Binding of Lumber Drafts.

TM 38-400/NAVSUP PUB 572/AFMAN 23-210 MCO 4450.14/DLAM 4145.12

length to adequately support each board and prevent

(b) Effect of stack height on air drying. The effect

warp.

of stack height on drying rate is similar to that of stack

(d) Stickering of seasoned lumber.

width. Increasing the stack height tends to retard drying,

particularly in the lower parts of the stack. The air

Drafts of seasoned lumber having a moisture content of

traveling downward in a stack becomes cooled and

19 percent or less may be placed directly into storage

approaches saturation at a point higher up in a tall stack

and stickered at sufficient intervals to stabilize the draft.

than in a short one, unless the air is replenished by

(7) Air drying of lumber. The air drying of

horizontal movement as it moves downward. Tall

lumber is dependent upon the temperature, the RH of

stacks also tend to restrict general wind movement at

the outdoor air, and the extent air is caused to enter and

the ground level of the yard. Lumber stacked in the

circulate within the stack so that it reaches each

form of drafts may range from about 4 to 20 feet in

individual board.

height. Movement of air through the 6-inch between-

(a) Air flow. Air, at any condition below

draft-spacings will increase to some extent air

100 percent RH or moisture saturation, possesses the

circulation at the lower levels of the stacks.

ability to take up moisture from green lumber. Air that

enters a stack becomes cooled as it takes up moisture

5-4. Binding of Lumber Drafts.

from the lumber and, as its temperature decreases and

RH increases, it loses its ability to dry the lumber. As a

a. Binding requirements. Each draft of lumber,

consequence, if drying is to continue, the air within the

stack must be replenished by ejecting the saturated air

which is assembled for storage or shipment, should be

and admitting fresh drier air. This is accomplished by

bound with an appropriate binding. Binding of the draft

natural horizontal and vertical air movements.

is necessary to prevent movement of lumber during

Horizontal movement within the stack is brought about

handling operations. Shifting of the lumber could alter

by differences in pressure between the two sides of the

the pitch on the draft face or cause the dislocation of

stack caused by prevailing winds, while vertical

stickers and the subsequent distortion of the lumber in

movement is brought about by the increase in density of

the draft. Bindings must be placed directly over the

the air within the stack as the air is cooled. Since it has

stickers in order to secure a tight binding and to prevent

been established that the horizontal movement of air

distortion of the lumber. Also, binders placed other than

within a lumber stack is the principal means of

over the sticker ends will tend to force the lumber in the

accomplishing drying, it is highly important that channels

draft together, thus closing any edge spacing between

for this movement be provided. Vertical movement in

board edges which will restrict the vertical flow of air

itself accomplishes little drying except in the case of

through the draft and retard drying. Bindings should be

squares or when stock is stacked on edge, but vertical

over the second and last sticker in each draft, as shown

movement through interior spaces induces horizontal air

in figure 5-3. Lumber, which is to be transferred

movement across the faces of the boards from which

immediately from unloading point to point of use, will not

most of the evaporation of moisture occurs. Horizontal

require binding or stickering except as desirable to

movement of air within the stack takes place through the

stabilize the draft for transportation purposes.

spaces formed by the stickers.

Spaces for the

downward movement of air are obtained to a minor

b. Binding Materials. Binding should be either 10-

degree in the draft from the natural openings between

gauge round steel galvanized wire of 3/4 by 0.023-inch,

the board edges; however, the major provision for the

type I or IV flat steel strapping in accordance with QQ-S-

downward movement of air is the between-stack-

781. Corner protectors are not required in the binding of

spacing. The wider these spaces, with respect to the

lumber, as the bite of the binding will tend to hold the

total width of the stack, and the smoother the vertical

binding in place over the stickers.

sides of the spaces, the greater will be the passage of

air through them. Edge-to-edge stacked boards, in

5-5. Marking of Lumber Drafts.

drafts 31/2 to 4 feet wide, with good stack spacing in the

rows are comparable to boards in a wide hand-stacked

Each draft of lumber should be properly marked prior to

pile with chimneys at several foot intervals. In this

final storage. Marking should include stock number,

manner, the spacing between the stacks acts as a

board feet, and the date and year received. For

chimney to carry the damp or saturated air down, thus

example, lumber received on 11 July 1977 would be

stimulating horizontal movement of air within the draft.

dated 192/77 (192d day of 1977). Marking lumber will

facilitate issue and inventory and will make it possible to

issue the oldest lumber first. Lumber received from

other activities is

5-8