978-1-4799-3732-5/14/$31.00 ©2014 IEEE A redundant solution for collective residences inflammable gas leaking monitoring using ultra-low power transmission system and automatic control Mircea Risteiu, Ioan Ileana, Maria Muntean, Gheorghe Marc Computer Science and Engineering Department “1 Decembrie 1918” University of Alba Iulia Alba Iulia, Romania mristeiu@uab.ro, iileana@uab.ro, maria_muntean2007@yahoo.com , gheorghe.marc@uab.r o, Abstract — Because the gas monitoring domestic use is important issue for all involved actors, many researchers and designers have approached this field. After a detailed state-of- arts analysis, in this paper deep research has been devoted for information flow and communication link design. Two important criteria have been established for information linking between collective residences and a general monitoring system, then ultra- low power Wi-Fi, and Zigbee-based devices have been used for experiments. Then, because of many unpredicted risk situations, a fuzzy model of gas leak risk evaluation has been designed. The used core device was a microcontroller with major roles: fuzzy/defuzzy processes, packet data link operating and processing, and regulatory user interface. Timed communication events and sets of action rules have been tested on the implemented system. Keywords—gas leak monitoring, Zigbee, protocol, fuzzy logic, ultra- low power transmission, redundant monitoring system, smart monitoring I. INTRODUCTION The gas networks, the gas distribution, and the use are in continuing expansion. The gas networks consist in distribution stations and pipelines as mean way of transportation, and fittings. For this reason, the gas infrastructure reliability ensuring is critical. An important reliability factor is related to the leaks of the gas because of its major effects that they might have. The main causes of gas networks damages and then accidents are: external interferences, corrosion, construction defects, material failures, and ground/basements movements. The occurrence of the gas leak - related accidents have been investigated, studied and analyzed by many organizations and researchers. At European level, there is a research report done by Rainer Konersmann [1] which underlines some critical prevention aspects related to the monitoring of the all damages, not only gas leaks. For the purpose of the paper we have surveyed Romanian situation. The accidents and those causes are centralized at the national level in a site [2] financed by ESF program in a form that not clarify exactly the cause-effects relation. Anyway, the conclusions from [1] are available in Romanian surveying studies. The effects are calculated in terms of human victims, and damage costs. On the other hand, speaking about the protection measures which must be taken, and by who, this the only economical sector where the user has the smallest role [3]. Inflammable gas leaking is an extremely concern of the three related actors: users, authorities and gas suppliers companies. In one side, the gas users and suppliers are looking for continuously improving and efficiency changing in gas exploitation. On the other side, based on experiences, the legislative authorities try to cover some gaps in related regulations. Into gas distribution networks, the major parameters that describe gas characteristics are pressure, flow, temperature. They are measured in distribution stations. According to [3], they are three pressure classes: medium pressure (2-6 bars), reduced pressure (0.05-2 bar), and low pressure (bellow 0.05 bar). For collective residences, each individual consumer uses only low pressure and it’s consume is measured by regulated system [3]. From the gas leak protection point of view, according to [3] in most of modern residences, the gas leak monitoring system is compulsory. The monitoring system is based on inflammability and burning concentration limits of the gas. A methane sensor with catalytic burning principle is usually used [4]. Next table shows its important limits (in percent, or converted in ppm). TABLE I. CONCENTRATION LIMITS U.M. Inferior limit of inflamability Inferior limit of explosion Superior limit of explosion Superior limit of inflamability CH4 % 2 5 15 21