MIL-HDBK-1011/2
APPENDIX D (continued)
(20)
RFo =
0.56
=
0.56
for the outlet openings from Table C-5.
22.4 ft2 = 22.4 ft2
(21)
Calculate the effective outlet opening, Ae =
Ae.
Ae = Wo * RFo.
(22)
Compare the required outlet opening with the effective outlet
opening.
Worst Month:
September 2nd worst month:
August
Ao =
21
Ao =
19
Ae =
22.4
Ae =
22.4
If Ao < Ae then the required airspeed will be obtained and
comfort can be expected.
If Ao > Ae then the required airspeed will not be obtained.
1.4.1
Results of the Window Sizing Procedure. The procedure was
performed for the months of August and September. The required open effective
window area (Step 14) is 17.1 ft2 (1.6 m2) in August and 18.5 ft2 in
September. Assuming fly screens of 14 strands per in. (porosity 0.8), and
that the window wall consists of fixed louvers for the lower four feet
(porosity = 0.6) and operable louvers for the upper four feet (porosity =
0.8), the required open outlet area (step 18) is 19 ft2 in August and 21 ft2
in September. The actual effective outlet area based on the proposed design
(Step 20) is 22.4 ft2. Since the actual effective outlet area is greater than
the required outlet area, it can be expected that the design will be capable
of producing 0.5 m/sec ventilation in the rooms and will be comfortable for
all months except for about 14 percent of September.
Ceiling fans producing 197 fpm (1.0 m/sec) ventilation for a
substantial area within the room will provide comfortable conditions during
the periods when the outside wind speed is too low and during heavy rains.
These ceiling fans would also provide comfort during the 14 percent overheated
period of September.
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