Attch_2_-_Specifications.pdf

Naval Undersea Warfare Center Division

Newport, Rhode Island

SPECIFICATIONS FOR A NEW

ACOUSTIC EMI CHAMBER AND A NEW

RF SHIELDED DOOR ON AN EXISTING

EMI CHAMBER

6 May 2019

TABLE OF CONTENTS

TABLE OF CONTENTS

1.0 SPECIFICATIONS FOR A NEW ACOUSTIC EMI CHAMBER

1.1 GENERAL SPECIFICATIONS

1.2 PHYSICAL SPECIFICATIONS

1.2.1 Location and Dimensions of Chamber and Antechamber

1.2.2 Framing and Construction

1.2.3 Welding

1.2.4 Finished Flooring

1.2.5 Connector Access Panels

1.2.6 Doors

1.2.7 Grounding

1.2.7.1 Exterior Grounding

1.2.7.2 Interior Grounding

1.3 ANCILLARY EQUIPMENT

1.3.1 RF Absorber

1.3.2 Sound Pad

1.3.3 Air Vents

1.3.4 Power Requirements

1.3.4.1 Power Filters

1.3.4.2 Lighting

1.4 FIRE PROTECTION

1.4.1 Fire Alarm

1.4.2 Sprinkler System

1.5 PERFORMANCE SPECIFICATIONS

1.6 TESTING

2.0 SPECIFICATIONS FOR A NEW RF SHIELDED DOOR ON AN EXISTING EMI

CHAMBER

2.1 GENERAL SPECIFICATIONS

2.2 PHYSICAL SPECIFICATIONS

2.2.1 Location and Dimensions of Door

2.2.2 Construction

2.2.3 RF Absorbers & Ground Bar

2.3 ACCESS PANEL

2.4 PERFORMANCE SPECIFICATIONS

2.4.1 RF Shielding Effectiveness Performance Requirement Option 1

2.4.2 RF Shielding Effectiveness Performance Requirement Option 2

2.5 TESTING

1.0 SPECIFICATIONS FOR A NEW ACOUSTIC EMI CHAMBER

These specifications describe the minimum acceptable quality and/or performance level requirements of the item being purchased. The contractor shall fabricate and install an Acoustic Electromagnetic Interference (EMI) Chamber with Shielded Antechamber in accordance with the following specifications:

1.1 GENERAL SPECIFICATIONS

An Acoustic EMI Chamber with Shielded Antechamber shall be installed at the Naval Undersea Warfare Center Division Newport. The building and room number will be provided in the contract.

All construction material shall be new and delivered to the job site in undamaged condition.

Material shall be stored to ensure proper alignment and to protect material against dampness and accumulated moisture before and after delivery. Defective or damaged materials shall be replaced by the Contractor at no additional cost to the Government.

1.2 PHYSICAL SPECIFICATIONS

1.2.1 Location and Dimensions of Chamber and Antechamber

The Acoustic EMI Chamber and Shielded Antechamber shall be installed at a distance of 3-6 inches away from the nearest existing wall. The building number, room number, and placement within the room will be provided in the contract.

Figure 1.2.1-1 Acoustic EMI Chamber with Shielded Antechamber

The Acoustic EMI Chamber shall have 16 feet long x 16 feet wide x 12 feet high interior dimensions (pre-finished, sheet metal to sheet metal—aka prior to the installation of the RF absorbers). The exterior dimensions shall not exceed 17 feet long x 17 feet wide x 13 feet high.

The Shielded Antechamber shall have 8 feet long x 10 feet wide x 10 feet high interior dimensions (pre-finished, sheet metal to sheet metal—the antechamber will not have RF absorbers). The exterior dimensions shall not exceed 9 feet long x 11 feet wide x 11 feet high.

