4_hazard_reduction_precedence[1].doc

幻灯片16 Hazard Reduction Precedence减少危害的优先次序幻灯片2词汇l Precedent n.先例l Precedence n.优先, 居先l hierarchy n.层次，层级l Illustrate vt.举例说明, 图解, 阐明；l vi.举例l Asphyxiate vi.窒息 vt.使窒息l Asphyxiation n.窒息幻灯片3Translation paragraph 1l NASA has developed an extremely useful hierarchy of hazard reduction. This method is applicable to all industries. l 美国国家航空和宇宙航行局开发了一种非常有用的分层次降低危害的方法。这种方法可应用于所有行业。l The first step is to “design out” the hazard. If this is not possible, then the next best is to use safety devices. l 第一步就是设计出危害（安全设计？）。如果这一步不可能实现，那么下一个最好的选择是应用安全装置。幻灯片4Translation paragraph 1l If safety devices are not sufficient control, then cautions and warnings can be applied.l 如果安全装置不能有效控制，那么就要应用警告了。l And finally, special procedures and training can be used to control the hazard or mitigate the consequences.l 最后，应用专门的程序和训练来控制危害和减轻其结果。幻灯片5Translation paragraph 2l 6.1 “Design out” the Hazard 6.1“设计出”危害（安全设计）l The first step, and always the best (from a safety-only viewpoint), is to “design out” the hazardtake the hazard out of the system completely.l 第一步，常常是最优的（仅从安全的观点出发），就是“设计出”危害也就是把危害完全排除在系统之外。l For example, four things are required for a fire: combustible material, oxygen, chemical reaction, and an ignition source. If one leg is taken out of the fire tetrahedron, then it is physically impossible to have a fire. l 例如，火灾由四个因素构成：易燃物，氧气，化学反应和引火源。如果在火灾四面体中去掉任何一个因素，那么，火灾就完全不可能发生了。幻灯片6Translation paragraph 2l Engineering talent really comes into play in trying to decide which of the four legs should be designed out. l 工程技术的真正应用就是设法决定针对四个因素中哪一个作出设计。 l The system can be hermetically sealed and back-filled with dry nitrogen gas (taking away the oxygen). l 可以对系统采用密封并用干燥的氮气回吹的方法(可以带走氧气)；幻灯片7Translation paragraph 2l Or the system can be fabricated out of material that has a very high flash point (assuring that the electrical cable can never reach the burning temperature of its insulation, under all electrical load conditions). l 或者采用燃点非常高的材料来建造系统（保证在满电力负载条件下，电缆永远不会达到其绝缘的燃烧温度）；l Another solution is to disable the power so that electricity does not create an ignition source.l 另一种解决办法是破坏电源，以便使电流不会产生引火源。幻灯片8Translation paragraph 3l Figure 6.1 illustrates how easy designing out the hazard can sometimes be. l 图6.1阐明了安全设计有时是多么简单。l The first part is a typical engineering design. Gaseous nitrogen is needed to support the operators activities. l 第一幅图是一个典型的工程设计，在操作活动中需要应用到氮气。幻灯片9Translation paragraph 3l However, as can be seen in the second block, the nitrogen feed bottles do not need to be located in the same area as the operator.l 然而，就像我们在第二幅图中看到的，氮气瓶没有必要放置在与操作者相同的区域内。l The bottles have been moved outside the work area, thus alleviating the asphyxiation hazard.l 把氮气瓶移到工作区域之外，就可以减轻窒息的危害。幻灯片10Translation paragraph 4l Even though it may seen so, designing out the hazard is not always difficult.l 尽管安全设计看起来可能很难，但它不总是难以进行的。l One common example is the hazard of mismating power cables. l 一个常见的例子就是错误结合电力电缆的危害。l Many types of electrical instrumentation use various cable sizes both for power and for signal input and output. One hazard is mating a 208-V source to a 110-V system. l 许多型号的电力仪器采用不同大小的电缆作为电力线或者信号输入输出线。