Some effects of storage on seasoned lumber

SOME IFETCTS 4r STIACIE ON
SEASONI T LIUM IiE

Ievised August 1949





S ... . .. . . . .. .. . I

















No. 11071







UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
FOREST PRODUCTS LABORATORY
Madison 5, Wisconsin
In Cooperation with the University of Wisconsin
















Digitized by the Internet Archive
in 2013










http://archive.org/details/efffsto00fore





SO F' CTS IOF S'R .'. 37 .,. .. I -E'TR





SS. L
Snd
: r AS SSL.., L" i"eer

crest Pr c' c I v bo, ratry,1 crest Servic;
'. S. Dcart-erb.e of A (ri'ulture



Th. fulle~st efficie-nc, ain"d sat.'ofacticn to le derived d from thc u:-e of
wwood in any .structiou ure :n P-, ]ar;e pa,"rt wepende-nt upon it: (iturc
conte-.nt at the ct. of i 1stl.itic n. Af us-rs a er sur lied w-ith Aumier suit-
ably dried fc'" t ..'c o, t' -r-. i" ,: ,*' rs reason "t'r, they S oul,; e ( n-
corned abc .'-, it;. .o.r, ic bi lit s .- r a 2 s-,rinki. and .e< s ellinr' are
cor c e rnd.

So,:)i- n', i.s ;:'.c ire a.nd srii ,orcouThl; se(a onr d luihber to whole sale
and ret.il 'ard::, to ind t":; 't is s`:tore in ls unprotected from
the "I'ct.er Svb .ftora.c: lcar i"<'], .t: t'; b' i opropr ser-,
seca'.sc t. "oo --- absorb r.,ir tc arn n cosi r < e extent oefore it is
zned. T is 3r.'d ,r re,... fio.ed ry a n oitur, loss during f1I ricaiocn
or use -'.', ras;lt in, .ar"i-on- i id end che-" in'. Correct L; trtcc practiic is
necesae,,ar for r- r.. kiin.-drwcd '.or, there'fo re-, t., maintain -.he lumber
at t.-e ,asird :"9;i: '' .o.t. .nt sof d ,n, ct: as ;uell a.s c an,-ts in
.i...r. c o nc" o:; h 2i.: ........ ct:r:,'e '.7,'i1 be mini;':!ized, if 'ot cntrtlr
-1, i rd i o cr.' .
13 r


r v ri.... Co-it v,'-




In :.rdr to btai, definn.te In i rt tion uv nn the effect of storage on
the iostcrc oent.s t r c r-.ebhod at; '.v:.::i1 L "'-aoi:.. .o.. and re tuil d. r'tri twio- y' ard ,'
i.t-, i n r I r. of ths st States.

Tlu'-trai"e : th.. r s obtine i fi-'urI s cd a stud- at
a Lo .isia a. ....... S .... t <;iT1 r, c:" v r- 2tai ecd act Tlorida
sot' I.. l n a:t seV' r; ] ais+rib'1ii -n a 'rd iu tlrn vici.,it of Chica.c o
stock ,t the b ou":si ..'. .ill a,"v- Fo .... r ","lo"' pire .- bv ,A-iueh by 12- ot
d A -, -l I lidr
iir f o r,-' cf.s v, r "r. t t IocI' f m-, c. ('; s''" tl u ... t S:Oa-in
florino a 1- I r-i-cn by 12-o rdC' 3-r2 ", 011e 1n ind' solid
"i- -- t.a. ;, pi d -ltho st.i .. A o ards sel2 "cte, for
un0 f !r:' i, of' :Co sturcr o ni .t ',, m"ica s c, a ['c stuy" C.-to r '... Li d il Coach

.-1i .-'-: j- at J .. b'G. in coc erotioon *,ith> th. I'aivrsi o' "'" ,- nl _n.


P.rporrt '-. RI ,l, r,-vis.:d.





ff t1 c -..-i:. actions: (I) In a yard where the pile -;7-s -tell prctected
ba-- t roof; 2) in a artly on se wiith metal roof; ( in an oen
shed -ith wood rof;o and (4) in a clocd' shed w-ith a wood roof. Lach curve
ii f .... 2 1 represents the ch_.- es in ave-a-E.e moisture content of SO boards.

