material selection: practical use of the kepner …

2019 TAPPI PEERS Conference – St. Louis, MO of 9

MATERIAL SELECTION: PRACTICAL USE OF THE KEPNER TREGOE DECISION MODEL Jason M. Hinely, P.E. Corrosion Probe, Inc. 812 Town Park Drive East, Suite 100 Rincon, GA 31326 ABSTRACT This paper presents a basic overview of the Kepner Tregoe decision tool and how it can be implemented in a systematic way to assist a project engineering team with making tough material selection decisions that can add long-term value and reliability to their equipment.

In a more competitive pulp and paper industry, the project team has to be smarter regarding material selection for process applications. At a basic level, material selection is based on resistance to corrosion and/or other forms of deterioration, maximum temperature thresholds, availability and cost. However, other factors that can play a vital role in the selection of a material include:

Value (Life Cycle Cost Analysis, which considers costs associated with base material, fabrication, inspection/maintenance)

Repair Methods and Practicality Past Experiences Ability to Modify or Add-on Constraints

o Schedule o Safety o Budget

INTRODUCTION

Corrosion Probe has found through the years that many of clients limit material selection of fixed equipment to one primary factor, INITIAL INVESTMENT COST. Though this is a key factor, it represents truly short-term thinking. Many other factors should be considered for material selection (to be detailed later). First, introduction of the decision-making thought process is key for this method of material selection.

2D versus 3D problems

On the surface, many of the project engineering decisions appear to be 2D. More realistically, all of our problems are 3D: they have height, width, and depth. Take, for instance, the Rubik’s cube: a fairly simple 3D object composed of multiple cubes, individually colored on each square 2D face. The original 3x3x3 Rubik’s cube has 43,252,003,274,489,856,000 combinations to it…yes, that’s 43 quintillion. What’s even more astounding is that the world record for solving the cube is 3.47 secondsi. 43 quintillion combinations, solved in 3.47 seconds. Suddenly,


complex engineering problems seem less challenging. The key to solving the Rubik’s cube is to go through a systematic approach that yields positive results every time.

Figure 1 – The Rubik’s Cube

Systematic Methods

If the Rubik’s cube can be solved in 3.47 seconds using a systematic approach, solving the most challenging material selection challenges should be possible using a systematic, un-biased approach like the Kepner Tregoe Decision Model. The key benefits to a systematic approach like this are that it:

cuts through the clutter and complexity;

applies clear thinking; and

helps identify and plan for a decision/resolution.


Kepner Tregoe Decision Modelii

The Kepner Tregoe Decision Model was developed in the 1960’s by Charles H. Kepner and Benjamin B. Tregoe. It is a structured methodology for gathering, prioritizing, and evaluating information in an un-biased, professional manner. It has three major components:

Situation Appraisal – The first step in the decision model is to clarify the situation. This includes outlining any concerns and choosing a preferred direction.

Problem Analysis – The problem should be clearly defined in this step.

Decision Analysis – In this step, the alternative solutions are identified. Each solution is then analyzed through a risk-based process.

As part of the Decision Model, the following must be established:

Strategic Requirements (MUSTS) – The MUSTS of any project should be decided by a strategic team of key stakeholders. This team may include, but should not be limited to, purchasing, engineering, maintenance, and operations. MUSTS criteria may include budget and schedule constraints. They are the initial deciding factors of any possible solution. The MUST criteria should be listed as to have a “Yes/No” or “Pass/Fail” response. If any option fails the MUST criteria, it can be eliminated from consideration.

Operational Objectives (WANTS) – Distinguishing MUSTS from WANTS will help clarify the project team’s thought process and align them towards a common solution. Each WANT will be listed and then weighted by the importance of the WANT.

Risk Analysis – For long-term investing in financial markets, it would be considered wise to analyze all the major risks of an investment. For significant investments in fixed equipment, an evaluation of the risks should be performed if something doesn’t turn out as planned. Risk factors typically include:

o Exceeding schedule

o Exceeding initial budget

o Lack of performance versus design

o Poor fabrication

Pulp Mill Fixed Equipment Application

In this section, the team will perform a Decision Analysis using the tools described above on a Bleach Plant D-Stage Seal Chest.

Background

This D-Stage Seal Chest was originally constructed in 1985 using form-and-pour tile construction with steel-reinforced concrete walls. The current operational conditions include bleached softwood pulp; pH 3 – 4; 180°F; and > 500 ppm chlorides. The chest performed well for the first half of its life, but in recent years, maintenance costs have exceeded $X annually,


with multiple leaks occurring during operation. There is concern for the chests’ long-term reliability and structural integrity. Plans are being made to repair or replace this tank.

