Page 10 RAIN July 1978 Sedition/cpf lnsulalion_,si ! Cellulose, ~00~ The real fire problem, in my opinion, lie~ in the cellu_losic insulations. To begin with, the cellulosic insulation is most generally a pulverized or finely chopped-up paper material, frequently waste paper. In this condition, it is highly flammabl,e. Flame-retardant salts are then added ,to that paper by a dry mixing method. It has been reported that a few manufacturers are using some 'type of steam impregnation for adding salts. This may give better quality control, but the other problems remain. So, most salts do not become an integral part of the paper, but merely rest upon the surface. Originally borate and boric acid were used as flame r_efardants. Due to the cost or unavailability of boron-based materials, substitutes are being used, or the borates and boric acid are being used with extenders that dilute the effects. The substitute materials are, most generally, ammonium sulfate or aluminum sulfate. -These accentuate the corrosion problem, · since they are acid salts. Even the best of these flame-retardant treated cellulosics , will begin to smolder when heated to approximately 450 degrees Fahrenheit. When smoldering once begins, it is most difficult to extinguish. It reacts like a smoldering cotton mattress. The ordinary application of water or other extinguishing age1_1ts is i~effective. The material must be carefully pulled apart in its entirety, and each parcel extinguished separately. Ever since cellulose fiber insulation began to be promoted a couple ofyears ago as a low-cost "wonder drug" for building energy conservation, we've been expressing our concern over its potential combustibility and moisture problems. RAIN reader Paul Hewitt in Toronto wrote saying he shared our concern and would let us know if he found any documentation. It follows, below, excerpted from an article by]ohn G. Degenkalb on fire safety concerns of energy conservation measures in buildings. It's from the May 1978 issue of Fire Journal published by the National Fire Protection Associati'on, • 470 Atlantic Ave., Boston, MA 02210. In addition to detailing the fire hazards of cellulose insulation, Degenkolb's article gives the first overview I've seen of general fire hazards of well-insulated buildings (rapid fire spread from containment of heat, rapid smoke spread, etc.); electrical/fire hazards from insulation (overheating during electrical equipment operation, overheating from beat released from insulation while curing, chemical interaction of electrical and thermal insulation, and chemically induced -corrosion); and other hazards (corrosive effect on structural members of sulfuric acid produced by flame retardant salts in cellulose insulation that bas caused one and possibly more _buildings to collapse). Good things to know about. About an hour after Paul Hewitt's letter arrived, Laura Masin walked in the door at RAIN to let us know about a recently completed "Feasibility Study on Small-Scale Cellulose Insulation Manufacturing" by the Community Energy Network, 122 Anabel Taylor Hall, Cornell U,niversity, Ithaca, NY 14853. The study covers net energy analysis, moisture problems, market analysis, fire retardancy and research on alternative chemicals, economic analysis of small-scale '• production, etc: -TB In Jan_uary 1977, ERDA prepared a report entitled Survey of Cellulosic Insulation Materials. Nineteen off-the-shelf samples were obtained. They noted that "of the 19 samples received for analysis, 13 showed visible evidence that some of the fire-retardant chemical had separated from the cellulosic matrix; quantities of the additives were,•found at the bottoms of the containers." In other words, that paper from which the fire-retardant chemicals had dropped off was little more than waste paper in a highly flammable form. . V As to moisture absorption, the weight gain should not exceed ·1.5 percent if it is to meet the Standard. All 19 showed water solubles in excess of 15 percent. "The difference in moisture absorption increased with increasing time-some samples had moisture gains in the 75 percent range after g:.15 days of exposure. Also, in some samples the moisture gains reached a maximum and then decreased." After 15 days, nine of the samples exceeded 15 percent, with one as high as 70 percent, and two were in the 40 percent range when in a lowdensity packing configuration. Under different packing configurations, six of nine exceeded the 15 percent after 15 days. Since the flam'e retardants are water soluble, doesn't this indicate there is the defif)ite possibility that those salts may well be leached out over a period of time? Because the problem has been recognized, some comp·anies utilize permanently I
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