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 MIL-HDBK-419A
2.2.1 Drawings. Obtain, prepare, or complete an accurate set of architectural and engineering drawings for
the facility to include all structures associated with it. Of particular importance are the site layout drawings
which show the configuration of the earth electrode subsystem, location of utility piping and cable systems,
general landscape features and building profile drawings. Structural drawings show methods of connecting to
the earth electrode subsystem, methods used for structural steel assembly, locations and methods for the
installation of reinforcing steel as well as metal screens or sheets. Electrical diagrams and drawings generally
show wire sizes, breaker sizes, as well as cable type, routing and enclosures utilized. Drawings of the lightning
protection subsystem show heights and locations of air terminals, down conductor sizes and routing, fasteners,
guards, and connections to the earth electrode subsystem. Once the drawings are obtained, compare them with
the existing structure and update them as needed to reflect additions or modifications which have been made
but not entered on the drawings. If new drawings must be prepared, be sure they include all elements of the
structure. It is very important that an accurate representation of the existing configuration be on hand before
attempting any decision pertaining to upgrading or retrofitting the facility.
2.2.2 Facility Survey. After the drawings are obtained or prepared, conduct a comprehensive survey of the
grounding, bonding, shielding, and lightning protection practices throughout the facility. This survey should
cover all the major elements of the fault protection subsystem, signal reference subsystem, bonding (both in
current paths and between structural elements), lightning protection for the structure, shielding for both EMI
(and EMP, if required) and personnel protection. Visual observations should be concisely documented and
related to the engineering drawings for the facility. Measurements performed along with results obtained
should be accurately documented on the Grounding, Bonding, and Shielding Form of Section 2.2.2.4.
2.2.2.1 Survey Steps. The steps associated with the facility survey are:
Analyze the earth electrode subsystem and measure its resistance to earth.
a.
b.
Inspect a representative number (5 to 10 percent) of the bonds throughout the facility.
Inspect and evaluate the lightning protection subsystem.
c.
Inspect the fault protection subsystem, make spot checks of stray current levels.
d.
Map out and describe the signal grounding networks (or systems) present in the facility.
e.
f.
Perform a ground system noise survey.
g.
Evaluate (if applicable) the electromagnetic shielding of (or in) the facility.
h.
Before leaving the facility, review the Survey Form for accuracy and completeness.
2-4
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