1.1 本指南涵盖了进行财产复原力评估(PRA)的通用、系统方法，包括三个阶段:第一阶段，确定可能影响财产的自然灾害；第二阶段，评估这些危害带来的风险以及目标物业准备、适应、承受和恢复这些危害的能力；第三阶段，确定潜在的概念性弹性措施，以提高物业层面的绩效。PRA至少包括对居住者安全、损坏、功能恢复时间的基线评估，以及对社区复原力或其他物质依赖性的有限考虑。 1.2 背景- 该指南的目的是提高人们对评估财产级多种危害风险和财产-可以提高目标财产的绩效和恢复的具体弹性措施，以及提高对社区和基础设施考虑作为潜在额外调查领域的重要性的认识（超出本指南的范围）。本指南可用于各种结构和基础设施，尽管一些专业设施可能需要额外的专业知识。由于复原力的概念广泛适用于气候变化考虑之外，而且由于灾害在财产层面上相互作用，PRA过程包括对广泛的灾害的评估，包括与气候变化有关、因气候变化而加剧和不相关的灾害。 1.3 自然灾害- 本指南涉及的危害包括以下内容: 1.3.1 极端温度、降雪和冰雹:1.3.1.1 极端温度: (1) 冷； (2) 热度。 1.3.1.2 极端降雪和冰雹: (1) 大雪； (2) 冰雹。 1.3.2 地质现象: (1) 地震； (2) 滑坡； (3) 地面沉降； (4) 海岸侵蚀。 1.3.3 水: 1.3.3.1 沉淀: (1) 强降雨； (2) 干旱； (3) 风驱动的雨； (4) 冻雨； (5) 雪上的雨； (6) 冻融。 1.3.3.2 洪水: (1) 风暴潮； (2) 沿海洪水； (3) 河流洪水（河流）； (4) 地表洪水（雨水）。 1.3.4 野火: (1) 火焰暴露； (2) 吹过的余烬； (3) 抽烟。 1.3.5 风: (1) 热带气旋（飓风）； (2) 冬季风暴； (3) 严重雷暴和龙卷风； (4) 局部或区域风。 1.4 目标- 本指南的目标是:（ 1 )为进行和准备PRAs制定切实可行且合理的步骤；( 2 )协助制定适当研究和观察的行业基准标准；( 3 ）促进高质量的标准化PRAs；和（ 4 ）建立指南，通过这些指南，提供者可以以有意义和透明的方式向用户传达观察结果、意见和结论。 1.5 应用- 本指南可用于本文概述的目的，也可由中定义的用户使用 3.2.11 谁可以在房地产投资尽职调查、开发、投资组合风险分析、气候风险分析和报告、自然灾害识别和准备、设施管理、资本规划、运营和维护、承保或融资活动期间获得PRA。本指南中概述的评估目的、目标和过程不限于任何一个地区、地区或国家。使用的应用可能会有所不同，包括: 1.5.1 气候-相关风险报告- 许多组织和司法管辖区正在制定建议、指南和标准，以应对与气候变化相关的财产物理风险和复原力。由于这些风险因地区而异，因此保持一致的评估方法、术语和披露相关输出至关重要。国际标准化组织（ISO）、气候相关财务披露工作组（TCFD）和国际财务报告准则（IFRS）基金会等组织已经制定了评估、量化和减轻气候相关风险的建议、指南和标准。 1.5.2 自然灾害风险、灾难恢复和复原力评估- 许多组织已经制定或正在制定自然灾害风险、灾难恢复和复原力评估指南。诸如但不限于国家和社区复原力联盟(ANCR)、美国土木工程师协会(ASCE)、国土安全部(DHS)、国际规范委员会(ICC)、联邦紧急事务管理局(FEMA)、国家建筑科学研究所(NIBS)、国家标准与技术研究所(NIST)、联合国减少灾害风险办公室(UNDRR)、世界银行复原力建筑法规(BRR)等组织已经制定了关于识别危害、评估风险和增强复原力的指南。 1.5.3 补充申请- 在可行的范围内，本指南旨在补充现有和未来与气候和自然灾害相关的风险和复原力评估指南、框架和标准，以促进评估财产复原力的一致方法，无论其位置如何。本指南无意取代现有的指南或计划。PRA中生成的信息旨在尽可能支持这些计划并与之保持一致。作为工作范围的一部分，本指南中没有任何内容会阻止用户要求超过基线PRA来满足其需求。虽然本指南的大部分内容都集中在美国，但本指南的使用并不限于任何一个地区或国家。然而，应当指出，在其他区域也可能存在地理差异。本指南还旨在补充涉及现有ASTM标准（包括实践）的现有属性决策过程 E1527 ,指南 E2018 ，和指南 E2026 .参考 8.3.2.4 (1) 有关地震风险评估和PRA的更多信息。1.6 灵活性和透明度- 根据用户对PRA的预期应用以及所需的置信度，评估的深度可能会有所不同。例如，物业组合内的选址筛选或风险意识可能比财务披露、风险量化以及制定特定场地的改造和弹性策略需要更少的严谨性。该指南提供了与用户目标保持一致的灵活性，并强调PRA专业人员参与和完成的评估深度的透明度。 1.7 超出范围的考虑因素- 本指南的使用严格限于本文阐述的范围。本指南不涉及以下内容: 1.7.1 中未列出的危害和危害的影响 1.3 . 1.7.2 联邦或州、地方、部落或地区（SLTT）关于建筑施工或维护的法律法规。请用户注意，当前的联邦或SLTT法律法规可能与建筑物最初建造时有效的法律法规不同。 1.7.3 用于复原力和气候适应的先进（或基于性能的）设计。 1.7.4 社会经济因素。 1.7.5 运输和公用事业基础设施，除非另有说明 6.17 . 1.7.6 直接的人为影响，如恐怖主义和故意破坏。 1.7.7 自然灾害或气候变化的原因。 1.7.8 次生危害，如污染和害虫，可能存在于地方、区域或国家的基础上。 1.7.9 转型风险、文化影响、环境正义或对整个社会的影响。1.7.10 广泛的可持续性考虑或与减缓气候变化相关的报告要求，如温室气体排放报告，除非 9.11.8 （参见指南 E2725 ）和财务披露（参见指南 E2718 ). 1.7.11 PRA仅旨在提供概念级弹性措施和大致数量级的成本。在某些情况下，在完成PRA后，可能需要由合格的专业人员进行额外的研究或分析，以确定在目标物业实施的适当弹性措施。详细的工程和设计图纸以及详细的成本估算不包括在PRA范围内。 1.7.12 此列表并不全面，超出范围的其他注意事项见 8.7 . 1.8 本指南的组织-本指南由几个部分和附录组成。附录仅供参考，以帮助实施本指南。 1.8.1 部分 1 描述范围。 1.8.2 部分 2 识别参考标准。 1.8.3 部分 3 提供本指南独有和非独有的术语。 1.8.4 部分 4 阐述本指南的意义和用途。 1.8.5 部分 5 描述进行PRA的人员的资格。 1.8.6 部分 6 包含PRA评估方法和途径的摘要。 1.8.7 章节 7 通过 9 深入讨论PRA的三个阶段。 1.8.8 附录X1 提供特定于危险和其他与复原力相关的资源列表。 1.8.9 附录X2 提供与每种危险相关的建筑注意事项。 1.8.10 附录X3 提供危险专家的资格（如果使用），如中所述 5.2 . 1.8.11 附录X4 提供有关用户参与的更多详细信息。 1.8.12 附录X5 提供详细PRA报告的推荐内容。 1.8.13 附录X6 提供特定于危险的映射和建模讨论。 1.8.14 附录X7 提供关于气候和自然灾害地图和模型的更多细节。 1.8.15 附录X8 讨论级联和复合危害。 1.8.16 附录X9 提供风险和收益成本分析方法的示例。 1.8.17 附录X10 概述了每种灾害的复原力和适应措施示例。 1.8.18 附录X11 提供更多关于考虑社区复原力的信息。 1.8.19 文件末尾提供了参考文献和引文。1.9 单位- 以SI单位表示的值将被视为标准值。SI单位后括号中给出的值仅供参考，不被视为标准值。 1.10 本指南是信息概要。ASTM指南旨在提高对给定主题领域的信息、方法和现有标准的认识。本文件不能取代教育或经验，应结合专业判断使用。并非本指南的所有方面都适用于所有情况。本ASTM标准并不代表或取代必须判断给定专业服务是否充分的护理标准，也不应在不考虑项目的许多独特方面的情况下应用本文件。标题中的“标准”一词仅意味着该文件已通过ASTM共识程序获得批准。