I S D U S T R I A L A X D ENGINEERING CHEMISTRY
168
Vnl. 23. Kn. 2
Asphalt Shingles’ John Morris Weiss WEISSAND DOWNS, INC,,
NEW YOBK,N. Y.
Asphalt shingles surfaced with mineral granules have SPHALT shingles surExperimental Tests become an important roofing material, and the pubfaced with m i n e r a l lished specifications now in use do not appear to be granules are an imI n the last eight years the sufficient to secure adequate quality. The results of the portant material in the roofwriter and his associates have examination of sixteen brands of asphalt shingles that ing industry. According to had occasion to determine the are sold for roofing are presented, together with comthe statistics of the Departcomposition of a number of ments on the different compositions which are enment of Commerce, about grades of roofing. countered. Certain recommendations as to the direc10,856,690 squares of asphalt These tests were made on tion in which specifications should be changed are shingles were sold in 1928 samdes submitted to them, a and 11,974,539 squares in suggested. and isually consisted of three strips supposedly chosen to 1929 by the forty-one producers who comprise the industry. About 90 per cent represent the average of the material. The total weight of of the shingles sold are of the strip type. These consist the strips submitted was determined in the laboratory and the of several units joined together in flat strips and are pieces selected for actual test were selected so as to have the frequently called “multiple shingles.” They can be laid same average weight-area relationship as the average of the more rapidly and with less labor than individual shingles and strips received. The methods used for examining the have “cut-outs” so as to give the same roof appearance as samples were variations of the methods suggested by Abrawhen individual shingles are used. Figure 1 shows a photo- ham (1). The fiber counts of the felts were made according to A. S. T. M. Tentative Standard (D272-29T). graph of this type of roof. A common type is a four-shingle strip with square butts Table I shows the result of representative tests of the 32 or 36 inches long, 12l/2 inches wide with cut-outs 4 inches proximate composition of sixteen brands of 36 inches long, deep and a/4 inch wide. When these are laid, with a 4-inch 121/2inches wide strip shingles, with square butts. Shingle exposure to the weather, from 311 to 312 square feet of KO.8 represents an asbestos felt base shingle of a different actual shingle are required to cover 100 square feet of roofing class than the others, and is therefore not subject to direct surface, and this amount is known as a ‘‘roofing square.” comparison. Only one of the brands tested is below the minimum weight The amount required per roofing square varies with different of the A. S. T. M. requirements, which incidentally are subdesign shingles and with different exposures to weather. Such shingles are made from a base of roofing felt (a rag stantially the same throughout as those of the Underwriters paper with or without other fibers), saturated with a bitumi- Laboratories, whose approval tag is usually on brand shingles nous material (asphalt) and covered on the weather side with of this type, This approval is, however, primarily from the an asphalt coating in which are embedded mineral granules, standpoint of fire-retarding properties and not necessarily of usually slate. Often the bottom surface of the shingle is also durability and service. Two of the brands (Nos. 1 and 3) treated with a very thin layer of asphalt coating and finished have used less felt than the requirements of the A. S. T. M. by dusting with mica or soapstone. Such shingles are sold specification, while two others (Nos, 5 and 14) are above the under brand names and not on specification, and as the gen- maximum requirement for surface mineral matter. However, eral outward appearance of all shingles is the same, except for these will pass the specification since the excess over 35 the variation in color of the mineral surfacing, the purchaser pounds per 108 square feet is compensated by an excess in cannot intelligently select between one brand and another. total weight over the 80 pound minimum. A. S. T. M. Specifications Table I-Composition of Various Brands of Strip Asphalt Shingles
A
These shingles are the subject of a standard A. S. T. M. specification (D225-29) entitled “Standard Specifications for Asphalt Roll Roofing and Asphalt Shingles Surfaced with Mineral Granules.” Their requirements as to composition of the finished product may be summarized as follows: Weight per 108 sq. ft.. , . . . . . . . , . , . . . . . . . . Minimum 80 Ibs. Saturation in f e l t . . . . . . . . . . . . . , . , . . . . . . . . Minimum 150% Weight of felt per 108 sq. f t . . , . . , , , . , , . . . . Minimum 1 0 . 8 Ibs. Ash in dry f e l t . . , , . . . , , , , , . . . , . . . . . . . . , , Maximum 10% Mineral matter per 108 sq. It.. . . , , , , . , , . , . Maximum 35 Ibs.“ 0
limit.
