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A grit bin, salt bin or sand bin is an item of street furniture, commonly found in countries where freezing temperatures and snowfall occur, which holds a mixture of salt and grit that is spread over roads if they have snow or ice on them. Spreading rock salt over roads and pathways is commonly done either by hand or with a winter service vehicle and helps improve road safety in frosty conditions. The salt helps reduce the freezing temperature of the ice, which can be effective in temperatures of up to -9°C (16°F). Roads that are not gritted during winter are much more dangerous for vehicles and foot traffic, so busy routes can be gritted several times per day under harsh snowy conditions.
Anyone may use a grit bin to clear a public path or road, though they are generally not intended for personal use. [1] Typically, a spade or shovel is used to spread a thin layer of grit onto the road surface, covering any snow or ice. The salt lowers the melting point of the snow causing it to melt (see sodium chloride). The grit component improves the friction between a vehicle's tires and the road.
Some grit bins have a small compartment, which could be used for storing a spade or shovel. The one featured in the photograph at the top of the page is filled through the top hatch.
The salt boxes of Baltimore, Maryland, United States, have been in use since at least 1969, [2] and have attracted attention on social media as a symbol of Baltimore culture. [3]
In Sweden, the bins contain mainly sand and sometimes sand mixed with salt. The construction and appearance of the bins are similar to bins in other countries. [4] [5]
Grit bins were originally made of concrete, wood or even stone, though these are now increasingly being replaced by models constructed from plastic partly from safety concerns: vehicles/people hitting a plastic grit bin will suffer less damage. However, the lower weight of plastic makes grit bins easier to steal or tip over.
Grit bins can be subjected to vandalism, such as arson. The lid can also be left open, leaving rain to dilute the rock salt in the mixture, leaving it much less effective than dry rock salt. In the United Kingdom, the local county council is usually responsible for maintaining and refilling grit bins as well as spreading rock salt on the roads. [6]
In Norway, the problem with tipping grit bins over has been solved by making them large enough to hold about 500 kg (1,100 lb) of grit, and to continually keep it topped up. [ citation needed ]
Sodium chloride, commonly known as table salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form, salt is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. Another major application of sodium chloride is deicing of roadways in sub-freezing weather.
A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental and subarctic climates, these storms are not necessarily restricted to the winter season, but may occur in the late autumn and early spring as well. A snowstorm with strong winds and other conditions meeting certain criteria is called a blizzard.
Halite, commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride (NaCl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on inclusion of other materials, impurities, and structural or isotopic abnormalities in the crystals. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides, and borates. The name halite is derived from the Ancient Greek word for "salt", ἅλς (háls).
Black ice, sometimes called clear ice, is a thin coating of glaze ice on a surface, especially on streets. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it. The typically low levels of noticeable ice pellets, snow, or sleet surrounding black ice means that areas of the ice are often next to invisible to drivers or people walking on it. Thus, there is a risk of slippage and subsequent accident due to the unexpected loss of traction.
Freezing-point depression is a drop in the maximum temperature at which a substance freezes, caused when a smaller amount of another, non-volatile substance is added. Examples include adding salt into water, alcohol in water, ethylene or propylene glycol in water, adding copper to molten silver, or the mixing of two solids such as impurities into a finely powdered drug.
Ice sculpture is a form of sculpture that uses ice as the raw material. Sculptures from ice can be abstract or realistic and can be functional or purely decorative. Ice sculptures are generally associated with special or extravagant events because of their limited lifetime.
A domestic ice cream maker is a machine used to make small quantities of ice cream for personal consumption. Ice cream makers may prepare the mixture by employing the hand-cranking method or by employing an electric motor. The resulting preparation is often chilled through either pre-cooling the machine or by employing a machine that freezes the mixture.
Snow removal or snow clearing is the job of removing snow after a snowfall to make travel easier and safer. This is done by both individual households and by governments and institutions.
Deicing is the process of removing snow, ice or frost from a surface. Anti-icing is the application of chemicals that not only deice but also remain on a surface and continue to delay the reformation of ice for a certain period of time, or prevent adhesion of ice to make mechanical removal easier.
Cold-weather warfare, also known as arctic warfare or winter warfare, encompasses military operations affected by snow, ice, thawing conditions, or cold, both on land and at sea, as well as the strategies and tactics used by military forces in these situations and environments.
Carburetor heat is a system used in automobile and piston-powered light aircraft engines to prevent or clear carburetor icing. It consists of a moveable flap which draws hot air into the engine intake. The air is drawn from the heat stove, a metal plate around the exhaust manifold.
A winter service vehicle (WSV), or snow removal vehicle, is a vehicle specially designed or adapted to clear thoroughfares of ice and snow. Winter service vehicles are usually based on a dump truck chassis, with adaptations allowing them to carry specially designed snow removal equipment. Many authorities also use smaller vehicles on sidewalks, footpaths, and cycleways. Road maintenance agencies and contractors in temperate or polar areas often own several winter service vehicles, using them to keep the roads clear of snow and ice and safe for driving during winter. Airports use winter service vehicles to keep both aircraft surfaces, and runways and taxiways free of snow and ice, which, besides endangering aircraft takeoff and landing, can interfere with the aerodynamics of the craft.
