Raj Phani K
Technology and Management Systems, Inc., Burlington, MA 01803, USA.
J Hazard Mater. 2005 Jun 30;122(1-2):37-49. doi: 10.1016/j.jhazmat.2005.04.004.
In liquefied gas, bulk-storage facilities and plants, the separation distances between storage tanks and between a tank and a line of adjoining property that can be built are governed by local regulations and/or codes (e.g. National Fire Protection Association (NFPA) 58, 2004). Separation distance requirements have been in the NFPA 58 Code for over 60 years; however, no scientific foundations (either theoretical or experimental) are available for the specified distances. Even though the liquefied petroleum gas (LPG) industry has operated safely over the years, there is a question as to whether the code-specified distances provide sufficient safety to LPG-storage tanks, when they are exposed to large external fires. A radiation heat-transfer-based model is presented in this paper. The temporal variation of the vapor-wetted tank-wall temperature is calculated when exposed to thermal radiation from an external, non-impinging, large, 30.5 m (100 ft) diameter, highly radiative, hydrocarbon fuel (pool) fire located at a specified distance. Structural steel wall of a pressurized, liquefied gas container (such as the ASME LP-Gas tank) begins to lose its strength, when the wall temperature approaches a critical temperature, 810 K (1000 degrees F). LP-Gas tank walls reaching close to this temperature will be a cause for major concern because of increased potential for tank failure, which could result in catastrophic consequences. Results from the model for exposure of different size ASME (LP-Gas) containers to a hydrocarbon pool fire of 30.5 m (100 ft) in diameter, located with its base edge at the separation distances specified by NFPA 58 [NFPA 58, Liquefied Petroleum Gas Code, Table 6.3.1, 2004 ed., National Fire Protection Association, Quincy, MA, 2004] indicate that the vapor-wetted wall temperature of the containers never reach the critical temperature under common wind conditions (0, 5 and 10 m/s), with the flame tilting towards the tank. This indicates that the separation distances specified in the code are adequate for non-impingement type of fires. The model can be used to test the efficacy of other similar codes and regulations for other materials.
在液化气、大容量储存设施和工厂中，储存罐之间以及储存罐与相邻可建房产之间的分隔距离由当地法规和/或规范（例如美国国家消防协会（NFPA）58，2004年版）规定。分隔距离要求已在美国国家消防协会58号规范中存在了60多年；然而，对于规定的距离并没有科学依据（理论或实验方面）。尽管多年来液化石油气（LPG）行业一直安全运营，但当LPG储存罐暴露于大型外部火灾时，规范规定的距离是否能为其提供足够的安全保障仍存在疑问。本文提出了一个基于辐射传热的模型。当暴露于位于特定距离处的外部、非撞击、大型、直径30.5米（100英尺）、高辐射的烃类燃料（油池）火灾的热辐射时，计算蒸汽湿润罐壁温度随时间的变化。当壁温接近临界温度810K（1000华氏度）时，加压液化气容器（如美国机械工程师协会（ASME）液化石油气罐）的结构钢壁开始失去强度。接近此温度的LPG罐壁将成为主要关注点，因为罐体失效的可能性增加，这可能导致灾难性后果。不同尺寸的ASME（液化石油气）容器暴露于直径30.5米（100英尺）的烃类油池火灾的模型结果表明，在常见风速条件（0、5和10米/秒）下，火焰向罐体倾斜时，容器蒸汽湿润壁温从未达到临界温度。这表明规范中规定的分隔距离对于非撞击型火灾是足够的。该模型可用于测试其他类似材料规范和法规的有效性。