有一种危害就是将208V的电源和110V的系统匹配。幻灯片11Translation paragraph 4l If there is concern that cables could be mismated through human error, then the engineer needs to design out that hazard. l 如果注意到由于人员失误可能导致错误配合的情况，那么工程师就需要设计出这种危险。l Using cable connectors that are keyed differently and scoop-proof would assure that it is physically impossible to mismate the cables.l 利用不同键位和防凹口的的电缆连接器可以保证完全不可能发生电缆错配的情况。幻灯片12scoop-proof connectorsl Scoop n.铲子 v.掘, 挖l Scoop-proof means that because of the connector long shell design, it is impossible for the mating plug connector (插塞式连接器) to inadvertently be cocked into the mating receptacle(插座) and damage the pins or electrically short the contacts. l 由于连接器设计成长壳状的，可以避免与之匹配的插塞式接头因不注意而倾斜地插入插座而导致插脚损坏或使触头短路）幻灯片13scoop-proof connectors幻灯片14scoop-proof connectors幻灯片15Translation paragraph 5l In the late 1980s NASA experienced such a problem. l 在20世纪80年代末期，美国国家航空合宇宙航行局遇到了这样一个问题。l After arrival at Kennedy Space Center for Space Shuttle launch preparations, the Magellan spacecraft power control unit was reconnected. l 在麦哲伦号宇宙飞船抵达肯尼迪航空中心，作航天飞机发射准备后，对麦哲伦号宇宙飞船的能源控制单元作了再次连接。幻灯片16Translation paragraph 5l An extensive electrical power system check was necessary to ensure proper performance prior to applying power to other spacecraft subsystems. l 为确保正常运作，在把能源输送到航天器其他子系统之前，有必要的对电力能源系统进行大规模的检查。l A technician was making a blind mate (mating cables without visual verification during the operation) of an electrical harness power cable to the Magellan. l 一个技术师轻率的（光靠仪器）把电力输送电缆连接到麦哲伦号上。（在操作过程中没有实地查看确认）。幻灯片17Translation paragraph 5l Because the connection was buried deep in the spacecraft, out of view of the technician, it was impossible to verify visually that the connection was correct. l 由于连接处在飞船上埋藏较深，技术师没有查看，就不可能真实的核实是否连接正确。l Sparks, flames, and smoke resulted from the cable connection operation.l 结果，因电缆线错误的连接操作产生了火花、火焰和烟尘。幻灯片18Translation paragraph 6l 6.2 Safety Devices 6.2安全装置l If the hazard cannot be designed out, because it is either impossible or cost-prohibitive, then the next best solution is to use fail-safe devices.l 如果由于设计上不可能实现或者成本太高而使危害不能通过设计而避免，那么下一个最好的解决办法是应用自动防故障装置。l An example is a valve that fails in a safe manner. l 一个阀在安全意义上失灵就是一例。幻灯片19Translation paragraph 6l In many chemical processes it is critical that the temperature not exceed a certain level. l 在许多化学过程中保证温度不超过某一特定的水平是很关键的。 l If the control valve fails in an open position, then the system will still maintain cooling even if system power or control is lost for one reason or another.l 如果控制阀在打开位置失灵，即使系统由于一个或其他原因失去动力或控制，那么系统仍然会保持冷却，幻灯片20Translation paragraph 7l The pressure-relief valve is probably one of the most common applications of a safety device.l 减压阀大概是最常用的安全装置之一了。 l If the pressure within the line exceeds a predetermined level, then the pressure-relief valve opens, relieving the dangerous pressure buildup.l 如果在某一线路中的压力超过了预定的水平，那么减压阀将会打开，减轻聚集的压力形成的危险。幻灯片21Translation paragraph 7l Another example is a fuse in an electrical cable. l 另一个例子就是电缆中的保险丝。 l If the cable is electrically overloaded, the fuse will blow and cut electrical flow before the cable overheats and bums (burns) or the system is overstressed. l 如果电缆超电力负荷，那么在电缆过热燃烧或者系统超负荷之前，保险丝就会烧断，并切断电流。