ROOF COVERING MATERIALS

The applications of asphalt products in the industrial world are immense. Considerable amount of work has been published on the chemistry and application of asphalt.t t ]P l 

Polymeric materials and asphalt-based products have a variety of applications in the construction industry. Some of these applications are as roof coverings. Table 5 shows the various types of related material used as roof coverings. 

Irrespective of the system, new materials have been introduced as alternatives to the older ones (see Table 5). For example, some shingles are made of modified bitumen instead of blown bitumen. Asphalt-saturated organic felt is increasingly being replaced by asphalt-impregnated glass fiber mat in the manufacture of shingles and as felt plies in BUR. In the new systems, more factory prefabrication and less work atop the roof is involved than in the traditional roofs. 

Some find this choice overwhelming and confusing. Many years of experience have accrued in the application of BUR, but not so with the newer materials. As a result, the knowledge acquired in the past was of little use for explaining the problems experienced with the new generation of roof systems. 

As aconsequence, literally hundreds of new roofing materials have appeared on the market. Most of them are polymeric in nature. They are reinforced with a variety of woven and non-woven fabrics of S5mthetic and glass fibers. 

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Tests for Fire Resistance of Roof Covering Materials, 1983. (similar to ASTM E 108) Tests for Flame Propagation and Smoke Density Values for Electrical and Optical Fiber Cables in Spaces Transporting Environmental Air, 1991. 

As a consequence of a very serious fire under the steel roofs in a large car plant in USA the Underwriters Laboratories Inc., developed a new UL test method, which uses oxygen consumption cone calorimetry to quantify roof covering materials. This test was used to quantify the contribution of roof covering materials to the fire under the roof by capturing effluent from beneath the roof assembly and recording the rate of heat production in kW/min. 

The new UL test method utilises a collection hood and duct system prescribed under various nationally recognised fire test procedures including the UL 1715 Standard [54]. The test structure is a masonry room measuring 2.4 m wide by 3.7 m long by 2.4 m high, with one 2.4 m wide open end. Heptane fuel burners are used to provide the internal fire source. The test method utilises oxygen consumption calorimetry to quantify the roof covering materials. 

Table 5. List of Various Roof Covering Materials...

For low slope commercial roofing, bituminous-based roof coverings are the most common systems in the United States. Asphalt-based materials predominate over coal-tar based materials in these systems. For residential roofing materials, various types of roofing products, including asphalt, wood, and tile, ate used for both new constmction and reroofing. 

For some purposes where the strength and ductility of steel are not prerequisites, other metals or materials may be used to advantage, particularly when the component or article is not a load-bearing one. Some of the non-ferrous metals and plastics materials are extremely useful in this respect, especially the latter with their excellent corrosion-resistant properties and ease of formability. Non-ferrous metals in sheet form are often used as roof covering. In such situations they could well become subject to condensation. Condensation could be the result of thermal pumping or internal conditions. Under conditions in which condensation can occur, copper is not normally attacked, but lead, zinc and aluminium may be attacked and corrode from the inside of the building outwards. 

A single plane could carry 1000-2000 of such bombs. An electron bomb dropped from a height of ca 1 mile would usually penetrate an ordinary wooden roof deck ot covering material and start a fire in the top story or attic of a bldg. If not quickly extinguished the bomb would burn through the floors and set fires everywhere in the bldg... 

ASTM E 84 Standard Test Method for Surface Burning Characteristics of Building Materials ASTM E 108 Standard Test Methods for Fire Tests of Roof Coverings ASTM E 119 Standard Test Methods for Fire Tests of Building Construction and Materials ASTM E 136 Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C ASTM E 162 Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source... 

NFPA 255 Standard Method of Test of Surface Burning Characteristics of Building Materials NFPA 256 Standard Methods of Fire Tests of Roof Coverings (withdrawn)... 

Copper is a very important metal used for water pipes, electrical wiring, roof coverings, and other materials. When a sample of natural copper is vaporized and injected into a mass spectrometer, the results shown in Fig. 3.3 are obtained. Use these data to compute the average mass of natural copper. (The mass values for 63Cu and 65Cu are 62.93 amu and 64.93 amu, respectively.)... 

Roof sheathing or sheeting- The wood panels or sheet material fastened to the roof rafters or trusses on which the shingle or other roof covering is laid. 

Shingles- Roof covering of asphalt, asbestos, wood, tile, slate, or other material cut to stock lengths, widths, and thickness. ... 

Another type of tent dryer has its roof covered by polyethylene sheet. The drying material is spread over a concrete floor (e.g., coffee beans) [2]. Another type of the tent dryer is the terrace dryer. Its cross-section is sketched in Figure 14.2b [2]. The drying shelves 1 stand on posts 2 the roof and the front wall are covered with a polyethylene foil 3. 

Roofing n. (1) Any material used as a roof covering (such as shingles, slate, sheet metal, or tile) to make it wind- and waterproof, and often provide thermal insulation. (2) A roof. 

Sarking. A layer of insulating material under the main roof covering. In Scotland the term has the special meaning of sawn roof boarding usually 15 mm thick (cf. torching). 

Resistance to ultraviolet (UV) light is a matter of concern in the choice of materials for bumpers and lamp clusters, and hang-ons like door mirrors. It emerges from time to time with stylists innovative attempts to escape from the cost penalties of the paint shop, like vinyl roof covers. 

LDPE, ethylene copolymer teehnieal lining and sealing materials, eonstmetion sealing webs, roof coverings Chlorinated PE coating materials... 

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