NFPA 59A Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG) requires facilities to have the equipment necessary for the detection and control of fires, leaks and spills of hazardous materials, yet provides no requirements or guidance on the location of the detectors. Literature available in the public domain outlines key factors to consider in developing layouts for flame and gas detectors, but a methodology to use this information in evaluating a hazard detector layout is not clearly defined; instead, generic and non-quantifiable terminology such as “quick and reliable” is often used. As a result, there is no consistent approach to developing flame and gas detector layouts for land-based LNG facilities and there is no systematic method for regulators to evaluate these designs. The ability to quantify hazard detector performance and define performance targets are of particular interest to the Department of Transportation (DOT) Pipeline and Hazardous Materials Safety Administration (PHMSA), which regulates numerous LNG facilities in the United States. Blue Engineering and Consulting is working on a DOT-PHMSA sponsored project to develop a risk-based approach and criteria for hazard detector layouts at LNG facilities. This project builds upon performance-based design principles outlined in NFPA 72 National Fire Alarm and Signaling Code and the International Society of Automation (ISA) technical report 84.00.07 Guidance on the Evaluation of Fire, Combustible Gas, and Toxic Gas System Effectiveness. The methodology divides the LNG facility into Detection Areas based on the hazards present and the plant layout, identifies the appropriate hazard scenarios to evaluate the detector layout, establishes performance targets for each Detection Area, and quantifies hazard detector coverage. This paper will describe and demonstrate the proposed methodology. It should be noted that, while performance targets must be chosen for the purposes of the demonstrative included in this paper, these targets should not be interpreted as requirements of DOT-PHMSA nor as acceptable to them.

中文翻译：

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太多还是不够？评估液化天然气设施火灾和气体探测器布局的方法

NFPA 59A液化天然气 (LNG) 生产、储存和处理标准要求设施具有检测和控制危险材料的火灾、泄漏和溢出所需的设备，但没有对探测器的位置提供任何要求或指导。公共领域可用的文献概述了在开发火焰和气体探测器布局时要考虑的关键因素，但没有明确定义使用这些信息评估危险探测器布局的方法；相反，经常使用通用和不可量化的术语，例如“快速可靠”。因此，为陆基 LNG 设施开发火焰和气体探测器布局没有一致的方法，监管机构也没有系统的方法来评估这些设计。交通部 (DOT) 管道和危险材料安全管理局 (PHMSA) 对量化危险探测器性能和定义性能目标的能力特别感兴趣，该管理局负责监管美国的众多 LNG 设施。Blue Engineering and Consulting 正在开展 DOT-PHMSA 赞助的项目，为 LNG 设施的危险探测器布局开发基于风险的方法和标准。该项目建立在 NFPA 72 中概述的基于性能的设计原则之上国家火灾警报和信号规范和国际自动化学会 (ISA) 技术报告 84.00.07火灾、可燃气体和有毒气体系统有效性评估指南。该方法根据存在的危害和工厂布局将 LNG 设施划分为检测区域，确定适当的危害场景以评估检测器布局，为每个检测区域建立性能目标，并量化危害检测器的覆盖范围。本文将描述和演示所提出的方法。应该注意的是，虽然必须为本文中包含的演示目的选择性能目标，但这些目标不应被解释为 DOT-PHMSA 的要求，也不应被他们接受。