|
STANDARDS
Part II. Cathodic Protection Well Construction
Section 8. Surface Construction Features.
Surface construction features of the cathodic protection well shall serve to
prevent physical damage to the well; prevent the entry of surface water,
pollutants, and contaminants; and prevent unauthorized access.
- Locking Cover. The top of a cathodic protection well shall be protected
by a locking cover or equivalent level of protection to prevent unauthorized
access. All such covers shall allow the venting of gases.
- Casing Cap. The top of a cathodic protection well casing shall be fitted
with a watertight cap, cover, "U" bend, or equivalent device to prevent the
entry of water, pollutants, and contaminants into the well bore. All such
covers shall allow venting of gases from the well.
- Flooding. The top of the well casing shall terminate above ground
surface and known levels of flooding, except where site conditions, such as
vehicular traffic, will not allow.
- Bases. A concrete base or pad shall be constructed around the top of a
cathodic protection well casing at ground surface and contact the annular
seal, unless the top of the casing is to be below ground surface as provided
by Subsection E, below. The base shall be at least 4 inches thick and shall
slope to drain away from the well casing. The base shall extend at least 2
feet laterally in all directions from the outside of the well boring, unless
otherwise approved by the enforcing agency.
The base shall be free of cracks, voids, and other significant defects likely
to prevent water tightness. Contacts between the base and the annular seal,
and the base and the well casing must be water tight and must not cause the
failure of the well casing or annular seal.
Where cement-based annular sealing material is used, the concrete base shall
be poured before the annular seal has set, unless otherwise approved by the
enforcing agency.
- Vaults. At the approval of the enforcing agency, the top of a cathodic
protection well may be below ground surface because of traffic or other
critical considerations. A watertight, structurally-sound vault, or
equivalent feature, shall be installed to house the top of the well casing if
it terminates below ground surface.
The vault shall extend from the top of the annular seal to at least ground
surface. In no case shall the top of the annular seal be more than 4 feet
below ground surface.
The vault shall contact the annular seal in a manner to form a watertight and
structurally-sound connection. Contacts between the vault and the annular
seal, and the vault and the well casing (if any), shall not fail, or cause
the failure of the well casing or annular seal.
Where cement-based annular sealing materials are used, the vault shall be set
into or contact the annular sealing material before it sets, unless otherwise
approved by the enforcing agency. If bentonite-based sealing material is
used for the annular seal, the vault shall be set into the bentonite before
it is fully hydrated.
Cement-based sealing material shall be placed between the outer walls of the
vault and the excavation into which it is placed to form a proper,
structurally sound foundation for the vault, and to seal the space between
the vault and excavation.
Sealing material surrounding the vault shall extend from the top of the
annular seal to ground surface, unless precluded in areas of freezing. If
cement-based sealing material is used for both the annular seal and the space
between the excavation and vault, the sealing material shall be emplaced in a
"continuous pour." In other words, cement-based sealing material shall be
placed between the vault and excavation and contact a cement-based annular
seal before the annular seal has set.
The vault cover or lid shall be watertight but shall allow the venting of
gases. The lid shall be fitted with a security device to prevent
unauthorized access and shall be clearly and permanently labeled "CATHODIC
PROTECTION WELL." The vault and its lid shall be strong enough to support
vehicular traffic where such traffic might occur.
The top of the vault shall be set at grade, or above, so that drainage is
away from the vault. The top of the casing contained within the vault shall
be capped in accordance with requirements of Subsection B, above so that
water, contaminants, and pollutants that may enter the vault will not enter
the well casing.
- Protection From Vehicles. Protective steel posts, or the equivalent,
shall be installed around a cathodic protection well casing where it is
terminated above ground surface in areas of vehicular traffic. The posts
shall be easily seen and shall protect the well from vehicular impact.
Additional requirements for surface construction features are contained in
Section 10 of the Water Well Standards.
|
