Spectrex 20/20Q QuadSense IR3 Flame Detector, Emerson SharpEye 20/20Q Triple IR Flame Detector for Hydrocarbon Fires

What is the Spectrex 20/20Q flame detector?

The Spectrex 20/20Q is a QuadSense flame detector in Emerson’s SharpEye 20/20 series. It applies triple infrared (IR3) analysis with four infrared sensors, which helps it separate a hydrocarbon flame from background radiation, and it detects a 1 ft² gasoline or n-heptane pan fire at up to 150 ft. (45 m) on its highest sensitivity setting. Emerson calibrates it at the factory for life use and runs a continuous infrared built-in test (BIT) of the optics and electronics.

Status: Emerson lists the 20/20Q as active and names it as one of two upgrade options for the Spectrex 20/20MI, which was discontinued on Sept 30, 2025; the other named option is the Rosemount 965 IR3.

Replacement note: swapping a 20/20MI for a 20/20Q changes more than the label. The 20/20MI data sheet prints 4-20mA levels of 5 mA normal, 10 mA warning and 15 mA alarm, while the 20/20Q default stepped output is 4 mA normal, 16 mA warning and 20 mA alarm (the 20/20Q output is configurable). The 20/20MI connects through a 12-wire, 6 ft. (2 m) cable; the 20/20Q has 9 terminals and one M20 cable entry. Emerson states both upgrade options offer easy, compatible installation; still check the control system’s mA thresholds and the wiring at changeover.

What are the Spectrex 20/20Q flame detector specifications?

Detection technology	QuadSense triple infrared (IR3), 4 infrared (IR) bands between 4 μm and 5 μm
Detection range, gasoline and n-heptane	150 ft. (45 m), highest sensitivity, 1 ft²/0.1 m² pan fire
Other fuels (same test)	JP5, kerosene, diesel fuel, methane, LPG: 107 ft. (32 m); ethanol 95 %, IPA, methanol: 100 ft. (30 m); polypropylene: 83 ft. (25 m); paper, wood: 57 ft. (17 m)
Detection response time	Typically < 5 s
Sensitivity ranges	9.8 ft. (3 m); 32.8 ft. (10 m); 65.6 ft. (20 m); 98.4 ft. (30 m); 147.6 ft. (45 m)
Field of view	Horizontal: 100°, Vertical: 95° (at 50 % of maximum distance)
Operating temperature	-40 to +158 °F (-40 to +70 °C)
Humidity	Non-condensing relative humidity up to 100 %
Operating voltage	24 Vdc nominal (12-32 Vdc)
Power consumption (24 Vdc)	Normal: 25 mA, 0.6 W
Relays	Fault normally closed (NC), alarm normally open (NO); SPST volt-free contacts rated 2 A at 30 Vdc
0-20 mA (stepped) default	Fault < 1.1 mA; BIT fault 2 mA; Normal 4 mA; Warning 16 mA; Alarm 20 mA (± 0.3 mA)
Digital communication	RS-485 Modbus compatible
Cable entries	1 x M20; 9 terminals and a single cable conduit
Enclosure options	Low-copper aluminum polyurethane painted; engineered polymer
Dimensions	Detector: 4.25 x 3.15 x 4.64 in. (108 x 80 x 118 mm)
Weight	Detector: 1.65 lb. (0.75 kg); engineered polymer: 0.62 lb. (0.28 kg); tilt mount: 1.54 lb. (0.7 kg); polymer tilt mount: 0.26 lb. (0.12 kg)
Enclosure ratings	IP66 and IP68; UL50E Type 4X; EN60529; NEMA 250 6P
Lifespan	150,000 hours
Warranty	Two-year warranty

Selection note: the polymer build saves weight on light structures: the engineered polymer detector weighs 0.62 lb. (0.28 kg) against 1.65 lb. (0.75 kg) in aluminum, and the polymer tilt mount 0.26 lb. (0.12 kg) against 1.54 lb. (0.7 kg). Power draw is low too: 25 mA (0.6 W) in normal operation, against 60 mA (1.4 W) for a SharpEye 40/40C-I without heater.

Where is the Spectrex 20/20Q used, and when is another Emerson model the better fit?

Emerson aims the 20/20Q at large indoor and outdoor spaces: transport hubs such as airport terminals and train stations, public buildings including malls, hospitals, banks, offices and historical or cultural sites, storage areas and archives, car parks and parking towers, aircraft hangars, cable tunnels and automotive parts plants. Its ordering table lists only a non-hazardous areas approval.

