Consulting-Specifying Engineer - May 2008 - (Page 44) National standards Direction for the use of CO detectors is not summarized by any single code, but is distributed throughout various sections of several recognized national standards. These standards apply only to specific applications and the requirements for CO detection, and are the result of extensive studies over several decades. The intent is to determine where CO detection is effective for the safety and operation of a facility without requiring installation of superfluous devices. In National Fire Protection Assn. (NFPA) standards, NFPA 720, The Standard for the Installation of Carbon Monoxide Warning Equipment in Dwelling Units, has the most pervasive effect. The scope of this standard acknowledges that most CO casualties occur in the home. And as residential occupants are most vulnerable when asleep, the primary prescriptive requirement of this standard is: NFPA 720 (2005) – 5.1.1.1: A carbon monoxide alarm or detector shall be centrally located outside of each separate sleeping area in the immediate vicinity of the bedrooms. This standard, however, does not require that the detector be connected to the fire alarm system or other control unit. Detection can be stand-alone detectors: NFPA 720 (2005) - 4.1.1: The warning functions intended in this standard shall be performed by single- or multiple-station alarms or by detectors connected to a control unit and associated equipment, or any combination thereof. Finally, this standard requires that all dwelling unit sleeping areas are protected and does not limit the use to dwelling units with carbon fuel combustion equipment. This broad approach is necessary because of the significant CO threat from portable heating and cooking equipment. NFPA’s primary mission is protection against the threat of fire. Standards such as NFPA 101, 2006 edition (Life Safety Code) and NFPA 72, 2007 edition (The National Fire Alarm Code) have become integral to many adopted ordinances and codes. Both of these standards include the requirements of NFPA 720 by reference without specifically calling for CO detection by name. In NFPA 72, CO detectors can be connected to fire alarm systems as supervisory initiating devices and NFPA 101 does not include any requirements beyond those of NFPA 720. Additional requirements are found in other standards for other specific occupancy types and equipment installations. Several of these NFPA standards indicating required placement are listed in Table 2. Table 2 does not list all of the NFPA standards with requirements for CO detection. Many other facilities (such as electric power generation stations or hazardous storage) require CO detection or fume-management methods specific to the use of the facility. Where designers, contractors, and local authorities are required to comply with the codes published by the International Codes Table 1: This summary of CO production rates from combustion sources is condensed from NFPA: Development of a Technical Basis for Carbon Monoxide Siting Research Project. Source Gasoline-powered generators Wood-burning appliances Gas appliances (abnormal) Non-road diesel engines Gas appliances (max normal) Natural gas combustion Fuel oil combustion Liquefied petroleum gas CO output (mg/sec per kW of nominal input) 100 to 220 1.4 to 8.7 3.4 2.2 0.27 0.041 0.031 0.017 Table 2: National Fire Protection Assn. standards with carbon monoxide detection requirements. Application Protects sleeping and living areas in fire stations Standard - paragraphs NFPA 1500 (2007) - 9.1.4 Protects animal housing facilities NFPA 150 (2007) - 11.3.2 , where fuel-burning equipment is 12.3.2, and 13.3.2 present Engineered mechanical chimney draft installations NFPA 211 (2006) - 4.1.2.5 (3) Council (ICC), they will find no requirements for CO detection. CO detection placement is not directed in the International Building Code, International Fire Code, or any of the other international code documents. Instead, requirements of the International Residential Code for One- and Two-Family Dwellings (2006) and International Fuel Gas Code (2006) rely upon installation of methods of combustion equipment to be correct. For example: 304.12 Protection from fumes and gases. “Non-direct vent-type appliances shall be located in a mechanical room separated or partitioned off from other areas with provisions for combustion air and dilution air from the outdoors. Direct-vent appliances shall be installed in accordance with the appliance manufacturer’s installation instructions.” As a result, some of the national standards organizations are revisiting detector placement. Most notably, the NFPA Carbon Monoxide Technical Committee has been directed to revise the scope of Standard 720 to cover occupancy types other than dwelling units and provide more generic CO detection requirements. A key first step was completed with the October 2007 release of “The Development of a Technical Basis for Carbon Monoxide Detector Siting Research Report.” The report is a publication of 44 Consulting-Specifying Engineer • MAY 2008
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