# Special Equipment Safety Supervision System Architecture Based on Blockchain Technology
## 1 Introduction  
\"Special equipment\" is a special term defined by China, which refers to some equipment widely used in industrial production and in people's lives. In China, special equipment is classified into eight categories, including boilers, pressure vessels, pressure pipelines, elevators, lifting machinery, passenger ropeway, large-scale amusement facilities, and special motor vehicles, inside the field (factory) [1]. This equipment is characterized by high temperature, high pressure, and high speed, and poses potential danger [2]. Once an accident happens, it will cause serious casualties and huge property losses. In 2019 alone, 130 accidents related to special equipment occurred in China, resulting in 119 deaths [3]; therefore, the safety supervision of special equipment is particularly important, and is the most effective measure to prevent safety accidents. In China, special equipment is under unified supervision of the government's specialized agencies, and a supervision system involving multiple participants of supervisory agencies at all levels, primary supervisors, equipment users, and inspection agencies, has been established. The government has enacted a series of laws and regulations to keep thesupervision system running efficiently, and try to prevent unsafe behaviors since 2003 [4]. Nonetheless, the system did not work as expected. From the statistical reports of safety accidents over the years [5; 6; 7; 8], the safety accidents caused by supervision factors account for the largest proportion. In the traditional supervision system, there is no effective accountability mechanism, and detailed work records cannot be obtained when tracing the accident responsibility, which often leads to unfair punishment results. In the context of China's social relations, represented by the reciprocal social network, the data-sharing mechanism and transparency mechanism established based on the connection of independent systems and databases cannot meet the requirements of practical work. With the use of this traditional supervision system, inefficient safety management, job burnout of supervision participants, and many other safety supervision problems emerge endlessly [9]. In order to address these safety supervision problems and further reduce the frequency of safety accidents of special equipment, it is necessary to establish a function to perform efficient and accurate accident responsibility tracing, and improve the transparency of supervision information and efficiency of data sharing in safety supervision systems, which means that the original supervision system needs to be upgraded. Blockchain technology provides the possibility for such upgrading, which including a distributed, unalterable, digital ledger [10; 11] that can record work information in multiple series of blocks. This distributed digital ledger, with query data, inherent transparency mechanism, and efficient data-sharing mechanism, meets the requirements and technical features of special equipment safety supervision. In this paper, we conduct a comprehensive requirement analysis based on the current situation of safety supervision of special equipment, and get the specific requirements of improving the traditional safety supervision system. Driven by these requirements, we designed a new system architecture for special equipment safety supervision based on blockchain technology. Taking the particularity of industrial blockchain application and the demand for rapid development of this system into consideration, the Hyperledger Fabric, which is a permissioned blockchain platform [12], is adopted. We regard the \"transaction\" of blockchain as the update of information; each supervision participant enters a specific channel of the supervision system after obtaining permission, and they record their work information by updating the smart contract of the blockchain. Once the working information is recorded, it becomes unalterable. The ledger database, composed of all work information, can provide basic data for accident responsibility tracing.