1.11 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.12 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ======意义和用途====== 4.1 本指南旨在供房地产投资者、业主、运营商、贷款人和保险公司（用户）等各方自愿使用，他们希望更好地了解可能影响财产的自然灾害，包括因气候变化而变得更加极端的自然灾害。用户可以包括目标物业的购买者、租户、所有者、投资者、贷款人、开发商、设计师、建筑专业人员或物业经理。考虑到用户的需求，本指南概述了为特定用户进行PRA的程序。 4.2 用途- 本指南可用于上述目的，也可由中定义的用户使用 3.2.4 谁可以在房地产投资、开发、风险管理和报告、设施管理、资本规划、运营和维护、承保或融资活动中获得PRA。作为其工作范围或审批流程的一部分，本指南中没有任何内容会阻止用户要求超过基线PRA来满足其需求。 4.3 调查类型- 本指南提供了执行PRA的建议方法。用户可以仅在阶段1 PRA中签订阶段1合同，或者从阶段1到阶段3的整个过程。用户还可以为单个建筑、多个建筑或物业组合签订PRA合同（参见 6.3 ).虽然PRA指南的大部分内容是针对现有建筑的PRA流程，但假设提供了足够的设计细节，PRA流程也可以应用于计划开发、新建筑和重大改造项目。此外，本指南可用于各种结构和基础设施，尽管一些专业设施可能需要额外的专业知识。 4.4 报告的应用和时间相关性- 用户应仅将PRA用于预期的特定目的，并在确认目标物业处于评估时的状态，并且PRA中评估的考虑因素没有发生重大变化后。此外，由于气候条件的不断变化以及持续的运营和维护考虑，PRA的有效期有限。超过12个月的PRA，或自PRA发布以来受重大灾害事件影响或自然灾害资源（如洪水地图）重大更新的目标财产的PRA，不应再被视为可靠，除非PRA专业人员确定上述内容没有导致重大变化，并且PRA仍然有效。本指南的目的不是用户需要每年将当前的PRA存档，而是如果正在做出决定，超过12个月的PRA可能不可靠。 4.5 信息的可用性- 本指南认识到，提供者的意见和观察可能会受到提供者在PRA过程中随时可用的信息的影响或取决于提供者。例如，提供者的观察可能会受到使用建筑物的人数或提供信息的物业管理的可用性的影响，例如详细的建筑物施工信息、立面图证书或施工文件。 4.6 特定属性- PRA是特定于物业的，因为它们与单个物业、单个地点的多个改进或物业组合相关。虽然本指南中的评估实践通常是针对特定物业的，但本指南中没有任何内容会阻止PRA专业人员在第一阶段对物业组合进行危害筛查。然后，为阶段2和阶段3选择的属性应接收单独的PRA报告，如中进一步讨论的 4.7.3 和 6.3 . 4.7 原则- 以下原则是本指南不可或缺的一部分，在解决任何歧义或行使授予用户或提供商的自由裁量权时应参考。这些原则也应用于判断用户或提供者是否进行了适当的PRA。 4.7.1 不确定性未消除- 任何评估都无法完全量化或完全消除对财产的危害和潜在风险的不确定性，尤其是对未来气候条件的估计。本指南中描述的连续调查阶段旨在减少但不消除不确定性。本指南承认与选定评估阶段相关的合理时间和成本限制。 4.7.2 并非详尽无遗- 在某一点上，收集信息的成本超过了信息的有用性，事实上，可能不利于在可用于支持调查的资源范围内有序完成交易。本指南承认这一点，并建议在限制成本和时间需求与通过获取尽可能多的信息来限制由此产生的不确定性这两个相互竞争的目标之间寻求平衡。 4.7.3 评估范围- 不是每一处房产都需要相同程度的评估。根据良好的商业或习惯惯例，选择适当的评估范围以待评估目标物业的类型和年龄、可用资源和时间、预期的危害和风险、用户的专业知识和风险承受能力以及PRA期间开发的信息为指导。用户可以选择与PRA专业人员合作，对物业组合进行第一阶段PRA筛选，然后随着时间的推移，仅针对那些根据用户的目的和风险阈值被确定为关注的网站完成PRA流程的第二阶段和第三阶段。本指南提供了与用户目标保持一致的灵活性，并强调PRA专业人员参与和完成的评估深度的透明度。其他信息见 附录X4 . 4.7.4 随后使用PRA- 本指南认识到，基于本文讨论的方法对建筑物的评估可能包括后续用户希望使用的信息，以避免进行重复的调查。因此，除了本指南中规定的具体程序外，还应遵守以下原则，使用先前报告。 4.7.4.1 事先信息的使用- 先前报告中包含的信息可能有助于了解目标物业和规划当前PRA，但仅应作为对提供者的帮助，并应在完成当前评估期间进行验证。如中所述，如果没有对可能影响结果的条件进行当前调查，则不应使用既往PRAs 4.4 . 4.7.4.2 使用先前的评估- 目标、信息和评估方法可能会随着时间的推移而改变。如果根据PRA专业人员的判断，先前报告的编制符合或超过了本指南当前版本的要求，并且PRA考虑因素自先前报告编制以来不太可能发生重大变化，则可完整使用为特定评估阶段编制的先前PRA，而不考虑本指南中规定的特定程序。在做出这一判断时，PRA专业人员应考虑先前报告的范围和局限性，以及与危险、建筑物或目标财产相关的任何新信息，以及当前的现场条件。4.7.4.3 实际知识例外- 如果用户或PRA专业人员实际知道使用的来自先前PRA的信息不准确或怀疑不准确，则不应使用来自先前报告的此类信息。

1.1 This guide covers a generalized, systematic approach for conducting a Property Resilience Assessment (PRA) consisting of three stages: Stage 1, identifying the natural hazards likely to affect a property; Stage 2, evaluating the risks posed by those hazards along with the capacity of the target property to prepare for, adapt to, withstand, and recover from those hazards; and Stage 3, identifying potential conceptual resilience measures to enhance property-level performance. The PRA includes, at minimum, a baseline assessment of occupant safety, damage, functional recovery time, and a limited consideration of community resilience or other material dependencies. 1.2 Background— The intent of the guide is to increase the awareness of methods to assess property-level multi-hazard risks and property-specific resilience measures that can enhance performance and recovery of the target property, as well as to enhance awareness of the importance of community and infrastructure considerations as potential additional areas of inquiry (beyond the scope of this guide). This guide may be used for a broad variety of structures and infrastructure, though some specialized facilities may require additional expertise. Since the concept of resilience applies broadly beyond climate change considerations and since hazards interact at the property level, the PRA process includes evaluation of a broad range of hazards, including those related to, exacerbated by, and unrelated to climate change. 