Glaze or glaze ice, also called glazed frost, is a smooth, transparent and homogeneous ice coating occurring when freezing rain or drizzle hits a surface. It is similar in appearance to clear ice, which forms from supercooled water droplets. It is a relatively common occurrence in temperate climates in the winter when precipitation forms in warm air aloft and falls into below-freezing temperature at the surface.
A snowmelt system prevents the build-up of snow and ice on cycleways, walkways, patios and roadways, or more economically, only a portion of the area such as a pair of 2-foot (0.61 m)-wide tire tracks on a driveway or a 3-foot (0.91 m) center portion of a sidewalk, etc. It is also used to keep entire driveways and patios snow free in snow prone climates. The "snow melt" system is designed to function during a storm to improve safety and eliminate winter maintenance labor including shoveling, plowing snow and spreading de-icing salt or traction grit (sand). A snowmelt system may extend the life of the concrete, asphalt or under pavers by eliminating the use of salts or other de-icing chemicals, and physical damage from winter service vehicles. Many systems are fully automatic and require no human input to maintain a snow/ice-free horizontal surface.
Rain and snow mixed is precipitation composed of a mixture of rain and partially melted snow. Unlike ice pellets, which are hard, and freezing rain, which is fluid until striking an object where it fully freezes, this precipitation is soft and translucent, but it contains some traces of ice crystals from partially fused snowflakes, also called slush. In any one location, it usually occurs briefly as a transition phase from rain to snow or vice-versa, but hits the surface before fully transforming. Its METAR code is RASN or SNRA.
The winter of 2009–10 in the United Kingdom was a meteorological event that started on 16 December 2009, as part of the severe winter weather in Europe. January 2010 was provisionally the coldest January since 1987 in the UK. A persistent pattern of cold northerly and easterly winds brought cold, moist air to the United Kingdom with many snow showers, fronts and polar lows bringing snowy weather with it.
The 2011 Groundhog Day blizzard was a powerful and historic winter storm that affected large swaths of the United States and Canada from January 31 to February 2, 2011, especially on Groundhog Day. During the initial stages of the storm, some meteorologists predicted that the system would affect over 100 million people in the United States. The storm brought cold air, heavy snowfall, blowing snow, and mixed precipitation on a path from New Mexico and northern Texas to New England and Eastern Canada. The Chicago area saw 21.2 inches (54 cm) of snow and blizzard conditions, with winds of over 60 mph (100 km/h). With such continuous winds, the blizzard continued to the north and affected Eastern and Atlantic Canada. Blizzard conditions affected many other large cities along the storm's path, including Tulsa, Oklahoma City, Kansas City, St. Louis, Springfield, El Paso, Las Cruces, Des Moines, Milwaukee, Detroit, Chicago, Indianapolis, Dayton, Cleveland, New York City, New York's Capital District, and Boston. Many other areas not normally used to extreme winter conditions, including Albuquerque, Dallas and Houston, experienced significant snowfall or ice accumulation. The central Illinois National Weather Service in Lincoln, Illinois, issued only their fourth blizzard warning in the forecast office's 16-year history. Snowfall amounts of 20 to 28 inches were forecast for much of Northern and Western Illinois.
An ice dam is an ice build-up on the eaves of sloped roofs of heated buildings that results from melting snow under a snow pack reaching the eave and freezing there. Freezing at the eave impedes the drainage of meltwater, which adds to the ice dam and causes backup of the meltwater, which may cause water leakage into the roof and consequent damage to the building and its contents if the water leaks through the roof.
Cold-weather biking, cold-weather cycling, or winter biking is the use of a bicycle during months when roads and paths are covered with ice, slush and snow. Cold weather cyclists face a number of challenges in near or below freezing temperatures. Urban commuters on city streets may have to deal with "[s]now, slush, salt, and sand", which can cause rust and damage to metal bike components. Slush and ice can jam derailleurs. Some cyclists may bike differently in winter, by "slow[ing] down on turns and brak[ing] gradually" in icy conditions. Gaining traction on snow and ice-covered roads can be difficult. Winter cyclists may use bikes with front and rear fenders, metal studded winter tires and flashing LED lights. Winter cyclists may wear layers of warm clothes and "ea[r], face, and han[d]" coverings may be used. Specialized winter bikes called fatbikes, which have wide, oversized tires that are typically inflated with low pressure, are used in snow trail riding and winter bike competitions.
A Baltimore salt box is an example of a grit bin as used in Baltimore, Maryland. They are wooden boxes with hinged covers and are annually distributed around as a supplement to the city's snow removal and road salting operations. They are a service of Baltimore's Department of Transportation, which distributes the boxes around the city in the late fall in anticipation of winter weather. The boxes are filled with a mixture of road salt and sand for citizens to spread as needed to assist with traction and to prevent or melt icy patches on city streets.