Appendix D - SRG Grounding System Commissioning.docx

UNCLASSIFIED – FOR OFFICIAL USE ONLY

Date: 24 September 2020

Purpose This specification details the requirements for Commissioning the Signal Reference Grid (SRG).

SCOPE

The SRG system is a part of a completely interconnected grounding system that includes the equipment grounding for NEC compliant fault and personnel protection, the lightning protection subsystem and the telecommunications and data processing and signaling surge protection grounding subsystem.

The SRG is an isolated subsystem of the grounding system – connected only at the SRG Grounding Bus.

All of the grounding systems in the facility are electrically common to one another by use of carefully installed conductors and bonding materials.

Testing shall be performed in a planned sequence of events. In the event of a failure to achieve the required results, the Testing Contractor shall immediately notify the installation Contractor so that corrective action can be taken.

All testing must be done while the facility continues to operate. This will require isolation of subsystem to be tested and temporarily providing for continued operation of the Owner equipment thus isolated.

REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred within the text by the basic designation only. The current revision of the reference, including all issued updates, must be followed.

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

InterNational Electrical Testing Association (NETA) NETA ATS Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems National Institute of Standards and Technology (NIST) FIPS Pub 94 Guidelines for Electrical Power for ADP Installations

U.S. DEPARTMENT OF DEFENSE (DOD)

MIL HDBK 419A Grounding: Bonding, and Shielding for Electronic Equipments and Facilities Qualifications Contractor shall retain the services of a third-party, NETA-certified testing organization to perform the required grounding system tests.

Testing organization shall have a minimum of five (5) years’ documented experience in the testing and commissioning of grounding systems.

SUBMITTALS

Government approval is required for all submittals, extensions of design, critical materials, deviations, equipment whose compatibility with the entire system must be checked, and other items as designated by the Contracting Officer. Government approval is required for any deviations from the Solicitation or Accepted Proposal and other items as designated by the Contracting Officer. DISA, Facilities Engineering, Denver will review and approve for the Contracting Officer those submittals reserved for Contracting Officer approval to verify submittals comply with the Contract requirements.

Submit the following in accordance with Section 01 33 00, Submittal Procedures:

SD-06 Test Reports Testing and Commissioning Plan Testing and Commissioning Report SD-07 Certificates Certificates of Calibration Requirements General Description All testing must be made with the facility in operation. Therefore, the testing of the ground electrode subsystem must be performed on various portions of the system individually. Provisions will be made by the Owner to temporarily isolate the portions of the system for the individual tests. The contractor shall be required to provide temporary grounding jumpers so that the integrity of the operating facility is not compromised while portions of the grounding system are isolated for testing. The sequence for isolating and testing the various portions of the system is described in general in this document and must be included in detail in the contractor’s testing and commissioning plan.

Testing and Commissioning Plan Contractor shall submit a detailed testing and commissioning plan and schedule 60 days prior to the scheduled testing for review and acceptance by the Owner and Engineer of Record.

Testing and commissioning plan shall be specifically prepared for this project and shall detail the various points to be tested, preparations to be made, proposed current and voltage probe locations for earth electrode tests, and test equipment to be used (make and model).

Testing and commissioning plan shall include appropriate forms for recording the data obtained in the testing.

Notification Notify the Owner and Engineer a minimum of 30 days prior to performing the ground system testing and commissioning.

Notify the Owner and Engineer if any section or subsystem being tested does not meet the requirements of this specification before proceeding further. In no case shall a permanent connection be made before receiving approval to proceed from the Owner and Engineer.

Testing Submit certificates of calibration for all test equipment to be used prior to testing. Testing shall include the following:

Earth electrode resistance tests shall be performed using the “fall of potential” method as described in MIL HDBK 419A Volume 1 Paragraph 2.72 and IEEE 81 Paragraph 8.2.1.5.

Bonding resistance tests shall be performed using the “four wire” method utilizing a balanced DC resistance bridge as described in MIL HDBK 419A Volume 2 Paragraph 2.2.2.3.1.

In accordance with the DISA standard for Signal Reference Grid for Grounding Bonding Connections Each computer room signal reference ground loop tie conductor to the ground loop, minimum of 30% of installed locations per computer room. Each SRG loop back to SRG Ground Bus.

The maximum acceptable resistance value from any of the above points through all bonding connections to the Lightning Protection counterpoise is 50 milliohms.

Reports A report of all test results shall be submitted at the conclusion of the testing for review by the Owner and Engineer prior to final acceptance of the installed grounding system upgrades. The report shall also include copies of the original test forms.

Submit three copies of the report one hardcopy indexed by subsystem tested to the site, and one electronic .pdf copy bookmarked by subsystem to both the site and DISA Denver.

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