1 Scope

NOTE This standard covers public address (PA) and paging systems that distribute audio for routine announcements, background music, general intercom, and zone-based paging across a building or campus. (1.1)

NOTE It applies to schools, universities, offices, industrial facilities, warehouses, healthcare campuses, correctional facilities, and transportation terminals where clear voice communication must reach occupants across multiple zones. (1.2)

NOTE The standard addresses three system families in current use — 70-volt constant-voltage analog distributed audio, IP-networked audio, and a hybrid of the two — and the early architecture decision between them governs nearly every downstream selection. (1.3)

NOTE Equipment furnished under this standard includes master and remote paging stations, zone selectors, power amplifiers, pre-amplifiers, digital signal processors, loudspeakers, supervision hardware, rack infrastructure, and standby power. (1.4)

NOTE The standard also defines the supervised interface by which a PA system yields priority to a fire alarm Emergency Communications System (ECS), but the ECS itself is specified elsewhere. (1.5)

NOTE What this standard does not cover (1.6)

Life-safety voice evacuation and emergency mass notification initiated by a fire alarm control unit are covered by Mass Notification SystemsMass Notification SystemsResolves to the current edition.sync/mass-notification-systems and Fire Alarm SystemsFire Alarm SystemsResolves to the current edition.sync/fire-alarm-systems; NFPA 72 Chapter 24 Emergency Communications System requirements belong in those standards.
Fire alarm initiating devices, annunciators, and listed fire alarm control units are covered by Fire Alarm SystemsFire Alarm SystemsResolves to the current edition.sync/fire-alarm-systems.
Backbone cabling infrastructure, conduit fill, pathway design, and telecommunications and equipment rooms are covered by Structured CablingStructured Cabling SystemsResolves to the current edition.sync/structured-cabling.
Distributed Antenna Systems for cellular and public-safety radio are covered by Distributed Antenna SystemsDistributed Antenna SystemsResolves to the current edition.sync/distributed-antenna-systems.
Security intercom and access-control intercoms at building entrances belong to the access control standard.
Auditorium sound reinforcement and audio-visual presentation systems belong to a separate AV standard.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.

2.2 Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

Standard	Title
NFPA 72	National Fire Alarm and Signaling Code (Chapter 24 — Emergency Communications Systems; intelligibility and supervision)
NFPA 70	National Electrical Code (Article 640 — audio signal processing, amplification, and reproduction equipment; Article 725 — Class 2 and Class 3 circuits; Article 800 — communications circuits)
NFPA 101	Life Safety Code (occupancy requirements that may mandate paging capability)
UL 1480	Speakers for Fire Alarm, Emergency, and Commercial and Professional Use
UL 2572	Mass Notification Systems
ANSI/ASA S12.60	Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools
IEEE 446	Recommended Practice for Emergency and Standby Power Systems for Industrial and Commercial Applications

3 System Architecture

NOTE The architecture decision is the single most consequential choice in a PA project, and the most common design error is specifying a constant-voltage analog system where the program actually needs networked paging across multiple buildings. (3.1)

NOTE A 70-volt analog system distributes audio as a constant-voltage signal from centralized rack amplifiers through passive loudspeakers, each fitted with a step-down transformer tapped at a chosen wattage; it is simple, robust, and well suited to small-to-medium single-building facilities. (3.2)

NOTE An IP-networked system carries audio as packets over the data network to PoE zone controllers and addressable endpoint speakers, scaling cleanly across a campus and integrating with SIP telephony and unified-communications platforms, at the cost of dependence on the IT network. (3.3)

NOTE A hybrid system overlays an IP paging console and routing core onto an existing constant-voltage speaker backbone, which is the economical path when reusing legacy distributed-audio wiring while adding networked control. (3.4)

3.4.1 The system architecture shall be as indicated in the datasheet.

System architectureradio

○ 70-volt constant-voltage analog (centralized rack amplifiers, passive speakers)

○ IP-networked audio (PoE zone controllers, addressable endpoints)

○ Hybrid (constant-voltage backbone with IP paging overlay)

NOTE The architecture follows from the number of buildings served, the condition of any existing speaker backbone, and whether the owner's IT organization will carry the audio network — none of which the standard can assume — so the field carries no default. (3.4.2)

3.4.3 The audio transport protocol shall be as indicated in the datasheet.

IP audio transport protocolselect

AES67

Dante

AVB/Milan (IEEE 802.1 AVB)

Proprietary IP transport (vendor-native)

Not applicable (analog system)

3.4.4 For IP-networked or hybrid architectures, the audio transport protocol shall be coordinated with the network design so that the required VLAN, multicast, and QoS configuration is provisioned under Structured CablingStructured Cabling SystemsResolves to the current edition.sync/structured-cabling.

