3.7
EXCAVATION
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NOTE: Some states may require the use of VOC
emission suppression protocols during excavation,
stockpiling, and transportation operations for VOC
contaminated soil. The designer may need to include
requirements for submittals of VOC suppression
products (polyethylene sheeting, foam, or liquid VOC
suppressants) and use field demonstrations to show
there are no interferences from the suppression
technology used with field screening devices.
Approval from state/local regulators may be required
prior to usage of these products and the designer
should specify accordingly.
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Excavation areas, as well as work near roadways, shall be marked in
accordance with Section 01351 SAFETY, HEALTH, AND EMERGENCY RESPONSE
(HTRW/UST).
3.7.1
Exploratory Trenches
Exploratory trenches shall be excavated as necessary to determine the tank
location, limits and the location of ancillary equipment.
3.7.2
Tank Excavation
Excavation around the perimeter of the tank shall be performed limiting the
amount of potentially petroleum contaminated soil that could be mixed with
previously uncontaminated soil. Petroleum contaminated soil shall be
segregated in separate stockpiles. The Contractor shall maintain around
the tank an excavation of sufficient size to allow workers ample room to
complete the work, but also protect the workers from sliding or cave-ins.
Sheeting, bracing, or shoring shall be installed in the absence of adequate
side slopes if there is a need for workers to enter the excavated area.
Surface water shall be diverted to prevent direct entry into the
excavation. Dewatering of the excavation may require a discharge permit by
the State and shall be limited to allow adequate access to the tank and
piping, to assure a safe excavation, and to ensure that compaction and
moisture requirements are met during backfilling. Dewatering may result in
the production of petroleum contaminated water and/or free product. Free
product shall be recovered from the groundwater only as part of necessary
dewatering.
3.7.3
Piping Excavation
Excavation shall be performed as necessary to remove tank piping and
ancillary equipment in accordance with paragraphs: Shoring, Tank
Excavation, and Open Excavations.
3.7.4
Open Excavations
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NOTE: The time that tank excavations are left open
depends on a variety of factors, a major one being
the capability of the Contractor's lab to provide
analyses within the specified turnaround time.
Since short turnaround time adds cost, carefully
SECTION 02115A
Page 17
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