US1705015A

US1705015A - Material

Info

Publication number: US1705015A
Authority: US
Publication date: 1929-03-12
Anticipated expiration: 1946-03-12

Description

March 12, 1929. |RV|NG 1,705,015

ROOFI NG MATERIAL Filed Nov. 22, 1922 FIEIA.

/3 IN V EN TOR.

14.11. Irv/1 5;, ATTORNEYS.

Patented Mar. 12, 1929. I

narrso srarss rarest orrica.

ANDREW H. IRVING, OF BERKELEY, CALIFORNIA, ASSIGNOR TO THE PARAFFINE COMPANIES, INC., OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELA- WARE.

ROOFING MATERIAL.

Application filed November 22, 1922. Serial No. 602,540.

My invention relates to roofs and roofing material and especially to a sheet roofing ma terial largely bituminous in nature of special value on tanks or reservoirs for pet-roleum oils.

One of the objects of the'i'nvention is the provision of a. felt base roofing material having a high degree of resistance to the attacks of the fumes or vapors rising from below.

Another object of the invention is the provision of a roof of the character described which is low in cost, possesses a high standard of durability, and which is capable of the same Wide variety of surface treatment or finish possessed by the general classof bituminous, felt roofings.

My invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that Ido not limit myself to the showing made by the said description as I may adopt variant forms of my invention within the scope of the claims.

Referring to the drawings: Fig. 1 is a vertical section taken thru a portion of the'outer element of my roofing structure. Fig. 2 is a similar section thru the inner element. Fig. 3 is a vertical section taken thru a portion of roofing in which the two element-s shown in Figs. 1 and 2 are combined. Fig. 4C is a perspective view of a portion of a roof laid in accordance with my invention, the near edge being in section.

The figures of the drawing are not drawn to scale, but certain portions thereof are exaggerated in order to show the structure more clearly.

A roof in accordance with myinvention will find wide application in oil fields, pipe line stations, petroleum refineries and in other localities where storage tanks or reservoirs for petroleum oils are used; also in establishments where volatile petroleum solvents are used for extraction, Washing and in other Ways. Not only is the roofing of my invention low in cost, but it is easy to apply, very durable in respect of weather wear and, as its dominant quality ishighly resist-ant to attacks by the oil fumes or other vapors Which form Within the tank or other inclosure covered by the roof.

Bituminous felt roofings have heretofore been applied to the uses referred to, but with rather unsatisfactory results. Oil vapors arising from the oil in the reservoirs collect under the roof structure and effect highly in jurious changes in the covering material, which appears to absorb the vapors largely for the reason that the asphalt contained in the roofing is closely akin to the vapors themselves. Probably the phenomenon of condensation plays an important part in the vapor attack as the oil in the reservoir is often warm, whereas the roofing may be chilled due to weather conditions. however, the results appear to be the same in all cases. The roofing changes from a firm, dense sheet of saturated and coated felt into a pulp-like mass of felted fibers which rapidly dries out with loss of considerable asphalt. Weather action still further disintegrates the injured fabric, until finally destruction of the roofing occurs at the point of attack, and with the sweeping away of the destroyed material by wind and rain, a hole appears.

My roofing material is prepared by saturating a roofing felt with a semisolid bituminous compound, giving to the saturated felt a coating, designed to resist weather action, and applying to the back of thesheet a backing composed of a material which is not easily dissolved by and does not readily absorb petroleum fumes or vapors. By the term dissolved, I means the absorption or condensation of the vapors on or in the backing compound.

Suitable materials for the backing compound cover a wide range. Some of these are bituminous and some are nonbituminous in character. Among them may be mentioned inontan wax, shellac, rubber, stearin pitch particularly when oxidized by exposure to the air, the dried film of linseed and similar varnish oil, and various forms of nitro-cellulose. Particular mention is made of coal tar pitch, especially a pitch having a high percentage of free carbon. Such pitches are not easily attacked by petroleum vapors, although they will absorb to a certain degree the vapor of benzol or toluol to which they are more closely akin.

