Need to save a card for later?
Create a bookmark folder in your browser of choice (Chrome, Firefox...), and save individual cards in your bookmarks to view here later.
Standalone HydraCALC (Location)
Reviewing the results you notice a discrepancy between the k-factor of an equivalent k versus a sprinkler head using that equivalent k-factor
In the example below, EQ02 has a k-factor of 5.37. Reference point 1 is supposed to use the k-factor of EQ02 (5.37) but in fact is using a different value (5.36).
Elevations were used in the Equivalent K Piping tab of HydraCALC
It is not recommended to enter elevations in the Equivalent K Piping tab.
In this case the sprinkler is at 8'-4" and the branchline pipe at 7'-10".
Remove all elevations plus the blank row references to EQ01 & EQ02 in the 3rd and 5th rows.
In the System Piping tab, enter the sprinkler elevation as the elevation for node 1, not the branchline elevation.
The program is using a rounded flow to establish the k-factor for an equivalent k, but the actual flow to establish the k-factor for the flowing sprinkler.
While very rare, this rundown will explain how this is possible...
When calculating the equivalent k, the formula of [k √ p = Q] is used;
5.6 * sqrt(7) results in a flow of 14.816207 gpm at SP02, or rounded to 14.82 gpm.
At EQ02, a new pressure of 7.627 psi is calculated and with the rounded flow of 14.82 gpm, we have a new k-factor of 5.37 psi
The k-factor at reference point 1 is calculated based off the same pressure of 7.627 but the non-rounded flow of 14.816207. This results in a k-factor at node 1 of 5.36.
The formulas below demonstrate this;