The a-e.r posture con'..nt -alues, :.hioh were initially about 7.5
........ betve 1 and 11 percent after 10 .ontl.s in thz three sheds.
h y-.d ^c a-rf rZ;oizsu: content reach-d 13.5 percent during thE sae
pier io s -hos ar.. acra-e valuc; th.e ends .nd other surfaces of the boards
::"poco dirctly to ...-. T.: relatiively lar.-e absorption of -oisture at the ends is
1ajbtixIeble either in the ro:.L, i,.br or in a finished product such as
lor i, -. -.7 .- h rough lumber is surfaced, the boards will have a unifcrr
.-dth only t he it.e of .achinin_; subsequently the ends will shrin]c and
t:ile re narro-e: .a... the remaining :ortions o' th- boards. In a 1 irlshed
3 asusL, -. t>,-t the board's are :.'irly uniform in moisture content '"h--
.c h ne d a-,-4d ub2Q._nty absorb moiszure during stor'ace, the ends w'ill
beco- -.:i or anda thickr than thrT should be.

f efzct of tez raturs an: relative humidity on equilibriumi moisture
contend: is shon in 2i-'.re . 'or e:v-:... 1 e, at the aver-.-e indoor temperature
of 7& F and relative euafidity of 42 ereent, the equilibrium moisture
c nt of wo is .t. It has been found that, for the most satis-
fac.or sr. ce, such rod. .s as floorin and inter-ior finish in _rood-vork
in ?o-.'.ratiorall heated d,:el! .:-- in nost p>rts of the United States should
4 ,4-
...e ir:lled, at a` out 7 -" .c. moisture content.

ur ta ia u3..tc.d :sh t,,he temp-rature and relative humidity
Srespecively 30 *. and 75 percent. According to figure 2, the corre-
So2TinO eiuiirun 7oi.bCure co ntent is 15 percent. If the shed is tir.-.tly
.o. ru te so .Ih no extOraneo sources o noistur are present, the
o--u-liri" n.stre ..'....t ca... ,us reduc to .0 -'rcent by merely heating
.:- .ir i: =h shed to about do -. 0 :e dotted Jine in figure 2.) In this
";ri:"* stt ot.. sh:rasts, -: r s~r;'ys, siccans, or refri7jration are not required.
"r-" .....r "cO ht loss: u:or this condii-on is less thoa i- a concmon t :.i".per-
r-..... .. or, s<-i, or 7^0 7. '*rore :.aintaio.d.

ndj..: c.--. -e .r. '.: re content of lu -bcr -within cloeId
stoe-. ".:. sh,.jds can- b^:< lu-rgely" pr:e 7eT'" o,. ..

>.r'.- stor'.,-, 'j lu r ..nd3 to come to thc sare moisture
co-toL'. I otr ,ur- the rm.nge : ns":ure content betnTeen i naividu.i
ces b3os.oes i s3 ni'h "or'.... (f-.. 3. 3 his is advantageous if storage
-Zc *6, Z ii s a ,
oc .. ar :op~r*, .a.:cai.-od, I;0-rticul',rly if the moistur-e co-ntent of
-j ir..r ":'-r-. co siderabi t.-'r kin drying.


* .~1 N, re<


-cr- :3t -oo.cts Laboraotor R .p... lo. RIllO, moisture e Flctu!ations in Lumber
hin Cl-osed Stor' s Ctrol Jth Eloctrical Eqkr "







r:T 1* 7"-%r4*p "''* Str s's S


A .fa zrther adv^.rta -- storage is ha; it ies tie -or the -cisture
cc -'-. to e-uT'alze t- Irou:o 0.. t1hicknss of each piec3. Zith so:-.e woods
..r aod, S e t,:eriod an, eaauaiza-ion of _-ioi- r content
ma L ... "i .... -, .. :r o
7a~y 4e t' for th-e relief of crying s";ressos. c s 1-. s, c-
....e... :: ;- of. ?uoraT e.

r-r .w 3'% r s-'o2rA ' cc''. i 't r s "f-'i rr r.i'.con! i.. n l'' t

.... s ..... of kri-riday causc reversT cas -
h r-i r n o7 -''aa ,ir,,- 'c a- 7' o :' c-%c-r r.i.. ar t..r, n; :Csorrt ion

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,- , lc^ "'^ 1'' t'._r" I'- 2- i'^" o. ; m : ci occ'?r du.ring s-+or
_Lzn~hV., ore


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'*,0i2L fP '1 30 -:ir '^_< T*'* ^y" = "-.'-[.. " S ^' f; O' -r) 2 S^ O',C a ':* f.^ "o p'.r*^ -__ lu '' Sf


uT' 0o "^ .-3 ss.'' c' ^ -' ..' < .. *-* 3 ^': ... ;*', o-- t h p ",' -r *- sh^ c f ,,'^ w -" :~ "* r.' r^ r. __ -... ,,!






staclkei so t' i-s-- .tz oho;. ---.rci:,.__y txos~d tc -:. lc': e2aiiiriuxr


i:: stx.c-: ;. "i;; cr -oist-re c:c>. Ken.2, one foce v_ .... -2.,e .'Ocs 'ee'r
-;-od .... 'j.- oif>. :iis zo:, o-"i:: ... s--rt -.
2:Q& :tialiv c:- ... (,
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4-i..;.. on-: fu*'; c1 a s::z n S le meSt









