Abstract
An description of how the Fysisk Indeks should be calculated
Author
Steve Peregrine BEng Hons, Senior Technical Manager
Page Contents
Introduction
In the Danish DanDas standards, we have a calculated scoring value for the pipe called the Fysisk Indeks (Physical Index).
This is calculated in WinCan VX at the end of an inspection or when the user triggers a manual scoring of the inspection using the scoring machine.
The values that the calculations create are in 2 parts. First a structural grade is calculated (S) and then it is inserted into a second calculate that works out the Fysisk Indeks (F).
The values used to calculate S are taken from a look up table. The values used here are the same for DanDas 2.5 and 2.6 standards with only one minor difference, explained further down this page.
The calculations are the same for both standards.
The Lookup Table
These are the lookup values for the scores that are used to calculate the Fysisk Indeks. The values are the same for DanDas 2.5 and 2.6 Except for the two values at the bottom that are highlighted in red. These values are only used in DanDas 2.5 and are not used in DanDas 2.6.
The table is split by code groups in each line and by class in the columns 0-4.
Where observation codes have more than 2 characters, they begin with the two-letter code group, then a class number and then some other characterisations to describe the code, so the class number is always the 3rd character in the code string and the code group is always the first 2 characters in the code string.
Note the code group PF has 2 lines with different scores for each line, so;
codes PFn[D,F,I] should be scored by the first line, and
codes PFn[A,H,M,R] should be scored by the second line in the table.
The code VA is treated differently in DanDas 2.5 and 2.6 although the scoring is the same.
In DanDas 2.6, the user enters the class value with the code, but we do not record the class with the code string. It is instead stored in OBS_Q1_Value for this code.
In DanDas 2.5, the user enters a percentage value for the VA (water level) and the class is derived from this value so that:
0% = class 0
<=20% = class 1
<=40% = class 2
<=60% = class 3
>60% = class 4
The codes S1, S2 and S3 are used for inspection start, end and abandon.
These codes also have a user defined class which must be treated in the same way as VA code. The class for a Sn code represents the water level code.
VA and S1 classes are continuous from where they begin, so their score must be calculated along the length of the continuous item, but they are not marked as continuous observations in WinCan VX.
An example might be:
0m, S1, class 2
3.6m, VA, class 3
8.4m, S2, class 4
So in this case, the class 2 score from the S1 code is calculated until it changes or ends, and it changes at 3.6m with the VA code, so we get from the table 3.6 x 0.05 = 0.18
Then we have the VA class 3 code from 3.6m to 8.4m, so we have 0.2 x (8.4 - 3.6) = 0.96
The class 4 S2 (finish) code at the end is disregarded because it is at the end of the inspection and has no length, so this should not be considered in the calculations, similar for S3 (abandon) because the inspection cannot carry after this point.
The result of this is that the VA (water level) is defined in the inspection from the beginning to the end.
The Calculations
The calculations of S and F look like this:
Translated terms:
S = Structural Rate
L = Section Length
Ln = Length of the Observation - assume 1m if the observation is not continuous and S1 and VA codes are always continuous.
pn = Look Up value from the table above for the code group and class.
F = Fysisk Indeks = Service Rate or Physical Index.
The maximum F that any one inspection can score is 10, so no total calculation can be more than this.
Codes IN4, OB4, OS4 and RB4 automatically give the inspection a F of 10, regardless of how many times they appear in the inspection.
If a continuous observation is recorded by the user as 1m long or less, then we do not use the L term in the equation, we assume that the observation is not continuous. Continuous observations must be more than 1m long, or else they are not continuous.
Testing
The attached spreadsheet can be used for testing the calculation of Fysisk Indeks.
In it, you will enter the lengths of all observations in each code group with the specified class in the red cells, then enter the section length in the blue cell and the calculations will be made.
Where an observation code is a single point observation, enter a length of 1. If the code appears 4 times in the inspection, enter 4.
Where an observation is continuous, enter the full length of the continuous and sum up continuous lengths of the same code and class,
The code S1 (start) is treated the same as a the VA (water level) code, so if the section is 20m long and it has S1, class 2 at the beginning and no other VA codes during the inspection, then we enter 20 into the length for this code and class.
If there is a VA code class 3 at 8m, then we have 8m of S1 class 2, and then 12m of VA class 3 which gives us the total 20m.