|
13 June 1997
Source: http://www.hnd.usace.army.mil/techinfo/cegssgml/16650.sec (SGML format) See Guide Specifications for Military Construction: http://jya.com/cegs.htm ------------------------------------------------------------------------------- ************************************************************************** DEPARTMENT OF THE ARMY CEGS-16650 (May 1996) U.S. ARMY CORPS OF ENGINEERS _____________________ GUIDE SPECIFICATION FOR MILITARY CONSTRUCTION ************************************************************************** SECTION 16650 ELECTROMAGNETIC (EM) SHIELDING 05/96 ************************************************************************** NOTE: This guide specification covers the requirements for electromagnetic shielded facilities. This guide specification is to be used in the preparation of project specifications in accordance with ER 1110-345-720. ************************************************************************** PART 1 GENERAL ************************************************************************** NOTE: The following information will be shown on the project drawings: 1. Assembly details. 2. Typical penetration details. 3. Method of mounting shielded enclosure within building. 4. Shield penetration plan containing wall elevations, floor and ceiling plans showing the locations of all penetrations (to include all mech., electrical, fire protection, etc.) to the HEMP shield. 5. Location of mechanical and electrical equipment within shielded enclosure. 6. Detail equipment mounted or suspended from the shielded ceiling. 7. Shield penetration schedule to include: a. Location of the waveguide. b. Size of waveguide (dimensions). c. No. Of penetrations in the waveguide. d. Penetration designation of each penetration in the waveguide (if more than one). e. Size of pipe for each penetration in the waveguide. f. Type of pipe for each waveguide penetration. g. Type of penetration. h. The detail/sheet no. of the waveguide detail. i. Any remarks pertaining to the waveguide. 8. Filter schedule to include: a. Location of filter. b. Type of filter (power or signal). c. No. Of filters in the filter enclosure. d. Electrical characteristics of the filter (voltage, amperage, no. of poles, frequency). e. Purpose of the filter. f. The detail/sheet no. Of the typical filter detail. g. Any remarks pertaining to the filter. 9. Typical filter details. 10. Hardness critical items (HCI) should be identified using the (HCI) symbol on project drawings. Refer to MIL-HDBK 419 for special grounding and bonding requirements for EM shielded enclosures. Refer to the U.S. Air Force Handbook for the Design and Construction of HEMP/TEMPEST and Other Shields in Facilities (March 1993). This document can be obtained from HQ AFIC/LEEE, San Antonio, Texas 78243-5001. Also refer to AR 380-19. MIL-HDBK 423 should be used for projects requiring HEMP protection. The designer should consult these documents and other appropriate sources before applying this guide specification to large-scale EM shielded enclosures or to HEMP or TEMPEST projects. The requirement for thermal expansion joints inherent to large-scale enclosures is not addressed in this guide specification. The extent and location of the work to be accomplished and wiring, equipment, and accessories necessary for a complete installation should be indicated on the project drawings. The Air Force contracts with an independent testing laboratory to perform their acceptance testing. The test can consist of a SELDS or equivalent test and H-field and plane wave CW tests per MIL-STD 188 125 and/or IEEE STD 299. See the U.S. Air Force Handbook for the Design and Construction of HEMP/TEMPEST and Other Shields in Facilities for more details. Methodology and procedures for setting up equipment are contained in MIL-HDBK-423. Full MIL-STD 188 125 acceptance testing (PCI tests as specified in appendix B) should be avoided. (Also see designer notes K and U). Although not addressed in this specification, fiber optic cable has gained acceptance as an effective method of transmitting data across the boundary of shielded enclosures without filtering. If fiber optic cable is used, describe the waveguide penetration of the shield in detail. Fiber optic cable is specified in CEGS 16768, FIBER OPTICS DATA TRANSMISSION SYSTEM. ************************************************************************** 1.1 REFERENCES ************************************************************************** NOTE: Issue (date) of references included in project specifications need not be more current than provided by the latest change (Notice) to this guide specification. ************************************************************************** The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only. AMERICAN HARDBOARD ASSOCIATION (AHA) AHA A135.4 (1995) Basic Hardboard AMERICAN INSTITUTE OF STEEL CONSTRUCTION (AISC) AISC-MO16 (1989) ASD Manual of Steel Construction AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) ASTM A 36 (1994a) Carbon Structural Steel ASTM A 123 (1989a) Zinc (Hot Dip Galvanized) Coatings on Iron and Steel Products ASTM A 227 (1993) Steel Wire, Cold-Drawn for Mechanical Springs ASTM A 366 (1991; R 1993) Steel, Sheet, Carbon, Cold-Rolled, Commercial Quality ASTM A 526 (1990) Steel Sheet; Zinc-Coated (Galvanized) by the Hot-Dip Process, Commercial Quality ASTM A 568 (1993a) Steel, Sheet, Carbon, and High-Strength, Low-Alloy, Hot-Rolled and Cold-Rolled, General Requirements for ASTM A 569 (1991a; R 1993) Steel, Carbon (0.15 Maximum, Percent), Hot-Rolled Sheet and Strip Commercial Quality ASTM A 611 (1994) Steel, Sheet, Carbon, Cold-Rolled, Structural Quality ASTM A 653 (1995) Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process ASTM B 194 (1995) Copper-Beryllium Alloy Plate, Sheet, Strip, and Rolled Bar ASTM B 545 (1992) Electrodeposited Coatings of Tin ASTM B 633 (1985; R 1994) Electrodeposited Coatings of Zinc on Iron and Steel ASTM E 84 (1995a) Surface Burning Characteristics of Building Materials ASTM E 90 (1990) Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions AMERICAN WELDING SOCIETY (AWS) AWS A5.18 (1993) Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding AWS BRH (1991) Brazing Handbook AWS D1.1 (1994) Structural Welding Code - Steel AWS D1.3 (1989) Structural Welding Code - Sheet Steel AWS D9.1 (1990) Sheet Metal Welding Code DEPARTMENT OF COMMERCE (DOC) DOC PS 1 (1983) Construction and Industrial Plywood INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE) IEEE C62.11 (1993) IEEE Standard Metal-Oxide Surge Arresters for AC Power Circuits IEEE C62.33 (1982; R 1994) Varistor Surge-Protective Devices IEEE C62.41 (1991) Surge Voltages in Low-Voltage AC Power Circuits IEEE STD 142 (1991) IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems IEEE STD 299 (1991) IEEE Standard Method of Measuring the Effectiveness of the Electromagnetic Shielding Enclosures MILITARY HANDBOOKS (MIL-HDBK) MIL-HDBK 419 (Rev A) Grounding, Bonding, and Shielding for Electronic Equipments and Facilities MILITARY STANDARDS (MIL-STD) MIL-STD 188 124 (Rev B) Grounding, Bonding and Shielding (Metric) MIL-STD 188 125 (Rev A) High-Altitude Electromagnetic Pulse (HEMP) Protection for Ground-Based C4I Facilities Performing Critical, Time-Urgent Missions, Vol. I Fixed Facilities (Metric) MIL-STD 220 (Rev A; Notice 1 & 2) Method of Insertion-Loss Measurement NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA) NEMA ICS 2 (1993) Industrial Control Devices, Controllers and Assemblies NEMA ICS 6 (1993) Enclosures for Industrial Controls and Systems NEMA MG 1 (1993; Rev 1-1993; Rev 2-1995) Motors and Generators NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) NFPA 70 (1996) National Electrical Code NFPA 77 (1993) Static Electricity NFPA 80 (1995) Fire Doors and Windows NFPA 80A (1993) Protection of Buildings from Exterior Fire Exposures NFPA 101 (1994) Safety to Life from Fire in Buildings and Structures NFPA 780 (1992) Installation of Lightning Protection Systems UNDERWRITERS LABORATORIES (UL) UL 486A (1991; Rev Oct 1991) Wire Connectors and Soldering Lugs for Use with Copper Conductors UL 1283 (1993; Rev Aug 1993) Electromagnetic Interference Filters UL 1449 (1985; Errata Apr 1986) Transient Voltage Surge Suppressors 1.2 SYSTEM DESCRIPTION ************************************************************************** NOTE: Projects involving military communications equipment must be designed to incorporate the applicable requirements of MIL-STD 188 124, which will be provided in the ELECTRICAL WORK, INTERIOR specification. ************************************************************************** The shielded facility shall meet or exceed minimum attenuation decibel (dB) levels specified herein. The EM shielding system shall include, but is not limited to, the following: a. The [welded steel] [bolted] EM shield. b. EM shielded doors for access into the facility. c. Electrical and electronic penetrations of the shield. d. EM filter/surge arrester assemblies, including their EM enclosures. e. EM shielded pull boxes and junction boxes. f. EM shielded conduit runs. g. Special protective measures for mission-essential equipment outside the EM shield. h. Structural penetrations. i. Mechanical and utility penetrations (such as air ducts, gas, and water). j. Instrumentation and control. k. Equipment door/access panels. 1.3 SUPERVISION Work performed under this section shall be supervised and inspected by the shielding specialist. Materials and equipment shall be approved and verified by the shielding specialist before being submitted to the Contracting Officer for approval. The submittal shall be date stamped and signed by the shielding specialist. The shielding specialist shall be responsible for coordinating the required shielding work with the work of all other trades that will interface or affect the shielding work in any way. The contractor shall provide sufficient supervisory and/or quality control personnel on site to supervise the installation crew and to conduct in-progress quality assurance tests. 1.4 SUBMITTALS ************************************************************************** NOTE: Submittals must be limited to those necessary for adequate quality control. The importance of an item in the project should be one of the primary factors in determining if a submittal for the item should be required. Indicate submittal classification in the blank space using "GA" when the submittal requires Government approval or "FIO" when the submittal is for information only. ************************************************************************** Government approval is required for submittals with a "GA" designation; submittals having an "FIO" designation are for information only. The following shall be submitted in accordance with Section 01300 SUBMITTAL PROCEDURES SD-01 Data Electromagnetic Shielding System; GA. Manufacturer's data, catalog cuts, and printed documentation regarding the work. SD-04 Drawings Electromagnetic Shielding System; GA. Installation details showing location, number, and method of penetrating the shielding material. Fabrication details for penetrations of the shielding material and the complete EM shielded enclosure to include doors and filters. Drawings shall show erection details and sequence of erection and shall clearly indicate the methods necessary to ensure shield integrity under all columns and other structural members. SD-06 Instructions EM Shielding System Installation Plan; GA. Quality Control Plan; GA. Instruction for the shielding installation provided by the shielding installers. SD-07 Schedules EM Door; GA. EM Filter Assemblies; GA. EM Penetrations Schedule; GA. Filter schedule shall include voltage, amperage, enclosure type (low, high, band pass), system, location, cut-off frequency, band pass frequencies, and electrical surge arresters (ESA). SD-08 Statements EM Shielding Specialist Qualifications; GA. EM Shielding Testing Specialist Qualifications; GA. EM Shielding Installers Qualifications; GA. Welders Qualifications; GA. SD-09 Reports Enclosure Sound Transmission Testing; GA. Swinging Door Static Load Test; GA. Swinging Door Sag Test; GA. Door Closure Test; GA. Door Handle-Pull Test; GA. Door EM Shielding Effectiveness Test; GA. Door Sound Transmission Test; GA. Filter Current Overload Capability Test; GA. Filter Insertion Loss Test; GA. Filter Operating Temperature and Temperature Rise Test; GA. Filter Voltage Drop Test; GA. Filter Dielectric Withstand Voltage Test; GA. Filter Insulation Resistance Test; GA. Filter Enclosure Shielding Effectiveness Test; GA. Filter Terminals Test; GA. Filter Harmonic Distortion Test; GA. Filter Reactive Shunt Current Test; GA. ESA Breakdown Voltage Test; GA. ESA Impulse Sparkover Voltage Test; GA. ESA Clamping Voltage Test; GA. ESA Extinguishing Test; GA. ESA Extreme Duty Discharge Test; GA. ESA Surge Life Test; GA. EM Waveguide Assembly Testing; GA. EM Cabinet and Pull Box Shielding Effectiveness Testing; GA. Field Testing Reports; GA. SD-13 Certificates Welders Certification; GA. SD-18 Records Field Testing Results; FIO. SD-19 Operation and Maintenance Manuals EM Shielding System; FIO. 1.5 QUALIFICATIONS 1.5.1 Shielding Specialists, Installers and Testing Specialists The name and background qualifications of individuals who will be responsible for installation, supervision, and testing of the shielding systems on this project shall be provided. Shielding and testing specialist credentials shall include a bachelor's degree in science or engineering and post-degree training and experience with EM shielding. 