1.1本规程涵盖了两种氡控制方案的设计和施工，用于新的低层住宅建筑。这些不引人注目的（内置）土壤减压选项安装有适合其预期初始操作模式的管道路径，即风扇供电或被动。其中一条管线应在住宅建筑期间安装 ’ 的初步建设。临界气体渗透层、氡系统规范 ’ s管道和减少氡进入途径是两条管道路线的综合和共同点。 1.1.1第一种方案具有适用于风机驱动氡还原系统的管道路径。氡风机应在 (1) 初始氡测试结果显示氡浓度不可接受，因此需要运行氡风机，或 (2) 业主指定了一台正在运行的氡风机，以及入住前可接受的氡测试结果。风机操作的土壤降压氡系统可将室内氡浓度降低高达99%。 1.1.2第二种方案具有更有效的管道路线，适用于被动操作的降氡系统。被动操作的降氡系统提供高达50%的降氡率。当带有运行被动系统的建筑物的氡测试结果不可接受时，该系统应转换为风机供电运行。安装管道线路用于被动操作的氡系统可以很容易地转换为风机供电操作；这种风扇操作系统可将室内氡浓度降低高达99%。 1.2这些选项提供了不同的好处: 1.2.1使用管道线路进行风机供电操作的选项适用于建筑商，其客户希望在住宅楼被占用之前最大程度地减少内置氡，并提供有效氡减少系统的书面证据。带有风机供电型管道线路的氡系统在通风管布线和风机位置方面具有最大的建筑自由度。 1.2.2使用管道路线进行被动操作的选项适用于建筑商及其客户，他们希望以尽可能低的运营成本降低嵌入式氡，并在入住前提供可接受氡系统性能的书面证据。如果是被动系统 ’ s氡的减少是不可接受的，将其转换为风扇可以显著提高其性能- 电动操作。 1.3风机供电、土壤降压、降氡技术，如本规程中规定的技术，已在世界各地成功应用于地面、地下室和爬行空间地基。 1.4空气中氡测试用于确保这些土壤降压氡系统的有效性。美国国会在1988年《室内氡消除法案》中制定的美国室内氡浓度国家目标是尽可能将室内氡减少到接近室外空气水平。假设室外空气中的氡浓度为0.4皮卡每升（pCi/l）（15贝克勒尔/立方米（Bq/m 3. )); 美国。 ’ s室内空气中的平均氡浓度为1.3PCI/L（50Bq/m 3. ). 该实践的目标是提供室内氡浓度低于2.0 pCi/L（75 Bq/m）的新住宅 3. )在可占用空间中。 1.5本规程旨在协助业主、设计师、建筑商、建筑官员和其他设计、管理和检查新低层住宅建筑氡系统及其施工的人员。 1.6本规程可作为一套示范规程，可由州和地方司法机构采用或修改，以实现其住宅建筑规范和法规的目标。这一做法也可作为联邦、州和地方卫生官员和辐射防护机构的参考。 1.7本惯例涵盖的新住宅单元从未被占用。 规程E 2121涵盖了现有低层住宅建筑的氡减少 或州和地方建筑规范和辐射防护法规。 1.8风机驱动的土壤降压是本实践中描述的主要策略，在所有现有策略中提供了最有效和最可靠的降氡方法。从历史上看，成功安装和运行的风机驱动土壤降压降氡系统远远超过所有其他降氡方法的总和。这些方法不是降低室内氡浓度的唯一方法 (1-3) . 1.9第7节为 职业氡暴露与工人安全 . 1.10附录X1为 风机驱动土壤降压降氡的工作原理 . 1.11附录X2是一个 规程E 1465小结-在新的低层住宅中安装降氡系统的要求 . 1.12以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.13 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 根据这一做法，在新的住宅建筑中安装风扇驱动的降氡系统可能会降低室内氡水平升高，因为土壤- 气体是氡的来源，低于每升2.0皮卡（pCi/L）（每立方米75贝克勒尔（Bq/m）） 3. ))在可占用空间中。被动降氡系统并不总是将此类室内氡浓度降低到低于2.0皮克/升（pCi/L）（75贝克勒尔/立方米（Bq/m）） 3. ))在可占用空间中。当按照这种做法建造的被动系统未达到可接受的氡浓度时，应将该系统转换为风扇供电运行，以显著提高其性能。 例外情况 — 在膨胀土和喀斯特上建造的新住宅楼可能需要额外的措施，以实现可接受的氡减少，但本实践中未包括。考虑咨询土壤/岩土专家、合格的基础结构工程师，并联系州政府 ’ s radon in air专家提供有关施工方法的最新信息。您所在州氡专家的姓名可从美国环保局网站获得(http://www.epa.gov/radon). 笔记 1-由于氡从室内用水（如淋浴用水）中排出气体，使用私人水井的住宅室内氡浓度可能会升高 (7) . 考虑联系您所在的州 ’ s氡专家，以获取有关从私人井水中去除氡的可用方法的最新信息。 所有土壤降压降氡方法都需要可降压的气体渗透层。透气层位于建筑物下方 ’ s密封地面覆盖物。在主动土壤降压系统的情况下，氡风机将空气从排气管中抽出，以对气体降压- 渗透层。在被动土壤减压系统的情况下，当通风烟囱中的空气比室外温度高时，烟囱中的热空气上升，导致透气层减压。被动系统间歇性地对透气层降压；风机驱动系统持续降低透气层的压力。透气层的性能取决于其设计；见6.4.1.3。被动运行的降氡系统需要最有效的气体渗透层。 U、 美国环境保护局关于室内氡的建议行动水平规定，如果氡浓度为每升4皮克（pCi/L）（每立方米150贝克勒尔（Bq/m）），则应始终降低氡浓度 3. ))或更高。 据美国环保局称，当室内空气中的氡浓度降至2.0皮卡每升（pCi/L）（75贝克勒尔/立方米（Bq/m））以下时，风险也会降低 3. ))在可占用空间中 (4) . 将室内氡浓度降至4 pCi/L（150 Bq/m）以下可获得显著效益 3. ). 据美国环保局称 ’ s风险评估 (8) 在1000名吸烟者中，约有62人将终生死亡 ’ s平均氡暴露量为4 pCi/L（150 Bq/m 3. ); 对于从不吸烟的人来说，1000人中有7人会死于相同的终生暴露。吸烟者 ’ 当他们的平均氡暴露量从4 pCi/L减少到2 pCi/L（150到75 Bq/m）时，肺癌死亡的终身风险减少了约一半（50%） 3. ); 他们的风险降低了大约两倍- 当他们的暴露量从4减少到1.3 pCi/L（150到75 Bq/m）时，三分之一（67%） 3. ). 从不吸烟 ’ 当他们的平均氡暴露量从4 pCi/L减少到2 pCi/L（150到75 Bq/m）时，肺癌死亡的终身风险降低了约40% 3. ); 当他们的暴露量从4减少到1.3PCI/L（150到50Bq/m）时，风险降低了70% 3. ). U、 美国环保局建议的将氡降低到低于4 pCi/L（150 Bq/m）的行动水平 3. )是 “ 氡水平低于4 pCi/L（150 Bq/m 3. )仍然存在风险，在许多情况下可能会降低 ” (4) . U、 美国环保局建议: “ 考虑固定在2到4 pCi/L（75到150 Bq/m）之间 3. ). ” （见1.4和6.11.4中的氡减少目标。） 这种做法假设客户了解暴露于氡的肺癌风险，并能够通过合同确定新住宅楼允许的最大可接受室内氡浓度。 由于美国有目标和建议的行动水平，但没有政府规定的新住宅建设的最大室内氡浓度，因此客户及其代理人应通过合同协商确定最大可接受室内氡浓度。客户应该记住 ’ 室内氡浓度不得低于建筑物附近室外空气中的氡浓度；目标氡水平低于2 pCi/L（75 Bq/m 3. )可能更贵；氡浓度低于2 pCi/L（75 Bq/m 3. )使用当前商用技术很难测量。（参见 (4, 7) ，1.4和6.11.4。） 