Quality Tools for Oil and Gas Industry

Introduction

Quality tools are the charts, check sheets, diagrams, graphs, techniques, and methods that are used to create an idea, engender planning, analyze the cause, analyze the process, foster evaluation, and create a wide variety of situations for continuous quality improvement. Applications of tools enhance chances of success and help maintain consistency, accuracy, increase efficiency, and process improvement.

Categorization of Tools

There are several types of tools, techniques, and methods, in practice, which are used as quality improvement tools and have a variety of applications in manufacturing and process industry. However, all of these tools are not used in construction projects due to the nature of construction projects, which are customized and nonrepetitive. Some of these quality management tools that are most commonly used in construction industry are listed under the following broader categories:

Classic Quality Tools

• 2. Management and planning tools
• 3. Process analysis tools
• 4. Process improvement tools
• 5. Innovation and creative tools
• 6. Lean tools
• 7. Cost of quality
• 8. Quality function deployment (QFD)
• 9. Six Sigma
• 10. Triz

Brief description of these tools is given below.

4.2.1 Classic Quality Tools

Classic quality tools have a long history. These tools are listed in Table 4.1.

All of these tools have been in use for since World War II. Some of these tools date prior to 1920. The approach includes both quantitative and qualitative aspects, which, taken together, focus on companywide quality.

Brief definition of these quality tools is as follows (values shown in the figures and tables are indicative only).

TABLE 4.1

Classic Quality Tools

Source: Abdul Razzak Rumane. (2013). Quality Tools for Managing Construction Projects. Reprinted with permission from Taylor & Francis Group.

4.2.1.1 Cause-and-Effect Diagram

Cause-and-effect diagram is also called as Ishikawa diagram, after its developer Kaoru Ishikawa, or fishbone diagram. It is used to identify possible causes and effects in process. It is used to explore all the potential or real causes that result in a single output. The causes are organized and displayed in graphical manner to their level of importance or details. It is a graphical display of multiple causes with a particular effect. The causes are organized and arranged mainly into six categories. These are as follows:

• 1. Machine
• 2. Manpower
• 3. Material
• 4. Method
• 5. Measurement
• 6. Environment

The effect or problem being investigated is shown at the end of horizontal arrow. Potential causes are shown as labeled arrows entering the main cause arrow. Each arrow may have a number of other arrows entering as the principal cause or factors are reduced to their subcauses. Figure 4.1 illustrates an example cause-and-effect diagram for rejection of concrete works for not complying with contract specifications

FIGURE 4.1 Cause-and-effect diagram for rejection of concrete work. (Abdul Razzak Rumane. (2013). Quality Tools for Managing Construction Projects. Reprinted with permission from Taylor & Francis Group.)

4.2.1.2 Check Sheet

Check sheet is a structured list, prepared from the collected data to indicate how often each item occurs. It is an organized way of collecting and structuring data. The purpose of check sheet is to collect the facts in the most efficient manner. Data are collected and ordered by adding tally or check marks against predetermined categories of items or measurements. Figure 4.2 illustrates check sheet for checklist approval record for control valves.

4.2.1.3 Control Chart

Control chart is the fundamental tool of statistical process control (SPC). The control chart is a graph used to analyze how a process behaves over time and to show whether the process is stable or is being affected by special cause of variation and creating an out-of-control condition. It is used to determine whether the process is stable or varies between the predictable limits. It can be employed to distinguish between the existence of a stable pattern of variation and the occurrence of an unstable pattern. With control charts, it is easy to see both special and common causes of variation in a process. There are many types of control charts. Each is designed for a specific

FIGURE 4.2 Check sheets.

FIGURE 4.3 Control chart for HVAC air handling unit air distribution (cfrn). HVAC, heating, ventilation, and air conditioning. (Abdul Razzak Rumane. (2013). Quality Tools for Managing Construction Projects. Reprinted with permission from Taylor & Francis Group.)

kind of process or data. Figure 4.3 illustrates control chart for distribution of HVAC (heating, ventilation, and air conditioning) air handling unit air.

4.2.1.4 Flowchart

Flowchart is a pictorial tool that is used for representation process in sequential order. Flowchart uses graphic symbols to depict the nature and flow of the steps in a process. It helps to see whether the steps of process are logical, uncover the problems or miscommunications, define the boundaries of a process, and develop a common base of knowledge about a process. The flow of steps is indicated with arrows connecting the symbols. Flowcharts can be applied at all stages of the project life cycle. Figure 4.4 illustrates flowchart for contractor’s staff approval in construction projects.

4.2.1.5 Histogram

Histogram is a pictorial representation of frequency distribution of the data. It is created by grouping the data points into cell and displays how frequently different values occur in the data set. Figure 4.5 illustrates histogram for employee reporting time.

4.2.1.6 Pareto Chart

Pareto chart is named after Vilfredo Pareto, a 19^,h-century Italian economist who postulated that a large share (80%) of wealth is owned by a small (20%) percentage of population. Pareto chart is a graph bar having series of bars whose height reflects the frequency of occurrence. Pareto charts are used to display the Pareto Principle in action and arrange data so that the few vital factors that are causing most of the problems reveal themselves. The bars are arranged in descending order of height from left to right. Pareto charts are used to identify those factors that have greatest cumulative effect on the system, and thus, less significant factors can be screened out

FIGURE 4.4 Flowchart for contractor’s staff approval. (Abdul Razzak Rutnane. (2013). Quality Tools for Managing Construction Projects. Reprinted with permission from Taylor & Francis Group.)

from the process. Pareto chart can be used at various stages in a quality improvement program to determine which step to take next. Figure 4.6 illustrates Pareto chart for division cost of construction project.

4.2.1.7 Pie Chart

Pie chart is a circle divided into wedges to depict proportion of data or information in order to understand how they make up the whole. The entire pie chart represents all the data, while each slice or wedge represents a different class or group within the whole. The portions of entire circle or pie sum to 100%. Figure 4.7 illustrates the contents of contractor’s site staff at construction project site.

4.2.1.8 Run Chart

Run chart is a graph plotted by showing measurement (data) against time. Run charts are used to know the trends or changes in a process variation over time over the average and also to determine if the pattern can be attributed to common causes of

FIGURE 4.5 Employee reporting histogram. (Abdul Razzak Rumane. (2013). Quality Tools for Managing Construction Projects. Reprinted with permission from Taylor & Francis Group.)

FIGURE 4.6 Pareto analysis for construction cost.

variation or if special causes of variation were present. A run chart is also used to monitor process performance. Run charts can be used to track improvements that have been put in place, checking to determine their success. Figure 4.8 illustrates run chart for weekly manpower of different trades of a project. It is similar to control chart but does not show control limits.

FIGURE 4.7 Pie chart for site staff. (Abdul Razzak Rumane. (2013). Quality Tools for Managing Construction Projects. Reprinted with permission from Taylor & Francis Group.)

4.2.1.9 Scatter Diagram

A scatter diagram is a plot of one variable versus another. It is used to investigate the possible relationship between two variables that both relate to the same event. It helps to know how one variable changes with respect to other. It can be used to identify potential root cause of problems and to evaluate cause-and-effect relationship. Figure 4.9 illustrates scatter diagram for pipe length quantity of various lengths.

4.2.1.10 Stratification

Stratification is a graphical representation of data collected from different data. Figure 4.10 illustrates stratification diagram for pipe bundles.