https://www.cpsc.gov/Regulations-Laws–Standards/Voluntary-Standards/Carbon-Monoxide-Alarms

We are very grateful to Charon McNabb (info@ncoaa.us) who said that according to the United States Consumer Product Safety Commission, “CO alarms are life safety devices, not injury prevention devices”  Stephanie asked Charon for a reference to this and she kindly sent the above link and read the following

‘CPSC staff is currently participating in voluntary standards activities related to improving the reliability and performance of carbon monoxide (CO) alarms. CO alarms are life safety devices to warn consumers of the accumulation of potentially hazardous levels of CO in their home before their ability to react has been compromised. CO alarms are not intended to protect consumers against low-level CO exposures.’

This is very similar to what CO-Gas Safety has been saying about CO alarms to EN 50291.

Alarm thresholds for domestic alarms https://www.co-gassafety.co.uk/about-co/alarms-2/

• at 30ppm CO, the alarm must not activate (tested for at least 120 minutes)
• at 50ppm CO, the alarm must not activate before 60 minutes but must activate before 90 minutes
• at 100ppm CO, the alarm must not activate before 10 minutes but must activate before 40 minutes
• at 300ppm CO, the alarm must activate within 3 minutes