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Product Features
  • Infrared sensors available

  • Built-in pump option

  • IP65 specifications

Delivery options

At Cadmus Products we aim to deliver orders efficiently and at highly competitive rates. 

  • We can ship consignments of all shapes and sizes and hazardous content across the UK and worldwide. Most of our orders are sent via DHL, however sometimes we may use other couriers.
  • If you are purchasing a laboratory product online you can find out the price of shipping checkout. If you are obtaining a quote for a product, then we will email you
    with our best shipping prices along with your quote.
  • Please see our delivery page for full information

The Crowcon Detective+ is a multi-gas temporary area monitor for use in turnaround/shutdown procedures, hot work maintenance, confined space entry work and many other utility, construction and oil and gas industry applications. Go solo or link together using Detective Net to form a perimeter, the Detective+ gives a loud and clear alarm providing effective warning of gas hazards. The rugged, water and impact-resistant design makes the Detective+ the ideal choice for your transportable gas detection needs.

Rugged and robust, the Crowcon Detective+ features either fixed or folding legs and a protective frame that allows stacking for easier storage. Available with an optional internal pump for sampling versatility, alarms are announced with an extremely loud sounder, while multiple beacons ensure 360-degree visibility.

The Detective+ can be equipped with infra-red (IR) sensors, providing either CO2 detection, or allowing higher levels of flammable gas monitoring. IR sensors also provide immunity to the poisoning effects which standard flammable gas sensors can suffer from. This extends sensor life and further increases measurement confidence in tough applications such as water treatment plants and certain chemical or hydrocarbon processing facilities. Detective+ can be specified with a wide range of sensors, including hydrogen, to monitor a wide range of gases which pose a variety of threats.

Versatile and user friendly

  • Infrared sensors available – allows sampling of highly flammable gas levels and carbon dioxide. They are also unaffected by poisoning and have a very fast response time.
  • Built-in pump option – provides sampling versatility
  • Built-in display – provides clear information and allows identification of gas hazard

Rugged, tripod design

  • Raised sensor apertures – prevents water ingress
  • Folding leg option – allows stacking for easier storage and transportation
  • IP65 specifications – for use in challenging environments
  • Triple leg design – Increases unit physical visibility and is the perfect height to allow 360 gas inlet

Loud and clear alarms

  • 25 Detective NET units or 12 Detective+ with cables can be networked together forming effective perimeter defence – Units on the network can be placed up to 100m from each other and if one alarms, all units on the network alarm.
  • Intelligent and flexible units sending an alarm flash faster – provides a guarantee that the unit is functioning properly and they are protected
  • Audible and visual confidence blip
  • Vivid red LED clusters for visual alarm
  • Multiple beacons – ensures 3600 visibility

Detective+ is now wireless.

Detective Wireless is a wireless module that gives you up to 100 meters range excluding the use of cables. The Detective Wireless modules can also be used as a repeater giving you a stronger signal in those areas that are built up and that have issues with signal strength. Detective Wireless is backwards compatible enabling use with all version of Detective and Detective+, so it can be used on your existing fleet. Find out more.
Size 640 x 455 x 455mm (25.2 x 17.9 x 17.9ins)
Weight 7.5kg (19lbs)
Alarms Three large, top mounted red LED clusters and a single red LED on front panel.
Alarm mode: LED clusters flash in quick succession. LED clusters of linked Detectives repeating the alarm, flash
slower than LED lights on those Detectives sensing the hazard
Normal working: Slow flashing green LED
Battery low: Rapid flashing green LED
Wailing alarm, omni-direction siren, 104 dBA at 1m
Display High contrast LCD with back light. Values and units for up to 4 gases displayed simultaneously at current, TWA or peak levels, low battery, real time and elapsed time calibration and configuration data also displayed.
Data logging 125hrs at 10-second intervals (45,000 logs)
Event logging Alarm, over range, calibration, bump, on/off, TWA, 1000 events
Battery Standard 6V, 7.2Ah, sealed lead acid battery pack
Optional 6V, 12Ah high capacity pack
Up to 36 hours with flammable/ CO2 sensor fitted with 7.2Ah battery
Up to 60 hours with optional 12Ah battery pack
Typical response times Methane 20s, oxygen 10s, typical toxic gas 20s, IR 20s
Operating temperature -20°C to +50°C (-4°F to 122°F)*
Expected sensor life Flammable 5 years, toxic 3 years (typical), oxygen 2 years minimum, IR>5 years
Humidity 15-95% RH non-condensing
EMC Directive 2014/30/EU EN50270
Ingress protection IP65
Approvals Europe: ATEX II 2G Ex ib d IIC T4 (Tamb -20°C to +50°C)
International: IECEx Ex ib d IIC T4 (Tamb -20°C to +50°C)
Standards EN50014, EN50018, EN50020, EN50104, EN45544, IEC60079-0/-1 IEC60079-11
PC Interface Via RS232 lead. Portables PC software can be used to set alarms, clock, datalogging interval and password, manages datalogging giving graphical display of instrument log file and allows to export to spreadsheet.
Calibration Quick calibration using internal menu command, Portables PC
Accessories Baffle plate, interconnecting leads, RS232 communications lead, Detective NET
Sampling Internal electric sampling pump option, manual aspiration
Linked Detectives With cable connection, up to 12 units can be linked to provide perimeter or area monitoring
Crowcon Connect Compatible? No

**Toxic and Oxygen sensors RH Specifications vary, consult Crowcon for specific operating humidities.

Gasses and Ranges

Gas Range Typical Alarms
Flammable gas  0-100 LEL 20% LEL
Oxygen (O2)  0-25%  19% & 23%
Hydrogen sulphide (H2S)  0-50 ppm 10 ppm
Carbon monoxide (CO)  0-500 ppm 30 ppm
Sulphur dioxide (SO2)  0-10 ppm  2 ppm
Chlorine (Cl2)  0-5 ppm  0.5 ppm
Nitrogen dioxide (NO2)  0-10 ppm  2 ppm
Phosphine (PH3) 0-5 ppm  0.5 ppm
Ammonia (NH3)  0-50 ppm  25 ppm
 Ammonia (NH3)  0-1000 ppm n/a
Hydrogen (non-flammable levels)  0-2000 ppm n/a
Hydrogen cyanide (HCN)  0-25ppm  10ppm
Hydrogen chloride (HCl)*/+  0-10 ppm  5ppm
Chlorine dioxide (ClO2)+  0-1 ppm  0.1 ppm
Hydrogen fluoride (HF)+  0-10 ppm  1 ppm
Ethylene oxide (C2H4O)*  0-10 ppm  5 ppm
Volatile organic*/+ 1-100 ppm n/a

* One biased sensor per Detective+

+ Reactive gas, care required during sampling, contact Crowcon
for details.


Infrared Sensors

Gas Range Typical Alarms
Flammable gas  0-100 LEL 20% LEL
Flammable gas  0-100% v/v  None
Available for methane, propane, butane or ethylene
Carbon dioxide (CO2)  0 to 5% v/v 0.5 and 1.5% v/v




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