国际电工委员会第89技术委员会动态介绍

介绍了ＩＥＣ组织、ＩＥＣＴＣ８９的最新工作开展情况及其制修订标准的主要内容。     

Addressing the challenges of implementing safety instrumented systems in multi-product batch processes

Adapting the requirements of IEC 61511 to a batch system can be frustrating, particularly for multi-product units. While a Safety Instrumented System (SIS) for continuous operation is often a straightforward detect-decide-act loop, implementing a SIS for a batch system may involve multiple safety functions, time- or state-dependence, intricate calculations, or complex installations. Relationships between the SIS elements and the basic process control system (BPCS) must be tightly managed, providing both for the safety of the unit and its ability to operate without spurious trips or other hindrances. These issues are further complicated when multiple products requiring different functions or setpoints are produced in the same SIS-protected batch unit.This paper will discuss the challenges particular to the design, operation, and maintenance of a SIS in multi-product batch operations and present practical options for successfully resolving the concerns. A key insight into successful adaptation is treating the batch SIS as a “permission” system for the BPCS to operate. Although many items can be addressed through clever engineering practices, sustainable success relies on proactive, robust management of the safety lifecycle.     

Procedure for assessing hardware safety integrity in legacy systems

Functional safety is related to the safety functions of a safety-related system that uses electrical/electronic/programmable (E/E/PE) devices such as sensors, logic solvers, and final elements. A legacy system is a safety-related system which offers safety functions but which was not designed to comply with the IEC 61508 standard. This paper presents a procedure for assessing the hardware safety integrity of a legacy system so as to confirm its functional safety. The procedure defines the systematic relationship between the safety function and hardware system using a function-structure map (FSM) and assesses the hardware safety integrity centered on the safety function. The proposed procedure is applied to a boiler control system of a fossil-fuel power plant.     

IEC61511标准及在石化行业安全管理中的应用

功能安全的定量评定技术已成为确保石化行业安全生产的重要手段。针对石化行业普遍存在的功能安全问题,笔者以国际电工学会(IEC)专门制定的功能安全评定标准IEC61508及IEC61511为指导,介绍其标准制定的背景、目的、体系结构以及如何利用标准开展石化行业安全联锁系统(Safety Instrumented System,SIS)的安全与误跳车定量分析。通过对SIS开展定量安全评估,可发现联锁功能存在的安全不足与误跳车现象,对于提高我国石化行业安全生产水平具有重要的促进作用,标准中有关寿命周期功能安全管理方法及重要的工程经验也对提高我国石化安全生产水平具有借鉴作用。     

IEC 60068-2-5中辐照度和温度的解读

为了更好解读IEC 60068-2-5:2010中的辐照度和温度设定,及如何执行该标准,结合标准中对辐照度和温度设定的要求,提供具体的解决方案。建议在执行标准时,应使用日光过滤片来过滤氙灯光源,实现该标准对光源的要求。同时建议使用340 nm点控制,辐照度设定为0.60 W/m2@340 nm。对于温度的设定,建议按照标准中图2的温度上升、下降与时间的关系,对其进行设定。另外,标准中程序A的循环接近最严酷的自然条件,而程序B和程序C的循环比程序A的严酷很多。因此,一般情况下推荐程序A,对于耐候性好的材料,需要加速测试的,推荐程序B。     

An evaluation approach using a HARA and FMEDA for the hardware SIL

Safety instrumented systems (SIS) are becoming increasingly complex, and form a growing proportion of programmable electronic parts. The IEC 61508 global standard was established to ensure the functional safety of SIS; however, it was expressed in highly macroscopic terms. The safety integrity level (SIL) is a criterion describing whether a component meets the safety requirements of a SIS. The safety requirements give a target SIL for the expected risks using hazard analysis and risk assessment (HARA). The SIL must correspond to the safety requirements. This study introduces an evaluation process for determining the hardware SIL through failure modes, effects, and diagnostic analysis (FMEDA). First, the components of the SIS subsystem are defined in terms of failure modes and effects, and then the failure rate and failure mechanism distribution are assigned to each component. The safety mode and detectability of each failure mode are determined for each component and, finally, the hardware SIL is evaluated. We perform a case study to evaluate the hardware SIL of the flame scanner system using HARA and FMEDA, where the safety requirement of the flame scanner was determined using the risk graph method. We verified that the hardware SIL of the flame scanner corresponded to the safety requirement.     

PESD测试中静电枪表现的性能的研究

在本文中,我们介绍了两种不同类型的ESD静电枪(ESS-200AX和ESD 3000),分别用两种ESD静电枪对芯片进行抗干扰度测试,研究两种类型的ESD静电枪对同种样本芯片表现的性能。结果显示,对于完全符合IEC 61000-4-2要求的不同的ESD静电枪表现出不完全的一致性。为了比较IC的ESD性能,我们目前主要采用同一系列的芯片采用相同的ESD静电枪进行测试。     

SIL determination: Recognising and handling high demand mode scenarios

The International Standards for Functional Safety (IEC 61508 and IEC 61511) are well recognised and have been adopted globally in many of the industrialised countries during the past 10 years or so. Conformance with these standards involves determination of the requirements for instrumented risk reduction measures, described in terms of a safety integrity level (SIL). During this period within the process sector, layer of protection analysis (LOPA) has become the most widely used approach for SIL determination. Experience has identified that there is a type of hazardous event scenario that occurs within the process sector that is not well recognised by practitioners, and is therefore not adequately handled by the standard LOPA approach. This is when the particular scenario places a high demand rate on the required safety instrumented function. This paper will describe how to recognise a high demand rate scenario. It will discuss what the standards have to say about high demand rates. It will then demonstrate how to assess this type of situation and provide a case study example to illustrate how to determine the necessary integrity level. It will conclude by explaining why it is important to treat high demand rate situations in this way and the resulting benefit of a lower but sufficient required integrity level.     

铅酸起动蓄电池组IEC60095:2006与2000版标准差异

本文主要介绍了IEC 60095-1铅酸起动蓄电池组-第一部分:一般要求和测试方法2006年版与2000年版试验方法和要求的差异比照.     

对功能安全基础标准IEC61508的研究

IEC61508经过在欧美国家近十年的应用,目前正在修订中,为深入理解和跟踪该标准,文章介绍了该标准的发展历史,并详细阐述了该标准的精髓内容及目前的修订现状.指出实施功能安全管理的关键是研究开发定量风险评价方法,同时收集整理危险事件发生概率及后果的基础量化数据,并建立数据库.正在修订的第二版标准中仍未考虑操作人员错误,未给出影响操作人员决策的充分指标信息,未定义安全相关人机界面是否友好等.提出建立功能标准与功能安全技术和管理相辅相成、互相促进的良性循环.