16822 - Centralized Sound Masking System



|Section Cover Page |

| Section 16822 |

|2000-06-01 Centralized Sound Masking System |

Use this Section to specify a centralized electronic sound masking system generating masking sound from speaker assemblies strategically located above conventional suspended acoustic tile ceilings. Each speaker assembly generates a diffuse and unobtrusive sound with a spectrum shape designed to mask speech and unwanted noise.

Confirm with mechanical consultant that radiated noise specification for mechanical equipment in ceiling plenums is prepared in relation to transmission loss of specified ceiling assembly. Ceiling assemblies often have much lower transmission loss than assumed by mechanical equipment manufacturer's data.

This Master Specification Section contains:

.1 This Cover Sheet

.2 Data Sheet – Reference Documents

.3 Specification Section Text:

1. General

1.1 Related Sections

1.2 Detail Drawings

1.3 Description of System

1.4 Performance Requirements

1.5 Shop Drawings

1.6 Project Record Documents

1.7 Operating and Maintenance Data

1.8 Installer Qualifications

1.9 Performance Verification by Minister

10. Scheduling

2. Products

2.1 Speaker Assembly Components

2.2 Amplifiers

2.3 Noise Generator

2.4 Equalizer Filter

2.5 Supervisory Monitor

2.6 Equipment Cabinet

7. Accessories

3. Execution

3.1 Installation, Equipment and Speaker Assemblies

3.2 Installation of Wiring

3.3 Identification

3.4 Testing, Adjusting and Balancing

3.5 Schedule

3. Detail Drawings:

16822.1 Masking Spectrum and Tolerances

16822.2 Schematic Diagram

Applicable Standards

.1 ANSI S1.4-1983(R1994) Sound Level Meters

.2 ANSI S1.11-1986(R1993) Octive-Band and Fractional Octive-Band Analog and Digital Filters

These reference documents may be available for reference purposes in the Technical Resources and Standards Branch Library, Alberta Infrastructure, 3rd Floor, 6950 - 113 Street, Edmonton; Telephone:  (780) 427-7924.

END OF DATA SHEET

1. General

1.1 RELATED SECTIONS

SPEC NOTE:  THIS SECTION DOES NOT INCLUDE REQUIREMENTS FOR ELECTRICAL WIRING. SPECIFY APPROPRIATE CROSS REFERENCES, DEPENDENT ON WHETHER THE BMS (BASIC) OR SFMS (SHORT FORM) ELECTRICAL MASTER SPECIFICATION IS BEING USED, RESPECTIVELY.

.1 Electrical General Requirements: Section 16010

.2 [Testing, Adjusting and Balancing of Electrical Equipment and Systems Section 16970].

OR

.1 Basic Electrical Requirements: Section 16005

.2 [Testing, Adjusting and Balancing of Electrical Equipment and Systems Section 16970].

1.2 DETAIL DRAWINGS

.1 FOLLOWING DETAIL DRAWINGS ARE APPENDED HERETO AND FORM PART OF THIS SECTION.

Number Title

16822.1 Masking Spectrum and Tolerances

16822.2 Schematic Diagram

1.3 DESCRIPTION OF SYSTEM

.1 PROVIDE AN ELECTRONIC, FREQUENCY-CONTOURED SOUND MASKING SYSTEM WHICH INCLUDES THE FOLLOWING:

.1 Strategically located speaker assemblies installed above conventional suspended acoustic tile ceiling in areas indicated.

.2 Speaker assemblies generating unique, diffuse, and unobtrusive sound with spatial and temporal uniformity, and having a spectrum shape designed to mask speech and unwanted noise.

.3 Operation using two (2) independent 70 volt constant line audio channels with alternating speaker placements.

.4 System Components:

.1 Speaker assemblies.

.2 Amplifiers.

.3 Broadband noise generators.

.4 Active filter equalizers.

.5 Related wiring and accessories.

.6 Equipment cabinet(s).

.7 Supervisory monitor(s).

.5 Supervisory monitor(s) may be installed in an equipment cabinet or be remotely located, unless otherwise specified. Refer also to detail drawing 16822.2.

.2 Provide a single 2-channel system for single and multi-storey coverage unless amplifier power limitations require additional independent 2-channel systems.

