Variation management in prefabricated MEP installations: challenges and opportunities

Managing variation is an essential lean principle. Tolerance management remains marginal in construction and focuses on architectural and structural trades. Especially mechanical, electrical and plumbing systems have largely been neglected in tolerance management research, despite their critical role in project delivery.
This research studies variation management, its challenges and opportunities for improvement in a plumbing renovation project through semi structured interviews and thematic analysis. The interview questions addressed prefabrication practices, planning processes, production and control activities, tolerance management, accuracy, and sources of variation. Three aggregate themes emerged as key results: (1) detection and management of deviations, (2) design information and tolerance management, and (3) management of change and personnel. Together these themes highlight the multifaceted nature and difficulty of variation management.
The results emphasize that both technical and human factors must be addressed simultaneously while maintaining constancy of purpose. Improving installation guidelines and accelerating issue resolution were identified as key development areas. Stabilizing the production system provides an opportunity to further enhance productivity and shorten cycle times.