1.3 Natural Hazards— Hazards addressed in this guide include the following: 1.3.1 Extreme Temperature, Snow, and Hail: 1.3.1.1 Extreme Temperature: (1) Cold; (2) Heat. 1.3.1.2 Extreme Snow and Hail: (1) Heavy snow; (2) Hail. 1.3.2 Geologic Phenomenon: (1) Seismic; (2) Landslide; (3) Land Subsidence; (4) Coastal erosion. 1.3.3 Water: 1.3.3.1 Precipitation: (1) Heavy rainfall; (2) Drought; (3) Wind-driven rain; (4) Freezing rain; (5) Rain on snow; (6) Freeze-thaw. 1.3.3.2 Flood: (1) Storm surge; (2) Coastal flood; (3) Riverine flood (fluvial); (4) Surface flood (pluvial). 1.3.4 Wildfire: (1) Flame exposure; (2) Blown embers; (3) Smoke. 1.3.5 Wind: (1) Tropical cyclone (hurricane); (2) Winter storm; (3) Severe thunderstorm and tornado; (4) Local or regional wind. 1.4 Objectives— The objectives of this guide are to: ( 1 ) develop practical and reasonable steps for conducting and preparing PRAs; ( 2 ) assist in developing an industry baseline standard for appropriate research and observations; ( 3 ) facilitate high-quality standardized PRAs; and ( 4 ) establish guidelines by which a provider can communicate observations, opinions, and conclusions to a user in a manner that is meaningful and transparent. 1.5 Application— This guide may be used for the purposes outlined herein and by the users defined in 3.2.11 who may obtain a PRA during real estate investment due diligence, development, portfolio risk analysis, climate risk analysis and reporting, natural hazard identification and preparedness, facilities management, capital planning, operations and maintenance, underwriting or financing activities. The purpose, goals, and processes of evaluation outlined within this guide are not limited to any one area, region, or country. The applications for use may vary, including: 1.5.1 Climate-Related Risk Reporting— Many organizations and jurisdictions are developing recommendations, guidance, and standards to address climate change-related property physical risks and resilience. As these risks vary by region, it is critical to maintain consistent assessment methodology, terminology, and disclosure-related outputs. Organizations such as, but not limited to, the International Organization for Standardization (ISO), Task Force on Climate-Related Financial Disclosures (TCFD), and International Financial Reporting Standards (IFRS) Foundation have developed recommendations, guidance, and standards to assess, quantify, and mitigate climate-related risks. 1.5.2 Natural Hazard Risk, Disaster Recovery, and Resilience Assessments— Many organizations have developed or are developing natural hazard risk, disaster recovery, and resilience assessment guidance. Organizations such as, but not limited to, the Alliance for National and Community Resilience (ANCR), American Society of Civil Engineers (ASCE), Department of Homeland Security (DHS), International Code Council (ICC), Federal Emergency Management Agency (FEMA), National Institute of Building Sciences (NIBS), National Institute for Standards and Technology (NIST), United Nations Office for Disaster Risk Reduction (UNDRR), World Bank Building Regulation for Resilience (BRR), and others, have developed guidance on identifying hazards, evaluating risk, and enhancing resilience. 