Grading System Example

As observations are added to an inspection, users assign them a defect and the system automatically fills in attribute information about that defect. Based on the PACP/MACP system, the program calculates the grade of the damage (the severity of the damage) and the number of occurrences the damage represents (usually 1, but may be more if it is a continuous defect). The system then uses these grades and occurrences to calculate the pipe or structure's rating.

Below is an example of a Grading System Code Matrix that complies with NAASCO PACP/MACP standards and explanations of how the Ratings fields are calculated.

Sample Grading Matrix

This matrix represents the calculations performed automatically by the system based on the PACP/MACP code selected by the user in the Observations record.

* Grades are automatically calculated by the system on the Observation record in the Grade fields.

* Occurrences are automatically calculated by the system on the Observation record in the Number fields.

* Ratings are automatically calculated by the system on the Condition Ratings tab in the Ratings fields.

Pipe Ratings

Pipes and structures are graded based on the number and severity of defects observed. Ratings are found on the Condition Ratings tab.

Structural and O&M Ratings

Structural and O&M Ratings are calculated by:

1. Grouping the observations by type and grade.
2. Multiplying each grade by the # of occurrences.
3. Adding the results of Step 2.

Example

Total Ratings

Total Ratings are calculated by:

• Adding the results of the Structural and O&M Ratings.

Example

Rating Indexes

A Rating Index is the average grade of a type of defect found in the inspection. These calculations are based on the pipe ratings and on the number of occurrences. An index is calculated by:

• Rating Index Structural = Total Structural Rating/Total Structural Occurrences
• Rating Index O&M = Total O&M Rating/Total O&M Occurrences
• Rating Index Total = Total Rating/Total Occurrences

Example

Quick Ratings

Quick Ratings are codes that give users an overview of the worst defects observed during the inspection.

Structural and O&M Quick Ratings

Structural and O&M Ratings are calculated by:

1. Grouping the observations by type and grade.
2. Identifying the highest grade for a type of defect.
3. Identifying the number of occurrences of that grade.
4. Identifying the second highest grade for a type of defect.
5. Identifying the number of occurrences of that grade.
6. Forming the Quick Rating using the following syntax:

[Highest Grade for Type][# of Occurrences][Second Highest Grade for Type][# of Occurrences]

Example

Total Quick Ratings

Structural and O&M Ratings are calculated by:

1. Grouping the observations by type and grade.
2. Identifying the highest grade of all defects.
3. Identifying the number of occurrences of that grade.
4. Identifying the second highest grade of all defects.
5. Identifying the number of occurrences of that grade.
6. Forming the Quick Rating using the following syntax:

   [Highest Grade][# of Occurrences][Second Highest Grade][# of Occurrences]

Example

Note: According to PACP/MACP, if the number of occurrences is greater than 9, the letters A-Z are used to represent additional occurrences in the Quick Ratings.