Environmental Engineering Reference
In-Depth Information
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On July 14, 2008, at 10:30 a.m., an employee of Trison Construction was
injured. The employer reported the accident on July 17, 2008, at 10:30 a.m.
The injured employee was removing a “drill stem” from a 3-inch pipe on a
Driltech Marlin M5, serial #732658, truck-mounted drilling machine. He
wedged a 60-inch pipe wrench near the operator's platform to break the
connection. The pipe wrench broke loose, striking the employee on the right
knee and fracturing it. This contractor specializes in geothermal drilling.
As indicated by the fatality and accident reports above, the construction of geo-
thermal energy production sites and the use of geothermal energy can be a poten-
tially dangerous undertaking or occupation. Geothermal systems use the heat from
the Earth to create electricity and to heat and cool buildings. Some geothermal sys-
tems pump water underground through piping, allow it to be heated by the Earth, and
then use the hot water to create electricity or heat and cool buildings. Other systems
drill directly into the Earth's natural geothermal reservoirs, using the resulting hot
water and steam to create electricity. Some geothermal systems use a brine or saltwa-
ter solution while others use glycol. These solutions may pose hazards of their own
to workers. The hazards associated with the growing industry include some very
familiar safety issues for which the Occupational Safety and Health Administration
(OSHA) already has standards and information. The hazards (along with controls)
that workers in the geothermal industry may face are provided below.
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Trenching and excavations
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Silica
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Personal protective equipment
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Electrical
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Welding and cutting
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Fall protection
Each of these hazards and controls is briefly discussed below. OSHA and other regu-
latory requirements are contained in 29 CFR 1910 and 1926, along with detailed
explanations of each standard, regulation, or requirement.
Trenching and Excavation Hazards
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A large number of trenching and excavation specialty companies (e.g., utilities,
green energy industries) experience cave-ins. Attempting repair work on above-
ground pipes is relatively easy as compared to making repairs on underground pip-
ing systems. When repairs are to be made on underground lines, either trenching or
excavation is required. A trench is a narrow excavation that is less than 15 feet wide
and is deeper than its width. An excavation, on the other hand, is a cavity or depres-
sion that is cut or dug into the Earth's surface. Whether trenching or excavating,
*
Adapted from OSHA's
Green Job Hazards: Geo-Thermal Energy—Trenching and Excavation
,
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