History of Snow Removal
According to the National Snow and Ice Data Center, early snow control attempts involved citizens leveling drifts of snow to ease sleigh traffic in the 1700s. Several cities had ordinances requiring homeowners to clear their sidewalks, but streets were not cleared on a city-wide basis. Travel and the exchanging of goods, therefore, depended on individuals clearing the streets themselves. Wintertime travel in the early 1800s was mostly on foot as a result. With increased industrialization in the mid 1800s came the first snow plow, drawn by horses, and enabling transportation to recover quickly following winter storms. The snow plow created the basis for municipal responsibility in snow removal but new problems were also created, as merchants complained about 메리트카지노 the removed mounds of snow blocking their storefronts and sidewalks.
Sleigh drivers also disapproved of the ruts and uneven surface of the streets following plowing. Some cities responded by hiring shovelers to work in conjunction with the plows to haul the snow away and dump into rivers. Salt was used in a few cities but was strongly protested because it ruined the streets for sleighing and damaged the clothes and shoes of pedestrians. Following the blizzard in 1888, cities recognized the need for more organized and efficient snow removal. Rather than waiting until the storm was nearly over, city officials began to plow as the storm began, giving better results and more rapidly cleared roads. By dividing cities into sections and hiring more drivers, streets were cleared with greater efficiency.
With the advent of motorization, snow removal was revolutionized in the 20th century. Motorized plows and dump trucks arrived as early as 1913. Many cities abandoned horse-drawn carts and motorized their snow removal fleets. Caterpillar tractors equipped with plow blades were utilized, along with trucks, for plowing, while steam shovels, cranes and railway flatcars were used to haul snow away. Snow loaders also came into use in the early 1900s. As more cars took to the road, though, new problems ensued, as public safety demanded removal of even light snowfalls. Furthermore, residential streets, as well as main streets, needed clearing. Plowing left behind a slick layer of ice on the road so city officials began spreading salt by the ton. No longer concerned with protests, motorized salt spreaders became an essential tool. Later complaints of damage to vegetation and automobiles by salt led to improved salt spreaders with more efficient gauges. With so many cars on the road, shopping centers and office buildings began to see a need to clear their parking lots for employees and customers, thereby creating a specialized market. Smaller plows and snow blowers were in demand and many of these companies turned to private snow removal contractors to clear their lots.
While the introduction of motorized vehicles and subsequent technological advancements has made snow management and plowing faster, the basic process of plowing today is not much different than it was 75 years ago. Although the refinement of weather forecasting has allowed professionals to better predict and prepare for a storm, we still have to wait for the snow to fall, at which point we push it out of the way.
Why the need for snow removal?
While falling snow can be a majestic site, a parking lot, street or sidewalk of snow is hazardous and troublesome to those determined to not let a snowfall alter their day. With so many people out and about, the potential for motor vehicle accidents increases, as well as personal injury from wet and icy parking lots and sidewalks. As 90% of slips and falls occur in less than an inch of snow, it is important for businesses to manage winter conditions properly to reduce their liability. The protection of concrete and/or asphalt is an added benefit of removing snow from your property.
Liability issues The National Safety Council estimates there are approximately 300,000 injuries and more than 1,500 deaths per year as a result of wintertime weather. Premise liability laws concern a building owner's responsibility to remove potentially dangerous conditions around their property to prevent injury to guests. This is the category of law under which accidents from ice and snow fall. Building owners are given a window of time following the end of the storm in which to clear their parking lots and sidewalks of snow and ice and to take measures preventing ice from forming in the future.
This often involves monitoring outside temperatures, if not pavement surface temperatures, and requires some form of surface treatment to aid in the prevention of ice. While many building owners hire outside companies to manage snow conditions, liability for injury is not necessarily transferred to their snow management contractors. It is important, therefore, to understand your snow removal options, research potential snow removal companies and formulate a plan that will protect you, your property, your employees and your customers. These recent verdicts against building owners and managers indicate how serious slip and fall claims can be and underscore the importance of managing snow and ice on your property in a conscientious way:
Effects of snow on concrete and asphalt Although concrete may appear to be a completely solid object, it actually contains numerous microscopic passageways. These tunnels are formed during the initial crystallization process as concrete is transforming from a liquid to a solid state and the needles of interlocking cement paste crystals grow. When water freezes, its volume expands by about nine percent and any water that has entered these passages can break the needles of the interlocking paste crystals. Snow left on concrete will melt and enter the tunnels only to refreeze at night and, over time, will cause cracks and potholes on your lot. Removing snow from the surface of your lot will keep the water content of the concrete down and minimize freezing damage, thereby helping to preserve your investment.
Asphalt is a mixture of tar, oil byproducts, curative and aggregate gravel spread over compacted earth and gravel for drainage. Under heat and stress from traffic, asphalt eventually cracks leaving gaps for snow and water to enter. This water freezes during winter and the resulting expansion forces dirt and gravel out, leaving a hole when the water melts again. The thin asphalt layer over the hole is left weakened and eventually collapses causing a pothole. To help prevent this unsightly and potentially damaging hazard, snow must be consistently removed from the surface. While it is impossible to keep the asphalt completely dry during and following winter storms, removing snowfall will decrease the volume of water available to seep into the cracks and will minimize freeze damage to your lot.
How surface treatments work
Snow-melt products are designed to weaken the bond between ice/snow and the ground, not to completely melt all the ice and snow that accumulates. Chemical deicers in their solid state are unable to melt anything. When they come into contact with water, however, they dissolve into liquid brine and this salt solution lowers the freezing point of water and melts ice and snow on contact. The brine spreads out under the ice and breaks the bond between ice and pavement, allowing plows to separate the ice from a surface. The melting action will continue until the brine is so diluted that the freezing point of the solution reaches ground temperature. Some surface treatment chemicals also release heat when they dissolve in water, thereby melting snow more quickly. The efficiency of the various chemicals also depends on the temperature and whether the salt needs direct contact with moisture to dissolve or if it can absorb moisture from the air. All of these factors are important to consider when selecting the best deicer for your job.
Eutectic temperature The lowest possible temperature at which deicer brine can dissolve ice is called its eutectic temperature. The eutectic temperature, however, only applies to a specific concentration of the deicer in water and no deicer is capable of staying at this concentration for long, as it continually becomes more diluted as more ice and snow is melted. As the solution gradually becomes weaker, the freezing point gradually increases. Therefore, eutectic temperatures are significantly lower than the temperature at which a deicer can be effective. For example, the eutectic temperature of sodium chloride is -6ËšF but its effective temperature is only 15ËšF. The lowest effective temperature is a more meaningful number to consider when selecting a deicing product. Be sure to research a product's ingredients and effective temperature, as deicer manufacturers will sometimes mislead consumers by advertising the eutectic temperature on packaging without making clear what it means.
Melting capacity As temperatures drop, salt becomes less effective at melting ice and more chemical is needed to get the job done. The table below demonstrates how temperature affects the melting capacity of sodium chloride and shows that, at colder temperatures, more salt is needed to melt ice. In colder environments, choosing a chemical with a lower effective temperature allows a larger amount of snow to be melted per pound of salt.
Melting rate Melting rate is a measure of how fast melting occurs at different temperatures and, like melting capacity, the rate is influenced by temperature.
Anti-icing
Deicing products can, alternatively, be spread before snow falls in an effort to prevent ice from building up. Sitting on a surface, rock salt will do nothing, but as the snow falls the resulting brine prevents any bond from forming and leaves a parking lot ready to be plowed. In addition