Upon completion of laying underground pipe for a sprinkler system and attached to a public water supply system or other, the underground piping shall be tested to the following procedures.

Prior to covering the pipe

• Cover the main pipe with dirt but leave all joints exposed for inspection
• Contact NCSU Project Manager and the Engineer to set up a test date and time. The NCSU Project Manager will contact NCSU Fire Protection to schedule this test.
• On test date, all parties shall walk the underground pipe and inspect it to ensure all joints are exposed. Drawings shall be available for review.
• Test procedures shall be reviewed by all parties present.

Flushing of Piping

• Underground piping, from the water supply to the system riser, and lead-in connections to the system riser shall be completely flushed before the connection is made to downstream fire protection system piping. (NFPA 24, Section 10.10.2.1*)
• The flushing operation shall be continued for a sufficient time to ensure thorough cleaning. (NFPA 24, Section 10.10.2.1.2)
• The minimum rate of flow shall be not less than one of the following:
  1. Hydraulically calculated water demand flow rate of the system, including any hose requirements.
  2. Flow necessary to provide a velocity of 10 ft/sec in accordance with Table 10.10.2.1.3.
  3. Maximum flow rate available to the system under fire conditions.

  Table: 10.10.2.1.3
  Flow required to produce velocity of 10 ft/sec in pipes

  Pipe size ( inches)	Flow rate (gpm)
  4	390
  6	880
  8	1,560
  10	2,440
  12;	3,520

Test Procedures

• All piping and any attached devices subjected to system working pressure shall be hydrostatically tested at 200psi or 50psi in excess of the system working pressure, whichever is greater, and shall maintain that pressure without loss for 2 hours. (NFPA 24, Section 10.10.2.2.1*)
• Pressure loss shall be determined by a drop in gauge pressure or visual leakage. (NFPA 24, Section 10.10.2.2.2)
• The test pressure shall be read from a gauge located at the low elevation point of the system or portion being tested. (NFPA 24, Section 10.10.2.2.3)
• The permitted amount of underground piping leakage shall be as follows (allowable leakage shall be determined prior to test):

1. The amount of leakage at the joints shall not exceed 2qt./hr per 100 gaskets or joints, irrespective of pipe diameter. The number of gaskets / joints shall be predetermined.
2. The amount of leakage specified in 10.10.2.2.4(1) shall be permitted to be increased by 1 fl.oz. per inch valve diameter per hour for each metal-seated valve isolating the test section.
3. If dry barrel hydrants are tested with the main valve open so the hydrants are under pressure, an additional 5 fl. Oz. / min. of leakage shall be permitted for each hydrant.
4. The amount of leakage in buried piping shall be measured at the specified test pressure by pumping from a calibrated container.

(NFPA 24, Section 10.10.2.2.4 (1)(2)(3)(4)).

Starting / ending the test

1. The pressure shall be increased in 50psi increments until the test pressure described in Section 10.10.2.2.1 is attained.
2. Each joint is checked between the 50psi increments for stability, protrusion or extrusion of the gasket, leakage or other factors that may effect the continued use of a pipe in service. The next increment shall not be added until the joint is determined to be stable.
3. Upon reaching the desired test pressure, it shall be held for 1 hour without loss of pressure (200psi).
4. At the end of the first hour with no pressure loss, the system shall be decreased to 0psi and checked for leaks.
5. After checking the system for leaks at 0psi, slowly increase the system to the desired test pressure of 200psi minimum and held for 1 more hour without loss at 200psi and checked for leaks. (NFPA 24, Section A.10.10.2.2.1)

 

_____________________________________       ________________________
        (Signature of NCSU Project Manager)                                              (Date)

 

______________________________________          _____________________
          (Signature of Engineer)                                                                      (Date)

 

_____________________________________          ______________________
          (Signature of NCSU Fire Marshal)                                                     (Date)