NOTE: The cathodic protection system will fail
unless full consideration is given to specifications
for electrically insulating pipe joints,
electrically conductive pipe joints, and casing
cradles and seals. Mechanical and electrical
specifications should reference paragraphs
"Electrically Isolating Pipe Joints" and
"Electrically Conductive Couplings."
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As a minimum, isolating flanges or unions shall be provided at the
following locations:
a.
Connection of new metallic piping or components to existing piping.
b.
Pressure piping under floor slab to a building.
Isolation shall be provided at metallic connection of all lines to existing
system and where connecting to a building. Additionally, isolation shall
be provided between [water] [_____] and/or [gas] [_____] [forced main]
line; and foreign pipes that cross the new lines within 3.05 m 10 feet.
Isolation fittings, including isolating flanges and couplings, shall be
installed aboveground or in a concrete pit.
2.2.11.1
Electrically Isolating Pipe Joints
Electrically isolating pipe joints shall be of a type that is in regular
factory production.
2.2.11.2
Electrically Conductive Couplings
Electrically conductive couplings shall be of a type that has a published
maximum electrical resistance rating given in the manufacturer's
literature. Cradles and seals shall be of a type that is in regular
factory production made for the purpose of electrically insulating the
carrier pipe from the casing and preventing the incursion of water into the
annular space.
2.2.11.3
Insulating Joint Testing
A Model 601 Insulation Checker, as manufactured by ["Gas Electronics"],
[_____], [or] [an approved equal], shall be used for insulating joint
(flange) electrical testing.
2.2.12
Underground Structure Coating
This coating specification shall take precedence over any other project
specification and drawing notes, whether stated or implied, and shall also
apply to the pipeline or tank supplier. No variance in coating quality
shall be allowed by the Contractor or Base Construction Representative
without the written consent of the designer. All underground metallic
pipelines and tanks to be cathodically protected shall be afforded a good
quality factory-applied coating. This includes all carbon steel, cast-iron
and ductile-iron pipelines or vessels. Coatings shall be selected,
applied, and inspected in accordance with NACE RP0190 and as specified. If
non-metallic pipelines are installed, all metallic fittings on pipe
sections shall be coated in accordance with this specification section.
a.
The nominal thickness of the metallic pipe joint or other component
SECTION 13110A
Page 19
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