1.2.2 Framing and Construction

Fabreeka pad, or equivalent pad, meeting the specifications in MIL-C-882 and MIL-E-5272 shall be installed between the existing finished floor and the Acoustic EMI Chamber with Shielded Antechamber to isolate vibration and reduce noise. The Fabreeka pad, or equivalent pad, thickness shall be approved by the Government prior to installation. The Fabreeka pad, or equivalent pad, shall be trimmed where needed to avoid pinch points. The Fabreeka pad, or equivalent pad, shall be protected from damage due to welding.

The Acoustic EMI Chamber with Shielded Antechamber shall have a welded steel frame construction, in accordance with International Building Code (IBC), Chapter 16, as modified by

UFC 3-301-01.

The Chamber’s and Antechamber’s shielding panels material shall meet the specifications of ASTM A1008 or ASTM A568/A568M-17A steel. The steel panels used for the walls and ceilings shall have a minimum thickness of 3/16”. The steel panels used for the floors shall have a minimum thickness of ½”. The Acoustic EMI Chamber and Shielded Antechamber shall have a continuous welded seam construction and shall be field-welded. The Acoustic EMI Chamber and Shielded Antechamber shall be welded to each other.

1.2.3 Welding

All welding shall be performed in accordance with the latest edition of the AWS D1.1 Structural Welding Code-Steel and AWS D1.3 Structural Welding Code- Sheet Steel. All welded surfaces shall be flat and level.

Structurally weld the shielding steel to the steel frame and seal electrical seams RF tight by the MIG method, using electrodes structurally and electrically compatible with the adjacent steel sheets.

Plug weld or tack weld steel sheets to framework at 12 inches on center to support steel sheets, then use continuous seam welding to seal RF seams in the chamber.

Welded seams shall be free of slag inclusions, gas pockets, voids, or incomplete fusion anywhere along the seams.

In-process weld testing shall be conducted. Completed welds shall be inspected by the contractor after the welds have been thoroughly cleaned by hand or power wire-brush. Welds shall be inspected by the contractor for surface cracking, porosity, slag inclusion, excessive roughness, unfilled craters, gas pockets, undercuts, overlaps, size, and insufficient throat and concavity.

Weld failures shall be corrected by grinding out such welds and replacing with new welds.

1.2.4 Finished Flooring

The Acoustic EMI Chamber and Shielded Antechamber shall have an interior finished floor consisting of ¾ inches minimum thickness plywood (treated fire retardant plywood) with a vinyl surface covering. The bottom of the Acoustic EMI Chamber and Shielded Antechamber doors shall be 4 inches above the interior finished floor. The interior flooring of the Acoustic EMI Chamber and Shielded Antechamber shall not warp or sag.

1.2.5 Connector Access Panels

The Acoustic EMI Chamber and Shielded Antechamber shall have four (4) access apertures as follows and in accordance with Figure 1.2.1-1:

One (1) access aperture shall have a clear opening 24 inches wide x 12 inches high and shall interface between the Acoustic EMI Chamber and the Shielded Antechamber.

One (1) access aperture shall have a clear opening 24 inches wide x 12 inches high and shall interface between the Acoustic EMI Chamber and Room 1.

One (1) access aperture shall have a clear opening 8 inches wide x 8 inches high and shall interface between the Acoustic EMI Chamber and Room 1.

One (1) access aperture shall have a clear opening 8 inches wide x 8 inches high and shall interface between the Shielded Antechamber and Room 1.

Both of the 24 inches wide x 12 inches high access apertures shall have identical bolt pattern such that the access panels can be interchangeable between both locations. Both of the 8 inches wide x 8 inches high access apertures shall have identical bolt pattern such that the access panels can be interchangeable between both locations. The center of all four (4) access panels shall be 24 inches from the floor. All access aperture’s edges shall be ground smooth. Two (2) blanking panels shall be provided per each access aperture. All four (4) access apertures shall meet the performance criteria stated in Section 1.5 when covered with bolt-on panels.

