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Hydrostatic Testing Calculator
Calculate working pressure, test pressure, and make-up water allowance
Step 1: Determine Minimum Required Working Pressure (WP)
WP = RP + H1 + FL
Auto-filled based on system year
Height of hydraulically most disadvantaged hydrant from lowest hydrant in the system
Min allowable FL = 100 kPa, Max Allowable FL = 150 kPa
Reference Tables
Table D.1: Minimum Residual Pressure
| Year(s) | Fire Hydrant System | Minimum Residual Pressure (kPa) |
|---|---|---|
| 1921 to 1974 | HOB Act / CA17 | 700 |
| 1974 to 1994 | Ordinance 70 | 700 |
| 1994 onwards | AS 2419.1 | 700 |
Step 2: Determine Hydrostatic Test Pressure (HTSP)
HTSP = (WP +/- H2) × FoS
Height from booster to lowest hydrant in system
Auto-filled based on system year selected in Step 1 (can be manually changed)
Table D.2: Minimum Required Factor of Safety
| Year(s) | Fire Hydrant System | Factor of Safety |
|---|---|---|
| 1921 to 1974 | HOB Act / CA17 | 1.25 |
| 1974 to 1994 | Ordinance 70 | 1.25 |
| 1994 onwards | AS 2419.1 | 1.5 |
Step 3: Determine Make-Up Water Allowance
⚠️ Important:
If there is any section of underground pipework in the system, you must select the "Includes Underground Pipework" option.
The formula can only be used when there is no underground pipework in the system.
If there is any section of underground pipework in the system, you must select the "Includes Underground Pipework" option.
The formula can only be used when there is no underground pipework in the system.
Ordinance 70 Table
| Number of Hydrants | Flow Rate (L/sec) | Make-up Water Allowance (Litres per 30 min) |
|---|---|---|
| 1 | 10 | 2.5 |
| 1 | 11 | 2.75 |
| 1 | 15 | 3.75 |
| 2 | 20 | 5 |
| 2 | 22 | 5.5 |
| 3 | 30 | 7.5 |
| More than 3 | Greater than 30 | Flow rate (l/sec) × 0.25 |
Q = 0.07 × L × D × H
Pipeline length in kilometres
Internal pipe diameter in metres
Average test head over system length
⚠️ Important: Make-up water must not exceed the calculated allowance for the system to pass the hydrostatic test.
Step 4: Test Result & Report Details
Name of person who witnessed the test (optional)
Total water used during the 30 minute test (auto-fills from interval readings below)
Address of the site where the test was performed
Interval Readings (6 minute intervals)
Record pressure and make-up water at each 6-minute interval. Total make-up water auto-fills above.
| Interval | Pressure (kPa) | Make-Up Water (litres) |
|---|---|---|
| 6 min | ||
| 12 min | ||
| 18 min | ||
| 24 min | ||
| 30 min |
Notes will be included in the PDF report
Testing Procedure & Acceptance Criteria
📋 Testing Procedure
Follow the standard hydrostatic testing procedure as outlined in the relevant fire hydrant system standard (AS 2419.1, Ordinance 70, or HOB Act/CA17).
✅ Acceptance Criteria
The system passes if the make-up water required during the test period does not exceed the calculated allowance above.