table: pipe_status

id     maintenance_id         pipe_id        status
1      1                      1              clean
2      1                      2              clean
3      1                      3              dirty
4      1                      4              dirty
...
1000   1                      1000           dirty
1001   2                      1              clean
1002   2                      2              clean
1003   2                      3              dirty
1004   2                      4              clean
....
2000   2                      2000           dirty