1.5.1.1 Testing Experience The testing specialist shall have experience during the previous 5 years in shielded enclosure leak detection system (SELDS), IEEE STD 299, and other methods of shielded enclosure testing. 1.5.1.2 Work Experience The EM shielded system shall be provided by an experienced firm or individual that has been regularly and successfully engaged in the installation, supervision, and/or testing of equivalent EM shielded systems for at least the previous 5 years. The principal work of this firm or individual shall be the satisfactory installation and construction of EM shielded protection systems. Such experience shall include achieving specified requirements for shielded system attenuation and maintainability of attenuation levels on work performed. 1.5.1.3 Project Experience A project experience list shall be furnished on projects of similar scope which have been completed during the previous 5 years. Project completion dates and the name and telephone number of the user and/or owner of each project shall be included. Project experience for installers shall indicate the installation responsibilities, performance, materials, and methods used. Project experience for the shielding specialist shall indicate the responsibilities performed. Project experience for the testing specialist shall indicate the test methods performed. 1.5.2 Qualifications of Welders Welding shall be performed by certified welders. The Contractor shall provide the names of the welders to be employed and certification that each welder has passed qualification tests within the last 2 years in the processes specified in AWS D1.1, AWS D9.1, and as required by the Contracting Officer. 1.6 FILTER AND ELECTRICAL WORK REQUIREMENTS Filter and electrical work shall comply with NFPA 70, UL 486A, and UL 1283. The label and listing of the Underwriters Laboratories or other nationally recognized testing laboratory shall be acceptable evidence that the material or equipment conforms to the applicable standards of that agency. In lieu of the label or listing, a certificate may be furnished from an acceptable testing organization adequately equipped and competent to perform such services. The certificate shall state that the items have been tested and that they conform to the specified standard. 1.7 FIELD EXAMPLES ************************************************************************** NOTE: Requests for field examples and mock-ups usually add cost to the project. Samples should only be required for special applications and should be limited to scaled-down items. For example, the designer may ask for a welded floor/wall corner section. Do not normally ask for samples of filters and full-size waveguide vents. ************************************************************************** Field examples shall be provided for the following: [shielding sheet installation,] [shielding fastening,] [doors,] [[30] [100] [_____] ampere power filter,] [communication filter,] [waveguide,] [penetration,] and [_____]. 1.8 PREINSTALLATION CONFERENCE A preinstallation conference for EM shielding shall be held with the Contractor and installers working in, on, or near the EM shield. Coordination requirements shall be discussed and instructions shall be stated to ensure the integrity of the EM shield. 1.9 DELIVERY AND STORAGE Equipment shall be delivered and stored with protection from excessive humidity and temperature variation, dirt, and other contaminants. 1.10 FIELD MEASUREMENTS The Contractor shall become familiar with details of the work, verify dimensions in the field, and shall advise the Contracting Officer of any discrepancy before performing the work. 1.11 PROJECT/SITE REQUIREMENTS Welding of EM shielding material and sheet steel shall be performed at an ambient temperature of [10 degrees C] [50 degrees F] minimum to [32 degrees C] [90 degrees F] maximum. Shielding shall not be installed until the building has been weather enclosed. Sheet steel welding shall not be performed in direct sunlight. 1.12 EXTRA MATERIALS [One] [_____] extra EM power filter[s] and [one] [_____] extra communications filter[s] of each different type furnished on the project shall be furnished as a spare. 1.13 SOURCE QUALITY CONTROL Factory tests shall be performed as described herein. The Contracting Officer reserves the right to witness the specified factory tests. The Contracting Officer shall be notified at least 30 days before factory tests are scheduled to be performed. Test data shall include a detailed description of the test instrumentation and equipment, including calibration dates, a detailed description of the test procedure, and the recorded test data. 1.14 OPERATING AND MAINTENANCE MANUAL The manual shall address all components and aspects of the EM shielding and shall include, but not be limited to, the following: a. A complete set of assembly drawings to include penetration locations and installation details. b. The construction specification on EM shielding. c. Shield penetration schedule. d. Power/signal filter schedule. e. Test plan. f. The prepared preventive maintenance instructions for periodic inspection, testing and servicing, lubrication, alignment, calibration, and adjustment events normally encountered. Complex preventive maintenance events shall be extracted from or shall refer to detailed vendor or manufacturer data. This information shall be derived from an evaluation of engineering data considering local environmental conditions, manufacturer's recommendations, estimated operating life for the specific application and use of the equipment, and types of job skills available at the operating site. g. Spare parts data approved and verified by the shielding specialist prior to submission. The data shall include a complete list of recommended parts and supplies with current unit prices and source of supply. h. Provide a list of hardness critical items (HCI) requiring periodic inspection to maintain EM shield integrity. Hardness critical items are those components and/or construction features which singularly and collectively provide specific levels of HEMP protection, such as the EM shield, surge arresters, EM shielded doors, shield welding, electrical filters, honeycomb waveguides, and waveguides-below-cutoff. PART 2 PRODUCTS 2.1 GENERAL 2.1.1 Standard Products Materials and equipment shall be the standard products of a manufacturer regularly engaged in the manufacture of such products and shall essentially duplicate items that have been in satisfactory use for at least 2 years prior to bid opening. Equipment shall be supported by a service organization that is, in the opinion of the Contracting Officer, reasonably convenient to the site. 2.1.2 Nameplates Each major item of equipment shall have the manufacturer's name, address, type or style, model or serial number, and catalog number on a plate secured to the item of equipment. 