1.5.3 Complementary Application— This guide, to the extent feasible, is intended to complement existing and future climate and natural hazard-related risk and resilience assessment guidelines, frameworks, and standards to facilitate a consistent approach to evaluating property resilience, regardless of location. This guide is not intended to replace existing guidance or programs. The information generated in a PRA is intended to be supportive of and aligned with those programs, to the extent possible. There is nothing in this guide that would prevent users from requiring more than a baseline PRA to meet their needs as part of the scope of work. Although most of the context of this guide is focused on the United States, the use of this guide is not limited to any one area or country. It should be noted, however, that geographical variances are possible in other regions. This guide is also intended to complement existing property decision-making processes involving existing ASTM standards, including Practice E1527 , Guide E2018 , and Guide E2026 . Refer to 8.3.2.4 (1) for additional information regarding seismic risk assessment and the PRA. 1.6 Flexibility and Transparency— Depending on the intended application of the PRA by the user, as well as the level of confidence required, the depth of assessment may vary. For example, site selection screening or risk awareness within a portfolio of properties may require less rigor than financial disclosures, risk quantification, and development of site-specific retrofit and resilience strategies. The guide provides flexibility to align with the user’s goals and objectives and emphasizes transparency in the depth of assessment engaged and completed by the PRA professional. 1.7 Considerations Beyond Scope— The use of this guide is strictly limited to the scope set forth herein. This guide does not address the following: 1.7.1 Hazards and the effects of hazards not listed in 1.3 . 1.7.2 Federal or state, local, tribal, or territorial (SLTT) laws and regulations of building construction or maintenance. Users are cautioned that current federal or SLTT laws and regulations may differ from those in effect at the time of the original construction of the building(s). 1.7.3 Advanced (or performance-based) design for resilience and climate adaptation. 1.7.4 Socio-economic factors. 1.7.5 Transportation and utility infrastructure, except as noted in 6.17 . 1.7.6 Direct human-caused impacts such as terrorism and vandalism. 1.7.7 The causes of natural hazards or climate change. 1.7.8 Secondary hazards such as pollution and pests which may be present on a local, regional, or national basis. 1.7.9 Transitional risks, cultural impacts, environmental justice, or impacts to society in general. 1.7.10 Broad sustainability considerations or climate change mitigation-related reporting requirements such as greenhouse gas emission reporting, except as noted in 9.11.8 (refer to Guide E2725 ) and financial disclosures (refer to Guide E2718 ). 