If above 35 pounds totxl weight must be equally above 80 pound
Apart from the above, requirements are general and not specific in character, except for a heat test at 80’ C. for 2 hours, which practically all commercial materials will pass. All that these specifications really provide is that there shall be a certain minimum weight per unit area of shingle, a minimum weight of felt per unit area, a minimum percentage of saturation in the felt, a maximum of ash in the felt, and a maximum of mineral matter per unit area of shingle. 1 Received
October 11, 1930.
WEIGHTOF COMPONENT PARTSP E R 108
TOTAL WEIGHT SHINGLEPER 108 No. SQ. FT.
1 2 3 4 5 6 7 S 9 10 11 12 13 14 15 16
Felt
Lbs. 10.5 11.6 10.2 11.7 12.1 11.9 11.7 20.9 11.6 11.6 11.7 11.8 11.1 11.0 11.1 11.9
Lbs. 83.6 84.4 83.2 81.4 82.8 80.9 80.0 84.0 82.0 78.4 90.1 85.3 87.1 93.9 81.8 90.8
A. S. T . M. require- Min. SO ments
1
Min. 10.8
SQ BT.
Mineral Bottom Bottom Top Saturant coating surfacing coating mineral
Lbs. 19.1 17.1 18.1 21.5 22.2 17.8 20.3 16.2 24.8 22.6 25.2 19.4 21.1 21.0 19.1 17.4
Lbs. 27.1 21.0 19.5 23.4 9.9 27.0 20.4 17.4 24.2 20.4 21.3 20.5 23.8 23.3 26.6 29.6
Lbs. 25.8 32.4 27.3 22.5 36.3 21.3 25.8 28.4 20.5 22.4 29.6 33.1 30.2 37.9 18.5 29.0
Lbs. 0.5 1.2 7.0 1.6 1.2 2.1 1.0 0.2 0.3 0.7 1.2 0.2 0.6 0.3 5.7 2.5
Lbs. 0.6 1.1 1.1 0.7 1.1 0.8 0.8 0.9 0.6 0.7 1.1 0.3 0.3 0.4 0.8 0.4
Max. 35.0
From a material cost standpoint, felt is the most expensive item in shingle manufacture, saturant and coating come next,
INDUSTRIAL A N D ENGINEERING CHEMISTRY
February, 1931
and mineral surfacing is the cheapest. The raw material cost for N o . 9 is about 25 cents more per roofing square than that for No. 1, although the finished weight per roofing square is considerably less in Xo. 9 than in No. 1. Kos. 3 and 15 have a very heavy bottom protective coating, which differentiates them from the other brands tested.
Figure 1-Roof
Covered w i t h Multiple Asphalt Shingles
Table I1 shows the percentage saturation in the felt, and the tests of the dry felt. Excluding N o . 8, the asbestos shingle, two (Sos. 2 and 16) are below the A. S. T. M. saturation limit and one (KO. 6) is just on the limit. The last three (Kos. 14, 15, and 16) are too high in ash. Too light weight felt has been used in Xos. 1 and 3, as was indicated also in the tests of Table I. All of these represent considerable differences in cost of manufacture and probably in service. Those with low saturation in the felt usually show curling and blistering in service to a marked degree, although low saturation is not the only cause of such blistering. Figure 2 shows a roof on which curling has occurred and illustrates the undesirable appearance caused by this action. As to the felts, a variation from a 45.5 to a 53.5 felt is quite considerable and represents a 17 per cent variation in the most expensive of the components. Table 11-Saturation
GLE
No.
RATIOh
lo 3 4 5 6
7 8
9 10 11
12 13
14 15 16
182 148 177 184 184 150 174 SO 214 195 216 165 190 191 172 146
Ash
A. S. T. M .
require- Min. ments 150
% 47.0 51.5 45.5 52.0 53.5 52.5 52.0 95.0 49.5 52.0 48.5 52.8 50 0 49.0 49.5 52 9 Min.
4s
% % . . . . . . . . . . . . . .
