Application of SPAR-H human reliability method to Pipeline inspection Gauges (PIG) operations

Pipeline inspection gauges (PIG) operation which is called “pigging operation” is a practical online monitoring method for maintaining pipeline in a healthy and safe condition. This operation requires high man-machine interactions. Therefore, it is sensitive to human error which can lead to catastrophic consequences.

This descriptive study was carried out to estimate the probability of human error in pigging operation in a gas transmission plant in Iran. First, hierarchical task analysis (HTA) was conducted through walking through the pigging operation and doing interviews with workers. Next, the Standardized Plant Analysis Risk-Human (SPAR-H) methodology was utilized for estimation of human error probability.

SPAR-H methodology was implemented on PIG operation.  The mean human error probability (HEP) value was calculated to be 0.218. HEP value in “opening bypass valve for decreasing pressure” subtask was recognized as the highest probability of human error (0.841).

SPAR-H method is a useful tool for practitioners to calculate HEP. Besides that, based on results some of the preventive actions to reduce HEP are as follow: using more clarified procedures, the automation of the launching and the receiving processes and etc