1.4 PERFORMANCE REQUIREMENTS

.1 PROVIDE SOUND MASKING TO ALL AREAS INDICATED [ON DRAWINGS,] [AND] [AS SCHEDULED,] TO PROVIDE PERFORMANCE IN ACCORDANCE WITH SYSTEM DESCRIPTION AND TO COMPLY WITH THE FOLLOWING ONE-THIRD OCTAVE BAND SOUND PRESSURE LEVELS:

| | | |

|1/3 Octave ISO |1/3 Octave Band | |

|Centre Frequency |Sound Pressure Levels |Tolerances |

|(Hz) |(dB) |(± dB) |

| | | |

|125 |44 |± 4 |

|160 |43 |± 4 |

|200 |42 |± 3 |

|250 |41 |± 2 |

|315 |40 |± 2 |

|400 |39 |± 2 |

|500 |37 |± 1 |

|630 |35 |± 1 |

|800 |33 |± 1 |

|1,000 |31 |± 1 |

|1,250 |29 |± 1 |

|1,600 |27 |± 1 |

|2,000 |25 |± 1 |

|2,500 |23 |± 1 |

|3,150 |21 |± 1 |

|4,000 |19 |± 1 |

|5,000 |17 |± 1 |

|6,300 |15 |± 2 |

|8,000 |13 |± 2 |

Note:  The above values are graphically illustrated on detail drawing 16822.1.

.2 Spatial Average Overall Sound Pressure Levels: Minimum [42] [ ] dB and maximum [44] [ ] dB, A-weighted.

SPEC NOTE:  Consult with Alberta Infrastructure Acoustics Section before changing tolerances for average overall sound pressure levels.

1.5 SHOP DRAWINGS

.1 COMPLY WITH REQUIREMENTS OF DIVISION 1.

.2 Submit shop drawings indicating proposed quantity, location, and technical specifications of all system components and wiring, indicating compliance with specified requirements.

.3 Obtain Minister's approval for any changes in quantity or location of system components from Minister reviewed shop drawings.

1.6 PROJECT RECORD DOCUMENTS

.1 COMPLY WITH REQUIREMENTS OF DIVISION 1.

.2 After completing installation, testing, adjusting and balancing, submit the following:

.1 Project record drawings in form of reviewed shop drawings, revised as necessary to accurately indicate location and connection of all system components as installed, and to include the following:

.1 Final speaker transformer power tap settings, adjacent to applicable speaker locations on drawings, identified by legend.

.2 Cable identification corresponding to permanent cable markers specified in Part 3 of this Section.

.2 Printed record of all final sound pressure level readings, including the following:

.1 Accurate description of reading locations, test methods, and test equipment.

.2 Individual measurements on detail drawing 16822.1 format, or on similar charts generated by electronic methods.

.3 Charts for each area.

1.7 OPERATING AND MAINTENANCE DATA

.1 COMPLY WITH REQUIREMENTS OF DIVISION 1.

.2 Submit final manual control and level adjustments for each system component.

.3 Submit instruction manuals for all adjustable components.

1.8 INSTALLER QUALIFICATIONS

.1 SYSTEM COMPONENTS SHALL BE INSTALLED BY A QUALIFIED INSTALLER APPROVED BY COMPONENT MANUFACTURER. WORK SHALL BE DONE BY TECHNICIANS WITH EXPERIENCE INSTALLING AND ADJUSTING CENTRALIZED SOUND MASKING SYSTEMS.

1.9 PERFORMANCE VERIFICATION BY MINISTER

.1 MINISTER WILL [APPOINT AND PAY FOR SERVICES OF TESTING AGENCY] [UTILIZE HIS OWN FORCES] TO TAKE MEASUREMENTS TO VERIFY THAT THE INSTALLED SOUND MASKING SYSTEM MEETS SPECIFIED ACOUSTICAL PERFORMANCE REQUIREMENTS.

.2 Performance verification will be performed [after Interim Acceptance of the Work] [during Performance Testing and sub-phases of Facility Start-Up].

SPEC NOTE:  Unless Facility Start-Up program is being employed on project, specify time of performance verification as after Interim Acceptance.

.3 Verification by Minister will be performed with mechanical systems shut down in area being tested.

1.10 SCHEDULING

SPEC NOTE:  IF REQUIREMENTS IN THIS ARTICLE ARE NOT APPLICABLE OR PRACTICABLE, REVISE AS NECESSARY.

.1 Schedule installation, testing, tuning, and balancing to be performed after normal working hours of facility users, or as otherwise required by Minister.

SPEC NOTE:  Specify installation, etc. after normal working hours, in an occupied facility.

.2 Schedule testing, adjusting, and balancing work to be performed after above-ceiling mechanical and electrical work, suspended acoustic tile ceiling, and sound masking system installation are complete.

2. Products

2.1 SPEAKER ASSEMBLY COMPONENTS

.1 LOUDSPEAKER:

.1 Cone: 100-200 mm, single, 'Low Q' type.