It will be understood that the material selected for the back of the roofing to give it resistance to oil fumes must form a durable continuous film over the back of the satu- Regardless of theory,

rated roofing felt and must make a good and permanent bond therewith. Silicate of soda falls within the class of ma rials which will not be readily dissolved by condensed or absorbed oil vapors, and silicate of soda may be applied in the f ,rm of a water-glass in a film-like form to the back of a shoot of asphalt or bituminous saturated felt, but it will not form a permanent coverage because it will contract, pull apart and pull away from the felt 1- Wing an open road for the invasion of attacking oil vapors. Home of the matcrials mentioned cannot be made readily to adhere to an aspha t saturated felt surface, such for instance as rubber, but if vulcanized rubber be finely divided, as by a buffing wheel, and then mixed by means of heavyrollers with a small. proportion of pine tar and sulphur and then sheetod onto the asphalt saturated sheet and cured under an elevated temperature, all of which operations are easily comprehended. to those skilled in the manipulation and working of rubber, a backing for the roofing within the meaning and purpose of this invention is secured.

Linseed oil is readily soluble in petroleum oils. It cannot be applied to an asphz-ilt saturated felt sheet and dried as it might be applied to a sheet of metal and dried to a condition in which it resists dissolving petroleum oils. However, a heavily bodied linseed oil in which strong dricrs are incorporated, may be made to dry, particularly if mixed with a material such as certain stearin pitches, that is stearin pitches which skin over readily. A combination of such a stoarin pitch and heavily bodied linseed oil of quick drying properties can be applied to the back of roofing material and will be permanently impervious to oil vapors or fumes within the extent deemed practicable for this invention.

Minerallillers may be added to any of the materials which may be chosen for the oil resistant backing, and such a filler may be very desirable where price is a consideration. Generally speaking, however, the use of such mineral fillers in a large proportion tends to form avenues thru'which the vapors or condensed oil may find a way to the asphalt or bitumen in the felt and this, of course, impairs the durability of the product.

, As the application of a single coating of an oil resistant backing may productive of pinholes thru which the destructive vapor may find access to the bituminous saturation of the felt and the other easii destroyed portions of the roofing, it may be advisable at times to apply two coatings of the oil resistant backing. These tw coatings may be different in nature, that is, the first coat may be a shellac coating and the second, a coating of linseed oil which is subsequently dried and which may contain so icien t mineral fillers to materially reduce the well known contractive nature of the linseed oil film which oftentimes causes it to pull away from a satrated roofing felt sheet. The application of two coats brings about the'covering of the pinholes in the first coat by the second coat.

For the general run of work it is advisable not to concentrate the efforts on making the backing of the roofing perfectly oil-proof, but to give ita degree of oil-proofness con sistent with the cost of manufacture which necessarily forms a more or loss rigid limitation on. the labor and the materials which go to make the complete roofing sheet, and then give attention to the problem of lessening the amount of oil vapor which reaches the resistant under side of the roofing sheet.

In order to prevent the oil vapors from reaching the roofing, except in a diminished volume, various't xmes of dense paper sheets are used. These are durable when laid underneatha roofing of the kind herein described and they hold back the amount of oil vapor which normally would pass at the place they are laid. WVhile this invention does not contemplate a restriction to any one type or grade of paper, save that it gives preference to hard, strong, closely formed sheets, yet for practical purposes it is found thata good grade of paper known as rosin sized sheathing will give satisfactory results. Preferably the grade weighing fort-y pounds per roll, that is to say forty pounds per five hundred square feet, is used and this should preferably be well sized and calendered till it is dense and hard. One or more layers of such sheathing paper may be used beneath the roofing. They may be nailed down or otherwise secured as by cementing over a portion or all of the area with coal tar pitch. Two or more layers may be joined together by cementing the layers to each other with silicate of soda, or by coal tar pitch, or any other of the chosen oil-proof or oil-resistant materials which will exert a cementing action. If but one one layer of the sheathing paper is to be used, it is advisable that the lap joints between adjacent sheets be cemented with silicate of soda. In some instances it is found advisable to give to the sheathing paper a coating of the same sort as that used for the backing of the roofing felt. This renders the paper still more impervious to the oil vapors.

If desired, the sheathing may be coated on both sides, or two layers of sheathing, either or both being provided with the coating of oil resistant material, may be used.

The above contemplates the use of two roofing elements applied separately to form the complete roof. I may in some instances and for some uses prefer to use a single element, that is, to unite the two elements of felt and paper at the factory. It is obvious that at the factory, but may comprise an adhesive coat applied over the laid paper sheathing immediately prior to laying the saturated felt.

It will be apparentfrom theforegoing that a wide variety of combinations is possible with the. different elements of this invention adapting it to a wide range of conditions regards severity of exposure, and allowing a wide range of cost according to the completeness with which protection against vapor attack is carried out.