NOTE The transport protocol is meaningful only once the architecture is chosen, and the choice then turns on what the owner's head-end platform and network already support, so the field carries no default. (3.4.5)

3.5 Where an IP system is selected, the audio network and its supervision shall not depend on routing or services that the owner's IT group can change without notice to the PA system owner.

3.5.1 The PA system shall remain operable for in-zone local paging during a failure of the wide-area network connection between buildings.

4 Zone Configuration and Paging

NOTE A zone is an independently addressable group of loudspeakers, and the zone map is the contractual definition of which call stations reach which speakers. Where no zone matrix is issued, the contractor builds an all-call-only system and selective paging never works. (4.1)

4.1.1 The system shall provide the number of independently switchable speaker zones indicated in the datasheet.

Number of independent speaker zonesrange

zones

1256

Per drawings — zone matrix and speaker-zone plan (deferred by default)

4.1.2 The system shall support all-call paging that addresses every zone simultaneously.

4.1.3 The system shall support selective paging to any single zone and to engineer-defined zone groups.

4.1.4 A zone matrix identifying every call station, the zones it may address, and each zone's grouping shall be furnished as indicated on the zone matrix and speaker-zone plan.

4.1.5 Zone-to-speaker assignment shall follow the zone matrix.

NOTE Priority among audio sources determines which announcement is heard when two sources contend, and a documented priority order prevents a background-music source from masking a live page. (4.2)

4.2.1 Live paging shall take priority over background music and over any automated or scheduled audio source.

4.2.2 A fire alarm Emergency Communications System input, where present, shall override all PA sources, as required by the Fire Alarm Interface section.

4.2.3 The source priority order, highest to lowest, shall be fire alarm ECS override, live all-call page, live zone page, scheduled announcement, and background music; where no ECS interface is furnished, the same order applies with the ECS level omitted.

5 Paging Stations and Consoles

NOTE Master call stations, zone selectors, and remote microphones are the operator interface, and their type is selected to match the staff that will use them; a touchscreen IP console suits a campus dispatch desk, while a simple keypad microphone suits a single front office. (5.1)

5.1.1 A primary paging station with microphone, zone selection, and all-call capability shall be furnished at the location indicated on the contract documents.

5.1.2 Each paging station shall provide a press-to-talk control and a visual ready/busy indication so the operator knows when the channel is live.

5.1.3 The primary paging station type shall be as indicated in the datasheet.

Primary paging station typeradio

○ Desktop keypad paging microphone (analog)

○ Wall-mount paging microphone (analog)

○ Touchscreen IP paging console

○ Telephone-access paging interface (dial-in from any extension)

NOTE The station type is constrained by the architecture and by who will operate the system — a school front office, a campus dispatch desk, and a warehouse shift office give three different answers — so the field carries no default. (5.1.4)

5.1.5 The quantity of remote paging stations shall be as indicated in the datasheet.

Remote paging stations (quantity)range

stations

064

Per drawings — zone matrix and speaker-zone plan (deferred by default)

NOTE A telephone-access paging interface lets staff page by dialing an extension, but analog dial-access interfaces may not work across SIP trunks without an analog terminal adapter, so PBX compatibility must be confirmed before selection. (5.2)

5.2.1 Where a telephone-access paging interface is furnished, its compatibility with the facility telephone system, including any SIP-to-analog adaptation required, shall be confirmed in writing before rough-in.

6 Amplifiers and Signal Processing

NOTE Amplifier sizing is driven by the summed loudspeaker tap load plus headroom; specifying amplifiers at 100% of the calculated tap load leaves no margin for program peaks and shortens amplifier life. (6.1)

6.1.1 Each amplifier shall be sized so that the connected continuous loudspeaker tap load does not exceed 80% of the amplifier's rated continuous output.