1.2.6 Doors

The Acoustic EMI Chamber and the Shielded Antechamber shall each have one (1) door that meets the specifications below:

The doors shall not warp or sag and shall meet the performance criteria stated in Section

1.5 when closed.

The doors shall have a clear opening of 42 inches wide and 84 inches high.

The doors shall be reinforced steel or laminated type. Laminated type shall be the same construction as the chamber’s shielding panels, except the steel faces shall be electrically and mechanically joined by channels or overlapping seams, both of which shall be continuously seam welded along all joined surfaces.

The door assembly shall be designed to function properly throughout a minimum of 10,000 cycles without the shielding effectiveness decreasing below the overall shield required attenuation.

The doors shall be installed with a minimum of two (2) rows of double-sided RF finger stock around the door or its frame to meet the performance specifications of Section 5.

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 assemblies. Contact for doors shall be copper beryllium conforming to ASTM B 194, Condition HT. The finger stock shall be secured to the door or frame without using special tools or soldering or adhesives.

1.2.7 Grounding

The Acoustic EMI Chamber with Shielded Antechamber shall be grounded as specified in Section 1.2.7.1 and Section 1.2.7.2.

1.2.7.1 Exterior Grounding

The Acoustic EMI Chamber shall be grounded to the Shielded Antechamber by means of the continuous welded seams between them.

The Acoustic EMI Chamber with Shielded Antechamber shall be grounded to the nearest underground grounding system using a grounding lug as shown in Figure 1.2.7-1 and grounding lug shall be located at a height of 40” above the existing finished floor (outside the Acoustic EMI Chamber with Shielded Antechamber).

Figure 1.2.7-1 Grounding Stud for Shielded Antechamber

1.2.7.2 Interior Grounding

The Acoustic EMI Chamber with Shielded Antechamber shall have a solid copper ground bus bar along the inside walls at a height of 42 inches off the floor and a distance of 2.5 inches from the wall. Copper ground bus bars shall have its minimum diameter 5/16 inch studs welded to the wall at distances no greater than every two (2) feet. Copper ground bus bar shall be minimum

1.25 inches x .25 inches thick.

The DC resistance between the existing underground grounding system and the copper ground bus bar inside the Acoustic EMI Chamber shall be no greater than 0.0001 Ohms.

1.3 ANCILLARY EQUIPMENT

1.3.1 RF Absorber

The Acoustic EMI Chamber’s interior walls and ceiling shall be partially covered with EM absorber and ferrite tile, as shown in Figure 1.3.2-1 and Figure 1.3.2-2. The absorber material shall be in accordance with MIL-STD-461G, Section 4.3.2.1. The absorber and framing shall not extend more than 4.75 inches from the interior walls of the Acoustic EMI Chamber.

1.3.2 Sound Pad

The Acoustic EMI Chamber’s interior walls and ceiling shall be partially covered in sound pad material, as shown in Figure 1.3.2-1. The sound pads or Acoustic-Board Ultra – Soundproofing Backer, or its equivalent, shall meet the Sound Transmission Class (STC) requirements of ASTM E90-04, ASTM E4413-04 STC = 15, and the thickness shall be no less than a 0.50-inch-thick or as approved by the Government.

Figure 1.3.2-1 Acoustic EMI Chamber’s Coverage Area Top View

Figure 1.3.2-2 Acoustic EMI Chamber’s Coverage Area

1.3.3 Air Vents

Honeycomb-type air vents shall be installed and have cores fabricated of brass or steel, and each guide shall be electrically and mechanically bonded to all adjacent guides. Air vents shall be a permanent part of the Acoustic EMI Chamber and Shielded Antechamber and shall have a shielding effectiveness equal to that of the total chamber. At a minimum, provide two 14-inch square supply and one 14-inch square return waveguide-type air vents.