Repair/Replacement Options

In order to perform the decision analysis, the project engineering team has to select several options, trying to limit to a maximum of six (6) for practical and concise evaluation. For this D-Stage Seal Chest example, let’s look at five (5) options:

1. Repair (in kind) Using Localized Concrete Wall Replacement and Tile Lining System

2. Replacement with Fiberglass Reinforced Plastic (FRP)

3. Replacement with 6% Mo Stainless Steel

4. Replacement with Concrete Substrate Walls with Internal Thermoplastic Lining System

5. Replacement (in kind) with Tile-Lined Concrete Chest

MUST Criteria

For this specific application, the mill has several MUST criteria, they include:

Construction materials MUST be onsite ready for field assembly in March 2020.

MUST be implemented in less than 43 days (the longest outage window available).

Initial cost MUST not exceed $Y.

See Table 1 for the evaluation of the MUST criteria.

MUST Criteria Option

1 Option

2 Option

3 Option

4 Option

5

Construction materials can be onsite ready for field assembly in

March 2020 YES YES YES NO YES

Can be implemented in less than 43 days

YES YES YES YES YES

Initial cost does not exceed $Y YES YES YES YES YES

Table 1 – Evaluation of MUST Criteria (note that Option 4 does not pass the initial MUST criteria and can be removed from the evaluation).


After the MUST criteria have been evaluated, the next step is establishing WANTS. A concise and meaningful list of WANTS should be evaluated in an un-biased manner. The team can decide how many WANTS should be included in this part of the evaluation. These WANTS can include, but should not be limited to, the following:

Ability to resist temperature and chemical exposure

Lowest total installed cost

Minimum construction impact on schedule, sequencing, etc.

Personal experience with this material

Easily spot-repaired

Readily available materials and qualified installers

Minimal maintenance cost for first 5 years of service life

At least 25-year service life

Minimal safety exposures during construction

Can be maintained by local service providers

Can be easily modified in the future for larger capacity

Flexibility to accommodate future elevated process conditions

Mill manager confidence (I added this one just for fun!).

Once these WANTS are established, then the project team assigns a relative importance or weighting factor (1 = Lowest; 10 = Highest). This weighting factor is based on which of these WANTS are the most critical to “get right”. It is practically an importance ranking for the WANTS. Then the team will assign a performance factor by each option (1 = Poorest, 5 = Best). This performance factor can be a subjective or quantitative “score” of how well the project team anticipates this option to perform regarding the WANT criteria. This performance factor can be assigned based on previous experiences, known data points, and/or experiences from the team. For example, Decision Criteria 1 – Ability to Resist Temp/Chemical Exposure can be assigned a value of 1 to 5, 1 = >20 mils of corrosion rate per year, 5 = <2 mils of corrosion rate per year . As another example, Decision Criteria 2 – Lowest Total Installed Cost where 1 = 2($Z) and 5 = $Z (i.e. lowest cost). The total for each option is then tabulated with the highest relative performance score being the best option. See Table 2 as an example.

Risk Analysis

For this specific scenario, several key factors are analyzed based on risk associated with the project. These include schedule, budget, and performance. The project team should rate the seriousness of the impact of the risk factor (1 = least severe, 10 = most severe). The seriousness


factor depends of the impact of such an event. For instance, row 1 in Table 3 states “Exceeds 45 days to implement”. If the repair/replacement options has a possibility to exceed the 45 days and this causes a major impact to mill operation, then it would be fairly high on the seriousness factor.

Additionally, the team should evaluate the probability of the occurrence of each option (0 = no chance; 1 = 100% chance of occurring). For instance, Row 2 in Table 3 states “Continues to be a maintenance problem. The probability factors for Options 2 and 3 (new FRP and 6% Mo SS respectively) are fairly low (0.3) since they would be brand-new tanks made from corrosion-resistant materials. For Option 1 (Repair), the likelihood of continued maintenance is higher and thus has a probability ranking of 0.7.

The relative risk is the total score for the option. The lower score of the option is the lowest risk. See Table 3 for a detailed analysis.

Conclusion

The project team should then look at the Relative Performance Score (higher = better) and the Relative Risk Score (lower = better) and choose the “best” option. For this D-Stage Seal Chest, Option 3 has the highest Performance Score and the lowest Risk Score. Realize that this option was not the Lowest Initial Investment Cost (actually the highest). Utilizing the Kepner-Tregoe decision model as a template, a project engineering team can better refine their material selection process to include multiple weighting factors as well as a risk evaluation.


