Carbon monoxide (CO) is an odorless, colorless, and toxic gas. Because it is impossible to see, taste, or smell the toxic fumes, CO can be deadly and the presence in a building can be unknown. The effects of CO exposure can vary greatly from person to person depending on age, overall health, and the concentration and length of exposure. Examples sources of CO can include automobile exhaust, gas stoves, leaking chimneys, water heaters, and furnaces. CO inhibits your blood from carrying oxygen even after getting to fresh air.

CO is primarily a health risk when brief peak exposure is routine or levels in a space continue to rise or do not dissipate. Detection of singular large spikes do not always indicate a persistent problem or danger:

Take for example a diesel truck idling near an open window may look like this.

This would equate to about 35 ppm over 5 minutes. If no other events occur the occupants of that room would have been exposed to

In this case, the occupants might have been exposed to a peak event but the total exposure concentration is still very low and of no need for concern. A typical meter will enter an alarm state when exposed to 15-50 ppm over an hour or a sum of 50 ppm over 8 hours.

Now take this same example and say that this diesel truck will make 20 stops a day at this same spot that would be:

This would be a level that indicates actionable concerns like making an idle engine policy or closing the window should be taken. However, this would not necessarily be an emergency as there is no threat to well-being. If you begin to see events like this regularly and you cannot identify the source you may want to take investigative action. If your fire alarm system enters an alarm state due to the presence of CO always treat it like an emergency even if the SV25 does not detect it.

Now let's take a different example where this graph is also over the same interval of time however the circumstances were life-threatening conditions. Lucky for the occupants this SV25 was mounted directly next to a certified life safety carbon monoxide meter. The SV25 is not a certified life-safety carbon monoxide meter.

Just like the first circumstance the values began with a spike however the level persisted to rise. The building's fire alarm went off and the occupants were evacuated. This represents a life-threatening event as the occupants had they not been evacuated would have been exposed to:

In this case, the SV25 was able to provide insights to the fire department to identify a failed water heater.

If the SV25's Live reading shows unsafe values of carbon monoxide that are increasing or are not dissipating, evacuate the area and contact emergency services.