2.1.3 Special Tools One set of special tools, calibration devices, and instruments required for operation, calibration, and maintenance of the equipment shall be provided as follows: [SELDS Test Set] [_____] 2.1.4 Testability Equipment and materials of the EM shielding shall be designed and built to facilitate testing and maintenance. 2.2 EM SHIELDING EFFECTIVENESS ************************************************************************** NOTE: The designer will consider the shield as early in the design as possible while the geometry of the shielded enclosure can be located to utilize components inherent in the structure. Failure to consider the shield configuration first in the design will increase design costs, cause problems in its incorporation into the structure, and lose installation simplicity. The EM shielded enclosure design should be coordinated by the structural, mechanical, and electrical engineers and architect. The structural and shielding systems should drive each other on large projects. Multi-story shielded enclosures require continuous connections of shielding steel interconnected to the structural steel. In these cases, the shielding wall layout should coincide with the structural steel beam layout. The shield within an exterior building concept must employ a design which allows for settling, seismic motion, and differential thermal expansion between the steel and concrete of the building and the steel of the EM shielding. ************************************************************************** The EM shielded enclosure complete with all filters, doors, and/or waveguides shall have the following minimum EM shielding effectiveness attenuation. Minimum magnetic field attenuation shall be [20 dB] [_____] at 14 kHz increasing linearly to [50 dB] [100 dB] at [200 kHz] [1 MHz] [_____]. Minimum electric field and plane wave attenuation shall be [50 dB] [100 dB] [_____] from 14 kHz to [1 GHz] [10 GHz] [_____].2.3 EM SHIELDING ENCLOSURE REQUIREMENTS (WELDED CONSTRUCTION) ************************************************************************** NOTE: For the EM shielding enclosure, choose either welded or bolted construction. The unused method should be deleted from the project specification. Welded construction will usually consist of continuous 1.897 mm (14 gauge) thick steel plate and angles to form the enclosure. Thicker material may be used if it is more cost-effective or required for structural reasons. Welded construction is used when a shielded facility requires a long maintainable service life of high-level protection, 100 dB attenuation, or HEMP protection, 100 dB. Bolted construction is associated with a lower level (50 dB) of maintained shielding effectiveness. Bolted construction will usually consist of modular panels bolted together with metal strips or channels. Panels are commonly plywood with steel sheets laminated to one or both sides. Bolted construction is used when a shielded facility's service life is short, 10 years or less, or the system is required to be demountable for change of location. This system requires more maintenance than a welded system and requires access to the panels. The EM shield layout may restrict attenuation testing of the enclosure. It is desirable for large facilities to place the shield at least 1 meter (3.3 feet) inside the exterior walls, although cost and construction restrict this consideration. The floor shielding can be tested by SELDS test but not by IEEE STD 299 if it is on grade. The facility layout must be carefully planned to allow for testing and shield maintenance. ************************************************************************** 2.3.1 Welded Shielding Enclosure ************************************************************************** NOTE: Shielding steel thickness should not be based solely on the minimum thickness required for HEMP/TEMPEST attenuation. Thicker steel may be necessary because of structural factors and heat deformation or burn-through from seam welding. ************************************************************************** The intent of this section and the drawings is to provide a complete metal enclosure including floor, walls, ceiling, doors, penetrations, welds, and the embedded structural members to form a continuous EM shielded enclosure. Shielding sheets and closures shall be [1.897] [_____] mm [14] [_____] gauge thick cold-rolled steel for walls and ceiling conforming to ASTM A 366 and [3.416] [_____] mm [10] [_____] gauge thick hot-rolled steel for floors conforming to ASTM A 568 or ASTM A 569. Steel plates, channels, or angles of minimum 6 mm 1/4 inch thick shall be used to reinforce shield sheets for attachments of ducts, waveguides, conduit, pipes, and other penetrating items. Furring channels used to attach shielding sheets to walls or floors shall be the minimum gauge of the shielding steel. The shielding sheet steel gauge may be thicker at the Contractor's option to reduce labor and welding effort only if structurally tolerable with the existing design. Steel shall be free of oil, dents, rust, and defects. 2.3.2 Metal Members Structural steel shapes, plates, and miscellaneous metal shall conform to ASTM A 36. Furring channels shall conform to ASTM A 611. 2.3.3 Steel and Welding Material Welding materials shall comply with the applicable requirements of AWS D1.1 and AWS D9.1. Steel and welding material shall conform to AISC-MO16. Welding electrodes shall conform to AWS D1.1 for metal inert gas (MIG) welding method. Weld filler metal shall conform to AWS A5.18. 