Public Addressing
Public address system installation stops being an audio project the moment the system is expected to evacuate a building. Foxnet Securitas designs and installs PA and voice alarm systems for factories, warehouses, logistics parks, hospitals and corporate campuses across India — systems whose job is to get an intelligible instruction to a specific set of people, in a specific zone, within seconds of a fire panel input or an EHS decision. That means supervised speaker circuits, standby power, defined evacuation zones and a message set that has been tested, not a set of ceiling speakers and an amplifier in a cupboard.
What we deliver
- Zoned evacuation announcement design that maps announcement zones onto the building's actual fire compartments and escape routes, so a phased evacuation moves the right floors or bays first instead of emptying the whole site at once.
- Voice alarm system integration with the fire alarm panel, so a confirmed detector or call point activation triggers the correct pre-recorded evacuation message in the correct zones automatically, with manual override available to the incident controller.
- PA system for factory and warehouse environments — horn and projector loudspeakers rated for high ambient noise, dust and washdown, laid out from a coverage calculation rather than by eye.
- Mass notification capability beyond fire: shift changes, lockdown and shelter-in-place instructions, gas or chemical release announcements, severe weather, and all-clear messages, each with its own message and zone map.
- Supervised 100V line distribution with end-of-line monitoring, so an open or short on a speaker circuit is reported as a fault rather than discovered during an evacuation drill.
- Emergency microphone and paging station design, including a fireman's or incident controller's microphone with zone select and priority over background paging.
- Standby power sizing, amplifier redundancy and A/B circuit splitting so that the loss of one amplifier channel does not silence an entire zone.
- Commissioning that includes measured coverage and speech transmission index readings across sample points, documented per zone, plus written evacuation drill support for the EHS team.
- AMC covering amplifier and battery testing, line fault log review, message store verification, and periodic re-testing after every layout change on the plant floor.
How a Foxnet deployment works
1. Site survey and requirement capture. We walk the site with the EHS lead and the plant or facilities head, measuring ambient noise levels in each area at working load, recording reverberant spaces, hazardous-area classifications, existing fire panel make and available interface outputs, and the evacuation plan the site is already assessed against.
2. Design and BoQ. We produce a zone plan, loudspeaker layout with coverage and sound pressure level calculations, amplifier and standby battery sizing, the cause-and-effect mapping from fire zones to announcement zones, and the message script list. All of it is priced as a line-item bill of quantities.
3. Installation and commissioning. Speaker circuits and containment are installed with segregation and fire-rated cabling where required, then amplifiers, controllers and microphone stations. Commissioning proves every zone individually: fire panel trigger to correct message, correct zones, correct priority, plus measured intelligibility and coverage at agreed points.
4. Handover, training and documentation. You receive zone drawings, the speaker and circuit schedule, amplifier loading calculations, the message list, the fire-to-PA cause-and-effect table and the commissioning measurements. Security, EHS and the incident controllers are trained on live paging, zone selection, override and what a fault indication means.
5. AMC and ongoing support. Scheduled visits cover amplifier output checks, battery load testing, line fault history, message playback verification and a re-walk of any area where racking, partitions or machinery have moved since the last visit — because plant layout changes silently invalidate a coverage design.
Technical specifications and standards
The standards below are the benchmarks that voice alarm equipment is designed and certified against by its manufacturers. They describe the equipment and the design approach, not a certification held by Foxnet.
| Parameter | Reference point |
|---|---|
| Voice alarm control equipment | EN 54-16 is the European product standard for voice alarm control and indicating equipment; equipment designed against it provides supervised outputs, defined fault reporting and priority handling of emergency messages. |
| Loudspeakers | EN 54-24 covers loudspeakers for voice alarm use, including construction and performance under fire conditions; ceramic terminal blocks and thermal fuses are typical features of loudspeakers built to it. |
| System design guidance | IEC 60849 and its successor ISO 7240-19 set out the design logic for sound systems for emergency purposes — zoning, message priority, standby supply and intelligibility targets. |
| Intelligibility | Speech Transmission Index, measured in the field as STIPA per IEC 60268-16. Emergency sound system guidance commonly sets a minimum STI in the region of 0.5 at listener positions; intelligibility is treated as a measurable compliance property, not a subjective opinion. |
| Coverage and level | Announcement level is designed to sit clearly above measured ambient noise across the coverage area, with uniformity between listener positions controlled by loudspeaker spacing and mounting height. |
| Distribution | 100V constant-voltage line distribution with per-loudspeaker tapping, allowing long cable runs across a plant and simple load budgeting per amplifier channel. IP-networked PA is used where a campus backbone already exists and zones are far apart. |
| Circuit supervision | End-of-line or impedance-based monitoring of speaker circuits, amplifier fault detection with standby amplifier changeover, and earth fault monitoring — all reported at the controller. |
| Standby power | Battery sets sized for a quiescent standby period followed by a defined alarm-condition period at full rated load, calculated from actual amplifier loading. |
| Fire system interface | Potential-free contacts or addressable interface modules from the fire alarm panel into the voice alarm controller, mapping fire zones to announcement zones under a written cause-and-effect table. |
| Environmental ratings | IP66 and IP67 horn loudspeakers for outdoor yards, wet process areas and washdown zones, with hazardous-area rated variants where the plant's area classification requires them. |
Where we deploy
Foxnet Securitas fields engineers in 15+ Indian cities, and PA and voice alarm work tends to follow industrial geography: manufacturing and warehousing around Pune, Ahmedabad, Chennai and the Delhi NCR belt through Noida and Gurgaon, logistics parks on the outskirts of Mumbai and Kolkata, and large IT and BFSI campuses in Bangalore and Hyderabad.
