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 TB 55-1900-201-45/1
h. The age of the cylinders shall be determined. If over 12 years old, the cylinder will be discharged and hydro-
statically tested. However, if cylinders are 5 years old or older and found underweight by 10% of charge, then hydrostatic
test must be conducted at the time cylinders are removed for recharging. The hydrostatic test shall be 1-1/2 times the
maximum allowable working pressure.
2-75. Mechanical Foam System, Fixed and Deck. At each inspection and at such other times as considered neces-
sary, the surveyor should determine that the foam system equipment is in suitable condition and that the inspections and
tests have been conducted.
a. The deck foam system shall be tested biennially (2 years) by discharging foam for approximately 15 seconds
from any nozzle designated by the surveyor. It should not be required to deliver foam from all foam outlets.
b. Block valves in the deck foam main should be operated and left in the open position.
c.
The foam proportioner (and associated driving equipment if installed) should be operated.
d. Operating instructions and valve markings should be conspicuously located.
e. Examine quantity of foam concentrate in tank. Also check quality of foam.
f.
Hoses should be tested at a pressure of 100 PSI or the maxi- mum pressure to which it will be subjected in
service.
g. To assure that the fixed foam piping and outlets are free of obstruction, the system should be flow tested with
either air or water. Outlets may be temporarily capped, if necessary, to allow testing of one or two outlets at a time.
Water is the preferred test medium as this will give the best indication of the system's efficiency. The minimum outlet
pressure should test at 50 PSI with a Pitot tube. Air pressure can be used to give an indication that pipes are free of total
obstruction. However, this will not give an indication of pressure or quantity available. Neither will it pick up smaller ob-
structions that could eventually clog nozzles when the system is brought into use.
2-76. Manual Sprinkling System. It is difficult to perform effective tests of sprinkler systems due to the nature of the
spaces which they protect. Water damage can easily be incurred within accommodation or storage areas. However, it is
essential that the system be tested as thoroughly as possible at regular intervals.
a. If practicable operate the system with water. If this is not possible, remove a sprinkler or flushing connection
near the most remote sprinkler in the system. All other sprinklers must be plugged to prevent damage. More than one
connection or sprinkler
2-37
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