Treating Christmas trees to make them safe from fire


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Treating Christmas trees to make them safe from fire
Physical Description:
Mixed Material
Van Kleeck, Arthur
United States -- Forest Service
Forest Products Laboratory (U.S.)
University of Wisconsin
United States Dept. of Agriculture, Forest Service, Forest Products Laboratory ( Madison, Wis )
Publication Date:

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Resource Identifier:
aleph - 29347418
oclc - 79186661
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Full Text


November 1940



Madison, Wisconsin
In Cooperation with the University of Wisconsin

Digitized by

the Internet Archive

in 2013

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Py AIrT"-. VAN jZ.-._, Associate Chemist

After investigating various treatments suggested for the "urpose
of making spruce and balsam Christmas trees less inflammable, the Forest
products laboratory at Madison, Wisconsin, has reached the conclusion
that keepin? the tree standing: in water is about the most satisfactory
and convenient method of those tried that will keeL the fir- hazard low
and, at the same time, will keep the needles from discoloring or falling .
The procedure recommended is as follows:

1. Purchase a tre that, has noa e allowed to r cutJ ,fte.r
being cut and that has been cut as recently as possible.

2. Out off the en'i of -h- trunk iaally, at leas 1 inch a:oe
the original cut end. Ctand the tree at once in a container of water ani
keer the water level above the cut surfac- idurina the entire time that
the tree is in the home. If the tree is bought several days befr it
is to be set ur in the home, it should be kert rtardin.' in water in n
cool rlace.

if started in time, this treatment not only 'revents the needles
from drying out and becoming inflammale, ,but will also kee, the neeiles
fresh and green and retarl the needle fall of such s-ecies as srruce,
which lose needles very easily. Freshly cut spruce or falsam fir treps
standing in water cannot be set on fire by candle or match fires, but,
of course, cannot withstand a lar.-e source of heat.

In addition to the water treatment of the tre, all the usal
precautions against fire shou ld be taken, rarticular jaina bing taken
to avoid the use of defective electrical connettions, to r recent :the
accumulation of large amount of comqutiile iecorationsa on or beneathh
the tree, unless. they are firr, roofed, rand to La c the tre- o ta its
accidental burning would not easily ignite curtains or furihingi, cr
traL the occupants of the room or building.

,pruce rpprespnts the tyke of tree whic oses i-l v-ry :a
ujon dryinc. Balsam fir, on th-- other hand, .re.-nt t- y, wh.i...
retoins its needles well, Even ';hen the ranche: are extrem rely dry,
balsam fir needle will not f:ail, alth.ou,-h they will b come ri-t le
enough to break readily when handled.

Luring the investigation, soluticns of a .u..e or fire-r,'' ':At
chemicals were introduced into sr rare and balsa, fir tr-s or rr a" .
by the same method as that used for water. The qzan.tity rf slt' ay.
taken iT. br.y the specimens and their c,. ., s in wi..'-ht w-re ietermined iy


weighing the containers and specimens at frequent intervals. The method
most commonly used -for determirning the fire resistance of the specimens
was to measure the rate of loss in weight of a small pile of branches ex-
posed to a low 3unsen burner flame for a standardized period of time.
Some tests were also made with match flames and excelsior fires. Observa-
tions were also made on the effect of the treatments on the color and
fall of needles.

A summary of the results with water and with 4 fire-retardant
chemicals -- ammonium sulfate-, ammonium phosphate, ammonium sulfamate,
and calcium chloride! -- follows. This summary is of tests on spruce
and balsam fir trees only. It is probable that the effect of the treat-
ment with water on other species would be more or less similar to that
on spruce.and balsam fir, but other species may or mT not react similarly
to treatment with the chemical solution.

p'pecimens, cut several days previously to being placed in water,
gain a little in weight at'the start of treatment, then gradually lose
weight, reaching the ori-inal weight after about 1 week and about 90 rer-.
cent of the original weight after 2 weeks of treatment. Durin, treatment
the srecimen takes up w'ter very readily to replace that lost by evapora-
tion, an amount equal in weight to the original tree being absorbed in
4 to 5 d-Cy,7 in a relatively dry atmosphere. However, since the loss by
evaporationr equals the 7ain by absorption, the weight of the tree during
treatment does not fluctuate widely.

C'nr the other hand, the chemical solutions, tried were neither
t]kern u: -c rapidly nor in such large amounts as was water, and the trees
lost weight w rhile being treated. In other words, while they are taking up
fire retardant chemical, they are losing another good fire retardant,
water. In general, the more dilute the chemical solution, the greater
was the rate of absorption.

Specifically, treatments with solution. of the 4 fire retardant
chemicals tested gave the following results:

Ammonium sulfate.--TestF were rade with F, 2C, and 4C percentt soiu-
tions (by weight). All solutions caused bad diiscoloration cf noth spruce
and balsam fir needles. The needles from the siruce specimens started to
fall 2 days after treatment and by 4 to 5 days were falling. freely. Fire
tests chowed the sprce specim-ns to be decidedly more inflammable than

-'oluticn: of ;hece chemical are recommended in Dejartment of Agriculture
Lea~~ ~ 7 F he i.:eau of Agrici
Laflet 19, "Fireproofing of Christmas :'.s." The reau of Agriul-
..ra:l Oh'-mi try and Engineerin:' stateS that their f:i.ll..--, based on
tes*. on s.,all tree. cf eastern redc.edar (Junirerus virginiana) and
7irg7inia pine (Pinui virgirniana) indicate that these secies are more
:scej.tibic to treatment with Golutions of :m ur,.- n sulfate and cdlciium
chloride than trees of ap ruce and balsam fir,

specimens treated with water. Th' 1l-iam fir -r'cimns wer not '.o infilam-
mable as the spruce, b'ut no significant improvem nt over the -'wter-treated
specimens was noted,

Ammonium phosrhate.--Te3sts were made with :clution:- of both mono-
and diammonium hcspFhate and of a mixture of the two. The eff, ct wa:
similar to that of ammonium sulfate.

Calcium chloride.--ests were made with -C percent soi u-
tions. This chemical did not affect the olcr or the fail of th needles
seriously. The fire ritanc of reimens treated with 4 jer t solu-
tions was less than that of water-treated srecimens, rrcrhaoly due to the
fact that the srecimens failed tc take ur an arrecia1le amount of
calcium 7hloride and at the same time lost monsiaerarl- moi.tur-. .ome
s:recimensr treated with I -ercent solution comnrare f&'.ora' w'it 'fte-
'treated 71 ecimens, tut were not significantly sureri-r in fire resisnc.

Ammonium sul famate.- This ohlmical was the mcs ;rcmi in of al
tested. Its solutions causeddiscoloration of needle, et 1ii not
needle fall in 1'ite of the fact tha tne spe imen -o-t e. ci;h ..i..- f rein-
treatei. The needles became very brittle and wCre easily iCoosnei %; Y
haxnlin 1 but di not faii bein- jarre'. The fir r- ar .rc of he
few specimens treated with a 4C percent 7cl-tin c-f hisY :c a :as
very .-ood, ein a ,proximateiy equal to thaT of w...r tr i imen .
Specimens treated with this chemical .were remove fr-i th r- -
tion and air dried until no further io: in weiht ocurre. -r1- tests
made on the dry specimens showed tri the fire rCesistance was t, ,

While these experiment-s failed o iisalose a cm-"i-a tro atm-nt
more practical than water, they do nct Trove tnat s uch threat n, nt is
imrpossible. Until some other treatment for alsa.m fir n c- roven
to be substantially su-erior, however, water, if used unie r ;: csnitions
specified, will do a good job at little ct.



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