User's Manual

Design
P/N 81-CO2MAN-001 3-33 September 2013
EXAMPLE 9 - LOCAL APPLICATION: RATE-BY-AREA - Overhead Nozzles
Consider a dip tank with surface dimensions 4 ft. x 8 ft. . A survey of the hazard indicates
nozzles may be located 4 to 6 ft. above the liquid surface without being an obstacle to normal working
conditions. Determine the optimum nozzle height that minimizes the carbon dioxide supply and nozzle
quantity requirements.
Examine the Type "S" and Type "M" nozzle coverage for liquid surfaces in Table 3-4 and Table 3-5.
For a Type 'M' nozzle at 4 ft. above the protected surface:
From Equation (17):
Where is the Quantity Of Nozzles Along The Width Of The Protected Surface, is the Width of the
Protected Surface, and is the Maximum Side of Square.
From Table 3-4A:
s = 3.6 ft.
= 4  3.6
= 1.1
 2
From Equation (18):
Where is the Quantity Of Nozzles Along The Length Of The Protected Surface and is the Length
of the Protected Surface.
= 8  3.6
= 2.2
 3
From Equation (19):
Where is the Total Quantity of Nozzles.
= 2 x 3
= 6
From Equation (20):
Where is the Total Discharge Rate and is the Discharge Rate of a Single Nozzle.
From Table 3-4A:
= 59 lb./min
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