5.2 7.6 6.8 7.6 6.6 6.3 4.7 65.5 7.7 6.7 9.3 6.8 7.9 10.6 13 J 10 8 Max. 10
The asphalt roofing industry has been very highly competitive in the last few years and there has been a tendency to reduce the material costs, often a t the expense of real quality. More rigid purchase specifications are very desirable. The ideal specification, of course, would be a service test, but as yet no accelerated tests which have been so correlated with actual service records as to be reliable are available for general use. Somewhat stricter limits than the A. S. T. M. requirements are necessary to assure real quality of product and prevent competition from further abstracting from the inherently necessary higher grade of raw materials. These requirements should place some upper limit on the wood-fiber content of the felt, increase the minimum allowable saturation, and prescribe a ratio between surface coating and mineral matter so that if the latter is increased the coating will be proportionately increased to insure there being enough to hold the grit to the surface. I n general mineral-surfaced roofing lasts considerably longer than smooth-surfaced roofing where the asphaltic coating forms the wearing surface. There must be enough mineral matter to cover and protect the coating adequately. Xo. 15, with only 18.5 pounds of mineral surfacing per 108 square feet, seems deficient in this respect, and this is confirmed by the visual appearance of the sample. On the other hand, No. 5, with 36.3 pounds mineral surfacing and only 9.9 pounds asphalt coating, has not enough coating and the grit is loose and can easily be detached from the surface. The exact limits to be imposed will vary with the type of mineral surface employed.
Tests
Me‘hPa;li- khaniJute-
wood
1 2
Discussion of Specification Requirements
~
wool Cotton
No.
point as to how much wood can be used with safety, in the writer’s opinion No. 16, with almost 50 per cent wood and a saturation of only 146 per cent, will give service results which are decidedly inferior to many of the others with much higher rag content and more complete saturation.
FIBERCOUNT
FELT
SHIN- SATU
169
...
4.4 3.7 4.3 7.9 2.2 2.1 1.3 3.2 5.0 3.0 1.0
3.0
68:5 71.7 70.9 26.9 70.9 65.2 70.2 69.9 68.2 80.5 71.0 42.0
cal manila wood
Asbestos
% % % % . . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . . ... i5:o ii:i 1.0 15.0
7.4
10.0 13.0
ii:o
ii:g 10.4 17.0 9.0 16.3 10.0 16.9 5.1 16.9 4.4 7.4 19.0 6.0 12.0 34.0
2.2 1.8
...
3.0 5.3 3.2 3.0 4.8 4.7 4.0 9.0
,
The character of the felts is also of interest. The extremes wool) in KO.14 and 45 of 83.5 per cent rag fibers (cotton per cent in No. 16 is also of interest. Rags are far more expensive than wood fibers and, although it is a mooted
+
Figure 2-Roof
of Asphalt Shingles on Which Curling Has Occurred
On the saturation specification, the writer would be inclined to set a low limit of 170 per cent, which would exclude Nos. 2, 6, 8, 12, and 16 (see Table 11),and would further give consideration to the ratio between actual saturation and saturating capacity of the felt used. Felts vary in their capacity to take saturation. Some makers control saturation by making a kerosene absorption test on dry felt and regulating the saturation to a t least 90 per cent of that which the felt should theoretically absorb. This practice seems to be an excellent one to insure thorough saturation of the felt. It must also be considered that improper manufacturing
INDUSTRIAL A N D EXGINEERIXG CHEMISTRY
170
methods can detract from values even if adequate amounts of suitable-quality raw materials are used. Analyses of the type given here will naturally not detect such differences which are t o a certain extent evident by inspection of the roofing. However, in general, the higher the grades of materials used in the roofing the greater care will be taken by the makers. Tests of the kind outlined here will do much toward eliminating the lowest grades Of product from Con-
Vol. 23, S o . 2
sideration and should give the consumer a better chance of obtaining service from the brand of roofing which he purchases. From time to time, based on experience, the limits of acceptable quality can be narrowed so as to insure more adequate service. Literature Cited (1) Abraham, H., “Asphalt and Allied Substances,” 19%.
Solubilities of Oils and Waxes in Organic Solvents-11’ John Ward Poole and Collaborators F U E LA N D GASE N G I N E E R IDEPARTMENT, NG MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE, MASS.