2.3.4 Fasteners Self-tapping screws shall not be used for attachment of shielding. Power-actuated drive pins shall be zinc-coated steel, Type I, pin size No. 4 to secure steel sheets to concrete surfaces and to light gauge furring channels. The drive pins shall conform to ASTM A 227 Class 1 for materials and ASTM B 633 for plating. 2.3.5 Miscellaneous Materials and Parts Miscellaneous bolts and anchors, supports, braces, and connections necessary to complete the miscellaneous metal work shall be provided. The necessary lugs, rebars, and brackets shall be provided to assemble work. Holes for bolts and screws shall be drilled or punched. Poor matching of holes will be cause for rejection. Thickness of metal and details of assembly and supports shall provide ample strength and stiffness. The materials shall be galvanically similar. 2.3.6 Penetrations ************************************************************************** NOTE: Configure the facility to minimize the number of metallic structural elements required to penetrate the barrier. ************************************************************************** Penetrations of the shield, including bolts or fasteners, shall be sealed with puddle welds or full circumferential EM welds. Structural penetrations including beams, columns, and other metallic structural elements shall be provided with continuously welded or brazed seams and joints between the penetrating element and the shield. Nonmetallic structural elements shall not penetrate the electromagnetic barrier. 2.3.7 Penetration Plates (Welded Construction) The penetration plate shall be the central location for treatment of penetrations. The panel shall be constructed of 6 mm 1/4 inch thick ASTM A 36 steel plate welded to the shield. Waveguide, conduit, and piping penetrations shall be circumferentially welded at the point of penetration to the inner surface of the penetration plate. Penetration plates shall extend at least 150 mm 6 inches beyond all penetrations. 2.3.8 Floor Finish ************************************************************************** NOTE: Indicate or specify whether other flooring is to be provided or higher floor loads are required. This is most critical when raised floors are specified. Allowances must be made for elevated door thresholds. Specify special requirements for laboratory loads or seismic loading in this paragraph. If concrete floor wearing slabs are specified, they should be thick enough to hold anchor bolts for equipment, supports, and interior partitions. Concrete wearing slabs may be provided in most applications with a minimum thickness of 100 mm (4 inches). The Air Force is opposed to placing concrete wearing slabs over shielding steel because of problems with testing and repair. Placing concrete over floor shielding requires a waiver from HQ AFCESA/ENE. Indicate or specify whether other flooring is to be provided or higher floor loads are required. This is most critical when raised floors are specified. Allowances must be made for elevated door thresholds. Specify special requirements for laboratory loads or seismic loading in this paragraph. If concrete floor wearing slabs are specified, they should be thick enough to hold anchor bolts for equipment, supports, and interior partitions. Concrete wearing slabs may be provided in most applications with a minimum thickness of 100 mm (4 inches). The Air Force is opposed to placing concrete wearing slabs over shielding steel because of problems with testing and repair. Placing concrete over floor shielding requires a waiver from HQ AFCESA/ENE. ************************************************************************** * Floor EM shielding shall be covered by a reinforced cast-in-place concrete slab [100] [_____] mm [4] [_____] inches thick. 2.4 EM SHIELDING ENCLOSURE REQUIREMENTS (BOLTED CONSTRUCTION) ************************************************************************** NOTE: For the EM shielding enclosure, choose either welded or bolted construction. The unused method should be deleted from the project specification. Welded construction will usually consist of continuous 1.897 mm (14 gauge) thick steel plate and angles to form the enclosure. Thicker material may be used if it is more cost-effective or required for structural reasons. Welded construction is used when a shielded facility requires a long maintainable service life of high-level protection, 100 dB attenuation, or HEMP protection, 100 dB. Bolted construction is associated with a lower level (50 dB) of maintained shielding effectiveness. Bolted construction will usually consist of modular panels bolted together with metal strips or channels. Panels are commonly plywood with steel sheets laminated to one or both sides. Bolted construction is used when a shielded facility's service life is short, 10 years or less, or the system is required to be demountable for change of location. This system requires more maintenance than a welded system and requires access to the panels. The EM shield layout may restrict attenuation testing of the enclosure. It is desirable for large facilities to place the shield at least 1 meter (3.3 feet) inside the exterior walls, although cost and construction restrict this consideration. The floor shielding can be tested by SELDS test but not by IEEE STD 299 if it is on grade. The facility layout must be carefully planned to allow for testing and shield maintenance. ************************************************************************** 2.4.1 Panel Construction Flat steel sheets shall be laminated to each side of a 20 mm 3/4 inch thick structural core of either plywood or hardboard. Panels shall have a flame spread rating of less than 25 when tested according to ASTM E 84. Flat steel shall conform to ASTM A 653 and ASTM A 526 with G-60 coating, minimum 0.5512 mm 26 gauge thick, zinc-coated phosphatized. Plywood shall conform to DOC PS 1 for exterior, sound grade hardwood, Type I. Hardboard shall conform to AHA A135.4, Class 4, SIS, for standard type hardboard. Adhesive for laminating steel sheets to structural core shall be a waterproof type which maintains a permanent bond for the lifetime of the enclosure. 