幻灯片22Translation paragraph 8l Plastic injection-molding machines are very common in many manufacturing plants around the world. l 在世界许多制造厂中，塑料的喷射塑模机非常常用。l Occasionally, the technician needs to reach inside the machine to clear out debris. l 有时候，技术师需要进到机器里面去清除碎片。l Many hands and arms have been lost from trying to clean the debris while the machine was still powered on (though not running).l 很多人试图在机器的电源处于接通状态（虽然没有运转）时去清除碎片，却弄断了手指或手臂。幻灯片23Translation paragraph 8l An electrical interlock that automatically disconnects the power source when the inside envelope of the machine has been violated is another example of a safety device.l 电气联动装置是另一种安全装置，这种装置可以保证当机器的内舱有外来物时，可以自动断开电源。幻灯片24Translation paragraph 9l 6.3Warning Devices 6.3警报装置l If the hazard cannot be design out or sufficiently controlled, then the next best step is to ware (warn) operators of the imminent danger. l 如果危害不能通过设计来避免或者不能充分地控制，那么下一个最好的步骤就是警告操作者注意面临的危险。l A good example of a warning device is the smoke detector in a home. l 警报装置一个很好的例子就是家庭用烟尘探测器。 幻灯片25Translation paragraph 9l When a certain level of smoke is detected, an alarm is sounded and we are alerted to immediately evacuate the area. l 当检测到烟尘达到了一定的水平，警报就会响起，警告我们立即撤离那个区域。l Of course there are pitfalls. l 当然这也是有缺陷的。幻灯片26Translation paragraph 9l Too many different warning devices or too many false warnings can be very confusing for people, and the warning itself could cause a hazard (too many burned hamburgers can give the false impression that the next smoke alarm is from dinner and not a serious fire). l 太多不同的警报装置和太多的错误警报会使人感到迷惑，警报本身也会导致危害（太多的烧糊了的汉堡包会造成这样的错误的印象，就是下一个烟尘警报来自于晚餐而不是来自于严重的火灾）。幻灯片27Translation paragraph 9l Other typical safety warning devices are stop signs, no smoking signs, oxygen alarms, fire alarms, and product labels (e.g. “WARNING：DO NOT USE NEAR OPEN FLAME”).l 另一些典型的警报装置有停止标志，禁止吸烟的标志，氧气警报，火灾警报，和产品标签（如：注意：不要在靠近明火处使用）。 幻灯片28Translation paragraph 10l Gas monitoring and warning detectors are very common examples of warning devices. l 气体检测和警告探测器是非常常见的警报装置的例子。l Some typical gas detectors are ammonia, hydrocarbon fuels, hydrogen, methane, and even oxygen monitors. l 一些典型的气体探测器包括对氨气、碳氢化合物燃料、氢气、甲烷、甚至氧气的检测器。l Care should be exercised in the use of warning devices.l 使用报警装置必须小心。幻灯片29Translation paragraph 10l It is not uncommon that industrial facilities use too many warnings for different hazards. l 工业企业生产设备对不同的危害应用用太多的警报装置是很普遍的。 l One manufacturing plant used a buzzer for ammonia leaks, a siren for nitrogen leaks, a horn for oxygen leaks, and a bell for fires. l 一个制造厂使用蜂鸣器作为氨气泄漏的警报，使用汽笛声作为氮气泄漏警报，喇叭声表示氧气泄漏，铃声表示火灾。幻灯片30Translation paragraph 10l The problem is that the individual wastes precious time in deciding how to respond. l 这里的问题是每个人花费了宝贵的时间去决定该作出什么反应。l A more desirable solution would be to connect all the different gas-monitoring sensors to one type of audio and visual alarm, such as a horn and flashing red light. l 一个最好不过的解决办法可能是将不同的气体检测传感器连接到同一个声频和视频警报器上，例如一个发出喇叭声同时闪光的红灯。幻灯片31Translation paragraph 10l The person then knows to immediately evacuate the area; it doesnt matter if it is because of a fire or an ammonia leak.l