i” 
: 
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} 
KILN DRYING HANDBOOK 57 
TABLE 13.—Special kiln-drying Schedule 108 for southern yellow pine * 
Dry-bulb| Wet-bulb! pojative 
Time in the kiln after which changes should be made, hours tempera- | tempera- ras 
ture ture humidity 
C8, ois Per cent 
eee meee en ee ee Se Ye Ok ee So el ee eee 175 170 89 
ee rane ue Rn Gee ae ee ea Se ae eet 190 170 63 
BS Ne re ee oem ie Co a a i i oh ey AW es iy Ci ee ees Lok 2 200 170 51 
BY 6 te Se OEE SSG re Se Se ee ae EEL EE UE og 190 182 84 
Dies a a ee Ne mE A RP gn We Ae ee A End of run. 
1 For use with 1 by 6 inch and wider No. 2 Common lumber. 
TABLE 14.—Special kiln-drying Schedule 109 for southern yellow pine* 
Dry-bulb | Wet-bulb Relative 
Time in the kiln after which changes should be made, hours tempera- | tempera- pine dit 
ture ture y 
ells Ar Per cent 
(ae a PE ease al he US Ee aS we Raa) i RR a eh as oe aN TE 175 170 89 
Ecce cece eee SS EN LI Ae eae se og pecs RO eR sl NN Le Bec 180 170 79 
UN (Sapa pe se eek eee ne Se 2s ee OS Oe Ne ae 190 170 63 
Hs es teh ea el aa Oe OR RL en A Dace Ma OG OTR 200 170 51 
COS Sis hee sey EN SE i ARE ea ee ee Oe DN at ee eg 200 160 39 
TT eA IO alta aE ge A es i ey) Ye he ee er cea 190 182 84 
S12 () ese meneame NN EMMI PIE Bs nes 2 IN RS eT PN Mk a End of run. 
1 For use with all widths of 5/4 and 6/4 inch finish stock. 
TABLE 15.—Special kiln-drying Schedule 110 for southern yellow pine * 
Dry-bulb| Wet-bulb Relati 
Time in the kiln after which changes should be made, hours tempera- | tempera- |, coe ae 
ture ture ey, 
CMe ay Per cent 
(Ve pe eS Ne a ee Seo en pl ua Ea at a AL ey Ea 175 170 89 
Le i pee I a UE RN ee a a 180 170 79 
TDN ea sacl lp a et Tg SL LA ep I LR 190 170 63 
FSA a eh IE Si aA Oe ML Se aT Ep Cae a OY Ca eC 200 170 51 
DS as a me psec AS SNS tha IY a gh a ak 200 160 39 
DBS a es eR I aU MR Ls gS SA Fe 190 182 84 
FUCA ane Ome etn ven VLAN Rak ed) SCHR TSN ON CO a SU PN LS Sev a End of run. 
1 For use with all widths of 8/4 inch finish stock. 
The conditions of the final steaming periods of five to six hours 
specified in special Schedules 106 to 110, inclusive, (Tables 11 to 15, 
inclusive) are unusual in that the kiln temperature in each case is 
less than the maximum drying temperature of the schedule. The 
reason for this is the saving effected in total drying expense; correct 
calculation of the total expense requires taking into consideration 
both the cost of steam consumed and the cost of time. Although at 
first glance the facts in the case seem to conflict, the explanation is 
simple. In the average kiln it is very difficult to maintain a wet-bulb 
temperature much above 180° F. without a tremendous steam con- 
sumption. On the other hand, it is equally difficult to cool the charge 
quickly from 200° or 210° F. to much less than 190° F., because of 
the large amount of heat in the stock and in the kiln walls. To obtain 
the comparatively small difference between dry-bulb and wet-bulb 
temperatures desired for such conditioning, therefore, in these special 
schedules each temperature is shifted a little way toward the other, 