.2 Voice Coil: 25 mm c/w 280 g ceramic magnet.

.3 Frequency Response: 125-8000 Hz ±4 dB on axis.

.4 Sensitivity: 94 dB EIA minimum.

.5 Power Handling: 5 watts EIA minimum.

.6 Resonant Frequency: 99 Hz maximum.

.7 Mounting: four screws [studs] to grille cover.

.2 Transformer:

.1 Type: 70.7 volt.

.2 Primary Power Taps: COM, 0.25, 0.5, 1, 2, 4 watts.

.3 Mounting: directly to speaker frame.

.3 Enclosure:

.1 Internal Volume: 0.008-0.012 m3, closed and open types.

.2 Construction: 0.6 mm minimum thickness sheet steel.

.3 Undercoating: factory applied to eliminate resonance.

.4 Mounting: four or three point chain suspension.

.5 Back: [open] [closed].

SPEC NOTE:  Specify open back enclosures for plenum height less than 1 meter, where plenum is treated with spray applied fibrous fireproofing, or where plenum may be considered more sound absorptive than conventional construction.

.4 Grille Cover:

.1 Construction: one piece, 0.6 mm minimum thickness sheet steel.

.2 Perforated speaker opening to suit speaker size.

.3 Four screw clip mounting to enclosure.

2.2 AMPLIFIERS

.1 SINGLE CHANNEL, SOLID STATE, EIA RATED.

.2 Audio Power Handling: continuous for speaker load plus 3 dB margin.

.3 Bandwidth: minimum 40-15,000 Hz ±1 dB.

.4 Total Harmonic Distortion: less than 1% at full rated power.

.5 Transformer Output: 70.7 volt line internal.

.6 Gain: manually adjustable.

.7 Output Regulation: within 2 dB for no load to full load.

.8 Power Supply: self-contained, CSA approved.

.9 Mounting: standard EIA 480 mm rack.

2.3 NOISE GENERATOR

.1 SINGLE CHANNEL RANDOM NOISE GENERATION WITH CONSTANT ENERGY PER OCTAVE BANDWIDTH.

.2 Minimum spectrum accuracy: ±1 dB from 40-10,000 Hz.

.3 Stability: ±1 dB at 0-50°C and line voltage 105-130 VAC.

.4 Repetition Rate: greater than 20 minutes.

.5 Mounting: standard EIA 480 mm rack.

.6 Power Supply: self-contained, CSA approved.

2.4 EQUALIZER FILTER

.1 SINGLE CHANNEL, MINIMUM TWENTY-FOUR 1/3 OCTAVE BANDS.

.2 Equalization: 1/3 octave using ISO standard frequencies from 63-12,500 Hz minimum.

.3 Output: 600 ohms balanced and adjustable.

.4 Filters: adjustable, minimum 20 dB adjustment per band.

.5 Level Tolerance: ±1 dB from 200-4000 Hz.

.6 Total Harmonic Distortion: less than 0.5% at full rated output

.7 Equivalent Input Noise: less than -85 dBM from 20-20,000 Hz, unweighted.

.8 Output: transformer isolated.

.9 Front panel security cover.

.10 Mounting: standard EIA 480 mm rack.

.11 Power Supply: self-contained, CSA approved.

2.5 SUPERVISORY MONITOR

.1 FUNCTION: TO AURALLY AND VISUALLY MONITOR TWO INDIVIDUAL 70.7 VOLT CONSTANT LINE AUDIO POWER CHANNELS.

.2 Front panel shall incorporate monitor speaker complete with volume control, VU meter and meter calibration control.

.3 Fault sensing feature shall detect amplifier power loss.

.4 Piezoelectric transducer 'failure' alarm on front panel or on remote panel.

2.6 EQUIPMENT CABINET

.1 FREE STANDING 480 MM EQUIPMENT CABINET COMPLETE WITH MOUNTING BARS, EIA STANDARD.

.2 Height: to provide fixed mounting for all amplifiers, generators, equalizers and monitor panel.

.3 Doors: lockable front and back, vented.

.4 Construction: sheet steel, factory finish.

.5 Power Bar: hard wired, inside cabinet.

.6 Insulated screw terminal blocks for speaker cable lines inside cabinet.

2.7 ACCESSORIES

.1 SPEAKER WIRE: COPPER, TWISTED PAIR, INSULATED [IN ACCORDANCE WITH REQUIREMENTS OF CANADIAN ELECTRICAL CODE FOR JACKETING IN RETURN AIR PLENUMS].