2.4.2 Framing Panels shall be joined and supported by specially designed framing members that clamp the edges of the panels and provide continuous, uniform, and constant pressure for contact to connect the shielding elements of the panels. The walls shall be self supporting from floor to ceiling with no bracing. Deflection of walls under a static load of 335 N 75 pounds applied normally to the wall surface at any point along the framing members shall not exceed 1/250 of the span between supports. [Ceilings shall be self-supporting from wall to wall.] [Ceilings shall be supported by adjustable, nonconducting, isolated hangers from the structural ceiling above.] Ceilings shall be designed to have a deflection under total weight, including ceiling finish, of not more than 1/270 of the span. A one-piece factory pre-welded corner section or trihedral corner framed with a brass machine cast corner cap assembly consisting of inner and outer parts shall be provided at all corner intersections of walls and floor or ceiling. The modular enclosure shall be designed for ease of erection, disassembly, and reassembly. 2.4.3 Channel The framing-joining system members shall consist of 3 mm 1/8 inch thick zinc-plated steel channels having a minimum 16 mm 5/8 inch overlap along each side of the contacting surface. Screw fasteners shall be spaced at 75 or 100 mm 3 or 4 inch intervals. Screw fasteners shall be either zinc-or cadmium-plated steel, minimum size 6 mm 1/4 inch - 20 with a pan or flat Phillips head. Fasteners shall be heat-treated and hardened with a minimum tensile strength of 931 MPa. 135,000 psi. 2.4.4 Sound Transmission Class (STC) Enclosure panels shall have an STC of [30] [_____] dB minimum when tested according to ASTM E 90. 2.4.5 Penetration Plates (Bolted Construction) Plates shall be a minimum 3 mm 1/8 inch thick ASTM A 36 steel plate, sized [450] [_____] mm [18] [_____] inches by [450] [_____] mm [18] [_____] inches and shall have a 6 mm 1/4 inch thick extruded brass frame for mounting to the shielded enclosure wall panel. Penetration plates shall extend at least 150 mm 6 inches beyond all penetrations. 2.5 EM SHIELDED DOORS ************************************************************************** NOTE: Edit these paragraphs depending on type of door used on project. ************************************************************************** 2.5.1 General Material in shielded doors and frames shall be steel conforming to ASTM A 36, ASTM A 366 or ASTM A 568, and ASTM A 569 and shall be stretcher-leveled and installed free of mill scale. Metal shall be thicker where indicated or required for its use and purpose. Metal thresholds of the type for proper shielding at the floor shall be provided. Fire rated shielded doors and assemblies shall meet NFPA 80 and NFPA 80A requirements and shall bear the identifying label of a nationally recognized testing agency qualified to perform certification programs. The EM shielded doors shall be provided by a single supplier who has been regularly engaged in the manufacture of these items for at least the previous 5 years. The assemblies shall be supplied complete with a rigid structural frame, hinges, latches, and parts necessary for operation. The products supplied shall duplicate assemblies that have been in satisfactory use for at least 2 years. The door frame shall be steel suitable for [welding] [bolting] to the surrounding structure and shield. The EM filters, EM waveguide penetrations for door systems, and miscellaneous material shall be provided for a complete system. The enclosure door shall be nonsagging and nonwarping. The EM shielded door shall provide a shielding effectiveness of [10 dB] [20 dB] greater than the minimum EM shielding effectiveness requirements. The door shall have a clear opening [as shown on the drawings] [of [915] [_____] mm [36] [_____] inches wide and [2135] [_____] mm [84] [_____] inches high]. The door and frame assembly shall have a sound rating of STC [30] [_____] minimum. Testing shall be performed in accordance with ASTM E 90. 2.5.1.1 Door Latch The door latch shall be lever controlled with roller cam action requiring not more than 67 N 15 pounds of operating force on the lever handle for both opening and closing. The door shall be equipped with a latching mechanism having a minimum of three latching points that provides proper compressive force for the EM seal. The mechanism shall be operable from both sides of the door and shall have permanently lubricated ball or thrust bearings as required at points of pivot and rotation. 2.5.1.2 Hinges Doors shall be equipped with a minimum of three well-balanced adjustable ball-bearing or adjustable radial thrust bearing hinges suitable for equal weight distribution of the shielded doors. Hinges shall allow adjustment in two directions. Force necessary to move the doors shall not exceed 22 N. 5 pounds. 2.5.1.3 Threshold Protectors Threshold protectors shall be furnished for each EM shielded door. Protectors shall consist of portable ramps that protect the threshold when equipment carts or other wheeled vehicles are used to move heavy items across the threshold. The ramps may be asymmetrical to account for different floor elevations on each side, but the slope of the ramp shall not exceed 4:1 on either side. Ramps shall be designed to support a [227] [_____] kg [500] [_____] pound vertical force applied to a 75 by 13 mm 3 by 1/2 inch area for a personnel door, and a [907] [_____] kg [2,000] [_____] pound vertical force applied to a 75 by 13 mm 3 by 1/2 inch area for an equipment double leaf door. The force shall be applied to the contact area between the threshold and the door. Mounting brackets, convenient to the entry, shall be provided to store the ramp when not in use. 2.5.1.4 Frequency of Operation With proper maintenance, door assemblies shall function properly through 100,000 cycles and 15-year service life minimum without the shielding effectiveness decreasing below the overall shield required attenuation. 2.5.1.5 Electric Interlocking Devices Electric interlocking devices shall be provided for vestibules equipped with shielded doors at each end. Electric interlocking devices shall be provided so that shielded doors at the ends of the vestibule cannot be opened at the same time during normal operation. A manual override shall be provided to allow emergency egress, and an audible alarm shall be provided to indicate that doors at each end of the vestibule are open. The alarm will continue to sound while both doors are open. The Contractor shall provide a low-voltage piezoelectric-type alarm, in a tamperproof enclosure, at a location shown on the project drawings or as directed by the Contracting Officer's representative. The sound intensity shall be 45 dBA minimum at 3.05 m. 10 feet. Lights shall be provided on the side of each door outside the vestibule to indicate that the other door is open. Interlock systems may be integrated into a cypher lock system. The interlock system shall be powered by an uninterruptible power source and shall be fail-safe in an unlocked condition in the event of a power failure. 