6.1.2 The per-zone amplifier continuous output rating shall be as indicated in the datasheet.

Per-zone amplifier continuous outputrange

W

301200

NOTE Amplifier output is the summed tap load of the zone plus the 80% headroom allowance, which is a per-project calculation, so the field carries no default. (6.1.3)

6.1.4 Total harmonic distortion shall not exceed the maximum indicated in the datasheet at rated output.

Amplifier total harmonic distortion (THD) at rated output, maxrange

%

0.55

Default: 1 %

NOTE A 1% THD ceiling at rated output is met by every current commercial paging amplifier and is correct without knowing the project; a tighter limit is specified only where the system also carries program music at high level. (6.1.5)

6.1.6 The amplifier frequency response shall be as indicated in the datasheet.

Amplifier frequency response (±3 dB)radio

● 100 Hz to 10 kHz (voice-grade paging)

○ 50 Hz to 20 kHz (music-capable)

NOTE Voice-grade passband is the default because paging is the primary function and a restricted passband improves intelligibility in reverberant space; the music-capable passband is selected where background music is a real program requirement rather than an incidental feature. (6.1.7)

NOTE Amplifier redundancy protects against the loss of an entire zone when a single amplifier fails, and N+1 backup with automatic failover is standard practice for systems serving large occupant loads or critical facilities. (6.2)

6.2.1 The amplifier redundancy scheme shall be as indicated in the datasheet.

Amplifier redundancyradio

● No redundancy (one amplifier per zone)

○ N+1 backup amplifier with automatic failover

NOTE One amplifier per zone is the baseline commercial arrangement and is the datasheet default; N+1 with automatic failover is an added-cost upgrade selected on occupant load and facility criticality. (6.2.2)

NOTE A digital signal processor conditions the audio for each zone, and built-in equalization, delay, automatic gain control, and feedback suppression are what make a marginal room intelligible rather than merely loud. (6.3)

6.3.1 The system shall provide per-zone digital signal processing with at least parametric equalization and level control.

6.3.2 The DSP functions furnished shall be as indicated in the datasheet.

DSP functionscheckbox

☑ Parametric/graphic equalization (per zone)

☐ Delay compensation (loudspeaker time alignment)

☑ Automatic gain control

☐ Feedback suppression

☐ Ambient-noise-sensing automatic level control

7 Loudspeakers and Power Distribution

NOTE Loudspeaker type and mounting are selected for the space: recessed ceiling speakers for finished offices and classrooms, pendant speakers for open high-ceiling areas, and horn or compression-driver speakers for warehouses, loading docks, and outdoor areas where ambient noise is high and coverage distances are long. (7.1)

7.1.1 The predominant loudspeaker type shall be as indicated in the datasheet.

Predominant loudspeaker typeradio

○ Recessed ceiling speaker with back can

○ Surface-mount ceiling/wall speaker

○ Pendant speaker

○ Horn / compression-driver speaker

○ Line array (high-ceiling or reverberant spaces)

NOTE This standard covers finished office and classroom space, open warehouse, and outdoor areas in comparable numbers, and each takes a different predominant speaker, so the field carries no default. (7.1.2)

7.1.3 Loudspeakers shall be listed to UL 1480 for commercial paging use.

7.1.4 Loudspeakers installed in air-handling plenums shall be furnished with a listed plenum-rated back enclosure.

NOTE The constant-voltage distribution level and the per-speaker tap wattage together set how much acoustic power each speaker delivers; classroom and office speakers are commonly tapped at 1 to 2 W, while industrial and outdoor speakers are tapped much higher. (7.2)

7.2.1 The constant-voltage distribution level shall be as indicated in the datasheet.

Constant-voltage distribution levelrange

V

2570.7100

NOTE 70.7 V is the North American constant-voltage standard and is correct without knowing the project; 100 V reduces line loss on very long industrial runs, and 25 V is used on small systems where NEC Class 2 limits are easier to hold. (7.2.2)

7.2.3 The nominal per-speaker tap power for the predominant space type shall be as indicated in the datasheet.

Per-speaker tap power (predominant space)range

W

0.250.512481530

NOTE The low end of the tap range, 0.25 W, suits a quiet office carrying background music, while the high end, 30 W, is a high-output horn for an outdoor or industrial space. (7.2.4)

NOTE Tap power is an output of the coverage and SPL calculation for the predominant space, and the answer spans two orders of magnitude across the occupancies this standard covers, so the field carries no default. (7.2.5)

NOTE Outdoor and wet-location speakers fail early when generic indoor housings are used; horn speakers on docks, playfields, and parking structures need rated enclosures and UV-stable housings. (7.3)

7.3.1 Loudspeakers installed outdoors or in wet, washdown, or high-humidity locations shall be rated to at least the enclosure standard indicated in the datasheet, with UV-stable housings.

