Digitalization Over Prescription: A Lean Design Case Study for Target Value Design and Off-Site Construction's Conflict with Prescriptive Energy Codes
2026
Download PaperDOI: https://doi.org/10.60164/ky4tlud1y
Authors: Evan Kennedy, Yilin Cai, Ashrant Aryal, Julie Hartell
Citation:
Kennedy, E., Cai, Y., Aryal, A., and Hartell, J. (2026). Digitalization Over Prescription: A Lean Design Case Study for Target Value Design and Off-Site Construction’s Conflict with Prescriptive Energy Codes. Lean Construction Journal 2026 Special Issue CRC-CSCE pp 52-78 https://doi.org/10.60164/ky4tlud1y (Submitted 10Jan2026; Accepted 28Aug2026) www.leanconstructionjournal.org
Abstract:
Question: This systematic simulation approach functions as Set-Based Concurrent Engineering (SBCE), suggesting where investment in energy reduction provides maximum value and where it becomes wasteful, underscoring the necessity of Target Value Design (TVD) to find true value.
Purpose: The need for research into regulatory efficiency is indicated through growing energy demand from residential buildings, particularly during summer months in Texas environments due to increased frequencies of climatic disasters. Such metrics have prompted this study which investigates the conflict between Lean design processes (TVD) advanced Digitalization techniques (simulation), and Off-Site Construction against the baseline, prescriptive mandates of the 2021 International Energy Conservation Code. This research’s core capability rests upon the digitalization and repetition of 180 comparative energy simulations, which identified the optimal energy reduction and energy generation Target Value aimed at the greatest energy reduction capabilities for five major Texas city centers across three distinct climate zones (2A, 3B, and 4A).
Research Method: The simulation-derived single component substitutions, optimized scenarios, and the real-world performance of six companies utilizing Off-Site Construction (prefabricated and manufactured units) as their Production System Design for project delivery were benchmarked against the current 2021 IECC metrics.
Findings: Although the International Code Council (ICC) codes are effective in ensuring public safety, our analysis suggests that high-performing case studies often fail prescriptive requirements, yet their energy performance has been thought to exceed code minimums when simulated. This oversight is not a flaw, rather a possible Lean trade-off. In this case study, it was found that companies strategically mitigate resources to certain envelope sectors because of over-performance in others.
Limitations: Continued research will aim to harness calibrated digital models to better estimate true value saved through off-site means of construction.
Implications & Value for practitioners: This research exposes a gap that forces builders to engage in non-value-adding work (Waste), demonstrating that prescriptive regulation can functions against Lean principles by impeding efficient product development and optimal resource allocation aided by performance-based code compliance.
Keywords: Energy Efficiency; Housing Regulations; LEAN Construction; Performance-Based Codes
Paper type: Full paper