As an adjunct to their usual intrusion detection and fire alarm systems, more and more security and life-safety contractors are installing carbon monoxide (CO) alarms. While there is no current national requirement that these detectors be supervised by a central station, numerous system providers are offering this service.
CO is an odorless, colorless and tasteless gas. It is also a very toxic substance that can render a person unconscious or dead, depending on the concentration that may be within a space. With the publication of the 2012 edition of the International Residential Code (IRC) by the International Code Council (ICC), and the requirement for CO alarms within all single and multiple family dwellings, there will be an increase in the number of locations that will request monitored CO detectors be installed.
Knowing the requirements for monitoring these detectors, and making certain end users are also familiar with the requirements, will eliminate any confusion regarding the handling of these signals prior to when a signal is received. Let’s take a closer look.
Different Degrees of CO Poisoning
CO will produce the following symptoms within a person, depending upon the parts per million (ppm) that have been inhaled and absorbed by the body.
- 50 ppm — No adverse effects within eight hours of exposure
- 200 ppm — Mild headache after two to three hours of exposure
- 400 ppm — Headache and nausea after one to two hours of exposure
- 800 ppm — Headache, dizziness and nausea after 45 minutes of exposure; unconsciousness after two hours
- 1,000 ppm — Unconsciousness after one hour
- 3,200 ppm — Unconscious after 30 minutes
- 6,400 ppm — Unconscious and/or death after 15 minutes
- 12,800 ppm — Unconscious and/or death after one to three minutes
Every year there are a number of deaths and injuries from CO exposure. Most occur within residential occupancies. CO is the result of appliances or devices that produce products from combustion, such as natural gas, petroleum and wood. When there is direct injection of CO into a poorly ventilated space or through a leak within a heater or other fuel-burning appliance, the concentrations will begin to rise. When the ppm reach the levels as stated above, individuals within the space will become affected.
One concern that has been voiced regarding the monitoring of CO detectors is that a person within premises where the gas is present might be unable to act in response to a call, thus requiring emergency responders to make a forced entry. How then is the monitoring of CO addressed?
CO Standards for Monitoring
There are two standards that address the monitoring of CO detectors:
- NFPA 720 — Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment, 2012 Edition
- CSAA CS-CO-01 — Carbon Monoxide Supervising Station Response Standard, 2008 Edition
The 2009 edition of NFPA (National Fire Protection Association) 720 first addressed the supervision and handling of CO signals from a protected premise. The Central Station Alarm Association (CSAA) wished to supplement the requirements within 720 with additional information for central station operators.
Chapter 7, Off-Premises Signal Transmission within NFPA 720 details requirements that are to be followed. Section 18.104.22.168 requires that a CO alarm signal shall take precedence over supervisory or trouble signals. Section 22.214.171.124.1 requires that the actuation of a CO detector shall be indicated as a CO alarm signal. The handling of the signal by the supervising station is addressed within the following section:
7.2.2 Supervising Station: Upon receipt of a carbon monoxide alarm signal, supervising station personnel shall perform the following actions in the order listed:
(1) Where required by the emergency response agency, immediately retransmit indication of the carbon monoxide alarm signal to the communications center.
(2) Contact the responsible party(s) in accordance with the notification plan.
The notification plan is covered within the annex to this section:
The supervising station should have a notification plan on file, the manufacturer’s published instructions, and multiple points of contact with the subscriber to take action in accordance with the manufacturer’s published instructions.
Within the manufacturer’s instructions are guidelines to be followed if a detector should be activated. These instructions typically advise the end user to immediately move to a spot where fresh air is available, preferably outdoors. Opening windows may also be advised. These steps generally eliminate the immediate threat.