Option 1Repair

Option 2FRP Tank

Option 36%Moly SS Tank

Option 5Brick-Lined Tank

Decision Criteria Weighting

Factor Performance

Factor Score Performance



Factor Score

Ability to resist to temp/chemical exposure 10 2 20 4 40 4 40 3 30 Lowest Total Installed Cost 9 5 45 3 27 2 18 3 27 Minimum Construction Impact (schedule, sequencing, etc) 9 2 18 4 36 4 36 2 18

Ability to resist temp/pressure/chemicals during wash down 8 3 24 3 24 3 24 3 24

Previous experience with materials in this service 8 4 32 4 32 3 24 4 32 Easily spot repaired 7 3 21 3 21 4 28 3 21

Readily available materials and qualified installers 7 4 28 3 21 3 21 4 28

Minimal maintenance for initial 5 years of service 6 2 12 4 24 4 24 3 18

Minimal safety concerns during construction 6 3 18 4 24 4 24 3 18 Exceed 25-year service life 5 1 5 3 15 4 20 4 20

Can be maintained by local contractor service providers 5 4 20 3 15 4 20 4 20

Can modify/attach to tank wall easily 4 2 8 2 8 4 16 2 8 Process conditions change in future - (flexibility of solution) 4 3 12 3 12 4 16 3 12

Mill management experience with material 3 5 15 4 12 3 9 5 15 Relative Performance Scores by Option Option 1: 278 Option 2: 311 Option 3: 320 Option 5: 291

Table 2 – Evaluation of WANTS


Option 1 -Repair Option 2 -FRP Tank Option 3 -6%Mo SS

Tank Option 5 -Brick-Lined Tank

Risk Factors Seriousness

Factor Probability

Factor Score Probability



Factor Score

Exceeds 45-days to implement 10 0.4 4 0.1 1 0.1 1 0.4 4

Continues to be a maintenance problem 9 0.7 6.3 0.3 2.7 0.3 2.7 0.4 3.6 Potential to exceed budget 6 0.8 4.8 0.3 1.8 0.2 1.2 0.2 1.2 Relative Risk by Option Option 1: 15.1 Option 2: 5.5 Option 3: 4.9 Option 5: 8.8

Table 3 – Risk Analysis


Summary

Using a systematic approach, like the Kepner Tregoe Decision Model, can assist project engineers with selecting the best possible material for a project by analyzing a range of factors, including the risk of each material choice. Additionally, this effective tool helps improve communication between engineers, maintenance, and operations.

References

Kepner, C.H. & Tregoe, B.B. (1965), The Rational Manager

Kepner, C.H. & Tregoe, B.B. (1980), The New Rational Manager

i Retrieved from https://ruwix.com/the‐rubiks‐cube/history‐of‐the‐world‐record‐evolution/. ii Information retrieved from www.kepner‐tregoe.com

Gateway to the Future

Material Selection: Practical Use of the Kepner Tregoe Decision Model

Jason M. Hinely, P.E.Director of Pulp & Paper Services


2D VERSUS 3D Problems

The Rubik’s Cube• # of combinations

• World record

3x3x3 Rubik’s Cube


Benefits of a systematic, un-biased approach like Kepner Tregoe, for material selection:

• cuts through the clutter and complexity

• applies clear thinking

• helps identify and plan for a decision/resolution.


Kepner Tregoe Decision Model

Developed in 1960’s by Charles H. Kepner and Benjamin B. Tregoe

A structured method for gathering, prioritizing, and evaluating information in an un-biased and professional manner.


Three major components:

• Situation Appraisal – The first step in the decision model is to clarify the situation. This includes outlining any concerns and choosing a preferred direction.

• Problem Analysis – The problem should be clearly defined in this step.

• Decision Analysis – In this step, the alternative solutions are identified. Each solution is then analyzed through a risk-based process.


The following must be established:

• Strategic Requirements (MUSTS)

• Operational Objectives (WANTS)

• Risk Analysis


Strategic Requirements (MUSTS)

The MUSTS of any project should be decided by a strategic team of key stakeholders. This team may include, but should not be limited to, purchasing, engineering, maintenance, and operations.

MUSTS criteria may include budget and schedule constraints. They are the initial deciding factors of any possible solution.

The MUST criteria should be listed as to have a “Yes/No” or “Pass/Fail” response.

If any option fails the MUST criteria, it can be eliminated from consideration.