Referring now to the drawings which illustrate the preferred embodiment of my invention, a sheet of felt 2, of the kind used for making roofing sheets is saturated with a semisolid bituminous material, preferably asphalt having a softening point of approximately 100 F, and a penetration of about 180 11, by the methods of the American Society for Testing Materials, standard for 1921. The saturated felt is coated with an asphaltic coating 8, which may be finished with soapstone or flake granules or other mineral matter in accordance with prevailing practices in the roofing industry. On the opposite side of the saturated felt sheet is a backing l, of coal tar pitch, preferably one having a percentage of free carbon, as determined by the difference between the non-soluble in redistilled benzol and the incombustible matter of 30 per cent and havinga softoning point of 17 0 F. by the method of the American Society for Testing Materials, Serial D 6120.

In Fig. 2 is shown a sectional view of a piece of paper 6, such as is used for the sheathing, and to which a coating 7. of coal tar pitch of the same characteristics as above described, is applied by rollers or scrapers in a manner well known to manufactures of such coated papers. Preferably the coating amounts to about three pounds per hundred square feet of paper.

In Fig. 3, I have shown a sectional view of a complete roofing in which the )aper sheathing 6 is applied to the heated or semi-molten backing a of the fel 2, so that such backing adhesively unites the felt and paper into one composite sheet. This of course is done during the course of manufacturing the roofing and under factory conditions.

In Fig. 4 is shown a complete roof comprising the sheathing 67 of the character shown in Fig. 2, and nailed to a roof decking 8, by means of nails 9. The lap between the sheets of sheathingis filled with an adhesive paint 12, made by heating a coal tar pitch of the character already described and, while in a melted and warm condition, dissolving it in benzol.

It is preferred to lay this sheathing with the coated side upward because it interposes the thickness of the sheathing between the oil vapors and the first layer of coal tar pitch. It is found that coal tar pitch is resistant to oil be free to drop away from the paper and thus open an avenue for the vapor to pass into and thru the-paper to a much greater degree.

Grer the sheathing layer is a sheet of the doubly coated roofing mater'al shown in Fig.

1, with the oil resistant backing or coating next to the sheathing layer. Adjacent sheets are connected by lap joints secured by nails 13,. in the manner usually followed in applying felt base roofing. The lap is made weather-tight by a cement paint 14:, which ced not necessarily have oil resistant properties.

From the above it will be clear that my roofing provides the same excellent wearing surface as to weather conditions that is found in ordinary felt base roofing coated and surfaced described, and in addition such felt protected from the attack of vapors from below by the compacted paper sheet and two separate layers of coal tar pitch. It is quite obvious that under these conditions the saturated felt sheet which comprises the main portion of the roofing, is substantially free from the attack of oil vapors, and under difficult conditions shows a durability and useful life comparable to that of felt base roofings of similar grade under ordinary conditions of application.

I claim:

1. A roofing comprising an outer layer of felt saturated with bituminous material and coated on the under side with a material resistant to the attack of a vapor deleterious to said bituminous material, and an underlying sheathing of compacted rosin sized paper.

2. A roofing comprising an outer layer of felt saturated with bituminous material and coated on the under side with a material resistant to the attack of a vapor deleterious to said bituminous material, and capable of forming a permanent bond with said bituminous material, and an underlying sheathing of rosin sized paper.

3. A roofing comprising an outer layer of felt saturated with asphalt and faced on the upper side with a cea' 'ng of asphalt and on the lower side with a coating of coal tar pitch, and an underlying layer of rosin sized paper faced on the upper side with coal tar pitch.

l. A roofing for oil tank comprising an outer layer of felt saturated with bituminous material and coated on the under side with a material resistant to oil vapor, and an underlying layer of paper coated on the upper side with said resistant material.

'5, A. rooting comprising an outer layer of fibrous material saturated with a Weathercompound and faced on the lower 3; of coal tar pitch, and an no layer of compacted fibrous maul with resin and faced on the upper side with coal tar pitch.

5. A rooting comprising an overlying layeroit fibrous material saturated with bituminous material and coated on the under side With a material resistant to the attack of a vapor deleterious to said bituminous material, and an underlying sheathing of fibrous material sized With a resinous substance.

7. A roofing material adapted to form oil tank covers comprising an outer layer of fibrous material saturated with bituminous material and faced on the lower side with coal tar pitch and an underlying sheathing of paper.

8. A roofing material adapted to form oil tank covers comprising an overlying layer of fibrous material saturated with bituminous material and coated on the under side with a material resistant to the attack of vapor deleterious to said bituminous material, and an underlying sheathing of compact fibrous material.

In testimony whereof, I have hereunto set my hand.

ANDREW H. IRVING.