1.1本指南描述并比较了不同的方法，用于评估泄压引起的反冲和泄漏的可能性或存在性。 1.2在减压或自然条件下，对减压引起的回吸和溢出进行评估。 1.3本指南中涉及的家用通风燃烧设备包括热水器和加热炉。本指南也适用于锅炉。 1.4本指南中给出的方法适用于I类（配备通风罩和引风机）熔炉。本指南不适用于第三类（配备动力通风口）或第四类（直接通风口）熔炉。 1.5本指南中的方法不用于识别由于通风孔堵塞或热交换器泄漏导致的回吸或溢出。 1.6本指南无意为确定是否符合器具和通风装置的规范要求提供依据，但确实包括对装置的目视评估。 该评估可能表明需要由合格的技术人员进行彻底检查。 1.7本指南中方法的用户应熟悉燃烧装置的操作以及使用鼓风机门进行室内气密性测量。本指南中描述的一些方法需要熟悉差压测量和基于计算机的数据记录设备的使用。 1.8以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.9 本指南并非旨在解决与其使用相关的所有安全问题（如有）。用户有责任制定适当的安全和健康实践，并在使用前确定监管限制的适用性。 在执行本指南中给出的某些程序时，可能会发生一氧化碳（CO）暴露或火焰熄灭。有关在执行此类程序时必须采取的预防措施，请参见第7节。 ====意义和用途====== 尽管使用了许多不同的方法来评估回吸和溢出（见NFPA 54、CAN/CGSB-51.71和 1-4 )目前还没有一种公认的方法。在这一点上，不同的方法可以产生不同的结果。此外，尚未评估或描述不同方法的优缺点。 为了为选择方法提供一致的基础，本指南总结了可用于评估回拖和溢出的不同方法。讨论了每种方法的优点和局限性。 当怀疑通风燃烧装置的回吸或溢出是导致一氧化碳（CO）水平升高或水分过多等潜在问题的原因时，应采用本指南中描述的一种或多种方法。 以下是执行此类方法的具体条件示例: 当吸油罩上有明显的碎屑或烟尘时，表明过去可能发生过反冲， 在住宅中添加新的或更换的燃烧装置时， 当添加新的或更换的排气装置或系统时，如下吸式排风机、壁炉或风扇驱动的氡缓解系统， 当住宅被改造或以其他方式改变以提高能源效率时，如各种类型的气候化项目，以及 当CO报警装置发出报警，并且燃烧装置是报警的可疑原因之一时。 根据所进行测试的性质和测试结果，可能需要采取某些预防或补救措施。以下是示例: 如果任何短期测试表明存在回潮的可能性，特别是如果一次以上的测试表明存在回潮的可能性，则应由合格的技术人员对设备和通风系统进行进一步测试，或者可以根据第5.1.1.1条采取补救措施。 5.3. 如果连续监测表明正在发生回吸，特别是如果它表明正在发生影响室内空气质量的泄漏（例如，CO浓度升高或室内水分过多），则应采取补救措施。 可能的补救措施包括: 至少可以在室内安装CO报警装置。 限制使用增加室内减压的设备或系统，如壁炉和大容量排气扇。适当密封任何漏气部位，尤其是在顶层天花板水平，也可以减少房屋较低水平的房屋减压。 如果可用，部分打开熔炉或电器室的窗户。始终保持离电器室最近的门打开，或在门上安装百叶窗。 为设备提供更多的补充空气（例如，通过在设备附近提供一个通向室外的小管道或开口）。 如果补救措施不成功，则可以考虑纠正或更换通风系统，或在必要时，将溢出装置更换为更能承受室内减压的装置。 对回拖和溢出现象的理解正在不断发展。需要使用单一、可靠的方法进行全面研究，以更好地了解在广泛的家庭横断面中减压引起的泄漏的频率、持续时间和严重程度 (5) . 在没有一种公认的方法来评估回吸或溢出的可能性或发生情况的情况下，本指南中介绍了替代方法。本指南旨在促进这些方法在未来实地工作或研究中的一致应用。由此产生的数据将有助于就不同方法的相对优势和劣势作出明智的决定，并为任何适当的改进提供基础。 沿着这些方向继续努力将能够为所有相关方都可以接受的单一方法制定规范。

1.1 This guide describes and compares different methods for assessing the potential for, or existence of, depressurization-induced backdrafting and spillage from vented residential combustion appliances. 1.2 Assessment of depressurization-induced backdrafting and spillage is conducted under either induced depressurization or natural conditions. 1.3 Residential vented combustion appliances addressed in this guide include hot water heaters and furnace. The guide also is applicable to boilers. 1.4 The methods given in this guide are applicable to Category I (draft-hood- and induced-fan-equipped) furnaces. The guide does not apply to Category III (power-vent-equipped) or Category IV (direct-vent) furnaces. 1.5 The methods in this guide are not intended to identify backdrafting or spillage due to vent blockage or heat-exchanger leakage. 1.6 This guide is not intended to provide a basis for determining compliance with code requirements on appliance and venting installation, but does include a visual assessment of the installation. This assessment may indicate the need for a thorough inspection by a qualified technician. 1.7 Users of the methods in this guide should be familiar with combustion appliance operation and with making house-tightness measurements using a blower door. Some methods described in this guide require familiarity with differential-pressure measurements and use of computer-based data-logging equipment. 1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.9 This guide does not purport to address all safety concerns, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. Carbon monoxide (CO) exposure or flame roll-out may occur when performing certain procedures given in this guide. See Section 7, for precautions that must be taken in conducting such procedures. ====== Significance And Use ====== Although a number of different methods have been used to assess backdrafting and spillage (see NFPA 54, CAN/CGSB-51.71, and 1-4 ) a single well-accepted method is not yet available. At this point, different methods can yield different results. In addition, advantages