PV Safety for Public Buildings and Rail Transit
Schools, hospitals, metro depots — what these share is density: people below, activity directly under the roof, and no way to evacuate to a "safe distance". So the deciding factor is not cost, but whether you can produce acceptance evidence that survives cross-examination.
Where acceptance stalls, payment stalls
Public projects rarely lack budget — they lack someone willing to sign. The proposal has to prepare the signature basis.
Typical acceptance blockers
- How much voltage actually remains after shutdown? A datasheet is not evidence — a measurement is
- How does the fire interlock connect? The dry-contact signal path must be drawn explicitly
- Does it still shut down when the network is gone? This is the most frequently challenged point
- How long is data retained? Can an incident be traced back to a specific module?
The evidence chain we provide
- Measured report: array-external voltage ≤1 V after shutdown, re-checkable with a multimeter on site
- Wiring diagram: fire dry-contact access path and interlock logic
- Offline validation: measured records of TinyML edge-autonomous shutdown with connectivity removed
- Data retention: module-level archive plus operation audit log, traceable to serial number
A metro transit depot, East China
20-unit pilot, three months of continuous operation, 500,000+ valid records, with a third-party acceptance conclusion.
| Metric | Acceptance result | Test conditions |
|---|---|---|
| Communication success rate | ≥ 99.2% | Strong traction-return EMI environment, three consecutive months |
| Voltage measurement error | ≤ ±0.2 V | As above |
| Temperature measurement error | ≤ ±0.5°C | As above |
| Valid data volume | 500,000+ records | Three-month cumulative; completeness does not vary with weather |
Site characteristics: rapid deployment required on existing canopy structures without major groundworks; modules run continuously along the building facade, with links crossing multiple structural shadowing zones. The site has operated for over 12 months.
Why rail sites are especially hard — and especially suited to wireless
Three inherent difficulties
- Strong EMI: traction return currents generate interference far beyond a normal C&I roof
- No large-scale works: on an operating line, groundworks and outages affect service
- Heavy shadowing: canopies, shelters and facades stack multiple obstruction layers
How LDSW responds
- 2.4 GHz narrowband with self-organising mesh — interference tolerance and diffraction suited to complex structures
- Wireless and cabling-free: deployed along existing frames and facades, no groundworks
- Low duty cycle keeps terminals asleep most of the time, minimising interference windows
- Offline autonomy: even with the gateway disturbed, terminals protect on local policy
What acceptance needs is what we hand over up front
Equipment list & certificates
Model, quantity, serial numbers, and CE / IEC 62109 / NEC 2017 certification documents.
Shutdown test records
Batch shutdown tests recording shutdown time and measured array-external voltage.
Communication quality report
Link success rate, node online rate and error statistics, summarised weekly.
Fire interlock documentation
Dry-contact access method, interlock logic, emergency procedure and drill records.
Send us your acceptance requirements — let's check whether the evidence chain holds
Third-party test reports, sample acceptance packs from comparable projects and fire interlock designs are available, with support for design-office coordination.