UL testing of CO alarms not up to EN Standards

Any CO detector installed is a potentially life saving piece of equipment, and for this reason must be carefully chosen. CO detectors with certification in accordance to the European Norm EN50291 are tested to a higher standard of sensitivity and reaction time, than those tested to the US American UL2034 standard. CO detectors that meet the strict European EN standards have met the highest safety and quality requirements. UL marks are achieved through a similar, yet less rigorous testing in the USA and it has been known for UL tested carbon monoxide detectors to fail to meet the EN standards. Here a comparison of some of the requirements:

Test EN50291 Standard UL2034 Standard
Humidity Tested 20% to 80% relative humidity Tested 30% to 70% relative humidity
Temperature Threshold 13 to 27 degree Celsius 20 to 26 degree Celsius
Alarm Threshold Alarm does not sound until 120 mins exposure @ 30ppm Alarm does not sound until 30 day exposure @ 30ppm
Alarm Threshold Alarm must not be given before 60 mins but must before 90 mins @ 50ppm Alarm must not be given before 60 mins but must before 240 mins @ 70ppm
Alarm Threshold An alarm must be given within 3 mins @ 300ppm An alarm must be given within 15 mins @ 400ppm
Continuous Testing 2 samples tested by certification body annually No further testing
EMC Tests Tested from 30 to 1000Mhz Tested at a few discrete frequencies

When purchasing a CO detector (or any alarm/detector) it is advisable to always check for the type of certification that has been awarded. Please browse our full range of Kitemarked marked CO detectors.