MT12 MICROTRENCHER

 stopimg style="padding-right: 20px;" align="left" src="/uploadedImages/Left_Nav/Press_Room/Job_Related_List/1.jpg" alt="shetland_1" title="shetland_1" border="0" style="border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-top-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-style: solid; " />The Shetland Islands are a subarctic archipelago off the northeast coast of Scotland at the virtual crossroads of the North Sea and Atlantic Ocean. The islands have spectacular cliffs, deep-sea inlets, rock-strewn hillsides, miles of peat bogs, and underground caverns that open to the sea. Beautiful, arable land and heather-covered slopes are also part of the islands’ allure.

The islands, which belong to Scotland and are subject to Scottish laws, are part of the United Kingdom, governed by UK traffic regulations, and are part of the UK postal network. The population speaks standard English, although the old Shetland dialect can still be heard.

Much of the Shetlands’ appeal is its remoteness, yet residents enjoy most of the services and benefits of larger cities—except a high-speed connection to the Internet.

However, this is in the process of changing.

stopimg style="padding-left: 20px;" align="right" src="/uploadedImages/Left_Nav/Press_Room/Job_Related_List/2.jpg" alt="shetland_2" title="shetland_2" />Thirteen miles of fiber-optic cable has been laid between Lerwick, Shetland’s largest town, and Sandwick. Shetland Telecom, a unit of the Shetland Islands Council (SIC), hopes that the fiber network will transform communications between Shetland and the wider world to help attract new businesses by giving private telecommunications firms the capability of offering super-fast Internet speeds to their customers.

The fiber route is along road A970, and the use of an innovative new construction technique significantly lowered the cost of placing the cable underground.

Shetland-based contractor Tulloch Developments used a new microtrenching machine to cut a narrow trench in the paving adjacent to the roadway in which the cable was placed.

Not only does the equipment make it faster and less expensive to install the cable, it is more environmentally friendly, said Shaun Tulloch, project manager. Because the cut is only 20 mm (0.75 inches) wide and about 115 mm (4.5 inches) deep, there is less damage to the surface, which reduces disruption of road traffic and makes filling the trench faster and less costly, compared to other types of construction.

Equipment used for the project is a Ditch Witch^® MT12 MicroTrencher, a specially equipped four-wheel-drive RT45 trencher with a saw blade using replaceable carbide bits for cutting asphalt.

Tulloch said production averaged 450 meters (1476 feet) per day. “We are laying four to six times more cable in a day compared to normal open-cut excavation,” said Tulloch. “The slot we cut in the road is only 20 mm wide compared to 200-300 mm (7.9-11.8 inches) wide with an excavator. The cost per meter is slightly more, but our output is far higher, so overall cost is lower.”

Tulloch describes the process.

“First, a trench is cut with the Ditch Witch machine. Then we have a powerful Ditch Witch FX20 vacuum excavator that we use to clean the trench. We then use a fiber screed lance, which is a combination of compressed air and a propane burner, to further clean and dry the trench.

“A foam packer is then laid in the trench followed by the preloaded fiber cable, which is preloaded in HDPE duct, and then a stainless steel tracer wire is attached to the duct, and then another foam packer applied.”

Crack fill material is placed in the remaining void to complete reinstating the road surface.          

“Once cable is in the ground, we subcontract a telecommunications company to join and test each section of cable. Then it’s handed over to the council for connection to their network.”

Tulloch said the Ditch Witch MT12 MicroTrencher has performed well.

“Teeth and blade wore more than we anticipated,” he said. “There’s no consistency. Some days we would get 200 meters (656 feet) out of a set of teeth. Then the next day we might only get 60 to 80 meters (197 to 263 feet). We believe it’s caused by a variation of the abrasiveness of the surface dressing aggregate. We’ve seen this before with our ready-mix concrete.”

The teeth mount on a circular blade is enclosed in a shield. Blades are available in three width sizes: 19 mm, 25 mm and 32 mm (0.75, 0.95 and 1.25 inches). Trenching depth can be altered by raising and lowering the cutting motor on the saw in 25 mm increments. Tulloch said the minimum cutting depth on the saw used on the project was 150 mm (5.9 inches), but because project specifications allowed to cut to a maximum depth of 120 mm (4.7 inches), a steel packer was welded to the underside of the skid that floats on the road surface to provide the cutting depth of 115 mm (4.5 inches).

The blade can hydraulically travel 610 mm (24 inches) to right of the center point for cutting adjacent to curbs or other obstacles and can be manually tilted six degrees to the right or left for working on slopes. The blade is powered by a direct-coupled, high-torque digging drive motor.