1.7.11 The PRA is only intended to provide concept-level resilience measures and rough order of magnitude costs. In some cases, additional study or analysis by a qualified professional may be required following the completion of the PRA to determine the appropriate resilience measures to implement at the target property. Detailed engineering and design drawings and detailed cost estimates are not included within the PRA scope. 1.7.12 This list is not comprehensive, and additional considerations beyond scope are noted in 8.7 . 1.8 Organization of This Guide— This guide consists of several sections and appendices. The appendices are included for informational purposes only to assist with implementing this guide. 1.8.1 Section 1 describes the scope. 1.8.2 Section 2 identifies referenced standards. 1.8.3 Section 3 provides terminology both unique and not unique to this guide. 1.8.4 Section 4 sets out significance and use of this guide. 1.8.5 Section 5 describes qualifications of those conducting a PRA. 1.8.6 Section 6 contains a summary of the PRA Assessment Methodology and Approach. 1.8.7 Sections 7 through 9 provide in-depth discussion of the three stages of the PRA. 1.8.8 Appendix X1 provides a list of hazard-specific and other resilience-related resources. 1.8.9 Appendix X2 provides building considerations related to each of the hazards. 1.8.10 Appendix X3 provides qualifications of the hazard specialist, if utilized, as noted in 5.2 . 1.8.11 Appendix X4 provides greater detail on user engagement. 1.8.12 Appendix X5 provides recommended content of a detailed PRA report. 1.8.13 Appendix X6 provides hazard-specific mapping and modeling discussion. 1.8.14 Appendix X7 provides further detail on climate and natural hazard maps and models. 1.8.15 Appendix X8 provides a discussion of cascading and compounding hazards. 1.8.16 Appendix X9 provides example risk and benefit-cost analysis methodologies. 1.8.17 Appendix X10 outlines example resilience and adaptation measures for each of the hazards. 1.8.18 Appendix X11 provides more information regarding consideration of community resilience. 1.8.19 References and citations are provided at the end of the document. 1.9 Units— The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.10 This guide is a compendium of information. ASTM guides are intended to increase the awareness of information, approaches, and existing standards in a given subject area. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title means only that the document has been approved through the ASTM consensus process. 1.11 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.12 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This guide is intended for use on a voluntary basis by parties such as real estate investors, owners, operators, lenders, and insurers (users) who wish to better understand the natural hazards, including those made more extreme by climate change, that may be affecting a property. A user may include a purchaser, tenant, owner, investor, lender, developer, designer, building professional, or property manager of the target property. This guide outlines procedures for conducting a PRA for specific users, considering the user’s requirements. 4.2 Uses— This guide may be used for the purposes outlined above and by the users defined in 3.2.4 who may obtain a PRA during real estate investment, development, risk management and reporting, facilities management, capital planning, operations and maintenance, underwriting or financing activities. There is nothing in this guide that would prevent a user from requiring more than a baseline PRA to meet its needs as part of its scope of work or approval process. 