assembly is adequate prior to conducting final shielding acceptance test.
3.9.3.1
Test Procedure, Frequencies, and Equipment
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NOTE: Expert Government witness should be present
for all final acceptance testing. Note that IEEE
Std 299 requires one magnetic field test (150 KHz),
three electric field tests (200 KHz, one MHz, 18
MHz), and one plane wave test (400 MHz). Also, note
that IEEE Std 299 and NSA 65-6 differ on positioning
of source and receiver. IEEE Std 299 requires
source outside and receiver inside the shield while
NSA 65-6 requires source inside and receiver outside
(to simulate TEMPEST conditions). For TEMPEST
shielding effectiveness testing, continuous sweeping
of seams at one or more plane wave frequencies
should also be specified, in addition to testing
around all door panels, filters, air duct
penetrations and all other penetrations of the
shielding at all test frequencies. When finish
materials are in place (floor topping slabs,
gypsumboard wall finishes, roof insulation and
coverings, etc.) it is recommended that limited
testing be repeated. One plane wave frequency
sweep, baked up by magnetic field probing of any new
leakage areas discovered, with repair and retest as
necessary to bring the enclosure back into proper SE
performance, is recommended. If enclosure is
designed specifically for attenuating microwave
frequencies, specify additional test frequencies
above 1 GHz. Such testing is expensive and should
only be used when a firm requirement exists (e.g.,
NSA-65-6).
**************************************************************************
The test procedure, frequencies, and equipment shall be as specified in
IEEE Std 299 [plus the additional frequencies specified in the contract].
Perform the test as soon as possible after completion of the shielded
enclosure, including installation of services, power/telephone/signal
lines, RF filters, and waveguide vents. Conduct test with doors closed and
the filters under normal load conditions.
3.9.3.2
Additional Test Points
**************************************************************************
NOTE: Use this paragraph if design includes strict
tolerances, high attenuation requirements, and many
penetrations. If all of the welded seams are to be
tested using IEEE Std 299 procedure and frequencies,
the specification must clearly state this to avoid
change orders.
**************************************************************************
Measure additional test points beyond those specified in IEEE Std 299. Test
points include the periphery of doors and covers, handles, latches, power
filter penetrations, air vent filters, telephone and control line filter
penetrations, and points of penetration by pipes, tubes, and bolts.
SECTION 13094N
Page 19
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