During trenching, the microtrencher system’s Ditch Witch FX20 vacuum unit can be positioned either in front of the trencher or to the rear, removing spoils as they are created by the saw blade, reducing cleanup time and labor expense. In addition to its vacuum capabilities, the FX20 also is a “soft” excavation machine, using high-pressure water to displace soil for making “potholes” to uncover existing utilities. 

Shetland broadband deployment had been a special project for economic development official Marvin Smith, who has been working on how to improve broadband for several years. He said the next step would be transferring the benefits to every remote area of Shetland.

Based in the Shetland Islands, Tulloch Developments Ltd. was established in the 1970s as a builder of private homes, and their building expertise grew to include council housing schemes, care homes and leisure centers.

 In the mid 1990s, company directors made the decision to switch to the civil engineering side of construction. Since then, the company has completed major contracts for various national organizations in different disciplines of engineering.

“We are currently constructing a new berthing facility for the Lerwick Port Authority in Lerwick, clearing sites to enable works for new houses for the SIC, and restoring an old stone pier for the Sandsayre Pier Trust,” said Tulloch.

stopimg src="/uploadedImages/Left_Nav/Press_Room/Job_Related_List/FX-20.jpg" alt="shetland_6" title="shetland_6" stopimg3In addition to the Shetland fiber project, utility-related contracts have included a series of transformer upgrades for Scottish & Southern Energy, and laying the Faroese Fibre cable from the west side of Shetland to the east side. This cable links Faroe, Shetland & Orkney with the UK mainland, and the cable for Shetland telecom will be connected to this network.

The M12 MicroTrencher is manufactured in the United States by The Charles Machine Works, Inc. Other products in the DitchWitch line include a variety of sizes of trenchers and vibratory plows and attachments; horizontal directional drilling equipment, drill pipe, downhole tools, and electronic tracking systems; compact utility equipment, vacuum excavators, pipe and cable locators, and related equipment.

Assisting Tulloch on the project was Mark Davies at Ditch Witch of the United Kingdom.

stopimg title="keepCool_img1" style="padding-right: 20px;" align="left" style="BORDER-BOTTOM: 0px solid; BORDER-LEFT: 0px solid; WIDTH: 260px; PADDING-RIGHT: 10px; HEIGHT: 195px; BORDER-TOP: 0px solid; align: left" alt="keepCool_img1" src="/uploadedImages/Left_Nav/Press_Room/Job_Related_List/1_KeepCool_260x195(1).jpg" border="0" />Catastrophic tornadoes and floods have grabbed recent headlines, but each year one weather phenomenon kills more people than tornadoes, floods, hurricanes, and lightning combined: heat.

According to the National Oceanic and Atmospheric Administration (NOAA), an average of more than 1,500 people in the U.S. die each year from excessive heat—yet it is the most preventable of weather-related deaths.

If you work in construction, summer is one of your busiest times of the year because it’s typically the driest season and offers the most hours of daylight. But the sun providing all that productive daylight can be the biggest jobsite hazard you face all year. No matter how tough you are or how used to the heat you think you are, excessive heat can bring down anyone who doesn’t take the necessary precautions.

The following information applies to anyone who is employed in an outdoor profession—construction workers in particular—but also applies to those who work in hot factories and anyone who spends time outdoors exercising, gardening, or laboring in any capacity during the summer months. (This is general information. More specific information can be found in the sources cited below.)

Know Your Chemistry

Our bodies dissipate heat by varying the rate and depth of blood circulation, and by expelling water through the skin and sweat glands. When we reach the danger zone, when our blood is heated above 98.6 degrees, we begin to pant—we’re literally “working like a dog.”

Sweating alone does little to cool the body, unless the sweat is removed by evaporation. But high relative humidity inhibits evaporation. When you’re checking the forecast for tomorrow, pay close attention to the heat index: the combination of relative humidity and air temperature. For example, if the air temperature is 96° F and the relative humidity is 65 percent, the heat index is 121° F. This is the heat your body really feels.

Heat disorders involve a reduction or collapse of our bodies’ ability to shed heat by circulatory changes and sweating, or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body's inner core begins to rise, bringing on various degrees of heat-related illnesses.

stopimg title="keepCool_img2" style="padding-left: 20px;" align="right" style="BORDER-BOTTOM: 0px solid; BORDER-LEFT: 0px solid; WIDTH: 260px; PADDING-RIGHT: 10px; HEIGHT: 195px; BORDER-TOP: 0px solid; align: right" alt="keepCool_img2" src="/uploadedImages/Left_Nav/Press_Room/Job_Related_List/2_KeepCool_260x195.jpg" border="0" />Ranking Heat Disorders

The severity of heat disorders is relative to a person’s age, weight, fitness, medical condition, and degree of acclimatization to the heat. For example, heat cramps in a 17-year-old may translate as heat exhaustion in someone who is 40, and heat stroke in a person over 60. Common heat disorders include:

• Sunburn. Along with being painful and irritating, sunburn can significantly retard the skin’s ability to shed excess heat. The best solution for sunburn is prevention, by applying sunscreen throughout the day.
• Heat cramps. Symptoms are painful spasms, usually in the muscles of the legs and abdomen, often preceded by profuse sweating.
• Heat rash. Also known as prickly heat, heat rash can occur in hot, humid environments where sweat is not easily removed from the surface of the skin by evaporation. Serious heat rash can be so uncomfortable that it inhibits sleep and impedes a worker’s performance.
• Heat exhaustion. Symptoms include heavy sweating, weakness, headache, fainting, vomiting, and skin that is cold, pale and clammy. It is possible to have a normal temperature with heat exhaustion.
• Heat stroke or sunstroke. This is the most serious health problem for workers in hot environments. Heat stroke occurs when sweating stops and the body can no longer rid itself of excess heat. Symptoms include an excessively high body temperature (106° F or higher); mental confusion or delirium; convulsions; hot, dry skin; strong and rapid pulse; and possible unconsciousness. Make no mistake: heat stroke can be fatal, and victims need immediate medical attention.

Prevention: The Best Solution

The number one method of avoiding heat disorders: avoiding heat. But for construction workers in the summer, this is simply not possible. So, here are some tips for staying cool and staying alive, beginning with the most obvious:

• Drink plenty of fluids. Your body needs water to keep cool. Drink water even if you don't feel thirsty. Proper hydration actually begins the day before a long, strenuous day in the sun. Before increasing your fluid consumption, consult a physician if you (1) have epilepsy or heart, kidney, or liver disease; (2) are on a fluid-restrictive diet; or (3) have a problem with fluid retention.
• Do not drink alcoholic beverages. Alcohol dehydrates your body. Enough said.
• Limit caffeine intake.
• Do not take salt tablets unless specified by a physician.
• Put less fuel on your inner fires. Foods that are heavy in protein increase metabolic heat production and also increase water loss.
• Dress as lightly as possible. You need protective clothing, of course, but consider light-colored fabrics, such as cotton, that breathe.
• When possible, take longer breaks than normal in a cool, shaded area. A rested worker is a more productive worker.
• Know the symptoms of heat illnesses. Use a buddy system to keep tabs on your fellow workers.
• Acclimate yourself to the heat. You can “get used to” the heat, to some degree. Workers, especially those who follow the advice above, can eventually develop some degree of tolerance. However, new employees and workers returning from an absence of two weeks or more should have a five-day period of acclimatization: 50 percent of the normal workload and time exposure the first day, gradually building up to 100 percent on the fifth day.

stopimg title="keepCool_img3" style="padding-left: 20px;" align="right" style="BORDER-BOTTOM: 0px solid; BORDER-LEFT: 0px solid; WIDTH: 260px; PADDING-LEFT: 10px; HEIGHT: 195px; BORDER-TOP: 0px solid; align: left" alt="keepCool_img3" src="/uploadedImages/Left_Nav/Press_Room/Job_Related_List/3_KeepCool_260x195.jpg" border="0" />Supervisor Obligations

There are precautions every employer should take when temperatures are high and the job involves physical work.

• Understand the signs of heat stress and permit workers to interrupt their work if they are extremely uncomfortable.
• Provide training about the hazards leading to heat stress and how to prevent them.
• If possible, schedule the heaviest workload for the coolest part of the day: early morning or late evening, when the sun is less intense.
• Make sure your workers have easy access to cool water—a minimum of one quart of water per hour, per worker.
• Schedule frequent rest periods with water breaks in shaded or air- conditioned areas.
• Routinely check on workers who are at risk of heat stress due to protective clothing and high temperature. Pay close attention to those who are at risk because of age and physical condition (including obesity and diabetes).

When A Fellow Worker Is Ill From The Heat

• Call a supervisor for help. If the supervisor is not available, call 911.
• Have someone stay with the worker until help arrives.
• Move the worker to a cooler/shaded area.
• Remove outer clothing.
• Fan and mist the worker with water; apply ice (ice bags or ice towels).
• Provide cool drinking water, if the worker is able to drink.

For more information about preventing and treating heat-related illness, consult these articles:

• “Heat Wave: A Major Summer Killer,” [http://www.noaawatch.gov/themes/heat.php] by the NOAA
• “Protecting Workers From Heat Stress,” [http://www.osha.gov/Publications/osha3154.pdf] by OSHA
• “Protecting Workers In Hot Environments,” [http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FACT_SHEETS&p_id=167] by OSHA

Sources for this article:

• National Oceanic and Atmospheric Association (noaawatch.gov)
• Occupational and Safety Health Administration (osha.gov)