4.3 Types of Investigations— This guide provides suggested approaches for the performance of the PRA. A user may contract for Stage 1 only in a Stage 1 PRA, or the entire process from Stage 1 through 3. A user may also contract for a PRA for a single building, multiple buildings, or a portfolio of properties (see 6.3 ). Although much of the PRA guide is directed to the PRA process for existing buildings, the PRA process can also be applied to planned development, new construction, and substantial renovation projects assuming sufficient design detail is provided. In addition, this guide may be used for a broad variety of structures and infrastructure, though some specialized facilities may require additional expertise. 4.4 Application and Temporal Relevance of Report— The user should only rely on the PRA for the specific purpose that it was intended and upon confirmation that the target property is in the condition it was at the time of assessment and that the considerations evaluated within the PRA have not materially changed. In addition, due to the evolving nature of climate conditions and ongoing operations and maintenance considerations, a PRA has a limited time of effectiveness. A PRA over 12 months old, or a PRA for a target property impacted by a significant hazard event or subject to significant updates to natural hazard resources (such as flood maps) since the PRA was issued, should no longer be considered reliable unless a PRA professional has determined that the above resulted in no material changes and the PRA remains valid. The intent of this guidance is not that users would need to maintain a current PRA on file annually, but rather that if decisions are being made, a PRA older than 12 months may not be reliable. 4.5 Availability of Information— This guide recognizes that a provider’s opinions and observations may be affected by or contingent on information that is readily available for the provider during the PRA process. For instance, a provider’s observations may be affected by the number of people using the building or the availability of property management to provide information, such as detailed building construction information, elevation certificates, or construction documents. 4.6 Property-Specific— PRAs are property-specific in that they relate to a single property, multiple improvements at a single site, or a portfolio of properties. While the evaluation practices in this guide are generally property-specific, there is nothing in this guide that would prevent a PRA professional from conducting a hazard screening of a portfolio of properties in Stage 1. Properties selected for Stages 2 and 3 should then receive individual PRA reports, as further discussed in 4.7.3 and 6.3 . 4.7 Principles— The following principles are an integral part of this guide and should be referred to in resolving any ambiguity or exercising such discretion as is accorded to the user or the provider. The principles should also be used in judging whether a user or provider has conducted an appropriate PRA. 4.7.1 Uncertainty Not Eliminated— No assessment can fully quantify or wholly eliminate uncertainty regarding the hazards and potential risks to a property, especially with respect to estimates of future climate conditions. The successive stages of investigation described in this guide are intended to reduce, but not eliminate, uncertainty. This guide acknowledges the reasonable limits of time and cost related to a selected stage of assessment. 