SPEC NOTE:  If not applicable, delete requirement to comply with Canadian Electrical Code for jacketing in return air plenums.

3. Execution

3.1 INSTALLATION OF EQUIPMENT AND SPEAKER ASSEMBLIES

.1 INSTALL SPEAKER ASSEMBLIES ABOVE SUSPENDED CEILING IN ACCORDANCE WITH MANUFACTURER'S INSTRUCTIONS AND IN A MANNER TO PERMIT SPECIFIED ACOUSTICAL PERFORMANCE.

.2 Suspend speaker assemblies with mounting chains securely fastened to structure. Chain fasteners must be capable of supporting speaker assemblies three times their weight. Ensure that there is no strain on electrical wiring.

.3 Mount [closed enclosure to radiate sound upward] [open back enclosures to radiate sound horizontally]. Avoid mounting which could result in generation of vibration noise or distortion.

.4 Install signal generators, equalizers, amplifiers, securely inside equipment cabinet[s]. [Locate equipment cabinet[s] [in [       ]] [at location[s] indicated on drawings].]

SPEC NOTE:  Determine whether location of equipment cabinet(s) and supervisory monitor(s) are to be designated in contract or left to Contractor's option. Do not limit number of equipment cabinets required.

.5 Install supervisory monitor[s] [securely inside equipment cabinet[s]][at location[s] indicated on drawings]

.6 Ground audio system to building power supply ground.

3.2 INSTALLATION OF WIRING

.1 AVOID DAMAGE TO CABLES. PROVIDE ADEQUATE CABLE STRAIN RELIEF.

.2 Run speaker cables parallel and perpendicular to building lines. Attach wiring to top of structural elements in a non-obstructive fashion. Secure every 3 meters and at changes in direction.

.3 Connect each speaker wire pair to one terminal pair on screw terminal blocks at centralized cabinet equipment.

3.3 IDENTIFICATION

.1 LABEL ALL OPERATOR CONTROLS, SWITCHES, AND PANELS WITH ENGRAVED LAMINATE PLATES. MARK FINAL SETTINGS ON OPERATOR CONTROLS.

.2 Identify all wires and cables at each end with permanent cable markers.

3.4 TESTING, ADJUSTING AND BALANCING

.1 COMPLY WITH REQUIREMENTS OF SECTION 16971 - ELECTRICAL STARTING AND TESTING BY CONTRACTOR.

OR

SPEC NOTE:  Delete previous paragraph and specify following if sound masking is a separate contract and Section 16971 is not being used. Section 16971 contains the identical requirements.

.1 Calibrate measuring microphone and related test equipment prior to testing.

.2 Test, adjust, and balance system with mechanical system and other noise generating equipment shut down in areas receiving sound masking.

.3 Test, adjust, and balance system until sound spectrum and sound levels meet specified performance requirements. Adjust settings of, relocate, or add additional system components, if and as required.

.4 Upon completion of tests, perform walk-through verification of areas to be covered by sound masking. Adjust and re-test areas having abnormal characteristics or levels.

.5 Tests and Test Methods:

.1 Test to determine 1/3 octave band sound pressure levels at minimum of one reading per 400 m2 of floor area to be sound masked.

.2 Test to determine spatial averaged, A-weighted, overall sound levels at minimum of one reading per 80 m2 of floor area to be sound masked.

.3 Position measuring microphone 1200 mm above floor and minimum 1 meter away from any sound reflecting surface during testing. Position microphone in locations representative of each area to be sound masked.

.6 Measure Sound Pressure Levels using one of following methods:

.1 Equivalent Continuous Sound Level (Leq) mode for minimum interval of 15 seconds.

.2 IEC 651 'slow' time constant; average reading of the highest and lowest level during 15 second interval.

.7 Test Equipment:

.1 Sound Level Meter: to ANSI S1.4-1983, Type 1 or better.

.2 One-Third Octave Band Filter: to ANSI S1.11-1986, Class II or better.

.3 One-Third Octave Band, Real Time Audio Spectrum Analyzer: to ANSI S1.11-1986, Class II, Type E or better.

.4 Accuracy of Acoustic Calibrator: within ±0.3 dB at 25°C.

3.5 SCHEDULE

SPEC NOTE:  UNLESS INDICATED ON DRAWINGS, SCHEDULE LOCATIONS WHERE SOUND MASKING IS REQUIRED.

.1 Provide sound masking coverage in the following rooms and areas:

.1 [ ].

.2 [ ].

.3 [ ].

.4 [ ].

.5 [ ].

.6 [ ].

END OF SECTION

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