英语翻译2 事故原因的分析分析燃气锅炉房事故的原因,有两种可能：锅炉本体爆炸、锅炉房爆炸性气体达到爆炸浓度而发生爆炸.锅

英语翻译
2 事故原因的分析
分析燃气锅炉房事故的原因,有两种可能：锅炉本体爆炸、锅炉房爆炸性气体达到爆炸浓度而发生爆炸.
锅炉本体爆炸,是因为在炉膛或烟道内有爆炸性混合气体存在,当达到爆炸极限,被明火或锅炉本身的高温引燃造成事故.这一点与《建筑设计防火规范》相关条文说明相符.实际目前锅炉产品已经考虑了安全生产措施来避免.合格的燃气锅炉本身有防爆工艺设计,如燃烧器在异常情况自动停机,自控装置也停止输出燃料；燃气锅炉燃烧系统自动化程度较高,包括了燃气压力高、低限报警保护等,当控制到哪步逻辑判断不满足设定条件时,启动相应联锁保护.
避免了锅炉本体爆炸可能性,但是仍然存在上述的另外一种可能,能否避免?如何避免?
3 应对措施
其实在设计中,根据《锅炉房设计规范》和《火灾自动报警系统设计规范》GB50116-1998等规范,我们已经采取了以下措施：
天然气管道上阀门、表计等可能发生天然气泄漏处,锅炉间可能会产生天然气存积区域[相对密度0.8,一般是在屋顶区域],在这些部位均设有可燃气体浓度检测报警装置,根据可燃气体浓度情况发出声光报警信号及启动事故排风机,当泄漏浓度达到爆炸极限下限的50%[该值仅供参考],还立即关闭天然气源进气总管的总进气电磁阀.
在锅炉房及有天然气管线进出的房间,设置事故排烟风机,还与可燃气体报警器联锁（启动）.
电气、仪表用电缆选用铜芯,最小截面不低于1.5mm2.
燃气放散管的管顶或其附近应设置避雷针,其针尖高出管顶不应小于3m,并使其保护范围高出管顶不小于1m.
燃气管道应有静电接地装置,当管道为金属材料时,可与防雷或电气工程接地保护线相连,其实测电阻值R≤4Ω.在管道连接处,如弯头、法兰、阀门等处不能与金属管道良好接触,也用金属软线将两端跨接.
在锅炉房及有天然气管线进出的房间门、窗采取泄压措施.
根据《爆炸和火灾危险环境电力装置设计规范》第2.2.2条,符合下列条件之一时,可划为非爆炸危险区域：第3项,在生产过程中使用明火的设备附近；结合上述几条措施可以明确,电气设备选型为非防爆.
同时根据《爆炸和火灾危险环境电力装置设计规范》第2.2.2条,符合下列条件之一时,可划为非爆炸危险区域：第2项,易燃物质可能出现的最高浓度不超过爆炸下限的10%；关闭天然气源进气总管的总进气电磁阀时,浓度超过爆炸极限下限的10%,锅炉间屋顶附近区域是天然气存积区域,所以照明灯具及开关选用是防爆型.
4 结论
在燃气锅炉房电气设计中,照明选用防爆灯具,其它部分采用非防爆型.
参考文献
[1]锅炉房设计规范.GB50041-1992.
[2]爆炸和火灾危险环境电力装置设计规范.GB50058-1992.
[3]建筑设计防火规范.GB50016-2006.
[4]火灾自动报警系统设计规范.GB50116-1998.

2 accident reason analysis
Analysis of gas boiler room the cause of the accident, there are two possible: boiler ontology explosion, boiler room to explode gas explosion concentration and explosions.
Boiler blast furnace body, because be in, or flue gas mixture in explosive existence, when achieved by fire or explosion limit, boiler heat ignites causing accidents in itself. This point and the national norm of building fire system that conform to the relevant provisions. The actual current boiler product has considered safe production measures to avoid it. Qualified gas boiler itself has the explosion-proof process design, such as burner in abnormal situation automatic stop, self-control device also stop output fuel, Gas boiler combustion system higher automatization, including the gas pressure is high, low limit alarm protection, when the control logic where step does not meet the conditions set start corresponding interlock protection.
Avoid the boiler exploded possibility, but still ontology exist above another possibility, can avoid? How to avoid it?
Three measures
In fact in design, according to the boiler design code "and" automatic fire alarm system design code "GB50116-1998 etc standard, we have taken the following measures:
Natural gas pipelines valves, meter, may occur gas leak place, boiler room may produce gas storage product area [relative density 0.8, it is to be in commonly roof area in these areas], all equipped with combustible gas concentration measurement alarm device, according to combustible gas concentration situation give out sound and light alarm signal and start exhaust fan, when leakage accident concentrations reach explosion limit of the lower limit 50% [this value for reference only], but also immediately close natural air intake duct total intake solenoid valves.
In the boiler room and a natural gas pipeline in and out of the room, the incident, but also with the smoke exhaust fan combustible gas alarm interlocking (start).
Electrical, instrument by cable selection TongXin, not less than 1.5 mm2 minimum section.
Gas radiation tube tube top or the nearby, the lightning rod should be installed above the pipe jacking tip should be not less than 3m, and its scope of protection tube top above not less than 1-m.
Gas pipeline should be static grounding device that, when pipeline as metal materials, and lightning protection or electrical engineering protective grounding wire connected, the measured resistance R more than 4 Ω. In pipe joints, such as the bend, flange, valve and pipe with good place cannot metal contact, also with metal soft line will be both ends jumper.
In the boiler room and a natural gas pipeline in and out of the room door, window take pressure measures.
According to the explosion and fire dangerous environment electrical device design specification "the laws 2.2.2 bar, accord with one of the following conditions may, when the explosion danger area: devin in item 3, in the process of production use fire equipment near, A combination of these several measures can clearly, electrical equipment selection for the explosion.
At the same time according to the explosion and fire dangerous environment electrical device design specification "the laws 2.2.2 bar, accord with one of the following conditions may, when the explosion danger area devin: the first 2 items, and the highest possible flammable explosive chroma does not exceed 10% of the lower limit, Close air intake duct natural total intake solenoid valves, concentration exceed 10% of the lower limit explosion limit, boiler room near the roof area are gas storage product area, so lighting lamps and lanterns and switch choosing is explosion-proof type.
4 conclusion
In gas boiler room electrical design, lighting choose explosion-proof lamps, other part adopts the explosion-proof type.
references
[1] boiler design standard. GB50041-1992.
[2] explosion and fire dangerous environment electrical device design standard. GB50058-1992.
[3] the code for fire protection design of buildings. GB50016-2006.
[4] automatic fire alarm system design standard. GB50116-1998.