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Standalone HydraCALC (Location)

**Description:**

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).

1.

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.

2.

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;