.. ... .. P d-- a o t r -. afnd !Ci 2-'- 7se
-"< ~ -" t:-" ...... .. -iii r1
tLt :2-cS _..s2!1 %0 3T O:x, F =,aru2 ...s __J2< "\7
tnce wTho, f: x-.-- fro stcr:" : orsc- 4 .:- -L au-- 2-x oraLr S, 225.2 ,
35 IT, &'->.. VT:e of> s::ai: .L'2 -e s: "~ r:.. so :- -i'{u z .... 2 [ re ..t
-,ree : -.:r' U- sc:-s cf #1- ;r:ic .. .......s .:3s t rr 3-e.7 # e se~'
3. C;- *o.iotu s j~'o-r2O..... "~.-.a "
_' c' M--

.c.r _. sf' 7cr. ne e C77
^F *- ^/' .... \, d *'-3 \"" s x 12 v" r. 0 r*'" ^* io*'" x^ f" ^' i'" T f^" a ''- "*^^ > 5 r ^" "
eid., Soils, aad 3a'r. a.,f7:r.,


epsort -R, T1D(1, revised.


.<* _7"' **." 2* S- e> -" A. *,/ ^>* - t/,- ***' ;* "T sf '&'
*.. ;0 A v -cx U ^. ->u-2^- -*nn.-@ -


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ki in
The best pract-ie, hc-wever, is to start/dr'.i-n,_ as soon as possible after
cutting he log into luiioer.

If the season of th- year is advantageous, air-dried lumber :-ay be
sborad by leaving it sticlzered in the air-drying pile. -, best method of
storage, however, *vould be to pile it in open, partially closed, or unheated
-losed sheds. It could be sticker piled or, if the average moistur- content
13 belowr 20 percent, solid piled. Storage in this manner will best maintain
-".e final air-dried moisture content vrithout causing losses or decay fror.
epouro to the elements.

Kiln-rid luniber should -iven the best of car3 in storage. -D.. re
is .o ad.1: in .iln drying lumb-r to a lmvr moisture content if durin-
storage it ev-nttall]v attains tho moisture ccnt ,nt of air-dried stock.
Pref.rably, 1kin-driyd lumber should bec stored in closed heated sheds in
which th 1 uilibrium moisture content is controlled. If such sheds are not
ii.a..ic, stor ;t:.e in -ha upper part of a closed or partially closed zh.-d in
7hich !he ri..pmporatar ia sli'..!htly h.i gh.r than the outside temperature is
desirable.


Report No. RiO71,reviJ.'d






/4 F I
YARD
,/ ---- -__- -,_-.__


If/2 y _

1_ r Y, Y..----PARTLY OPEN SHED-METAL ROOF

/10.- "--LOSED SHED WOOD ROOF"

k "^ -OPEN SHED--WOOD ROOF




K.
'2 O 7 -- ----------- ------------____________



(^)


6 _----------_ __---------------



APR. /M-AY 1(1NE JULY AUG. SEP77 OCT. NOV. DEC. JAN. FE8. /MAR. APR. /YAY JUNE JULY AUG. SEPT
0 30 60 90 /20 /50 /80 2/0 240 270 300 330 360 390 420 450 480 510 540
/930 /93/
TIME (DAYS)

L'Iilre 1 X-vera~ge mi{Isturer conrteIt, chanIt's in1 sout li-'ri xu I 1n pit' 1 by 1 innrd florin 11. nl 1In t h
inch( b Ua~rd-s nir 'i~e tnn our s ides, stoured ini a s u i 1 p1 ie in <.tci ul' fnur dJ if.'(' r0!], 1 ou tios
9-





6




0 30 60 90 120 150 /30 210 240 270 300 330 360 390 420 450 460 510 540
1930 1-931
TIME (DAYS)

F 'igture I. --Ave r~ig wlo js lt. ( u e co t eI I t.II ('Ala I Igts, ill soutll,+Irn ,(lv ) i tt-A p ne [i t lv I ir ii r t) ool) r i ii,_ nr(i I h\+ v
irnch boairds,. surl'ai-.yedl f'our" si~des,+ sttored inl at soli J i k, ill (;o | I 1't(t 1)], Vo I It, d( i t''*,'rI+'I I ]( loo t i ow,+ .


ZM o0453 F










\0 \^- \ \0 \,.V) '- ,-J \. .



\^- \< \ \- \0 Vo- \-





15
2 s_ _0<
-o
0










0 I0k03 05 07 O9
Q99







2 ^ __ _ __ _ ___ ____ __- //1_









0 10 20 30 40 50 60 70 80 90
TEMPERA TURE (oF.)




Figure 2. --Re It i on of t.ie equil ior ium moisture content o(' wood to tlie p t, erert mire arid rel active
humidit y of tne 0orrournm inn attmosptiere. (Dotted iine illustrates tte extmp7le ited.)


ZN 44797 F














80 1








-450


40
K Ki






30I


-20 --


/0


0 4.0 (.0 /2?0 /6.0 2o.o 2.0 28.0
MOISTURE CONTENT CPER CENj)

Figure 5.--Range of moisture content of a package of 1- by
6-inch Douglas-fir boards before and after storage for
1 year within a closed unheated shed. Initial average
moisture content was 10.3 percent. Final average moisture
content was 12.1 percent.
Zn7S F





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