Honeywell Fire-Lite SD355 Photoelectric Addressable Smoke Detector

Fire-Lite SD355 Photoelectric Addressable Smoke Detector – Honeywell

The Fire-Lite SD355 is a two-wire, plug-in addressable photoelectric smoke detector that operates exclusively on Fire-Lite Addressable Fire Alarm Control Panels (FACPs) — specifically the MS-9200UDLS and MS-9600UDLS Signaling Line Circuit (SLC) loops. It communicates smoke-density data in analog format back to the panel, where the FACP’s onboard algorithm applies the alarm threshold decision rather than the detector itself.

Each unit occupies one of up to 99 address slots on the MS-9200 series or one of 318 slots (159 per loop) on the MS-9600 series, set via a rotary decade switch at commissioning. On marine vessels, the SD355 integrates into the ship’s central safety network, where the FACP is typically interfaced with bridge alarm management systems and, where fitted, the Honeywell Safety Manager or equivalent integrated platform management system (IPMS), enabling automated cross-zone suppression triggers and voyage data recorder (VDR) event logging.

Technical Specifications

Marine & Industrial Applications

• Accommodation block corridors, cabins, and stairwells on merchant vessels and passenger ships
• ECR (Engine Control Room) and cargo control rooms where smoldering fire risk from electrical panels is high
• Pump rooms, switchboard rooms, and electrical cable trunks on tankers and bulk carriers
• Offshore platform accommodation modules and hazardous-area adjacent corridors (non-ATEX zones)
• Ship’s pantry, laundry, and workshop spaces where smoke from overheating equipment precedes open flame
• Ro-Ro car decks and cargo holds (when part of a multi-zone early detection strategy)
• Shore-based industrial facilities: warehouses, server rooms, and control buildings integrated into Honeywell FACP networks
• Retrofit upgrades on vessels with existing Fire-Lite MS-9200 or MS-9600 loop infrastructure

Maintenance Guide: Hidden Failure Mode

There is a failure mode in the SD355 that rarely appears in technical documentation but is well-known to ETOs who have serviced fire systems on vessels with high-speed diesel main engines or Z-drives: rotary decade switch fretting. The address is set by two small plastic rotary wheels — one for tens, one for units — that physically contact a PCB trace ring beneath them. On vessels where structural vibration is transmitted into the deckhead mounting surface (typically 12 Hz–80 Hz from propulsion machinery), these plastic wheels experience micro-oscillation against their contact traces. Over 12–24 months, this produces oxide debris at the contact interface — essentially fretting corrosion on a scale invisible to the naked eye.

The symptom is intermittent address dropout: the FACP logs a random “device not responding” trouble event at that address, which clears on the next poll cycle. Most engineers chase this as a wiring fault or SLC loop issue, replacing cables and isolators, before eventually tracing it to the detector head itself. The fix is simple: apply a single drop of low-viscosity non-conductive contact lubricant to the switch wheel contact face, reset the address, and re-test. On vibration-heavy installations, fit anti-vibration mounts to the base plate, or switch to the screw-set address variant if loop architecture permits.

Datasheet & Installation Manual

• Official Product Datasheet (PDF):
  Download SD355 / SD355T Datasheet – Fire-Lite by Honeywell (Bass United Mirror)
  

• Installation & Operation Manual (PDF):
  Download SD355 / SD355T / AD355 Installation Manual – Fire-Lite (Brooks Equipment Mirror)

• Manufacturer Product Page:
  Honeywell Buildings – SD355 Series (Official Page)