The Existing Quality Paradigmand Implications for Lean Construction.

byMark Gilligan S.E.

Quality

What do we mean by quality?

• Quality of a product

• Quality of workmanship

• The way we do our work

• Process by which we manage quality.

Quality

We also talk about:

• Quality Assurance

• Quality Control

• Quality Management

Quality

• Tradesmen

• Engineers

• Architects

• Owners

• End Users

Everybody has a unique understanding of quality based on personal experience and values.

Quality

Workers attitudes towards quality has a strong impact on the final product.

Post Northridge Earthquake test program provided provided interesting insights.

Quality

Lessons learned:

• Workers opinions on quality matter.

• Workers idea of quality was flawed.

• Project specifications were not being followed.

These problems continue to be a challenge

Quality

Definition of Quality:

“Quality is compliance with the expectations of the Customer”

Quality

Understanding the Customers expectations can be a challenge.

Quality

Supplemental Definition:

Contract documents reflect the expectations of the Customer.

Quality

• The value of these definitions is that they can help focus our expectations.

Existing Quality Paradigm

• Existing attitudes.

• Common practices.

Existing Quality Paradigm

• Building Code requirements.

• Construction Contracts.

Existing quality paradigm has been shaped by:

Existing Quality Paradigm

• Focus is on Compliance (passing the tests specified in the code). The focus is not on Quality of the work.

• If the focus was on the quality of the work the test and inspection results would be used to refine the quality system and make improvements.

Existing Quality Paradigm

Building Code.

• Building Code has Quality Assurance requirements that are the responsibility of the Owner

• Some proscriptive Quality Control provisions are finding their way into the standards.

Existing Quality Paradigm

Quality Assurance

• Quality Assurance consists of tests and inspections performed by the Owner to give himself and the building official assurance that the work Complies with the construction documents.

Existing Quality Paradigm

Quality Assurance

• Passing Quality Assurance tests and inspections is a precondition to issuance of certificate of occupancy.

• Need to obtain certificate of occupancy creates a bias towards compliance.

Existing Quality Paradigm

Why are we not focusing on Quality?

• Lack of awareness of the problems.

• Clients and Engineers often do not appreciate the difference between quality and compliance.

• Other issues are seen as requiring immediate attention.

Existing Quality Paradigm

Quality Control

• Quality Control consists of those activities undertaken by the Contractor to monitor the quality of the work and to insure that the it is satisfactory.

• Quality Control activities can include tests and inspections but also includes efforts to improve the work.

• Quality control is open ended.

Existing Quality Paradigm

• The Contractor performs no Quality Control tests or inspections.

• Relies solely on Owners Quality Assurance tests and inspections.

• This practice is contrary to the intent of the contract.

Common Practice

Existing Quality Paradigm

Why are Contractors not proactive about Quality Control?

• Expected profit based on normal number of defects.

• Costs of addressing root causes would be charged against project.

• Long term risks are devalued.• No consequences.

Existing Quality Paradigm

• Some reference standards now provide detailed lists of Quality Control tests and inspections.

• These standards appear to give Contractor a safe harbor.

• Standards are inconsistent with the concept that the contractor’s quality control obligations are open ended.

Quality Control in Standards.

Existing Quality Paradigm

• Repairing defects improves the quality of the project.

• Tests and inspections improve the quality of the project.

Common assumptions by engineers:

Existing Quality Paradigm

• Tests and inspections can provide information about the current state of quality.

• The data does nothing to improve the quality of the project unless somebody uses that data to make improvements.

Existing Quality Paradigm

• Repairing a specific weld will improve the quality of that weld but does nothing to improve the other welds that likely have defects

Existing Quality Paradigm

• Engineer often not in the loop.

• Engineer often unfamiliar with testing and inspection issues.

• Additional tests and inspections not encouraged because of expense.

When defect rates are high the Engineer could recommend additional tests and inspections. Several reasons this is not the norm:

Existing Quality Paradigm

Our understanding of the Quality of the work is distorted by:

• Tests will not identify some types of defects.

• Poor testing and inspection practices.

• Inspectors do not find all defects.

• Inspectors not reporting corrected defects

Building Regulations

Attitudes are biased by the belief that we need to do no more than is required by the building code.

Building Regulations.

• Building Code does not require the contractor to address the root cause of defects.

• Building Code does not require changes to inspection frequency when problems are identified.

• Building Code does require the identified defects be corrected.

Building Code Limitations:

Statistical Control

• Statistical Control a a basic tool that helps us to understand the process.

• A process is “in statistical control” when the test values cluster around the mean and stay within the control limits

Statistical Control

Fig 1 Control Chart “in Control”

Statistical Control

Fig 2 Control Chart

Statistical Control

• If only every 4th test was performed none of the defects in Figure 2 would be found.

Statistical Control

Fig 2 Control Chart

Statistical Control

• If we have less than 100% testing and inspection the process must be more tightly controlled to have the same level of confidence in the completed work.

Statistical Control

• The need for historical data will result in data from multiple projects being used.

• This changes the focus from the current project to stability of the process over multiple projects.

Implications of Control Charts:

Why A New Paradigm

Why should we change if we are not experiencing problems?

• Minor problems are costing us money.

• Minor problems can be precursors to major disruptions.

• Need to minimize damage due to infrequent events such as earthquake, hurricanes, and tornados.

Why A New Paradigm

The Challenger disaster and the moment frame damage identified by the Northridge Earthquake were the result of ignoring problems.

Why A New Paradigm

• Practicing Lean means pushing the limits.

• “Design Paradigms” by Henry Petroski shows pushing the limits leads to failures.

• Thus if we implement Lean we need to focus on early detection of problems.

Why A New Paradigm

• The efforts to reduce time, control costs, and add value requires higher levels of quality.

• A lean system doesn’t have the buffers to absorb the defects.

Why a New Paradigm

• If we are concerned about the quality of our projects we need to change the way we do our work.

• We will need to be more formal in documenting our processes and training our personnel.

• We must be more involved in managing the quality of our work.

Why a New Paradigm

We Need:

• A long term approach to quality not one focused on documenting compliance for individual projects.

Built-In-Quality

We need to shift to an approach that is:

• Proactive

• Focused on meeting expectations the first time.

Built-In-Quality

Four Key concepts to Built-In-Quality

1. Do it right the first time

2. Find the problems early

3. Correct the problems when they are found.

4. Identify and address the root causes.

Built-In-Quality

1. Do it right the first time.

• Following the processes.

• Doing the work in accordance with the standards.

• Design the work so mistakes are prevented.

Built-In-Quality

All of the other concepts are in support of doing it right the first time.

Built-In-Quality

2. Find the problems early.

• Workers inspect the work as they touch it.

• Provide classical testing and inspection to monitor the quality.

• Periodically stress the system to find problems early.

• Adopt a culture of continual improvement.

Built-In-Quality

3. Correct the problems when they are found.

• Don’t allow defects to repeat.

• Do not let defects pass to the next stage.

• Provide prompt design assistance when needed.

Built-In-Quality

4. Identify and address root causes.

• Addressing root causes is essential if we do not want problem to repeat.

Built-In-Quality

• Built-in-Quality is a new paradigm for construction.

• Built-in-Quality is a basic part of the Lean journey.

Thank you