4.7.2 Not Exhaustive— There is a point at which the cost of gathering information outweighs the usefulness of the information and, in fact, may be detrimental to the orderly completion of transactions within the resources available to support the investigation. This guide acknowledges this and suggests that a balance be sought between the competing goals of limiting the costs and time demands versus limiting the resulting uncertainty by acquiring as much information as possible. 4.7.3 Assessment Scope— Not every property warrants the same extent of assessment. Consistent with good commercial or customary practice, choosing the appropriate scope of assessment is guided by the type and age of the target property subject to assessment, the resources and time available, the anticipated hazards and risks, the expertise and risk tolerance of the user, and the information developed during the PRA. Users may choose to work with a PRA professional to conduct Stage 1 PRA screenings of a portfolio of properties, and then over time, complete Stage 2 and 3 of the PRA process only for those sites that are identified as a concern based on the user’s purposes and risk thresholds. This guide provides flexibility to align with the user’s goals and objectives and emphasizes transparency in the depth of assessment engaged and completed by the PRA professional. Additional information is provided in Appendix X4 . 4.7.4 Subsequent Use of the PRA— This guide recognizes that assessments of buildings based on the approaches discussed herein may include information that subsequent users will want to use to avoid undertaking duplicative investigations. Consequently, usage of prior reports is based on the following principles that should be adhered to in addition to the specific procedures set forth in this guide. 4.7.4.1 Use of Prior Information— Information contained in prior reports may be helpful to assist in understanding the target property and planning the current PRA but should serve only as an aid to the provider and should be verified during completion of a current assessment. Prior PRAs should not be used without current investigation of conditions likely to affect the findings, as discussed in 4.4 . 4.7.4.2 Use of Prior Assessments— Objectives, information, and evaluation methods may change over time. A prior PRA prepared for specific stages of assessment may be used in its entirety, without regard to specific procedures set forth in this guide, if, in the judgment of the PRA professional, the prior report was prepared meeting or exceeding the requirements of the current version of this guide and the PRA considerations are not likely to have changed materially since the prior report was prepared. In making this judgment, the PRA professional should consider the scope and limitations of the prior report, and any new information related to the hazards, building or target property, as well as current site conditions. 4.7.4.3 Actual Knowledge Exception— If the user or the PRA professional has actual knowledge that the information being used from a prior PRA is not accurate or suspected of being inaccurate, then such information from a prior report should not be used.