2.5.1.6 Electric Connectivity Electric connectivity for sensors, alarms, and electric interlocking devices shall be installed in accordance with the door manufacturer's instructions, the approved drawings, and Section 16415 ELECTRICAL WORK, INTERIOR. 2.5.1.7 Threshold Alarm A press-at-any-point ribbon switch shall be applied to the threshold. The switch shall enunciate an alarm whenever pressure is applied to the threshold of the EM shielded door. 2.5.1.8 Hold Open and Stop Device Each EM shielded door leaf shall be provided with a hold open and stop device permanently attached to the door leaf. Shielded doors shall have a fastener plate welded onto the door. The device shall not interfere with the finger stock. No drilling or tapping of the shielded door will be allowed. 2.5.1.9 Emergency Exit Hardware Emergency exit EM shielded doors shall be equipped with single motion egress hardware. The force required to latch and unlatch emergency exit hardware on EM shielded doors shall meet life safety code NFPA 101. Field alterations or modifications to panic hardware will not be allowed. 2.5.1.10 Finish EM shielded doors shall be factory prime painted with zinc chromate primer. Doors may be factory finish painted or galvanized. The Contractor shall touch up any damaged finish. 2.5.1.11 Spare Parts The Contractor shall furnish one set of finger stock and EM gaskets (if used) for each hinged EM shielded door provided. In addition, one set of manufacturer recommended and Contracting Officer approved spare parts for EM shielded doors of each style installed shall be provided. 2.5.1.12 Tools The Contractor shall furnish one full set of tools that are required to maintain the doors and are not typically available from tool vendors. The Contractor shall furnish environmentally safe lubricants, cleaning solvents, or coatings in sufficient quantities to last for [6] [_____] months. 2.5.1.13 Maintenance Supplies and Procedures Maintenance supplies sufficient for a [3] [_____] year period or [50,000] [_____] open-close cycles, whichever is greater, shall be provided for each EM shielded door. The maintenance instructions required to maintain the door through the cycle count shall be prominently displayed nearby. 2.5.1.14 Door Counter A door operation counter shall be provided on the enclosure interior. 2.5.1.15 Additional Hardware ************************************************************************** NOTE: Alarms would normally be specified in Section 16725 INTRUSION DETECTION SYSTEM. Hardware will be specified in the hardware section. ************************************************************************** See door schedule on drawings and Section 08700 BUILDER'S HARDWARE, for additional hardware requirements. Fire rating and STC sound ratings shall be as required by the door finish schedule on the drawings or in the specifications. 2.5.2 Latching Type Doors ************************************************************************** NOTE: The knife edge shall be made of stainless steel 430 series if it will be exposed to moist air containing salt (near the sea coast) or in an uncontrolled or corrosive environment. ************************************************************************** Doors shall be [steel] [laminated] type. [Steel doors shall be a minimum of 3.416 mm 10 gauge thick steel sheet electrically and mechanically joined by welded steel frames overlapping joints with continuous EM welds.] [Laminated type shall be the same construction as enclosure panels, except the steel faces shall be electrically and mechanically joined by channels or overlapping seams, both of which shall be continuously seam welded or soldered along all joined surfaces.] The closure seal shall utilize an extruded brass channel containing a recess into which [two] [_____] sets of [beryllium copper condition HT in accordance with ASTM B 194] [stainless steel 430 (magnetic type) series] contact fingers and a closed cell foam rubber air seal are fitted and can be easily removed and replaced without the use of special tools and without the application of solders. The door shall mate to the frame in a manner that allows the insertion of a brass knife edge between the two rows of the radio frequency finger stock, to obtain optimum conductivity and electromagnetic shielding. High-temperature silver solder shall be used to attach the brass knife edge components to the door panels and the frame. The fingers that form a contact between the door and its frame shall be protected from damage due to physical contact and shall be concealed within the door and frame assembly. 2.5.3 Pneumatic Sealing Doors Pneumatic sealing mechanisms shall achieve EM shielding by using pressure to force the door panel against the frame surface. Contact areas of door and frame shall be a peripheral strip not less than 75 mm 3 inches wide completely around the door with a tinned or highly conductive noncorrosive surface. After the door is in a closed position, the pneumatic sealing mechanism shall exert pressure in not more than 10 seconds. The sealing mechanism release shall be actuated in not more than 5 seconds. Manual [override] [operation] shall not exceed a maximum of [155] [_____] N [35] [_____] pounds When the door is sealed, the attenuation around the edges shall meet the EM shielding effectiveness requirements of this specification. Swinging doors shall have a threshold of zinc-plated steel, not less than 9.5 mm 3/8 inch thick. The door shall be provided with a pneumatic system that maintains a nominal sealing pressure of [240] [_____] kPa. [35] [_____] psi. A label shall be attached to pneumatic doors warning against painting of the mating surfaces. 2.5.3.1 Door and Enclosure Design Doors shall be designed for long life and reliability without the use of EM gaskets, EM finger stock, or other sealing devices other than the direct metal-to-metal contact specified. The EM sealing device shall be fail-safe upon loss of air pressure and shall readily allow manual opening of the door. For either normal or fail-safe operation, the maximum time to reach the open position shall be no more than 7 seconds. The enclosure design shall include provision for removing the door for routine maintenance without disturbing its alignment and EM sealing properties. 