Lean Design Process Flashcards
What is Pull?
Production is triggered by the internal customer
Pull in Lean Design
Implemented by involving General Contractor (GC) or Sub in the design process, e.g., mechanical contractor in the Design Development (DD) phase
Integrated Design
- Integrated Design
- Collaboration
- Systems Thinking
Collaboration in Integrated Design
Role & Responsibility
All actors of the project cooperate across
disciplines and agree on far-reaching decisions
jointly from the beginning “ (AIA)
System Thinking in Integrated Design
Tradeoffs and synergies (e.g., energy use, daylighting, ventilation) and lifecycle impacts are discussed in joint meetings before design decisions
Scoring exercise (1-5 per item, total = 195)
170-195: Excellent
150-169: Very Good
120-149: Good
100-119: Average
Target Costing in Manufacturing
Value-based:
- Value = customer willingness to pay (e.g., $1,000)
- Cost = value - margin (e.g., 50% margin → $700 cost)
- Allocate cost to systems
- Develop design
Vs.
Traditional (Cost-Based): Design → Estimate Costs → Price = Cost x Margin (e.g., $200 cost → $260 price)
Target Costing - Origins and Requirements
Originated in manufacturing (Toyota). Requires:
- Process Knowledge
- Cost Database
- Integrated Design
Principles of Target Costing/TVD
- Design based on a detailed estimate (not vice versa).
- Design for constructibility.
- Work together to define issues and make decisions before designing.
- Work in pairs or groups face-to-face (collocation)
Target Value Design (TVD) in Construction
- Determine allowable costs (owner-set) and target costs (less than allowable)
- Allocate costs to systems (e.g., Exterior Walls, Structural, Mechanical)
- Develop design to meet target costs
Vs.
Traditional: Design → Estimate Costs → Price = Cost + Overhead + Margins + Contingency
TVD - Phase 2 (Validation)
Some schematic design to define variables.
Refine budget and schedule (Refined Expected Costs vs. Allowable Costs)
TVD - Phase 1 (Business Case Development)
Identify opportunities and needs.
Establish financial parameters (Expected Costs vs. Allowable Costs)
TVD - Phase 3 (Target Value Design Phase)
Set Target Costs before Phase 3.
Allocate to clusters (e.g., Civil + Electrical + Structural).
Develop design to target.
Allow budget adjustments between clusters.
Tools: Value Engineering, Set-Based Design, CBA, Last Planner System, Co-Location
In-Class Exercise - TVD Example
High-rise façade design in DD phase:
Traditional: Supplier consulted later.
TVD: Supplier involved in DD to optimize material, manufacturing, and installation within a strict budget
Determining Target Price - Avg % Discount Method
Market study → Avg Cost (e.g., $400/SQ).
Target Cost = Avg Cost x Discount % (e.g., $400 x 0.9 = $360/SQ).
Involves contractors early
CBA Vocabulary - Factor
Element for comparing alternatives (e.g., phone voice quality, typing skill). Chosen by stakeholders, not ranked, cost excluded as a factor
CBA - Principles
Decisions anchored to relevant facts.
Stakeholders provide subjective data based on values.
Decisions based on importance of advantages
CBA Vocabulary - Criteria
Must or Want conditions of a factor (e.g., Must have good typing skills, Want good phone voice)
Choose-by-Advantage (CBA) - Purpose
Decision-making method considering all factors (especially non-monetary/subjective). Uses specific vocabulary to structure discussions. Needed in TVD due to multi-party conflicts (e.g., window or chiller options)
CBA Vocabulary - Alternative
Two or more options to choose from (e.g., Steven, Mary, or Alexis as receptionist)
CBA Vocabulary - Attribute
Character, quantity, or quality of an alternative (e.g., words per minute, phone manner)
CBA Vocabulary - Advantage
Difference between attributes of alternatives or a benefit (e.g., quieter, more appealing). Equal advantages are not decision basis. Avoid double-counting
CBA Vocabulary - Importance
Stakeholders’ subjective ranking of advantages. No score for least preferred. One paramount advantage gets max value, others ranked relative to it
CBA Vocabulary - Total Importance
Sum of importance ratings for an alternative (objective arithmetic process)
CBA Example - Buying a New Car (Criteria)
Want min. 6 passengers
Want fancy interior
Must have min. 28 MPG
Must have min. 4 airbags
CBA Example - Buying a New Car (Factors)
Passengers
Interior
Hwy MPG
Airbags
CBA Example - Buying a New Car (Attributes)
Car A: 4 passengers, leather+wood, 32 MPG, 4 airbags
Car B: 5 passengers, leather+vinyl, 26 MPG, 6 airbags
Car C: 7 passengers, vinyl, 28 MPG, 4 airbags
CBA Example - Buying a New Car (Advantages)
Passengers: B (+1), C (+3)
Interior: A (more appealing), B (appealing)
MPG: A (+6), C (+2)
Airbags: B (+2)
CBA Example - Buying a New Car (Importance)
Passengers: B (30), C (40)
Interior: A (40), B (30)
MPG: A (70), C (50)
Airbags: B (100)
CBA Example - Buying a New Car (Total Importance & Cost)
Car A: 110, $20,000
Car B: 160, $25,000
Car C: 90, $30,000
Class Summary - Lean Design
Pull: Production triggered by internal customer.
Target Value Design: Integrated Design + Co-Location + Value Engineering.
CBA: Decision-making tool for advantages