and drawbacks of different methods have not been evaluated or described. To provide a consistent basis for selection of methods, this guide summarizes different methods available to assess backdrafting and spillage. Advantages and limitations of each method are addressed. One or more of the methods described in this guide should be performed when backdrafting or spillage from vented combustion appliances is suspected to be the cause of a potential problem such as elevated carbon monoxide (CO) levels or excessive moisture. The following are examples of specific conditions under which such methods could be performed: When debris or soot is evident at the draft hood, indicating that backdrafting may have occurred in the past, When a new or replacement combustion appliance is added to a residence, When a new or replacement exhaust device or system, such as a downdraft range exhaust fan, a fireplace, or a fan-powered radon mitigation system, is added, When a residence is being remodeled or otherwise altered to increase energy efficiency, as with various types of weatherization programs, and When a CO alarm device has alarmed and a combustion appliance is one of the suspected causes of the alarm. Depending on the nature of the test(s) conducted and the test results, certain preventive or remedial actions may need to be taken. The following are examples: If any of the short-term tests indicates a potential for backdrafting, and particularly if more than one test indicates such potential, then the appliance and venting system should be further tested by a qualified technician, or remedial actions could be taken in accordance with 5.5.3. If continuous monitoring indicates that backdrafting is occurring, and particularly if it indicates that spillage is occurring that impacts indoor air quality (for example, elevated CO concentrations or excessive moisture in the house), then remedial action is indicated. Possible remedial actions include the following: At a minimum, a CO alarm device could be installed in the house. Limiting the use of devices or systems that increase house depressurization, such as fireplaces and high-volume exhaust fans. Proper sealing of any air leakage sites, especially at the top floor ceiling level, can also reduce house depressurization at the lower levels of the house. Partially opening a window in the furnace or appliance room, if available. Keeping the door nearest the appliance room open at all times or putting louvers in the door. Providing increased makeup air for the appliance (for example, by providing a small duct or opening to the outdoors near the appliance). If remedial actions are not successful, then consideration can be given to correcting or replacing the venting system or, if necessary, replacing the spilling appliance with one that can better tolerate house depressurization. The understanding related to backdrafting and spillage phenomena is evolving. Comprehensive research using a single, reliable method is needed to better understand the frequency, duration, and severity of depressurization-induced spillage in a broad cross section of homes (5) . In the absence of a single well-accepted method for assessing the potential for or occurrence of backdrafting or spillage, alternative methods are presented in this guide. The guide is intended to foster consistent application of these methods in future field work or research. The resultant data will enable informed decisions on relative strengths and weaknesses of the different methods and provides a basis for any refinements that may be appropriate. Continued efforts along these lines will enable the development of specifications for a single method that is acceptable to all concerned.