1.3.4 Power Requirements

The Acoustic EMI Chamber shall have power filters installed to accommodate the following:

440VAC, 60Hz, 3-phase, 3-wire plus safety ground, ungrounded delta power (One

100Amp circuit) 115VAC, 60Hz, 3-phase, 3-wire plus safety ground, ungrounded delta power (One

50Amp circuit) 115VAC, 60Hz, single phase, 2-wire plus safety ground, ungrounded delta power (Three

20Amp circuits)

The Shielded Antechamber shall have power filters installed to accommodate the following:

115VAC, 60Hz, single phase, 2-wire plus safety ground, ungrounded delta power (Two

20Amp circuit)

1.3.4.1 Power Filters

Design filters to reduce conducted RF energy in electric power lines according to MIL-PRF- 15733J, and UL 1283 for facility type power line filters. Insertion loss between load side of filter and power supply side shall be not less than 100 dB at 14 kHz to 10 GHz. Each filter unit shall be capable of being mounted individually and shall include one filter for each phase conductor of the power line and the neutral conductor. Load terminal and power input compartments shall have no knockouts, and each compartment shall have one threaded conduit hub. Seam weld hubs in place, and size and locate hubs as required for conduits indicated.

Overload requirements shall be in accordance with MIL-PRF-15733J. Provide pass band suitable for use with 60 Hz power source. Total harmonics generated by the insertion of a power line filter shall not increase line voltage distortion by more than 2.5 percent with a unity power factor load.

Insertion loss measurements using procedures defined in MIL-STD-220C shall be provided.

Power receptacles shall be installed in a power raceway along the interior walls of the Acoustic EMI Chamber and Shielded Antechamber. The power filters shall be connected to the labelled power receptacles inside the Acoustic EMI Chamber and Shielded Antechamber. Power receptacles shall be evenly distributed throughout the Acoustic EMI Chamber and Shielded Antechamber. Power receptacle quantities shall be as many as permitted per NFPA 70 standard.

The receptacles shall be installed as low as possible, as permitted per NFPA 70 standard. The bottom of the power receptacle raceway shall be 4-5 inches above the floor.

Power for the receptacles inside the Acoustic EMI Chamber shall be provided from the contractor installed power filters located over the Acoustic EMI Chamber. Power for the receptacles inside the Shielded Antechamber shall be provided from the contractor installed power filters located over the Shielded Antechamber.

1.3.4.2 Lighting

Permanent lighting sources shall be installed in the interior of the Acoustic EMI Chamber and Shielded Antechamber. All lighting shall comply with OSHA regulations 1926.26 and 1915.82.

Lighting fixtures shall meet the requirements of MIL-STD-461 for both conducted and radiated interference.

Power for the light fixture inside the Acoustic EMI Chamber shall be provided from the power filters located over the Acoustic EMI Chamber. Power for the light fixture inside the Shielded Antechamber shall be provided from the power filters located over the Shielded Antechamber.

1.4 FIRE PROTECTION

1.4.1 Fire Alarm

Install two (2) fire alarm system filters. Fire alarm system filters shall meet the specifications of MIL-PRF-15733J. Filters shall have an insertion loss of 100 decibels in the frequency range of 14 kHz to 10 GHz measured according to MIL-STD-220, full load condition. Filters shall have a pass band of 14 kHz to 10 GHz with a characteristic impedance of 600 ohms.

1.4.2 Sprinkler System

A water sprinkler system shall be installed in the Acoustic EMI Chamber and the Shielded Antechamber. The water sprinkler system shall meet the specifications of NFPA 13, as modified by UFC 3-600-01.

1.5 PERFORMANCE SPECIFICATIONS

The RF shielding effectiveness performance requirements shall apply to the finished Acoustic EMI Chamber and Shielded Antechamber when all power line filters are installed and carrying current, ventilation systems are operating, the connector access panels are capped, lighting, and shielded door are in normal operation position. The specified shielding effectiveness shall be achieved without using conductive tapes, gaskets, or cement materials. Acoustic EMI Chamber and Shielded Antechamber shall, at a minimum, have the following magnetic, electric, and plane wave attenuation using the measurement procedures per IEEE-STD-299-2006:

Magnetic Field: 20 dB @ 1kHz increasing linearly to 88 dB @ 100kHz as shown in Figure 1.5-1.

