## 1 Introduction  
The demand for energy resources increased sharply over the past decades in China. In 2014, it was estimated that China consumed 20% of the global energy [1], ranking the first in the world. The growth rate of energy consumption in China will maintain an average speed of 4.5% in the next 20 years [2], which will result in the consumption of 82 billion tons of coal, 12 billion tons of crude oil, and 5.8 trillion of natural gas.  
Among various kinds of energy resources, the Liquefied Petroleum Gas (LPG) is recognized for its efficiency, environmental friendliness, and convenience. These unique features make LPG an ideal choice for rural heating, motor fuel, refrigeration, and cooking. However, LPG is a dangerous chemical which is highly flammable and explosive [3]. Every year, accidents related to LPG storage tanks lead to tremendous property and life losses [4]. For example, in 2009, an oil storage tank explosion in West India caused 13 deaths and more than 150 wounded; in 2013, an oil-transporting vehicle exploded in Democratic Republic of the Congo, leading to 242 deaths; and on 2 April 2013, an explosion of an oil storage tank in Dalian, China, caused two missing people and two badly injured. Since the accidents of LPG storage tank explosion significantly threat the lives of people, the importance to ensure the safe operation of the LPG storage tanks through monitoring technology is widely acknowledged.  
Among various monitoring parameters such as temperature, strain, pressure, refractive index, displacement, vibration, _etc._, temperature is one of the most critical factors to evaluate the safe status of the LPG storage tanks [5,6]. In recent years, as an alternative to manual surveying, various temperature sensors, and sensing systems for LPG storage tank monitoring has been investigated [7, 8, 9, 10, 11]. [PERSON] _et al._ designed a real-time distributed measurement system based on field bus technology for large-scale oil tanks. The system utilized optical fiber sensors to collect the oil tank's data and Ethernet to achieve long-distance data transmission by RS-485. Together with a computer to collect and analyze the data, monitoring and managing oil tanks is achieved intelligently [12]. [PERSON] _et al._ proposed to use fiber Bragg grating sensors to conduct real-time measurements of the temperature and pressure in the gas tanks [13]. [PERSON] proposed a multi-point temperature monitoring system based on infrared thermal imagers for the Liquefied Nature Gas (LNG) storage tank monitoring [14]. However, the long-term engineering validations reveal some shortcomings of the above wired monitoring systems such as high complexity for the field deployment of the monitoring system and potential new hazards in tank operations. As a result, the wired technology cannot meet the challenges of health monitoring for the LPG storage tanks.  
To solve the challenges of insufficiency of the current temperature monitoring systems, this paper developed an integrated monitoring system which combines wireless temperature sensors, fiber optical high-temperature sensors, a large scale sensor network, and a management software to sense, collect, store, display, and manage the monitored data. In Section 2, hardware for the monitoring system was designed and implemented followed by software in Section 3. In Section 4, the developed large-scale wireless temperature monitoring system was applied on a LPG storage tank to further test and validate the feasibility of the system.