本标准规定的协商可接受氡浓度可能因客户和合同而异。 所有者 ’ 在指定氡系统设计之前，应了解并考虑减少氡的目标。透气层孔隙结构的选择；排气立管直径和路径；氡风机容量；建筑特征影响降氡系统 ’ 的性能。（见1.4、3.2.1、5.3、5.4、5.5和6.4.1.3。） 本实践提供了有关氡减少方法的有组织的信息。这种做法不能取代教育和经验，应与经过培训和认证的氡从业人员的判断结合使用。并非本惯例的所有方面都适用于所有情况。 本实践本身并不是为了取代判断专业服务是否充分的谨慎标准，也不应在不考虑项目独特性的情况下单独应用本实践。 文字 “ 标准 ” 在本规程标题中，表示该文件已通过ASTM共识程序获得批准。 目前还没有可靠的方法来预测特定住宅建筑在建造之前的室内氡浓度。如果房屋与地面接触，则可能存在氡气。并非所有的房屋都需要氡气系统；在全国范围内，每15所房屋中就有1所，即7%的房屋的室内氡浓度大于4 pCi/L（150 Bq/m） 3. ). 在最高状态下，71%的房屋室内氡大于4 pCi/L（150 Bq/m） 3. ). 在15个州，不到10%的房屋超过4 pCi/L（150 Bq/m） 3. ). 在六个州中，40%或更多的房屋室内氡超过4 pCi/L（150 Bq/m） 3. ). 州和地方司法机构以及个人业主最有能力决定在哪里建造具有降氡功能的房屋。

1.1 This practice covers the design and construction of two radon control options for use in new low-rise residential buildings. These unobtrusive (built-in) soil depressurization options are installed with a pipe route appropriate for their intended initial mode of operation, that is, fan-powered or passive. One of these pipe routes should be installed during a residential building ’ s initial construction. Specifications for the critical gas-permeable layer, the radon system ’ s piping, and radon entry pathway reduction are comprehensive and common to both pipe routes. 1.1.1 The first option has a pipe route appropriate for a fan-powered radon reduction system. The radon fan should be installed after (1) an initial radon test result reveals unacceptable radon concentrations and therefore a need for an operating radon fan, or (2) the owner has specified an operating radon fan, as well as acceptable radon test results before occupancy. Fan operated soil depressurization radon systems reduce indoor radon concentrations up to 99 %. 1.1.2 The second option has a more efficient pipe route appropriate for passively operated radon reduction systems. Passively operated radon reduction systems provide radon reductions of up to 50 %. When the radon test results for a building with an operating passive system are not acceptable, that system should be converted to fan-powered operation. Radon systems with pipe routes installed for passive operation can be converted easily to fan-powered operation; such fan operated systems reduce indoor radon concentrations up to 99 %. 1.2 The options provide different benefits: 1.2.1 The option using the pipe route for fan-powered operation is intended for builders with customers who want maximum unobtrusive built-in radon reduction and documented evidence of an effective radon reduction system before a residential building is occupied. Radon systems with fan-powered type pipe routes allow the greatest architectural freedom for vent stack routing and fan location. 1.2.2 The option using the pipe route for passive operation is intended for builders and their customers who want unobtrusive built-in radon reduction with the lowest possible operating cost, and documented evidence of acceptable radon system performance before occupancy. If a passive system ’ s radon reduction is unacceptable, its performance can be significantly increased by converting it to fan-powered operation. 1.3 Fan-powered, soil depressurization, radon-reduction techniques, such as those specified in this practice, have been used successfully for slab-on-grade, basement, and crawlspace foundations throughout the world. 