Grading System Code Matrix Example

Below we've provided a sample Grading System Code Matrix that complies with NAASCO PACP standards. This matrix represents the calculations performed automatically by the system based on the PACP code selected by the user in the Observations record. For additional information on adding Observation records, follow this link.

1. Pipe segments are graded based on the number and severity of defects observed. To determine a pipe's segment Structural and O&M Grade Scores, the system multiplies the pipe Grade value by the Structural and O&M value. Examples of these calculations are listed below:
   • A pipe with a grade of 1 and a structural occurrence value of 1 receives a structural segment grade of 1 (1*1=1).
   • A pipe with a grade of 2 and an O&M value of 5 receives a O&M segment grade of 10 (2*5=10).
2. A pipe segment's overall scores equal the sum of the Structural and O&M Occurrence values as well as the sum of the Segment Grade Scores. Examples are listed below:
   • A pipe with a Structural Occurrence value of 1 and an O&M Occurrence value of 3 receives an Overall Occurrence value of 4 (1+3=4).
   • A pipe with a Structural Grade score of 6 and an O&M Grade score of 10 receives an Overall Grade score of 16 (6+10=16).
3. Consult the following matrix for additional sample calculations:

   

4. After performing the above calculations in the Observation records, the system uses these calculated values to determine the Pipe Ratings found at the top of the Condition Ratings tab. As you can see in the example below, these ratings reflect the sum of the Structural, O&M and Overall Segment Grade Scores:
   • Pipe Ratings Structural: 48
   • Pipe Ratings O&M: 35
   • Pipe Ratings Total: 83
5. The system then determines the Quick Ratings fields also found at the top of the Condition Ratings tab. These ratings depict the number and severity of the highest grade defects in the pipe segment. For example:
   • Quick Rating Structural: 5345
   • Quick Rating O&M: 5234
   • Quick Rating Total: 5545

     Note: These ratings are read differently than the Pipe Ratings; they are not read as whole numbers. Instead, the Quick Rating Structural above of 5345 represents three defects graded 5 on the pipe segment and five defects graded 4 on the pipe segment. Similarly, the Quick Rating O&M of 5234 represents two defects graded 5 on the pipe segment and four defects graded 3. You'll note that defects are listed in order of severity, with the worst grade listed first. Since the Quick Rating O&M value above goes from a defect of 5 to a defect of 3, that means that there were no defects graded 4 on that pipe segment.

6. The system also uses these values to determine the Structural Index, O&M Index, and Overall Index, although these values are not displayed on the Condition Ratings tab. For all the values listed above, our sample pipe segment receives the following index values:
   • Structural Index: 3.4
   • O&M Index: 2.5
   • Overall Index: 3.0