floor in each room. In addition at least one surface to ground measurement
shall be made for each point pair measured. In rooms where more than 93
square meters 1000 square feet of conductive tile has been installed a
minimum of one surface and one surface to ground measurement shall be made
for each 19 square meters 200 square feet of conductive tile and the
results averaged. No individual floor to ground measurement shall be less
than 10,000 ohms. Tests shall be made by a technician experienced in such
work.
3.6
TESTING FOR EXPLOSIVE AND AMMUNITION FACILITIES
**************************************************************************
NOTE: For explosive and ammunition facilities, edit
the following paragraph. For all other facilities
delete this paragraph.
**************************************************************************
Electrical resistance test shall be performed on the installed floor.
Instruments used in making tests shall be used only when the room is free
from exposed explosives and flammable gas mixtures. Maximum floor
resistance shall be measured with a suitably calibrated ohmmeter, which may
operate on a normal open-circuit output voltage of 500 volts dc and a short
circuit current of 2.5 milliamperes with an effective internal resistance
of approximately two million ohms. Minimum floor resistance will be
measured with a suitably calibrated ohmmeter appropriate for the task.
Each electrode shall weigh 2.3 kg 5 pounds and shall have a dry, flat,
circular contact area 63.5 mm 2-1/2 inches in diameter, which shall
comprise a surface of aluminum or tin foil 0.0125 to 0.025 mm 0.0005 to
0.001 inch thick, backed by a layer of rubber 6 mm 1/4 inch thick and
measuring between 40 and 60 durometer hardness as determined with a Shore
Type A durometer ASTM D 2240. The floor shall be clean and dry, "electrode
jelly" such as brushless shaving soap or saline solution shall not be used.
The resistance of the floor at any one location shall be more than 5,000
ohms in areas with 110-volts service and 10,000 ohms in areas with 220-volt
service, and an average of less than 1,000,000 ohms in all areas as
measured between a permanent ground connection and an electrode placed at
any point on the floor and also as measured between two electrodes placed
914.4 mm 3 feet apart at any point on the floor. Measurements shall be
made at five or more locations in each room. If the resistance changes
appreciably with time during a measurement, the value observed after the
voltage has been applied for above 5 seconds shall be considered to be the
measured value.
-- End of Section --
SECTION 09660
Page 8
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