Figure 4-19.Dry-barrel fire hydrant.
Figure 4-21 shows the proper method of installing
and supporting fire hydrants.
FLUSHING AND TESTING
Of course, newly installed pipe must be tested for
leaks by means of air or water. To make an AIR TEST,
plug up all openings in the system, connect a source of
compressed air to the system, and bring the pressure up
slowly to the designed working pressure. Use a soapy
water solution and cover each joint, then check for
leaks. When a leak is present, you can detect the
location by bubbles forming around the joint from the
escaping air. When a leak is discovered, mark each
spot with chalk or soapstone. DO NOT, AT THIS
TIME, ATTEMPT TO REPAIR THE LEAK. After the
line has been tested completely, relieve the pressure
from within and repair the joint. Repeat the testing and
repairing procedures until all the leaks have been
located and repaired.
The procedure for making a WATER TEST is
similar to that used for an air test. Water is used instead
of air, and you do not use a soapy water solution to
cover the joints. The pipe is filled with potable water,
and pressure is applied and maintained by means of a
hand pump. See that no air has been retained in the pipe
being tested. Let it stand under operating pressure from
4 to 8 hours and inspect for leaks and maintenance of
pressure during this period.
Q10. What department is responsible for selection of
fire hydrants to be used in a system?
Q11. What are the two types of fire hydrants?