2.5.3.2 Control Panel The inside and outside of the shielded enclosure shall contain a control panel including the necessary opening and closing pneumatic valves. The outside control panel shall also have a pressure regulator and filter. The door air supply shall be capable of quick opening from inside the enclosure to allow escape when opening pneumatic valves fail or malfunction. 2.5.3.3 Air System for Pneumatic Sealing A complete air system including compressor, filter alarm, tank, lines, air filter, dryer, air control valves, and controls shall be provided. Air tank capacity shall be sized so that the air volume and pressure are sufficient to operate the door through ten complete cycles after the loss of normal power. 2.5.4 Magnetic Sealed Door Type An EM seal shall be formed by a solid metal-to-metal contact around the periphery of the door frame. The materials at the contact area shall be compatible and corrosion resistant. The contact force for the door EM seal shall be provided by electromagnets. When the electromagnet is energized, the door leaf shall be pulled in to ensure a solid and continuous contact with the door frame. When the electromagnet is de-energized, the door leaf shall be free to swing. The EM shielded doors may use electromagnets or a combination of permanent magnets and electromagnets. 2.5.5 Sliding Type Door A sliding shielded door shall be of the size and operating direction indicated. Clear openings indicated on the drawings shall not require dismantling of any part of the door. The door shall be manually operable from either side, inside or outside, with a maximum pull (force) of 155 N 35 pounds to set the shielded door in motion. Shielded door face panels and frames shall be constructed of reinforced steel suitable for achieving the specified attenuation. Frames shall be constructed of steel shapes welded together to form a true rectangular opening. In the sealed position, the shielded doors shall provide the minimum shielding effectiveness specified without any derating. The doors shall be designed for long life and reliability and shall not use EM gaskets, EM finger stocks, or other sealing devices other than the specified direct metal-to-metal contact. A label shall be attached to sliding doors warning against painting of the mating surfaces. 2.5.6 Power Operators Power operators shall be [pneumatic] [electric] type conforming to NFPA 80 and the requirements specified herein. Readily adjustable limit switches shall be provided to automatically stop the door in its full open or closed position. All operating devices shall be suitable for the hazardous class, division, and group defined in NFPA 70. 2.5.6.1 Pneumatic Operators ************************************************************************** NOTE: Designer will coordinate with the drawings to ensure compressed air is available at door locations. ************************************************************************** Pneumatic operators shall be heavy-duty industrial type designed to operate the door at not less than 0.2 m/s 2/3 fps or more than 0.3 m/s 1 fps with air pressure of [_____] kPa. [_____] psi. A pressure regulator shall be provided if the operator is not compatible with available air pressure. Dryer, filter, and filter alarm shall be provided. Pneumatic piping shall be provided up to the connection with building compressed air, but not more than 6 m 20 feet from door jambs. Operators shall have provisions for immediate emergency manual operation of the door in case of failure. The operator shall open, close, start, and stop the door smoothly. Control shall be [electrical, conforming to NEMA ICS 2 and NEMA ICS 6; enclosures shall be Type 12 (industrial use), Type 7 or 9 in hazardous locations, or as otherwise indicated] [pneumatic] [with] [pushbutton wall switches] [ceiling pull switches] [rollover floor treadle] [as indicated]. 2.5.6.2 Electric Operators Electric operators shall be heavy-duty industrial type designed to operate the door at not less than 0.2 m/s 2/3 fps or more than 0.3 m/s. 1 fps. Electrical controls shall be [pushbutton wall switches] [ceiling pull switches] [rollover floor treadle] [as indicated]. Electric power operators shall be complete with an electric motor, brackets, controls, limit switches, magnetic reversing starter, and other accessories necessary. The operator shall be designed so that the motor may be removed without disturbing the limit switch timing and without affecting the emergency operator. The power operator shall be provided with a slipping clutch coupling to prevent stalling of the motor. Operators shall have provisions for immediate emergency manual operation of the door in case of electrical failure. Where control voltages differ from motor voltage, a control voltage transformer shall be provided inside as part of the starter. Control voltage shall be 120 volts or less. a. Motors. Drive motors shall conform to NEMA MG 1, shall be high-starting torque reversible type, and shall be of sufficient output to move the door in either direction from any position at the required speed without exceeding the rated capacity. Motors shall be suitable for operation on [[120] [208] [277] [480] volts, 60 Hz] [[220] [240] [380] volts, 50 Hz], [single] [three] phase, and shall be suitable for across-the-line starting. Motors shall be designed to operate at full capacity over a supply voltage variation of plus or minus 10 percent of the motor voltage rating. b. Controls. Each door motor shall have an enclosed reversing across-the-line type magnetic starter with thermal overload protection, limit switches, and remote control switches. The control equipment shall conform to NEMA ICS 2; enclosures shall conform to NEMA ICS 6, and shall be Type 12 (industrial use), Type 7 or 9 in hazardous locations, or as otherwise indicated. Each wall control station shall be of the three-button type, with the controls marked and color coded: OPEN - white; CLOSE - green; and STOP - red. When the door is in motion and the stop control is pressed, the door shall stop instantly and remain in the stop position. From the stop position, the door shall be operable in either direction by the open or close controls. Controls shall be of the full-guarded type to prevent accidental operation. 2.5.6.3 Leading Edge Safety Shutdown Leading edges of the door with operators shall have a safety shutdown switch strip the entire length of the leading edge. The safety strip shall be press-at-any-point ribbon switches. Activation of the strip shall shut down the operator and release the door with reset required to continue door operation.