Outdoor/wet-location speaker enclosure rating, minimumradio

○ IP55

○ IP65

○ IP66

○ NEMA 3R

○ NEMA 4

○ NEMA 4X

○ Not applicable (no outdoor/wet locations)

NOTE The rating depends on whether the exposure is rain, washdown, or salt air, and on whether the project has any outdoor speakers at all, so the field carries no default. (7.3.2)

NOTE Loudspeaker placement and spacing set whether coverage is even or patchy, and speaker locations must be reconciled with HVAC diffuser locations to avoid ceiling-conflict requests for information. (7.4)

7.4.1 The nominal ceiling-speaker spacing on center for the predominant ceiling height shall be as indicated in the datasheet.

Ceiling-speaker spacing (on center)range

ft

1040

NOTE Spacing follows from ceiling height and the loudspeaker's coverage angle — 20 ft on center is a customary starting point for an ordinary 9 to 10 ft ceiling, and open warehouse bays space far wider — so the field carries no default. (7.4.2)

7.4.3 Loudspeaker locations shall be coordinated with the reflected ceiling plan and with mechanical diffuser and lighting locations before permit as indicated on the coordinated reflected ceiling plan.

8 Cable and Power Distribution Infrastructure

NOTE Paging wiring is governed by two different NEC articles that apply in the same installation, and they must be kept distinct: Article 640 covers the audio equipment power wiring and grounding, while Article 725 and Article 800 govern the low-voltage signal and communications cable. (8.1)

8.1.1 Loudspeaker signal circuits shall be installed as NEC Class 2 circuits limited to 100 VA and 30 V where the constant-voltage level and load permit.

8.1.2 Cable run in air-handling plenums shall be plenum-rated CL2P or CL3P per NEC Article 800.

8.1.3 Speaker-circuit conductors shall be sized so that loop resistance does not exceed the loudspeaker manufacturer's stated limit, typically less than 10% of the total connected load impedance.

8.1.4 The minimum speaker-circuit conductor size shall be as indicated in the datasheet.

Speaker-circuit conductor, minimumradio

○ 18 AWG (70 V runs up to 50 ft)

● 16 AWG (standard for longer runs)

○ 14 AWG (long runs / high tap loads)

○ 12 AWG (very long runs / high-output horn circuits)

NOTE 16 AWG is the default because it carries the great majority of commercial 70 V circuits within the loop-resistance limit; 18 AWG suits short in-room runs, and the heavier sizes are selected from the loop-resistance calculation on long or heavily tapped circuits. (8.1.5)

NOTE Hum and noise complaints on constant-voltage systems are almost always a grounding or shield-termination defect rather than an equipment fault, so the rack ground and shield discipline must be specified rather than left to the installer. (8.2)

8.2.1 Equipment racks shall be bonded to a dedicated technical ground per NEC Article 640.

8.2.2 Cable shields shall be terminated at one end only, in a consistent scheme documented on the riser, to prevent ground loops.

9 Standby Power

NOTE Standby power keeps paging available through a normal-power outage, and the required backup duration depends entirely on whether the PA system also serves a life-safety function: 15 minutes is adequate for routine paging, while an NFPA 72 ECS function drives the requirement to 24 hours. (9.1)

9.1.1 The system head end, amplifiers, and call stations shall be supported by standby power for at least the backup duration indicated in the datasheet.

Standby power backup duration, minimumrange

hours

0.25424

NOTE The setpoints are stated in hours: 0.25 hours is the 15-minute duration adequate for routine paging, and 24 hours is the duration required where the PA system serves an NFPA 72 ECS function. (9.1.2)

NOTE The duration turns on whether the system carries a life-safety function, which is a project determination, so the field carries no default. (9.1.3)

9.1.4 The standby power source shall be as indicated in the datasheet.

Standby power sourceradio

○ Dedicated PA system UPS

○ Shared facility UPS

○ Facility standby generator with ride-through UPS

NOTE The source depends on what standby infrastructure the facility already has, so the field carries no default. (9.1.5)

9.1.6 The UPS supporting the amplifier room shall be sized for worst-case simultaneous all-call output, not merely idle draw, in accordance with IEEE 446.