1.4 Radon in air testing is used to assure the effectiveness of these soil depressurization radon systems. The U.S. national goal for indoor radon concentration, established by the U.S. Congress in the 1988 Indoor Radon Abatement Act, is to reduce indoor radon as close to the levels of outside air as is practicable. The radon concentration in outside air is assumed to be 0.4 picocuries per litre (pCi/l) (15 Becquerels per cubic metre (Bq/m 3 )); the U.S. ’ s average radon concentration in indoor air is 1.3 pCi/L (50 Bq/m 3 ). The goal of this practice is to make available new residential buildings with indoor radon concentrations below 2.0 pCi/L (75 Bq/m 3 ) in occupiable spaces. 1.5 This practice is intended to assist owners, designers, builders, building officials and others who design, manage, and inspect radon systems and their construction for new low-rise residential buildings. 1.6 This practice can be used as a model set of practices, which can be adopted or modified by state and local jurisdictions, to fulfill objectives of their residential building codes and regulations. This practice also can be used as a reference for the federal, state, and local health officials and radiation protection agencies. 1.7 The new dwelling units covered by this practice have never been occupied. Radon reduction for existing low rise residential buildings is covered by Practice E 2121 , or by state and local building codes and radiation protection regulations. 1.8 Fan-powered soil depressurization, the principal strategy described in this practice, offers the most effective and most reliable radon reduction of all currently available strategies. Historically, far more fan-powered soil depressurization radon reduction systems have been successfully installed and operated than all other radon reduction methods combined. These methods are not the only methods for reducing indoor radon concentrations (1-3) . 1.9 Section 7 is Occupational Radon Exposure and Worker Safety . 1.10 Appendix X1 is Principles of Operation for Fan-Powered Soil Depressurization Radon Reduction . 1.11 Appendix X2 is a Summary of Practice E 1465 Requirements for Installation of Radon Reduction Systems in New Low Rise Residential Building . 1.12 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.13 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== Fan-powered radon reduction systems built into new residential buildings according to this practice are likely to reduce elevated indoor radon levels, where soil-gas is the source of radon, to below 2.0 picocuries per litre (pCi/L) (75 becquerels of radon per cubic metre (Bq/m 3 )) in occupiable spaces. Passive radon reduction systems do not always reduce such indoor radon concentrations to below 2.0 picocuries per litre (pCi/L) (75 becquerels of radon per cubic metre (Bq/m 3 )) in occupiable spaces. When a passive system, built according to this practice, does not achieve acceptable radon concentrations, that system should be converted to fan-powered operation to significantly improve