Digital Radio Communication Across a Multi-Building Factory Campus: Improving Safety & Coordination

Communication across the factory campus had relied on a combination of fixed-line telephone extensions (in management and supervisory offices) and personal mobile phones (for supervisors on the production floor). Neither communication channel was effective for the factory's operational environment.

Fixed-line extensions were useful for office-to-office communication but provided no capability for supervisors who needed to communicate while moving around production areas. Production supervisors in the spinning and weaving buildings often needed to coordinate in real time — for example, when a weaving loom required a specific yarn count that the spinning floor was currently producing, coordinating a priority supply required the weaving supervisor to walk physically to the spinning building to speak with the spinning supervisor, taking 8-12 minutes round trip and requiring both supervisors to leave their respective production areas simultaneously.

Mobile phones were technically capable of bridging the campus but failed consistently in the factory's operational environment. The spinning and dyeing buildings were particularly hostile: spinning machines generate a constant high-frequency noise that made voice calls on mobile phones effectively unintelligible without shouting; the dyeing building produced steam and chemical vapour in the work environment, and workers in that area wore hearing protection that made mobile phone earpiece audio inaudible. Several supervisors had reported abandoning mobile phone calls mid-conversation because the other party simply could not hear them, and reverting to physical movement across the campus.

The emergency response situation was the most serious consequence of the communication gap. The factory's documented emergency response procedure required that any emergency — medical incident, fire, equipment failure, or safety incident — be reported to the Emergency Coordinator immediately, triggering a coordinated response. In practice, reporting an emergency to the coordinator required finding a working telephone or mobile signal (coverage inside the metal-framed buildings was intermittent) and making a connection. The average reported time from incident occurrence to Emergency Coordinator notification, based on drill exercises and two actual incidents in 2024, was 8 minutes. For a medical emergency involving a worker — a realistic event in a factory with 4,000 workers doing physically demanding work — 8 minutes is a clinically significant delay before first responder arrival.

In the most serious of the 2024 incidents — a worker experiencing a heat-related collapse in the dyeing building during summer — the delay in reaching the Emergency Coordinator contributed to a response time that, while ultimately adequate for that patient's outcome, prompted the factory's occupational health officer to formally flag emergency communication as a safety risk requiring mitigation.

Production coordination losses were also quantifiable. The factory's operations manager estimated that physical movement of supervisors to communicate — rather than radio communication — consumed an average of 2.5 hours of supervisor time per production shift across the three buildings. Over three shifts and 300 working days, this represented approximately 2,250 supervisor-hours per year consumed by walking instead of communicating.

SSAL designed and deployed a Hytera DMR digital radio network covering all three buildings across the 12-acre factory campus.

Hytera PD785 Digital Radios — 50 Units: 50 Hytera PD785 DMR Tier III trunked radios were deployed to supervisors and emergency response team members across the three buildings. The PD785 is an industrial-grade radio with IP68 waterproofing and MIL-STD-810G shock resistance — specifications necessary for the dyeing building environment where equipment is regularly hosed down and supervisors may carry radios while working in humid, steam-exposed conditions. Audio quality uses Hytera's AEC (Acoustic Echo Cancellation) and noise suppression, which is specifically calibrated for high-noise industrial environments — the technology that made voice communication audible even in the spinning building where ambient noise reaches 85-90dB.

Key Hytera PD785 features deployed:

Man-Down Detection: Enabled on all 15 supervisor radios (5 per building). A 30-second tilt/motion absence triggers an automatic emergency call to the Emergency Coordinator's radio with a synthesized voice announcement identifying the individual and radio ID. The Emergency Coordinator can then dispatch immediate assistance.

Emergency Call Button: A prominent orange emergency call button on the PD785 transmits a priority emergency call that overrides all other radio traffic, displaying the caller's identity on the Emergency Coordinator's base station screen.

Lone Worker Timer: Configurable timer that requires supervisors doing lone inspections (night shift walk-arounds, basement machinery checks) to periodically confirm their welfare. Failure to respond triggers an emergency alert.

Hytera RD985 Repeaters — 3 Units: Three Hytera RD985 digital repeaters were installed — one in each building's communications room — connected via fiber link to a central Hytera SmartDispatch base station in the factory security office. The repeater network extends radio coverage throughout all floors of all three buildings, including the basement areas and the metalwork-intensive sections of the spinning building that had completely blocked mobile phone signals. Coverage testing post-installation confirmed full signal in all working areas of all three buildings, including the dye vat area of Building C which has heavy stainless steel equipment that creates significant radio frequency shadowing.

Hytera SmartDispatch Console: The factory's Emergency Coordinator operates the Hytera SmartDispatch console in the security office, providing a visual map of all active radios, real-time call traffic monitoring, individual call history, and emergency alert display. The console enables the Emergency Coordinator to initiate all-call broadcasts to all 50 radios simultaneously — used for emergency announcements, shift change notifications, and production coordination messages.

PA System Integration: The Hytera SmartDispatch console's relay output was connected to the factory's PA system amplifier's priority input. An emergency call or all-call broadcast from the console simultaneously activates the PA system, broadcasting the radio audio through all PA speakers throughout all three buildings. This ensures that workers not holding radios — the majority of the 4,000 workers — receive emergency announcements through the PA while supervisors and response teams communicate directly via radio.

Radio Call Groups: The 50 radios are organized into call groups by building (Building A Spinning, Building B Weaving, Building C Dyeing, plus an All-Campus emergency group) and by function (Supervisors, Emergency Response, Management). Supervisors can communicate within their building group without broadcasting to the entire campus, while emergency calls automatically escalate to the All-Campus group.