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Hyun Woo “Chris” Lee, PhD School of Civil and Construction
Engineering Oregon State University
EXPLORING OPPORTUNITIES FOR APPLYING LEAN CONSTRUCTION TO ELECTRICAL PREFABRICATION
ELECTRI Council Meeting San Diego
January 23, 2015
Research Report • Funded by ELECTRI
through the Early Career Award in 2013
• For more details, refer to http://apps.necanet.org/store/products/index.cfm/f3406
Hypotheses 1. Electrical construction has
its own unique barriers to prefabrication
2. A project that applies more lean principles provides more opportunities for electrical prefabrication
Photo courtesy of Oregon Electric Group
Study Objectives and Steps
Identify unique barriers to electrical prefabrication
Investigate a list of lean principles
Develop a leanness scoring matrix
Increased Chances for Electrical Prefabrication
1
2
3
Interviews with 18
experts in OR, WA, CA
Literature review
4 case studies with 3 EC’s
Hypothesis testing
Cross case analysis
Benefits of Electrical Prefabrication
Controlled Environment
Shift from Job Site to Offsite
Shop
• Increased productivity • Increased quality • Increased safety
o Increased labor reliability o Reduced workers fatigue o Reduced job congestion o Less storage space o Increased recycling
Intr
insi
c •Lack of culture for early involvement and pre-planning
•Lack of large equip
•Lack of BIM capacity
Extr
insi
c •Small-sized materials
•Lack of repetition
•Elect trade not invited to pre-planning
•Lack of design quality
Unique Barriers to Electrical Prefabrication — Compared to Mechanical
Lean Principles Definitions
1) Organize Cross-Functional Teams A group of people working together and applying their different functional expertise to the job they are collectively working on.
2) Pursue a Set-Based Strategy Development of multiple alternatives and choosing from them at the last responsible moment.
3) Use the Reliability Based Scheduling Schedules with more details should be done near the execution time when more reliable information is available.
4) Use Just-In-Time (JIT) Delivery To produce the necessary units in the necessary quantities at the necessary time.
5) Use Fail-Safe for Quality Control To eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur (Poka-Yoke)
6) Lay out the Workshop According to Five S’s Five S’s refer to sort, straighten, standardize, shine, and sustain, which are methods used for managing and organizing workshop.
7) Standardize the Process The elements of work process should be kept consistent, such as the labor load, work methods, and materials.
8) Identify Waste in the Process To Identify non-value-added tasks and eliminate them.
8 Lean Principles for Elec Prefab
• Suppliers have materials stored at the prefab shop
• Required materials will be pulled from the rack when needed.
• An application, called iSAM, on smartphone/tablet is used to scan the bar code of materials, and they will be automatically invoiced.
Case 2 – Just-In-Time Delivery
CASE 3 – Conduit Bending with BIM
Prefab Process With BIM
Isometric (ISO) drawings easily produced by using BIM
Case 1 Case 2 Case 3 Case 4 Organize Cross-Functional Teams 3 3 4 2 Pursue a Set Based Strategy 0 3 3.5 0 Use Reliability Based Scheduling 3 4 4 4 Use Just-in-time (JIT) Delivery 3 5 5 3 Use Fail-Safe for Quality Control 1 3 3 3 Lay Out the Workshop According to 5S’s
3 4 4 3 Standardize the Process 2 4 4.5 3 Identify Waste in Process 2 4 4 2
“Leaness” Scoring Matrix for Cross-Case Analysis
Case 3
Case 2
Case 4
Case 1
Level of Prefab Sophistication
• Electrical prefabrication can lead to significant benefits.
• Electrical construction faces an unique set of barriers to prefabrication (Hypothesis 1).
• 8 lean principles were identified to help overcome the barriers.
• The cross-case analysis shows that projects with more lean principles provide more chances for electrical prefabrication (Hypothesis 2).
Conclusion
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