preventing Black Ice
To prevent the formation of frost or black ice (caused by radiational cooling of the pavement in the presence of high humidity) the chemical should be applied before ice is expected to form so the water component of the chemical will evaporate or be removed by traffic action. This will leave only the chemical on the road surface and result in the greatest concentration when frost or black ice conditions occur.