Failure Analysis of Edmonton International Airport’s Heating System
Analyzing the risk of heating system failure posed by extreme cold to North America’s northernmost airport.
Edmonton International Airport (EIA) is the most northern major airport in North America and is a base for domestic and international travel served by 17 different airlines. EIA is also the fastest growing major airport in Canada in the past decade. More than 20,000 people per day pass through its doors and the annual total grows by hundreds of thousands of people per year. The results of a 2014 Economic Impact Study indicate that EIA has a total economic output of over $2.2 billion in the region, and supports the tourism sector, the energy sector, and northern development. It is a critical piece of infrastructure for Alberta and Canada.
Operating at this latitude poses challenges – in Alberta’s extreme weather conditions, heating system shutdowns of only two hours could result in terminal closure and pipe damage. In the past decade, the temperature at EIA has dipped below -20°C an average of 39 days per year, below -30°C an average of 10 days each year, and below -35°C an average of three days each year. These exceptionally cold days are the critical times when the heating system must be 100% reliable in order to prevent damage to equipment and to preserve the continued operation of the airport.
EIA’s heating system has reached natural gas usage rates of 1,026 cubic metres per hour in exceptionally severe weather, equivalent to the gas usage of approximately 700 Edmonton homes! At times, an outage of as few as two hours could cause heating pipes to freeze and burst, and airport operations would be severely hampered until the system was repaired. Any such event could result in millions of dollars in damage, to say nothing of the harm to EIA’s reputation and the likelihood of making international news.
The main EIA passenger terminal is over 150,000 square metres — that’s 15 hectares under one roof. As one might expect, there are significant challenges related to the operation of such a large facility. Adding to the complexity of this problem is the reality of aging infrastructure: the original heating system was installed in the 1960s, with a major upgrade in the late 1990s and additional work as EIA grew.
Working with EIA and Dialog, SMA performed a detailed failure and reliability analysis to identify, quantify, and mitigate serious failures of the heating system, and developed a custom simulation model, which can model the entire system and the potential for overlapping failures, as well as external events to calculate the true risk of system failure and test potential improvements. The simulation can be then used to analyze and demonstrate the effectiveness of proposed solutions.
There are many techniques for performing the kind of analysis required to fully understand and improve a system’s reliability. SMA has developed an advanced failure and reliability analysis approach which integrates Failure Modes, Effects, and Criticality Analysis (FMECA) with reliability calculations and simulation modeling of actual failures to derive a full picture of system uptime and a resource-loaded maintenance schedule. This technique was applied to the critical heating equipment of the EIA, 66 major components in all.
The primary objectives of the FMECA study were to fully understand and document the heating system components, to determine which are vital to heating system operation along with their failure modes and their causes, and to identify key actions to improve the reliability of the system. The study identified 136 different failure modes with 326 potential causes, all of which were scored for likelihood of occurrence, impact, and detection.
The FMECA results were combined with the simulation results to present a total picture of EIA’s current risk exposure, which components were most important, and which mitigations should be implemented. The study ultimately calculated that EIA may experience heating system outages during severe weather approximately once every three years.
The Failure and Reliability Analysis produced a business case recommending upgrades to improve the system reliability. Overall, the study demonstrated that the heating system, despite its age, is a reasonably robust system with backups and fail-safes already incorporated. Results include a better understanding of the system and its components, as well as numerous mitigations which can reduce the risk of system failure during the bitterly cold times when it is needed the most.