Six Sigma Approach for Improving Construction Quality Process

1. Introduction:

High-quality management is placed to deliver the highest quality achievable with the given budget. They help in organization and achieving the outlined goal. Since there are many aspects affecting the construction process, high-quality management approaches observe and analyze the effect of each step. This helps in developing an understanding of the root cause of the problem and helps in developing effective and precise solutions.

The Six Sigma approach is a high-quality management approach first used Motorola was introduced by Mr. Bill Smith. The Greek letter ‘Sigma’ means deviation. In mathematics, ‘Sigma’ is used for the term of standard deviation from its mean.Six Sigma is an analytical and data-driven process that uses a wide range of tools to achieve improvement. This approach aims at reducing variation in processes in turn providing consistent and desired outcomes. It is a top-down and resource-intensive approach. It focuses on process improvement by controlling the 6 M’s of the production process. It has integrated DMAIC Model for continuous improvement. Six-sigma is a highly effective method designed for achieving customer satisfaction.

2. Six-Sigma Approach:

The DMAIC model of six sigma approach has 5 stages, which are show below graphically:

  1. Define the problem that you want to eliminate
  2. Measure the current performance
  3. Analyze root cause through organized data
  4. Improve the process by doing modification based on root cause analysis
  5. Control the future process
  1. Define the problem: 

This is the input phase which requires inputs from the management team. It defines the scope of the project and specifies the problems encountered. Here goals and implementation plan for process improvement are defined. The client’s value and definition of quality according to them is also integral input at this phase. Let us consider the example of quality control. The traditional method has certain drawbacks. The process needs to be standardized where all the data can be stored, organized, and retrieved easily. This is the definition of the problem in regard to the six sigma approach.

  1. Measure key Aspects:

As the name suggests the main aim of this step is to collect data. As the earlier phase, it is also the input stage. Here key aspects affecting the production procedure are recognized and impact is analyzed. This stage unlike the first one collects data in real time and analyzes the available data from earlier reports. The data collection plan collects input from different levels of organization and figures out the factor leading to variation. Now measuring key aspects of quality control is actual site inspection with holistic processes and checklists.

  1. Analyze the Data:

This stage is completely based on transforming raw collected data into a statistical format. It utilizes different tools for grouping and organizing the data. Some of the tools are fishbone diagrams, Hypothesis testing, work breakdown organization, flow charts, etc. At the end of this phase you, the team pinpoints the factor causing variation. This conclusion is validated through the data analysis and can be cited for variation in the production process. 

The data needs to be organized for root cause analysis. The example taken here is multiple works done by contractors and checklists and data retrieved show that the crew needs to be updated on the technology used. This conclusion is reached by considering all the various scenario that affects work condition from weather to skillfulness & accreditation of the personnel.

  1. Improve current Process:

Previously done analysis helped in the determination of variation causing factors. Now, the approach demands rectification in the process. This is done by developing a solution or solution set for a problem. Various options can be exercised to improve the current process. The most appropriate method can be selected for implementation on a large-scale basis. This implementation plan is designed to mitigate risk and specifics such as action to be taken, the person in charge, the person responsible for carrying out the procedure, and the inspection team are also mentioned. This implementation plan is also discussed with the client to increase customer satisfaction and transparency for the successful completion of the project.

For example, the quality control method on-site is conventional and needs upgradation to digital tools. This method needs a clear implementation plan and training. This can only be done by the head of the organization overseeing this process.

  1. Control the future Process:

The control of the future process is allotted to the responsible party who can efficiently implement the process. Standards are established according to requirements and verification of benefits and profits are also done. This implementation is also monitored, and detailed reports are submitted. The salient feature of this step is to hold the gain as well as increase it using new modifications. Further processes are controlled and evaluated through continuous data monitoring via central dashboard and rating provided on it.

3. The focus of Six Sigma Approach – 6 M’s 

As mentioned earlier the focus of this approach is to improve its implementation process. This is done by the principles of the DMAIC Process. But the main focus of these processes is on 6 control factors that cause variations. These 6 Factors are materials, method, machines, manpower, measurement, and mother nature. These factors cause variations as they fluctuate. 

Some of the reasons for fluctuations are mentioned below:

  1. Materials: Materials are manufactured by various methods. Its content and compositions differ from producer to producer. Now if a certain method requires a specific type of material to fulfill its basic requirement. The specifications are in their make & compositions. Now if the process utilizes different materials, then desired outcome cannot be achieved. Also, transportation, storage & duration of storage matter in construction materials. For example, cement needs to be stored in a cool dry place 150-200 mm above ground. 
  2. Method: Methods are a major cause of variation on construction sites. The method executed by a contractor can be different from another contractor. This can lead to differences in quality delivered. Concreting done on-site by a contractor uses accurate measures and uses a concrete mixer whereas another contractor also uses an automatic mixer, but no accurate measures are used. Then the quality of concrete will differ and can create technical problems.
  3. Machine: This includes all the machinery, tools, and equipment used in the construction process. This also includes factors such as the leasing period and renting cost if the equipment is not purchased. This needs critical inventory and needs to be updated regularly. Failure in this can cause disruption of work as construction site completely depends on mechanical tools to carry out even simplest of all activity such as lining.
  4. Manpower: Labor capital is the most sensitive factor amongst all. They need to be treated respectfully and paid accordingly. This factor only fluctuates if the rates, they are provided are not sufficient. Manpower also includes the management system and human resources required to run operations. It needs a clear chain of command and standards to follow.
  5. Measurement: It basically includes the inspections system and standards which the organization upholds in terms of quality. If the inspection personnel is not trained and motivated enough to carry out the process enthusiastically then it will lead to undesired results. Training also plays important role in this aspect of fluctuation. 
  6. Mother Nature: As the name suggests it includes climatical aspects which are out of human control. If climatic conditions are unfavorable all activities will be at a halt. This can be considered while planning a project but there is always a possibility of variation. 

4. Advantages of the Six Sigma Approach:

The advantages of the six sigma approach are as follows:

  1. Increased customer satisfaction. This generally leads to an increase in revenue stream as the idea spreads about company indulges high standards for quality management.
  2. As it is a top-down approach, it is highly structures and logical. It requires solid data backup and proof to introduce a change in the system.
  3. The output from one phase is the input for another end. This leads to highly data web which requires input from each level of the workforce.
  4. It reduces the deviation in any process by controlling factors affecting it and organizing the timeline and workflow.

5. Drawbacks of Six Sigma Approach:

The disadvantage to this method is that it is a highly complicated system. Thus, a company with an already existing system of quality control might find it difficult to adopt. New companies adopting this system needs patience and strong workforce subordinate to deliver the required results. This is the only drawback to this system and one might be able to overcome it if all levels of workforce in an organization are given importance and their input is considered valuable.

6. Conclusion:

The conclusion stands that the only way to implement this complex methodology is by adopting a holistic approach. This method is very efficient and preferred over another method as it considers six factors of deviation. This is a salient feature of this method and adds value to this method. The six-sigma approach is top a down approach which is a standard approach used by construction firms worldwide.


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