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MIL-STD-188-125-1 HEMP Shielding Effectiveness Testing

MIL-STD-188-125-1 HEMP Testing of Ground-Based Facilities

MIL-STD-188-125-1 provides guidance on the testing of the ability of ground-based facilities to survive a high-altitude electromagnetic pulse (HEMP) attack. Keystone Compliance has significant experience testing to this HEMP EMC test standard. We understand the requirements and have the capabilities to test rooms and entire facilities.

Our shielding effectiveness test engineers can effectively scan facilities to identify any entry points. As entry points are found, our team provides potential solutions to resolve the failures. This consultative approach is why thousands of manufacturers partner with Keystone Compliance to meet their regulatory compliance testing needs.

To get started on addressing your HEMP testing needs, please Contact Us or Request a Quote. The remainder of this page speaks to the MIL-STD-188 125-1 test standard.

Summary of MIL-STD-188-125 Regulatory Compliance

The official title of MIL-STD-188-125-1 is High-Altitude Electromagnetic Pulse (HEMP) Protection for Ground-Based Facilities Performing Critical, Time-Urgent Missions for Common Long-Haul/Tactical Communications Systems.

This standard is used to establish minimum requirements and design objectives for high-altitude electromagnetic pulse (HEMP) hardening of fixed ground-based facilities. These facilities perform critical, time-urgent command, control, communications, computer, and intelligence (C I) missions.

Facilities required to fully comply with the provisions of the standard are designated by the Joint Chiefs of Staff, a Military Department Headquarters, or a Major Command.

First off, MIL-188-125-1 prescribes minimum performance compliance testing requirements. These requirements are for low-risk protection from mission-aborting damage or upset due to HEMP threat environments.  This standard also addresses minimum testing requirements for demonstrating that prescribed performance has been achieved.

The MIL-STD-188-125 standard also provides guidance for verifying that the installed protection subsystem provides the operationally required hardness for the completed facility. If the prescribed testing results in any hardware damage or functional upsets, the operational authority for the facility will make the determination whether the observed event is mission aborting.

MIL-188-125-1 compliance testing defines the design and testing criteria for specifically designated fixed ground-based facilities in HEMP-hardened, critical, time-urgent networks.  Such nodes include subscriber terminals and data processing centers, transmitting and receiving communications stations, and relay facilities.

Furthermore, the standard applies to both new construction and retrofit of existing facilities.  Although only local portions of facility interconnects are addressed, it is assumed that survivable long-haul communications paths, fiber optic links, or other hardened interconnects between facilities will be provided as required for mission accomplishment.

Keystone encourages the use of the standard for HEMP protection of other ground-based communications-electronics facilities that require HEMP hardening. Survivable C I capabilities are essential to a credible military deterrent. This standard supports nuclear survivability objectives by providing a standardized, low-risk protection approach for fixed ground-based facilities in HEMP-hardened C I networks.  These uniform requirements ensure balanced HEMP hardening for all critical facilities in the network.

Scope of the Military Standard Test Method 188-125-1

To gain a better understanding of the requirements, it is important to understand the specific terminology used in HEMP testing.

Electromagnetic stress is a voltage, current, charge, or electromagnetic field that acts on a piece of equipment.  If the electromagnetic stress exceeds the vulnerability threshold of the equipment, mission-aborting damage or upset may occur.

Facility HEMP shield is the continuous conductive housing that substantially reduces the coupling of HEMP electric and magnetic fields into the protected volume.  The facility HEMP shield is part of the electromagnetic barrier.

HEMP hardness surveillance/re-verification testing is testing conducted at prescribed intervals during the operational phase of the facility life cycle. This testing is for evaluating whether the HEMP protection measures continue to provide the required HEMP hardness. HS/re-verification test requirements are established in the technical manual.

A main barrier electrical POE protective device is a protective device installed on an electrical conductor that penetrates from the system exterior, through the HEMP shield, and into the protected volume.  Main barrier protective devices must meet the performance requirements of this standard.

A special protective volume is a HEMP-protected space within the facility, where electromagnetic stresses due to HEMP may exceed the residual internal stress limits for the protected volume.  The special protective barrier may be a separate shield with protected penetrations. These are more commonly, shielded cables or conduits, and equipment cabinets and closed piping systems are used to provide the needed electromagnetic isolation from the protected volume.

The vulnerability threshold (of an equipment) is the minimum stress level that causes the equipment to suffer definite damage or performance degradation.  In the context of this standard, the vulnerability threshold is the minimum electromagnetic stress that causes mission-aborting damage or upset.

Expert MIL-STD 188-125 Standard Compliance Testing Laboratory

Keystone Compliance has completed numerous site surveys to determine the level of protection against HEMP attacks. Our professional team diligently completes the assessments and provides valuable feedback on any weaknesses that should be addressed. This feedback often includes suggestions for remediating any aperture points of entry (POE) and conductive points of entry.

Lastly, our experience provides insight on improving protection as well as in determining specific locations within the facility that be more likely to serve as a point of entry.

When the need arises for HEMP testing of your facility, please Contact Us or Request a Quote.