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 mounting the shielding to fixed objects must be also tried and tested in the
module such as soldering or welding to metal studs, metal roof decking, or
structural members. The contractor must submit a plan for the fabrication and
testing of the module, Test Fabrication and Testing Plan, for the module to
the ROICC for comment and approval. The Test Module Fabrication and Testing
Plan must also detail the types of tests that will be performed on the module,
which should be the same as on the project enclosure, including SELDS and NSA
65-6/ MIL-STD-285 test to be performed including test dates so that an expert
government witness may be present for the tests. The results of all module
testing must be included in a final test module report. The submittals
including catalog cuts, shop drawings, and material samples should not be
approved until the final report on testing of the module is reviewed and
accepted by the government. Construction on the enclosure should not begin
until the contractor has proven that all construction methods used in the test
module meet the specified requirements.
5.2.2
Supervision of Construction. The work should be performed under the
full-time direct supervision of personnel who are experienced in the
installation of shielded enclosures, and have supervised the installation of
not fewer than two such enclosures which have operated satisfactorily. The
construction contractor's progress and equipment delivery schedules must be
received and reviewed for inclusion of all shielding construction requirements
and milestones, including testing. Dates and durations of time must be
indicated and adhered to so that an government representative may be scheduled
to be present during the MIL-STD-220A testing (generally at the filter
manufacturers shop), SELDS testing, and MIL-STD-285/NSA 65-6 testing. The
results of the testing must be submitted to the ROICC on a daily basis and all
results incorporated into a Shielding Test Final Report.
5.3
Installation Workmanship. The shielded enclosure, including
shielding accessories and penetrations, should be furnished and installed by
an experienced firm regularly engaged in the design, manufacture, and
installation of electromagnetic shielded enclosures. The ROICC shall
disapprove any contractor who does not demonstrate satisfactory evidence of
such qualification.
5.3.1
Panels. On an all welded enclosure, all welding should be done by a
welder certified to perform MIG welding. All seam welds should be visually
inspected. All seam must be tested with a SELDS detector and any reading in
excess of 15db (or as specified in the specs) shall be removed and replaced.
Welds should be free of slag inclusions, gas pockets, holes and incomplete
fusion. All poor welds shall be corrected by grinding away such weld and
replacement with new welds.
5.3.1.1
Weather Protection During Construction. The enclosure must be
protected from the environment during construction and if the welding process
takes place in the open the shielded enclosure shall be protected from the
environment from the wind, rain and the sun. Exposing the enclosure to the sun
during construction will cause the enclosure to expand and contract and this
could cause the seams to split.
5.3.1.2
Requirements for Clean and Tight Seams. If the shielded enclosure
is the demountable (bolt-together) type, then seams will be a mechanical
clamping system. To obtain the required shielding effectiveness the clamps
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