Operational Objectives (WANTS)

Distinguishing MUSTS from WANTS will help clarify the project team’s thought process and align them towards a common solution.

Each WANT will be listed and then weighted by the importance of the WANT.


Risk Analysis

For significant investments in fixed equipment, we should also evaluate the risks if something doesn’t turn out as planned.

Risk factors typically include:

• Exceeding schedule

• Exceeding initial budget

• Lack of performance versus design

• Poor fabrication

• Others?


Practical Example

D Stage Seal Chest

• Built 1985 using form-and-pour tile construction with steel-reinforced concrete walls

• Bleached softwood pulp; pH 3 – 4; 180°F; >500 ppm chlorides

• Recent maintenance costs have exceeded $X/year

• Plans are to repair or replace this tank


D Stage Seal Chest

Repair/Replace Options

1. Repair (in kind) Using Localized Concrete Wall Replacement and Tile Lining System

2. Replacement with Fiberglass Reinforced Plastic (FRP)

3. Replacement with 6% Mo Stainless Steel

4. Replacement with Concrete Substrate Walls with Internal Thermoplastic Lining System

5. Replacement (in kind) with Tile-Lined Concrete Chest


MUST Criteria

For this specific application, the project team has several MUST criteria, they include:

Construction materials MUST be onsite ready for field assembly in March 2020.

MUST be implemented in less than 43 days (the longest outage window available).

Initial cost MUST not exceed $Y.

MUST CriteriaOption

1

Option

2

Option

3

Option

4

Option

5

Construction materials can be

onsite ready for field assembly in

March 2020

YES YES YES NO YES

Can be implemented in less than 43

daysYES YES YES YES YES

Initial cost does not exceed $Y YES YES YES YES YES

Gateway to the Future Option 1

RepairOption 2FRP Tank

Option 36%Moly SS Tank

Option 5Brick-Lined Tank

Decision CriteriaWeighting

FactorPerformance

Factor ScorePerformance



Factor ScoreAbility to resist to temp/chemical exposure 10 2 20 4 40 4 40 3 30

Lowest Total Installed Cost 9 5 45 3 27 2 18 3 27Minimum Construction Impact (schedule, sequencing, etc) 9 2 18 4 36 4 36 2 18Ability to resist temp/pressure/chemicals during wash down 8 3 24 3 24 3 24 3 24Previous experience with materials in this service 8 4 32 4 32 3 24 4 32Easily spot repaired 7 3 21 3 21 4 28 3 21Readily available materials and qualified installers 7 4 28 3 21 3 21 4 28Minimal maintenance for initial 5 years of service 6 2 12 4 24 4 24 3 18Minimal safety concerns during construction 6 3 18 4 24 4 24 3 18Exceed 25-year service life 5 1 5 3 15 4 20 4 20Can be maintained by local contractor service providers 5 4 20 3 15 4 20 4 20Can modify/attach to tank wall easily (new penetrations, instrument supports…) 4 2 8 2 8 4 16 2 8Process conditions change in future - (flexibility of solution) 4 3 12 3 12 4 16 3 12Mill management experience with material 3 5 15 4 12 3 9 5 15

Relative Scores by Option Option 1: 278 Option 2: 311 Option 3: 320 Option 5: 291

Evaluation of WANTS

Highest score = best option


Risk Analysis

Lowest Score = Lowest Risk

Option 1 -Repair Option 2 -FRP TankOption 3 -6%Mo SS

Tank Option 5 -Brick-Lined Tank

Risk FactorsSeriousness

FactorProbability

Factor ScoreProbability



Factor ScoreExceeds 45-days to implement 10 0.4 4 0.1 1 0.1 1 0.4 4Continues to be a maintenance problem 9 0.7 6.3 0.3 2.7 0.3 2.7 0.4 3.6Potential to exceed budget 6 0.8 4.8 0.3 1.8 0.2 1.2 0.2 1.2

Relative Risk by Option Option 1: 15.1 Option 2: 5.5 Option 3: 4.9 Option 5: 8.8


DecisionFor this D-Stage Seal Chest, Option 3 (New 6% Mo SS Tank) has both the highest Performance

Score and the lowest Risk Score.

Realize that this option was not the Lowest Initial Investment Cost (actually the highest).


Summary

Using a systematic approach, like the Kepner Tregoe Decision Model, can assist project engineers with selecting the best possible material for a project by analyzing a range of factors, including the

risk of each material choice.

Additionally, this effective tool helps improve communication between engineers, maintenance, operations, and management.


Any Questions?

material selection: practical use of the kepner …

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