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Army Corps

From Chapter 9 EMP and Tempest Protection Concepts of Pamphlet No. 1110-3-2 31 December 1990

U.S. Army Corps of Engineers, Publication Department,
2803 52nd Avenue, Hyattsville, MD 20781-1102.
For free copy of 469-page paper pamphlet, fax request to: (301) 394-0084

1. Purpose. This pamphlet provides unclassified engineering and design information about protecting fixed ground facilities against the effects of an electromagnetic pulse (EMP) produced by a nuclear explosion. It also provides unclassified engineering and design information about satisfying TEMPEST requirements.

b. Facility shielding. This method is by far the most common for high-level HEMP and TEMPEST protection. It maximizes flexibility since any standard equipment can be used inside the shielded facility. Facility shielding may be low-level or high-level (50- or 100-decibel) attenuation. HEMP shielding (100-decibel) consists of at least 3/16-inch welded steel (12-gauge walls and 10-gauge floors are recommended). TEMPEST shielding (50-decibel) consists of at least 22 to 26 gauge steel walls, floors, and ceiling with clamped joints.

Note: The lower the gauge number, the thicker the plate. The Ammo can is thicker yet at 21 gauge (.033"). 22 gauge is (.030") and 26 gauge is (.018"). So according to this we should achieve TEMPEST level of protection. They also have more information on how to build a Shielded Room.

Offered by Mike.