Electric Field/Plane Wave/Microwave: 100dB from 10kHz to 10GHz as shown in Figure 1.5-2.

Figure 1.5-1 Magnetic Field RF Performance Specification

Figure 1.5-2 Electric Field/Plane Wave/Microwave RF Performance Specification

1.6 TESTING

The contractor shall conduct performance testing and ensure the fabricated and installed Acoustic EMI Chamber with Shielded Antechamber meets the performance criteria stated in Section 1.5.

2.0 SPECIFICATIONS FOR A NEW RF SHIELDED DOOR ON AN EXISTING

EMI CHAMBER

These specifications describe the minimum acceptable quality and/or performance level requirements of the item being purchased. The contractor shall fabricate and install a Radio

Frequency (RF) shielded door and access panel to an existing EMI chamber in accordance with the following specifications:

2.1 GENERAL SPECIFICATIONS

An RF shielded door and access panel shall be installed at the Naval Undersea Warfare Center Division Newport. The building and room number will be provided in the contract.

All construction material shall be new and delivered to the job site in undamaged condition.

Material shall be stored to ensure proper alignment and to protect material against dampness and accumulated moisture before and after delivery. Defective or damaged materials shall be replaced by the Contractor at no additional cost to the Government.

2.2 PHYSICAL SPECIFICATIONS

2.2.1 Location and Dimensions of Door

The RF shielded door shall be installed in an existing EMI chamber. The building number, room number, and placement within the room will be provided in the contract.

The RF shielded door shall provide a clear opening of 6 feet wide x 9 feet high prior to reinstalling the ferrite tile and the pyramid EM absorbers on the new RF shielded door. The RF shielded door shall be a single panel door.

Figure 2.2.1-1 RF Shielded Door & Access Panel

2.2.2 Construction

Prior to installation of the RF shielded door, existing ferrite tile, pyramidal Electromagnetic (EM) absorbers, and a ground bar shall be removed as specified in Section 2.2.3. In addition, the existing sheet metal shall be cut to accommodate the new RF shielded door.

The RF shielded door shall be constructed as follows:

• The RF shielded door shall have a continuous welded seam construction around its steel frame. The steel shall be ASTM A1008 or ASTM A568/A568M-17A steel and shall have a minimum thickness of ¼ inch.

• The RF shielded door assembly shall be field-welded to the existing chamber in accordance with AWS D1.1 Structural Welding Code-Steel.

• The RF shielded door shall not warp or sag and shall meet the performance criteria stated in Section 2.4 when closed.

• When the RF shielded door is fully open, there shall be a clear opening of 6’ wide and 9’ high clear opening of 6 feet wide x 9 feet high prior to reinstalling the ferrite tile and the pyramid EM absorbers on the new RF shielded door.

• The RF shielded door panel(s) shall open a minimum of 90 degrees.

• The RF shielded door shall be reinforced steel or laminated type. Laminated type shall be the same construction as the chamber’s shielding panels, except the steel faces shall be electrically and mechanically joined by channels or overlapping seams, both of which shall be continuously seam welded along all joined surfaces.

• The RF shielded door assembly shall be designed to function throughout a minimum of 10,000 cycles without the shielding effectiveness decreasing below the overall shield required attenuation.

• The RF shielded door shall be installed with at least two (2) rows of double-sided RF finger stock around the door or its frame to meet the performance specifications of Section 2.4. 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 assemblies.

• Contact for doors shall be copper beryllium conforming to ASTM B 194, Condition HT.

The finger stock shall be secured to the door or frame without using special tools, soldering, or adhesives.

• The opening/closing mechanism shall be operable and lockable from outside the EMI chamber.