its performance. Exceptions — New residential buildings built on expansive soil and karst may require additional measures, not included in this practice, to achieve acceptable radon reduction. Consider consulting with a soil/geotechnical specialist, a qualified foundation structural engineer and contacting the state ’ s radon in air specialist for up-to-date information about construction methods. Names of your state radon specialist are available from the U.S. EPA website (http://www.epa.gov/radon). Note 1—Residences using private wells can have elevated indoor radon concentrations due to radon that out-gasses from the water used indoors, like water used to shower (7) . Consider contacting your state ’ s radon specialist for up-to-date information on available methods for removing radon from private well water. All soil depressurization radon reduction methods require a gas-permeable layer which can be depressurized. The gas-permeable layer is positioned under the building ’ s sealed ground cover. In the case of the active soil depressurization system, a radon fan pulls air up the vent stack to depressurize the gas-permeable layer. In the case of a passive soil depressurization system, when air in the vent stack is warmer than that outdoors, the warmer air rises in the stack causing the gas-permeable layer to be depressurized. The passive system depressurizes the gas-permeable layer intermittently; the fan-powered system depressurizes the gas-permeable layer continuously. The performance of gas-permeable layers depends on their design; see 6.4.1.3. A radon reduction system that operates passively requires the most efficient gas-permeable layer. U.S. EPA recommended action level concerning indoor radon states that the radon concentration should always be reduced if it is 4 picocuries per litre (pCi/L) (150 becquerels of radon per cubic metre (Bq/m 3 )) or above in occupiable spaces. According to U.S. EPA there is also reduced risk when radon concentrations in indoor air are lowered to below 2.0 picocuries per litre (pCi/L) (75 becquerels of radon per cubic metre (Bq/m 3 )) in occupiable spaces (4) . Significant benefit is obtained from reducing indoor radon concentrations to below 4 pCi/L (150 Bq/m 3 ). According to the U.S. EPA ’ s risk assessment (8) , about 62 out of 1000 people who smoke will die from a lifetime ’ s average radon exposure of 4 pCi/L (150 Bq/m 3 ); for people who never smoked about 7 out of 1000 will people die from the same lifetime exposure. Smokers ’ lifetime risk of death from lung cancer is reduced by about half (50 %) when their average radon exposure is reduced from 4 to 2 pCi/L (150 to 75 Bq/m 3 ); their risk is reduced by about two-thirds (67 %) when their exposure is reduced from 4 to 1.3 pCi/L (150 to 75 Bq/m 3 ). Never-smokers ’ lifetime risk of death from lung cancer is reduced by about 40 % when their average radon exposure is reduced from 4 to 2 pCi/L (150 to 75 Bq/m 3 ); the risk is reduced by 70 % when their exposure is reduced from 4 to 1.3 pCi/L (150 to 50 Bq/m 3 ). U.S. EPA recommended action level about reducing radon to less that 4 pCi/L (150 Bq/m 3 ) is “ Radon levels less than 4 pCi/L (150 Bq/m 3 ) still pose a risk, and in many cases may be reduced ” (4) . U.S. EPA recommendation is to “ Consider fixing between 2 and 4 pCi/L (75 and 150 Bq/m 3 ). ” (See radon reduction goals in 1.4 and 6.11.4.) This practice assumes that the customer is informed about the risks of lung cancer from exposure to radon and able to establish by contract the maximum acceptable indoor radon concentration allowed in the new residential building. Because there are goals and recommended action level but no government mandated maximum indoor radon concentration for new residential construction in the United States customers and their agents should negotiate to establish by contract the maximum acceptable indoor radon concentration. The customer should keep in mind that the building ’ s indoor radon concentration can never be less than the radon concentration in the outdoor air in the vicinity of the building; that establishing target radon levels below 2 pCi/L (75 Bq/m 3 ) could be more expensive; and that radon concentrations below 2 pCi/L (75 Bq/m 3 ) are difficult to measure using current commercially available technology. (See (4, 7) , 1.4, and 6.11.4.) The negotiated acceptable radon concentration defined by this standard can vary from customer to customer and contract to contract. The owner ’ s goal for radon reduction should be known and considered before the radon system design is specified. The construction choices for void space in the gas-permeable layer; vent stack pipe diameter and route; radon fan capacity; and building features influence the radon reduction system ’ s performance. (See 1.4, 3.2.1, 5.3, 5.4, 5.5, and 6.4.1.3.) This practice offers organized information about radon reduction methods. This practice cannot replace education and experience and should be used in conjunction with trained and certified radon practitioner's judgment. Not all aspects of this practice may be applicable in all circumstances. This practice is not intended, by itself, to replace the standard of care by which adequacy of a professional service may be judged, nor should this practice alone be applied without consideration of a project's unique aspects. The word “ Standard ” in the title of this practice means that the document has been approved through the ASTM consensus process. Reliable methods for predicting indoor radon concentrations for a particular residential building prior to its construction are not available at this time. If the house is in contact with the ground, it is possible for radon gas to be present. Not all houses will need a radon system; nationally, 1 out of 15, or 7 % of the houses have indoor radon concentrations greater than 4 pCi/L (150 Bq/m 3 ). In the highest state 71 % of the houses have indoor radon greater than 4 pCi/L (150 Bq/m 3 ). In fifteen states less than 10 % of the houses are over 4 pCi/L (150 Bq/m 3 ). In six states 40 % or more of the houses have indoor radon over 4 pCi/L (150 Bq/m 3 ). State and local jurisdictions and individual owners are in the best position to decide where houses with radon reduction features should be built.