SD365CO Multi-Criteria Fire/CO Detector - Datasheet

Nov 2, 2026

SD365CO is a plug-in, addressable device providing combined fire and carbon monoxide (CO) detection. It integrates four sensing elements—smoke, CO, light/flame patterns, and heat—to improve sensitivity to real fires while reducing nuisance alarms through multiple sensors and algorithms. CO is measured with an electrochemical sensing cell that outputs a separate life-safety CO signal. The detector supports UL 268, UL 521, and UL 2075, recommended with B200S series sounder bases for distinct fire/CO audible patterns and includes features such as automatic drift compensation and RealTest® CO testing.

LanguageEnglish

CategoryTechnology

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Pages2

Reading Time5 min

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General Description

Features

Specifications

Agency Listings and Approvals

Ordering Information

SD365CO Multi-Criteria Fire/CO Detector General Description SD365CO is a plug-in, addressable device that provides both fire and carbon monoxide (CO) detection. The detector combines four separate sensing elements in one unit to sense multiple components of a fire: smoke, CO, light/flame, and heat. This approach enables enhanced sensitivity to real fire with heightened immunity to nuisance particulates. For CO, the detector’s electrochemical sensing cell creates a separate signal for life safety CO detection. Multiple sensors and communication can greatly reduce nuisance alarms compared to single sensing methods. Sophisticated algorithms maximize the advantages of the sensor types creating our best detection strategy offering heightened immunity to nuisance particulate and enhanced sensitivity to real fire. • Photoelectric sensors detect airborne particles associated with smoke. • Thermal sensors detect heat and rate-of-rise (135°F fixed temperature threshold) . • Carbon Monoxide sensors detect this by-product of fire for accurate fire detection. • Infrared sensors discern light patterns in the environment as an additional data point for alarm determination. This ability to reject certain nuisance alarm triggers, such as theater smoke, supports the use of the fire/CO detector in applications where moderate to heavy nuisance conditions exist that might cause single sensing detectors to false alarm. The fire/CO detector meets both UL 268 and UL 521 listing requirements for fire detection as well as the UL 2075 standard for systemconnected life safety carbon monoxide detection. Released through the incomplete burning of various fuels, CO is a colorless, odorless and deadly gas that is virtually impossible to detect with the human senses. Because the potential exists for dangerous levels of CO to accumulate in almost any building, legislation mandating the use of CO detection in commercial spaces continues to grow. B200S series intelligent sounder bases are recommended for use with SD365CO. These bases can generate either a Temp 3 pattern for fire or a Temp 4 pattern for CO alarm indication. The B200S series bases recognize the System Sensor synchronization protocol, for use as a component of the general evacuation signal —along with other System Sensor horns, horn strobes, and chimes—when connected to a power supply or Fire Alarm Control Panel (FACP) output capable of generating the System Sensor synchronization pulses. Features • Unique ability to detect all four major elements of a fire • Separate CO detection signal • Highest nuisance alarm immunity • Automatic drift compensation for smoke and CO sensors • Uses only one address on the SLC • RealTest® CO testing capability • UL 268, UL 521, and UL 2075 listed • Separate audible signal for fire or CO alarm when used with a B200S series base • 10-year CO cell with end-of-life warning • New modern profile • Expanded color options SD365CO Multi-Criteria Fire/CO Detector installed in B200S-LF-WH sounder base Specifications PHYSICAL • Height: 2.7" (69 mm) installed in B200S series sounder base • Diameter: 6.875" (175 mm) installed in B200S series sounder base • Weight: 3.4 oz. (95 g) • Color: White • Operating Humidity Range: 15% to 90% Relative Humidity, Noncondensing • Operating Temperature Range: 32°F to 100°F (0°C to 38°C) • Air Velocity: 0 to 4000 ft./min. (0 to 1219.2 m/min.) ELECTRICAL SPECIFICATIONS • Operating Voltage Range: 15 to 32 VDC • Operating Current @ 24 VDC: 200 uA (one communication every 5 seconds with green LED blink on communication) • Maximum Alarm Current: 2 mA @ 24 VDC (one communication every 5 seconds with red LED solid on) • Maximum Current: 4.5 mA @ 24 VDC (one communication every 5 seconds with amber LED solid on) • Isolator Load Rating: 0.0063 CO MONITORING UL STANDARD REFERENCE Alarm thresholds are as follows: | Parts Per Million | Detector Response Time | | --- | --

FAQs

How does SD365CO detect both fire and carbon monoxide (CO)?

SD365CO combines four sensing elements for smoke, CO, light/flame, and heat. CO detection uses an electrochemical sensing cell that produces a separate life-safety CO signal.

What are the main benefits of using multiple sensors and algorithms?

Multiple sensors and sophisticated algorithms increase immunity to nuisance particulates and enhance sensitivity to real fires, helping reduce false alarms compared with single-sensor methods.

What CO alarm response times correspond to different parts-per-million thresholds?

At 70 ± 5 ppm, response time is 60–240 minutes; at 150 ± 5 ppm, 10–50 minutes; and at 400 ± 10 ppm, 4–15 minutes.

Nov 2, 2026

Uploaded by Emma Wilson