These data were collected to furnish fundamental oxide, and Butyl Cellosolve information for commercial and analytical processes all boil a t temperatures so the senior author in colwherein it is necessary to separate paraffin wax from elevated as to make their laboration with R. K. r e m o v a l difficult. Certain Opper and A. K. Scott [IND. liquid hydrocarbons. The solubility-temperature data are shown graphically for n-amyl alcohol, a commercial of this group are subject to ENG.CHEM.,21, 1098 (1929)] mixture of amyl alcohols (Pentasol), isopropyl alcohol, further drawbacks. Carbon there has been p u b l i s h e d n-butyl aldehyde, paraldehyde, ethyl chlorocarbonate, tetrachloride and tetrachloroqualitative data for twentyethylene dichloride, butyl formate, methyl ethyl ketone, ethane appear to be too reeight organic solvents. I n two solvent naphthas, and turpentine. active to be useful. Soluaddition, quantitative data Furthermore, consideration has been given to the tions c o n t a i n i n g either of on the solubilities of oil and important factor of oil concentration on the solubility the last two c o m p o u n d s wax in a c e t o n e , in n-butyl of wax in solvent-oil mixtures. Butyl acetate, paraldeand oil d a r k e n on standalcohol, in n-butyl aldehyde, hyde, n-butyl alcohol, chlorobenzene, and Pentasol ing. and in a “50-50” mixture of were investigated for this study. I n the previous article it acetone and n-butyl alcohol Finally, in order to broaden the field of solvents was reported that ethylene diwere presented graphically as available for dewaxing processes, twenty-six comchloride solutions also darka function of temperature. pounds on which data are practically non-existent have ened on s t a n d i n g . I n the Similar curves were given for been investigated qualitatively. present work, however, no the solubility of wax only, in such trouble was encountered butyl acetate, chlorobenzene, and toluene, With the last three solvents oil is completely when using fresh chemically pure solvent. I n view of the considerable number of determinations necessary to obtain miscible, a t least over the temperature range in question. The work reported in this article, however, did not finish the desired data, it seems probable that ethylene dichloride, as the program for this group of solvents. Certain solvents not such, is not undesirably reactive. quantitatively investigated seemed to offer considerable Experimental Procedure possibilities and a different type of data was also needed to The experimental procedure for the determinations redetermine the commercial and analytical significance of the selective powers shown. Furthermore, there were other ported in this paper was identical with that used in the presolvents known to possess, or which might possess, the quali- vious work. For each temperature two determinations were fications necessary for wax removal. This paper deals with made, and unless these checked within about 3 per cent of the total wax dissolved further determinations were run. progress in the above fields. In certain cases, usually with either very high or very low SOLUBILITIES OF PENNSYLVANIA OILS AND PARAFFIN WAX solubilities, it was necessary to make several determinations IN NAPHTHA, TURPENTINE, ETHYLENE DICHLORIDE, METHYL and average those which came close together. When a ETHYL KETONE, n-BUTYL ALDEHYDE, ISOPROPYL ALCOHOL, AND n-AMYL ALCOHOL widely divergent solubility was observed, extra determinations were always made. Each point shown on the plot With F. C. Fahnestock and E. L. Krall represents the average value for a t least two independent Of the solvents investigated in the previous paper only determinations, which frequently were identical. The data seven were investigated quantitatively, although it was are probably accurate to within 5 per cent of the total recognized that others in the group showed equal or nearly hydrocarbons dissolved. equal promise of high selectivity. The work covered in this Characteristics of Materials Used section represents the completion of various solubility-temperature curves for this group. The solvents used in this work were as follows: light It will be noted, however, that certain solvents are not naphtha-water white, A. P. I. gravity 59.9”, boiling range represented in the accompanying graphs. The reasons for 88” to 138’ C.; heavy naphtha-water white, A. P. I. this are several. Ethyl alcohol, diacetone alcohol, acetic gravity 49.5”, boiling range 157” t o 231” C.; commercial anhydride, glacial acetic acid, Cellosolve, and Methyl Cello- turpentine; n-butyl aldehyde, technical grade; ethylene solve either possess very low solvent power for oil or seem dichloride, chemically pure; n-amyl alcohol, chemically to have little selective ability. Amyl acetate, xylene, mesityl pure; methyl ethyl ketone, chemically pure; isopropyl alcohol, chemically pure. 1 Received November 24, 1930.
I
N A previous article by
-