10 Intelligibility and Coverage

NOTE Intelligibility, not loudness, is the measure of a usable paging system, and specifying an STI-PA target without also requiring a post-installation measurement leaves the owner no remedy for a system that is loud but unintelligible. (10.1)

NOTE Speech Transmission Index (STI-PA) quantifies how much of speech survives the room's noise and reverberation; NFPA 72 requires STI-PA at least 0.45 for an ECS, and 0.50 is a sound target for general paging. (10.2)

10.2.1 The system shall achieve the STI-PA value indicated in the datasheet at no less than 90% of designated listening positions in each zone.

Intelligibility target (STI-PA), minimumrange

STI-PA

0.40.7

Default: 0.5 STI-PA

NOTE 0.50 STI-PA is the general-paging target and is correct without knowing the project; it sits above the 0.45 NFPA 72 requires of an emergency communications system, giving margin for the measurement uncertainty of a field sweep. (10.2.2)

10.2.3 Paging audio shall produce a sound pressure level of at least the minimum indicated in the datasheet at the listener, measured 5 ft above finished floor.

Minimum SPL at listenerrange

dB(A)

6095

NOTE The absolute SPL floor is set from the space's measured ambient, which ranges from a 35 dB(A) classroom to a warehouse in the mid-80s, so the field carries no default. (10.2.4)

10.2.5 Paging audio shall be at least 10 dB above the measured ambient noise level in each occupied space, and at least 15 dB above ambient where the system serves an ECS function.

NOTE In schools, the acoustic environment is constrained by ANSI/ASA S12.60, and those background-noise and reverberation limits directly drive speaker count and tap selection because a reverberant or noisy classroom destroys STI before any amplifier can compensate. (10.3)

10.3.1 In core learning spaces, the loudspeaker layout shall be designed to achieve the intelligibility target within a reverberation time not exceeding 0.6 s, per ANSI/ASA S12.60.

10.3.2 Classroom paging design shall assume the ANSI/ASA S12.60 background-noise limit of 35 dB(A) HVAC-only ambient when selecting speaker gain and tap.

11 Supervision and Fault Monitoring

11.1 Supervision is what distinguishes a maintained system from one that quietly fails: a cut or shorted speaker line, or a failed amplifier, must annunciate rather than be discovered the next time someone tries to page.

11.1.1 Each loudspeaker circuit shall be supervised for open-circuit and short-circuit faults, and a fault shall be annunciated at the head end.

11.1.2 Each amplifier shall report a fault condition, including loss of output, to the head-end annunciator.

11.1.3 The supervision scope shall be as indicated in the datasheet.

Supervision scopecheckbox

☑ Speaker-line open-circuit monitoring

☑ Speaker-line short-circuit monitoring

☑ Amplifier fault monitoring

☐ Standby power / UPS fault monitoring

☐ Network link supervision (IP systems)

12 Fire Alarm Interface

NOTE The interface to the fire alarm system is the most commonly under-specified item in a paging project. Most institutional occupancies require the PA system to yield priority to the fire alarm ECS, and failing to specify the handshake produces a late, expensive coordination request for information with the fire alarm contractor. (12.1)

NOTE When the PA system is the listed NFPA 72 Chapter 24 Emergency Communications System rather than merely interfaced to one, it leaves the scope of this standard: it must then be listed to UL 2572 and specified under Mass Notification SystemsMass Notification SystemsResolves to the current edition.sync/mass-notification-systems, because a generic paging spec applied to a life-safety system will fail AHJ inspection. (12.2)

12.2.1 Where a fire alarm system is present, the PA system shall accept a supervised priority-override signal from the fire alarm control unit and shall mute or release all PA audio while that signal is active.

12.2.2 The fire alarm interface method shall be as indicated in the datasheet.

Fire alarm interface methodradio

● Supervised dry-contact relay input

○ Serial integration

○ IP integration

○ None (no fire alarm system present)

NOTE A supervised dry-contact input is the default because it is the interface every listed fire alarm control unit can provide and it does not depend on a shared protocol; serial and IP integration are selected where the two head ends are from compatible platforms and richer status exchange is wanted. (12.2.3)

12.2.4 The fire alarm override input shall be supervised so that a fault on the interface wiring is annunciated.

NOTE Public address must not be the sole means of communication for persons with hearing disabilities; ADA and Section 504 require a visual path, which is coordinated rather than furnished here. (12.3)

12.3.1 Audible paging shall be paired with a visual notification path, such as strobe or display tie-in, where required by the project ADA compliance plan, and that requirement shall be coordinated with Mass Notification SystemsMass Notification SystemsResolves to the current edition.sync/mass-notification-systems.