• 20/20Q vs SharpEye 40/40: for classified areas the 40/40 platforms carry hazardous area approval codes (ATEX/IECEx/UKCA, USA and Canada Explosion-Proof, INMETRO, EAC CU TR, Korea Flameproof) and reach further on gasoline: 215 ft. (65 m) for the SharpEye 40/40C-I and 300 ft. (90 m) for the SharpEye 40/40D-I.
• 20/20Q vs 20/20MI: on gasoline the 20/20Q reaches 150 ft. (45 m) against 133 ft. (40 m) for the discontinued 20/20MI, with five sensitivity levels against four; the 20/20MI data sheet showed a 3-Year Warranty, the 20/20Q has two years.
• 20/20Q vs Rosemount 965: Emerson’s other named upgrade for the 20/20MI; ask us if a site standardizes on Rosemount detectors.

For a wider comparison of detector technologies see the PE Energy flame detector selection guide.

Selection note: the 20/20Q carries performance approvals, not hazardous location approvals. Its ordering table offers a single hazardous approval code, 0 (non-hazardous areas approval), with performance approval T (FM3260 + EN54-10 + ULC386) or S (the same plus DNV). Where the area is classified, a SharpEye 40/40C or 40/40D with the right approval code is the Spectrex choice.

Which approvals, outputs and documents apply to the Spectrex 20/20Q?

EN54-10	Class 2 sensitivity 10 m; Class 1 sensitivities 20, 30, and 45 m; certificate number 2809-CPR-E0040
ULC	ULC/ORD-C386-15
FM	FM3260
Performance option S	FM3260 + EN54-10 + ULC386 + DNV (supplied with a stainless steel tilt mount)
Hazardous approval	0: Non-hazardous areas approval
Reliability	Safety Integrity Level (SIL): pending
EMC	EMI/RFI protected to EN61000-6-3, EN61000-6-4, EN61000-6-6 and EN 50130; electrical input protection according to EN 50130

Outputs are two relays (fault and alarm), a stepped 0-20 mA loop and an RS-485 Modbus link for computer-controlled installations; the output configuration code is R (analog 4-20 mA, RS-485 and relays). Data sheet: Spectrex 20/20Q flame detector data sheet, document MS-00913-0100-9020, Rev. AG of September 2026. Emerson model page: Spectrex 20/20Q Flame Detector on Emerson.com.

Maintenance note: the end-to-end test tool is the FS-1100 flame simulator. Its data sheet gives 20/20Q testing distances per sensitivity setting: 6.6 ft. (2 m) at 32.8 ft. (10 m), 16.4 ft. (5 m) at 65.6 ft. (20 m), 24.6 ft. (7.5 m) at 98.4 ft. (30 m) and 29.5 ft. (9 m) at 147.6 ft. (45 m); for the 9.8 ft. (3 m) setting no distance is printed. See the Spectrex FS Series flame simulator.

How do I request a quote for the Spectrex 20/20Q flame detector?

Send the options below, in the data sheet’s order, with the quantity:

Model	I: QuadSense triple infrared (IR3)
Enclosure	A: Aluminum + M20; K: Aluminum + connector backshell; P: Engineered polymer + M20
Output configuration	R: Analog (4-20 mA)/RS-485/Relays
Operating temperature range	6: -40 to +158 °F (-40 to +70 °C)
Hazardous approval	0: Non-hazardous areas approval
Performance approvals	T: FM3260 + EN54-10 + ULC386; S: FM3260 + EN54-10 + ULC386 + DNV
Tilt mount	Y: Including stainless steel tilt mount; N: Without tilt mount; P: Including engineered polymer tilt mount

Accessories with Emerson codes:

FS-1100	Flame simulator (explosion-proof)
965190	Tilt mount (stainless steel)
965290	Tilt mount (engineered polymer)
789260-2, 789260-1, 789260-3	Flame detector pole mount assembly, 2 in. (51 mm), 3 in. (76 mm), 4 in. (101 mm)
965603	Bracket
965650	Air shield
965605	Cable
877060	Cone viewer
965563	Cone of view limiter
794079	USB RS-485 harness kit

PE Energy confirms price, availability and lead time with the quote. Request a quote for a Spectrex 20/20Q flame detector.

Model code example: the data sheet does not print an assembled part number, so a quote is built from its option table in order. A polymer unit for an indoor public building would read: I (QuadSense IR3), P (engineered polymer + M20), R (analog 4-20 mA, RS-485 and relays), 6 (-40 to +158 °F), 0 (non-hazardous areas approval), T (FM3260 + EN54-10 + ULC386) and P (engineered polymer tilt mount). Choosing S instead of T adds DNV and brings a stainless steel tilt mount.