NFPA 13 PRESSURE TEST PROCEDURES

NFPA 13 PRESSURE TEST PROCEDURES  (Aboveground Fire Systems):

A hydrostatic test is a pressure test to reveal the presence of leaks in the piping system. For fire protection systems, the piping is pressurized to 200 psi (13.8 bar) for a period of 2 hours. During this time period, the system piping is inspected for leaks. 

Leaks in the piping system are revealed either by observation of water droplets or by a reduction in test pressure. Any leaks or reduction in test pressure necessitates a repair of the pipe joint involved and a retest to verify that the leak has been repaired.

In cases where high pressure exists, the standard requires that the test pressure be 50 psi (3.5 bar) in excess of the normal system pressure if the resultant test pressure will be greater than 200 psi (13.8 bar)..

By NFPA:

Unless permitted by 24.2.1.2 through 24.2.1.8, all piping and attached appurtenances subjected to system working pressure shall be hydrostatically tested at 200 psi (13.8 bar) and shall maintain that pressure without loss for 2 hours. [NFPA 13-10: 24.2.1.1]

Portions of systems normally subjected to system working pressures in excess of 150 psi (10.4 bar) shall be tested as described in 24.2.1.1, at a pressure of 50 psi (3.5 bar) in excess of system working pressure. [NFPA 13-10: 24.2.1.2]

Where cold weather will not permit testing with water, an interim air test shall be permitted to be conducted as described in 24.2.2. This provision shall not remove or replace the requirement for conducting the hydrostatic test as described in 24.2.1.1. [NFPA 13-10: 24.2.1.3]

Modifications affecting 20 or fewer sprinklers shall not require testing in excess of system working pressure. [NFPA 13-10: 24.2.1.4]

Where addition or modification is made to an existing system affecting more than 20 sprinklers, the new portion shall be isolated and tested at not less than 200 psi (13.8 bar) for 2 hours. [NFPA 13-10: 24.2.1.5]

Modifications that cannot be isolated, such as relocated drops, shall not require testing in excess of system working pressure. [NFPA 13-10: 24.2.1.6] While there are multiple methods for conducting the hydrostatic test, basic procedures for conducting these are as follows.

Hydrostatic Test Procedure for Water-Based Fire Protection Systems Description

1.       General acceptance test of water-based fire protection systems

2.       Accomplished by visual inspection and hydrostatic pressure

Objective

1.       To ensure piping integrity and absence of leaks

Conditions/Assumptions

1.       Piping system, including all valves, drains, and accessories, are installed

2.       Underground supply has been installed, flushed, tested, and activated

Specifications

1.       Appropriate NFPA installation standard

2.       Underwriters Laboratories (UL) Fire Protection Equipment Directory

3.       Factory Mutual (FM) Approval Guide

4.       Local/state building codes (as applicable)

5.       Approved fire protection shop drawings

6.       Project specifications

Test Procedure

1.       Inspect the system to verify that openings are plugged and valves are closed.

2.       Connect the test pump to a convenient location in the system.

3.       Connect the water source to the test pump.

4.       Open the main control valve to fill the system. (If the water service is not installed or has not been flushed, fill the system through the test pump water source.)

5.       Fill the system slowly to avoid entrapment of air.

6.       Open a valve (such as the inspector’s test connection or a temporary valve) to vent any trapped air.

7.       Close the valve when water flows continuously through it.

8.       When the system pressure equals that of the water source, close the supply valve and inspect the entire system for leaks.

a.       Leaks may result from flanges not bolted properly, plugs not properly installed, cracked or improperly tightened fittings, etc.

b.      If leaks are found, open the 2-in. main drain connection or other low-point drain connection and allow the system to drain. Repair any leaks found and repeat this procedure.

c.       If no leaks are detected, begin to increase pressure with the test pump up to 200 psi or 50 psi in excess of the static pressure when static pressure exceeds 150 psi.

9.       Monitor the test gauge to determine that the system pressure is stable. If pressure drops, check for leaks in the system, for open valves, or for leaks in the test apparatus.

10.   Once it is determined that the test pressure has stabilized, disconnect the power to the test pump and notify the commissioning agent or authority having jurisdiction that the 2-hour test period has begun.

11.   Record the time of day and test pressure at this time.

12.   Hold the test pressure for 2 hours.

13.   After the test, open the drain valve to drain the system, or, if the system is to be commissioned immediately, relieve the test pressure and leave the water in the system.

14.   Disconnect the test pump and plug the outlet or test port through which the system was tested.

15.   If the test will be required on existing fire sprinkler systems, review the proper impairment including the fire alarm system to avoid false signals

Measurements

1.       Test pressure is to be maintained for 2 hours without any visible leaks.

Pass/Fail Criteria

1.       The system must hold the test pressure for 2 hours without loss of pressure.

2.       Absence of water leakage is verified by visual examination of the system