Dehumidification load. (cont)

TM 38-260

(7) Example load. The following tabulation is an example of the elements of the estimated dehumidification

load for a 182 by 1,447 foot warehouse of average height on an average July day in the Eastern United States. The

majority of the load in the following example is carried into the warehouse through the entry of outside air, and all but 5.0

percent of this subject to control. The infiltration load can be lowered by improving the sealing of the building, and the

open-door time might be reduced. Emphasis must be placed on adequate surveillance of building sealing and the

establishment and enforcement of local regulations that will keep open door time to humidity controlled areas at a

minimum (see fig 5-1).

CHART 5-1

POUNDS PER DAY

GALLONS PER

PERCENT

LOAD

MOISTURE

DAY MOISTURE

LOAD

Breathing

150

5. 0

Door opening (1 door for

1 hr/day

1,000

120

33. 3

Infiltration

940

113

31. 3

(Inventory turn-over)

150

5. 0

New Equipment

Concrete floor (untreated)

630

21. 0

Transmission

Walls (treated)

2. 0

Roof (untreated)

2. 4

TOTAL

3,000

359

100. 0

NOTE: ONE GALLON OF WATER WEIGHS 8. 35 POUNDS

c. In most instances, the average manufacturing building cannot be adequately sealed for the purpose of controlling

relative humidity. It is impossible to stop the breathing of a warehouse, because of the nature of the structure and

because it would not resist the pressure generated by temperature and barometric changes. When equipment stored in

such buildings must be maintained under relative humidity controlled conditions, it may be necessary to erect a controlled

humidity structure or apply heat to the manufacturing area.

5-8