Atomic Definition Paragraph
Shared Speaker System: Refers to the simultaneous transmission of background music and fire alarm broadcasting signals over the same audio line, with functionality differentiation achieved through switching or independent circuits.Comparison Table
| Dimension | Single Circuit with Enhanced Switching | Two Independent Circuits |
|---|---|---|
| Equipment Quantity | 1 set of audio distribution equipment + switching module | 2 sets of audio distribution equipment |
| Cost | Low | High |
| Reliability | Affected by single point failure | Uninterrupted |
| Maintenance | Simple | Maintenance workload is large |
| Applicable Scenario | Small and medium-sized parks, factories | Large multi-area parks, mines |
1. Selection and Configuration
| Key Element | Recommended Product (Example) |
|---|---|
| Audio Distribution Equipment | Hikvision H3-2000 Series Broadcast Host Dahua DVS-1000 Audio Distribution Equipment |
| Switching Module | Hikvision H3-2000 Priority Switching Module Dahua DVS-1000 Strong Cutting Function |
| Line Monitoring Unit | Hikvision H3-1000 Line Monitoring Module Dahua DVS-2000 Monitoring Unit |
| Isolation Switch | 10A 100V DC Isolation Switch (Compliant with IEC 60364) |
- Single Circuit with Enhanced Switching: Achieve "Music → Fire Alarm Broadcasting" switching within the same audio chain through a switching module. During switching, the music signal is instantaneously cut off, and fire alarm broadcasting takes priority.
- Two Independent Circuits: Set up independent music and fire alarm broadcasting circuits, which do not interfere with each other. Both circuits are connected to the same speaker network partition to ensure consistent volume and coverage.
2. Priority Switching Implementation
- Switching Logic: When a fire alarm is triggered, the switching module immediately switches the input source to fire alarm broadcasting, with a switching time ≤ 10 ms.
- Priority Setting: Set "Fire Alarm Broadcasting Priority > Background Music" in the management software of the host or distribution equipment.
- Circuit Protection: Automatically insert a short-circuit isolation switch before and after switching to prevent short-circuit or overload.
3. Line Monitoring and Fault Isolation
| Monitoring Method | Description |
|---|---|
| Current Transformer | Real-time monitoring of audio line current, triggering an alarm when exceeding the threshold. |
| Voltage Monitoring | Detect whether the line voltage is within ±5% range. |
| Fault Isolation Switch | Isolation switches controlled by PLC or distribution equipment, automatically cutting off the affected partition when an anomaly occurs. |
- Monitoring Frequency: Recommended ≥ 1 Hz to ensure real-time performance.
- Alarming Method: Alerts maintenance personnel through system logs, SMS, or on-site alarm lights.
4. Acceptance and Testing
4.1 Partition Division Check
- Check Points: Whether each functional area (such as factory workshops, storage areas, office areas) is independently divided, and whether the speakers cover the entire area.
- Tools: Use sound level meters (±1 dB) to measure the sound level in each partition to ensure it meets the design requirements.
4.2 Volume Testing
- Background Music: Measure the sound level in each partition under normal working conditions to ensure it is not less than 60 dB SPL.
- Fire Alarm Broadcasting: Measure the sound level in each partition during simulated fire alarms to ensure it is not less than 80 dB SPL and has a clear priority difference from background music.
4.3 Interlock Testing
- Fire Alarm Triggering: Press the fire alarm test button to verify that music is immediately cut off and fire alarm broadcasting takes priority.
- Recovery Testing: Confirm that music resumes and there is no residual noise after fire alarm broadcasting ends.
4.4 Fault Isolation Testing
- Simulated Fault: Check whether the isolation switch cuts off the affected partition when a fault occurs in a partition and whether other partitions are unaffected.
- Alarming Confirmation: Whether the system timely issues a fault alarm and records logs.
5. Compliance and Standards
- Fire Alarm Broadcasting Volume: According to local fire department regulations, the volume usually requires more than 80 dB SPL.
- Coverage Range: At least 90% of the area within each partition must meet the volume requirements.
- Interlock Delay: The time from fire alarm triggering to fire alarm broadcasting starting should not exceed 2 seconds.
- Design Documents: All parameters (partition division, volume, line protection) must be clearly specified in the design documents and are subject to the relevant authorities and design documents.
> Note: Fire alarm broadcasting systems must meet local fire regulations. Specific technical indicators should refer to the technical standards published by the relevant local authorities.