Multi-site EHS teams face a specific problem that single-site vendors never see: every plant has a different PA vintage, different zone naming and a different evacuation message, so a corporate EHS audit produces ten different answers to the same question. Standardising the zone model, the message script and the fault-reporting format across sites is usually worth more to the compliance function than any single equipment upgrade.
Campus-scale delivery is our normal working pattern. At Avalara in Pune we delivered cloud access control and CCTV across roughly 90,000 sq ft — the same class of site where evacuation zoning, door release and camera verification have to be planned as one life-safety response rather than separate systems. In regulated environments such as our Sber Bank, Bangalore banking-grade security transformation, the ability to evidence what the system does — and prove it on demand — matters as much as the equipment specification.
Indicative investment
Cost is driven by covered area, ambient noise levels, zone count and whether the system has to be supervised to voice alarm standards. Indicative ranges only — actual pricing depends on site survey.
| Tier | Typical scope | Indicative range (INR) |
|---|---|---|
| Small office or single warehouse | Two to six zones, mixer-amplifier, ceiling and horn loudspeakers, single paging station, basic fire panel trigger. | ₹1.2 lakh – ₹6 lakh |
| Mid-size plant or campus | Ten to forty zones, supervised voice alarm controller, message store, standby amplifiers and batteries, multiple paging and emergency microphone stations, STIPA commissioning. | ₹8 lakh – ₹40 lakh |
| Enterprise multi-site | Networked voice alarm across several plants or cities, standardised zone and message model, central mass notification origination, integration with fire and command centre. | ₹45 lakh – ₹2 crore+ |
Cost rises with supervised voice alarm architecture, high zone counts, hazardous-area and IP-rated loudspeakers, outdoor yard coverage, standby amplifier redundancy and installation in a live plant with limited shutdown windows. It falls where an existing 100V speaker infrastructure tests sound and can be reused, where zones are large and acoustically simple, and where the design can be repeated across similar sites. AMC is quoted separately, typically as an annual percentage of installed system value, scaling with visit frequency and the number of zones to be re-tested.
Frequently asked questions
What is the difference between a PA system and a voice alarm system?
A public address system distributes announcements and paging. A voice alarm system does that but is also built to be depended on in an emergency: supervised speaker circuits, standby batteries, amplifier redundancy, fault reporting and priority handling so emergency messages override everything else. If your PA is expected to evacuate the building, it should be specified as a voice alarm system rather than as general paging.
How do zoned evacuation announcements work across a multi-building site?
Announcement zones are mapped onto fire compartments and escape routes, then linked to fire detection zones in a written cause-and-effect table. An alarm in one production bay can play an evacuate message in that bay, an alert-and-standby message in adjacent areas and nothing elsewhere. The incident controller can then escalate zone by zone from the emergency microphone as the situation develops.
Does the public address system have to be connected to the fire alarm panel?
If it forms part of the evacuation strategy, yes. The fire panel drives the voice alarm controller through interface modules or potential-free contacts so the correct message plays automatically without anyone reaching a microphone. We design and prove that link during commissioning, and it is documented alongside the fire alarm system cause-and-effect matrix.
How is speech intelligibility measured, and why does it matter for compliance?
It is measured in the field as a Speech Transmission Index using the STIPA method defined in IEC 60268-16. Emergency sound system guidance treats intelligibility as a measurable property with a target value, commonly around 0.5 STI at listener positions. That matters because an announcement that is loud but unintelligible in a reverberant warehouse fails its purpose while appearing to work.
Will a PA system work in a noisy plant or a hazardous area?
Yes, but only if the design starts from measured ambient noise at working load rather than an assumption. High-output horn and projector loudspeakers, tighter spacing, and in some cases visual alarm devices alongside audio are used where noise levels are extreme. In classified hazardous areas we specify loudspeakers rated for that area classification and route cabling accordingly.
Can the same system handle background music, paging and boardroom audio?
Background music and routine paging sit comfortably on a voice alarm system, with emergency messages taking priority. Performance audio does not. If you need boardroom, auditorium, atrium or event sound — conferencing DSP, line arrays, acoustic treatment — that is a different discipline; see Sound Technology instead of specifying it on the life-safety PA.
Related services
- Fire Alarm Systems — the detection side that triggers zoned evacuation messages; the natural pairing for any voice alarm project.
- Sound Technology — if you want performance audio for boardrooms, auditoriums and events rather than life-safety PA, start here.
- Command & Control Center — where mass notification is originated and incidents are managed across a multi-site estate.
- Surveillance & Monitoring — visual verification of the zone before an evacuation decision is escalated.