13 Submittals

13.1 Action Submittals

13.1.1 The Contractor shall submit the following action submittals for review before fabrication or ordering:

Product data for amplifiers, DSPs, paging stations, loudspeakers, and supervision hardware
Shop drawings showing the system riser, zone matrix, and speaker-circuit loading calculations
Loudspeaker coverage and intelligibility design calculations, including predicted STI-PA
Standby power sizing calculations
UL 1480 loudspeaker listings and, for dual-use systems, UL 2572 system listing

Action submittalscheckbox

☑ Product data (amplifiers, DSP, stations, speakers, supervision)

☑ Shop drawings (riser, zone matrix, circuit loading)

☑ Coverage and STI-PA design calculations

☑ Standby power sizing calculations

☑ UL 1480 / UL 2572 listing documentation

13.2 Closeout Submittals

13.2.1 The Contractor shall submit the following closeout submittals before final acceptance:

As-built riser and zone matrix reflecting installed conditions
Operation and maintenance manuals
Field test reports, including the intelligibility sweep and fault-simulation results
Operator training records

Closeout submittalscheckbox

☑ As-built riser and zone matrix

☑ Operation and maintenance manuals

☑ Field test reports (intelligibility, SPL, fault simulation)

☑ Operator training records

14 Quality Assurance

NOTE Quality assurance pins responsibility for a system whose performance is only proven after installation, so the standard requires qualified installers and, for dual-use life-safety systems, a dedicated commissioning agent. (14.1)

14.1.1 The installing contractor shall be trained and authorized by the equipment manufacturer for the furnished system.

14.1.2 Where the system serves a dual-use paging and emergency-notification function, a qualified commissioning agent independent of the installer shall verify NFPA 72 and UL 2572 compliance.

15 Factory and Field Testing

NOTE Testing is split between the factory, which proves the equipment works before it ships, and the field, which proves the installed system meets intelligibility and supervision requirements in the actual rooms. (15.1)

15.1.1 Rack equipment shall undergo factory power-on burn-in before shipment.

15.1.2 Speaker-line supervision shall be tested at the factory before shipment.

15.1.3 An all-call and zone-select functional test shall be performed at the factory before shipment.

15.1.4 A full field intelligibility sweep shall be performed with an STI-PA meter at each zone, and results shall meet the intelligibility target indicated in the datasheet.

15.1.5 Sound pressure level shall be measured at representative listening positions in each zone and shall meet the minimum SPL indicated in the datasheet.

15.1.6 Open-circuit and short-circuit faults shall be simulated on each speaker zone, and each shall annunciate at the head end.

15.1.7 Where a fire alarm interface is present, the priority override shall be demonstrated to mute or release all PA audio while the override is active.

16 Installation

NOTE Installation requirements protect the design intent through construction, where the recurring failures are ceiling conflicts, missing plenum ratings, and grounding shortcuts. (16.1)

16.1.1 Loudspeakers shall be installed at the coordinated locations and at the spacing required to achieve the specified coverage and intelligibility.

16.1.2 Plenum-rated cable substitutions shall not be installed without the Engineer's written approval.

16.1.3 Ground continuity shall be verified before energization.

16.1.4 Outdoor and wet-location speakers shall be installed with their rated enclosures intact and with drip loops and sealed entries appropriate to the location.

17 Warranty

NOTE The warranty obligates the manufacturer and installer to stand behind the system through its early service life. (17.1)

17.1.1 The system shall be warranted against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.

Warranty periodrange

years

123

18 Spare Parts

NOTE Spare parts let the owner restore service without waiting on procurement for the components most likely to fail or be damaged. (18.1)

18.1.1 The Contractor shall furnish the quantity of spare loudspeakers indicated in the datasheet, matching each installed type.

Spare loudspeakers (per installed type)range

ea

010

Default: 2 ea

NOTE The two-per-type spare allowance is a contractual stocking floor rather than a sized quantity, so the field carries a concrete default. (18.1.2)

18.1.3 The Contractor shall furnish at least one spare amplifier module of each installed rating where N+1 redundancy is not provided.