To help prevent CO problems and reduce the risk of CO poisoning: Clean chimneys and flues yearly. Keep them free of debris,
leaves, and nests for proper air flow. Also, have a professional check for rust and corrosion, cracks or separations. These conditions can prevent proper air movement and cause backdrafting. Never cap or cover a chimney in any way that would block air flow.
Test and maintain all
Make regular visual inspections of all
Check for exhaust backflow from CO sources. Check the draft hood on an operating furnace for a backdraft. Look for cracks on furnace heat exchangers.
Check the house or garage on the other side of shared wall.
Keep windows and doors open slightly. If you suspect that CO is escaping into your home, open a window or door. Opening windows or doors can significantly reduce CO levels.
POTENTIAL SOURCES OF CO IN RESIDENTIAL DWELLINGS
Damaged or insufficient venting: corroded or disconnected water heater vent pipe, leaking chimney pipe or flue, or cracked heat exchanger, blocked or clogged chimney opening.
Improper use of appliance/device: operating a barbecue grill, portable generator or vehicle in an enclosed area (like a garage or screened porch), or even your home.
Figure 1
Figure 1: POTENTIAL SOURCES OF CO IN HOME.
Transient CO Problems: transient or
The following conditions can result in transient CO situations:
1) Excessive spillage or reverse venting of fuel appliances caused by outdoor conditions such as:
Wind direction and/or velocity, including high, gusty winds. Heavy air in vent pipes (cold/humid air with extended periods between cycles).
Negative pressure differential resulting from the use of exhaust fans.
Several appliances running at the same time competing for limited fresh air.
Vent pipe connections vibrating loose from clothes dryers, furnaces or water heaters.
Obstructions in or unconventional vent pipe designs which can amplify the above situations.
2) Extended operation of unvented fuel burning devices (range, oven, fireplace)
3) Temperature inversions, which can trap exhaust close to the ground.
4) Car idling in an open or closed garage or near a home.
5) Portable generator used in an open or closed garage or near a home.
These conditions can come and go, they are also hard to recreate during a CO investigation.
PLACEMENT OF CO ALARMS
THIS EQUIPMENT SHOULD BE INSTALLED IN ACCORDANCE WITH THE NATIONAL FIRE PROTECTION ASSOCIATION'S STANDARD 720 (National Fire Protection Association, Batterymarch Park, Quincy, MA 02269).
For your information, the National Fire Protection Association's Standard 720, reads as follows:
NFPA 720, 2009 Edition, Chapter 9, Section 9.4.1.1 Where required by applicable laws, codes or standards for a specific type of occupancy, approved single and
1) Outside of each separate dwelling unit sleeping area in the immediate vicinity of the bedrooms.
2) On every occupiable level of a dwelling unit, including basements, excluding attics and crawl spaces.
3) Other locations where required by applicable laws, codes or standards.
The installation of additional CO alarms should result in a higher degree of protection. Adding alarms to rooms that are normally closed off from the required alarms increases the escape time because the CO levels do not need to build to the higher level necessary to force CO out of the closed room to the required alarms. As a consequence, it is recommended that the householder consider the installation of additional CO protection devices. However, it should be understood that NFPA 720 does not require additional CO alarms over and above those called for in Figures 2, 3, 4 and 5 where required CO alarms are shown.
Figure 2
Figure 2: A CO ALARM MUST BE LOCATED ON EVERY LEVEL OF DWELLING UNIT, INCLUDING BASEMENT AND OUTSIDE SLEEP- ING AREAS.
Where to Locate the Required CO Alarms. The major threat from CO in a dwelling unit occurs at night when everyone is asleep. Persons in sleeping areas can be threatened by CO levels in the remainder of the unit; therefore, CO alarms are best located between the bedroom areas and the rest of the unit as shown in Figure 3.
Figure 3
Figure 3: A CO ALARM MUST BE LOCATED BETWEEN THE SLEEPING AREA AND THE REST OF THE DWELLING UNIT.
In dwelling units with more than one bedroom area or with bedrooms on more than one floor, more than one CO alarm is required, as shown in Figure 4.
Figure 4
Figure 4: IN DWELLING UNITS WITH MORE THAN ONE SLEEPING AREA, A CO ALARM MUST BE PROVIDED TO PROTECT EACH SLEEPING AREA.