• The RF shielded door shall not have any RF reflective surfaces visible from inside the EMI chamber after having RF absorbers re-installed.

2.2.3 RF Absorbers & Ground Bar

Currently, there are ferrite tile, pyramidal EM absorbers, and a ground bar installed on the inside wall of the EMI chamber. The ferrite tile, pyramid EM absorbers, and the ground bar shall be removed, without damage, from the wall prior to installing the RF shielded door. Once the new RF shielded door is installed, the undamaged ferrite tile and pyramid EM absorber shall be re-installed such that no RF reflective surfaces are visible from inside the EMI chamber. The ground bar shall also be re-installed and aligned with the existing ground bar.

2.3 ACCESS PANEL

Prior to installing the new access panel, the existing ferrite tile and pyramidal EM absorbers shall be removed, without damage, from the wall prior to installing the access panel. In addition, the existing sheet metal shall be cut to accommodate the new access panel.

The access panel shall be installed in the existing EMI chamber as follows:

• The access aperture shall have a clear opening 24 inches wide x 12 inches high and shall be installed between the existing chamber door and the new RF shielded door, and interface between the existing EMI chamber and the EMC Laboratory, as shown in Figure 2.2.1-1.

• The access aperture shall have a bolt pattern such that the access panel can be interchangeable between this access panel and the 24” x 12” access panels referenced in Section 1.2.5.

• The access aperture shall meet the performance criteria stated in Section 2.4 when covered with bolted on panels.

• The top of the access panel shall not be any higher than 30 inches off the floor.

• All access aperture’s edges shall be ground smooth.

• Two blanking panels shall be provided for the access aperture.

Once the access panel is installed, the ferrite tile and pyramid EM absorber shall be re-installed around the access panel. The ferrite tile and pyramid EM absorbers shall be abutted to the access panel.

2.4 PERFORMANCE SPECIFICATIONS

The RF shielding effectiveness performance requirements shall apply to the EMI chamber where the RF shielded door and access panel are being installed when the connector access panel and the RF shielded door are closed. The specified shielding effectiveness shall be achieved without using conductive tapes, gaskets, or cement materials. The new RF shielded door and access panel shall, at a minimum, comply with the RF shielding effectiveness performance requirement specified in Section 2.4.1 or Section 2.4.2.

2.4.1 RF Shielding Effectiveness Performance Requirement Option 1

The RF shielded door and access panel shall, at a minimum, have the following magnetic, electric, and plane wave attenuation using the measurement procedures in IEEE-STD-299-2006:

Magnetic Field: 20 dB @ 1kHz increasing linearly to 88 dB @ 100kHz as shown in Figure 2.4.1-

1. Electric Field/Plane Wave/Microwave: 100dB from 10kHz to 10GHz as shown in Figure 2.4.1-2

Figure 2.4.1-1 Magnetic Field RF Performance Specification

Figure 2.4.1-2 Electric Field/Plane Wave/Microwave RF Performance Specification

2.4.2 RF Shielding Effectiveness Performance Requirement Option 2

The RF shielding effectiveness of the existing EMI chamber shall be measured for magnetic, electric, and plane wave attenuation using the measurement procedures in IEEE-STD-299-2006 prior to the installation of the RF shielded door and access panel.

The RF shielding effectiveness of the existing EMI chamber shall be measured for magnetic, electric, and plane wave attenuation using the measurement procedures in IEEE-STD-299-2006 after the installation of the RF shielded door and access panel.

This RF shielding effectiveness performance requirement shall be met if the RF shielded door and access panel have a magnetic, electric, and plane wave attenuation no worse than prior to the installation of the RF shielded door and access panel.

2.5 TESTING

The contractor shall conduct performance testing and ensure the fabricated and installed RF shielded door and access panel in the existing EMI Chamber meets the performance criteria stated in Section 2.4.

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2.5 TESTING