Friday, October 25, 2013

What Is EPDM Roofing Membrane



EPDM Roofing Membranes

There are many flat roofing or low slope roofing solutions. One of the more popular choices in today's market is the EPDM memberane. EPDM stands for ethelene propylene diene monomer, which is a rubber product. There are several manufacturers that produce EPDM such as GAF and Versico. Here are some of the facts and information about Versico EPDM membranes and systems. 

  • EPDM is comprised of a polyester reinforcement sandwiched between two layers of rubber. 
  • It is available in .45, .60 and .75 mil thicknesses. 
  • Designed for high traffic roof tops such as schools and hospitals. 
  • Versico's brand comes with QAT Seam Technology which is quick applied tape. This makes installation much faster and more effective. 
  • QAT quick tape has been known to reduce seaming time by 75%. It also reduces seam failure by providing 30% stronger peel strength and 32% stronger than most other seam tapes on the market. 
  • The polyester reinforcement in between the layers of EPDM rubber more than doubles the puncture resistant strength compared to non-reinforced membranes. 
  • Versicos EPDM membranes can be installed as a complete roofing system and qualify for a 20 year NDL "no dollar limit" warranty.
  • They can be installed by either mechanically fastening the membrane with screws and plates or by fully adhering (gluing) the membrane with special bonding adhesive. In order to qualify for the NDL system warranty DASH DC bonding adhesive must be used. In order to qualify for a no dollar limit warranty your system must be installed by a Versico approved roofing contractor.
  • Fully adhered systems can be warranted against wind resistance up to 120 mph. Mechanically attached systems can carry a 100 mph wind resistance warranty. 
For more in depth information please read the below excerpt from Wikipedia. You can also see Versicos EPDM page on their website at  http://www.versico.com/index.cfm?act=productdetails&RSC_ID=45.

EPDM rubber (ethylene propylene diene monomer (M-class) rubber),[1][2][3] a type of synthetic rubber, is an elastomer which is characterized by a wide range of applications. The E refers to ethylene, P to propylene, D to diene and M refers to its classification in ASTM standard D-1418. The M class includes rubbers having a saturated chain of the polymethylene type. Dienes currently used in the manufacture of EPDM rubbers are dicyclopentadiene (DCPD), ethylidene norbornene (ENB), and vinyl norbornene (VNB). EPDM rubber is closely related to ethylene propylene rubber (ethylene propylene rubber is a copolymer of ethylene and propylene whereas EPDM rubber is a terpolymer of ethylene, propylene and a diene-component).

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A roll of EPDM foil, used for waterproofing roofs
The ethylene content is around 45% to 75%. The higher the ethylene content the higher the loading possibilities of the polymer, better mixing and extrusion. Peroxide curing these polymers gives a higher crosslink density compared with their amorphous counterpart. The amorphous polymer are also excellent in processing. This is very much influenced by their molecular structure. The dienes, typically comprising from 2.5% up to 12% by weight of the composition, serve as crosslinks when curing with sulphur and resin, with peroxide cures the diene (or third monomer) functions as a coagent, which provide resistance to unwanted tackiness, creep or flow during end use.
Properties
EPDM exhibits satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis, and unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents and concentrated acids.
The main properties of EPDM are its outstanding heat, ozone and weather resistance. The resistance to polar substances and steam are also good. It has excellent electrical insulating properties. It has good resistance to ketones, ordinary diluted acids and alkalines.
Typical properties of EPDM vulcanizates are given below. EPDM can be compounded to meet specific properties to a limit depending first on the EPDM polymers available, then the processing and curing method(s) employed. EPDMs are available in a range of molecular weights (indicated in terms of Mooney viscosity ML(1+4) at 125 °C), varying levels of ethylene, third monomer and oil content.
Mechanical properties of EPDM
Property
Value
Appearance

Hardness, Shore A
40–90
Tensile failure stress, ultimate
25 MPa
Elongation after fracture in %
≥ 300%
Density
Can be compounded from 0.90 to >2.00 g/cm3

Thermal properties of EPDM
Property
Value
160 ┬Ám/m·K
Maximum service temperature[5]
150 °C
Minimum service temperature[5]
−50 °C
−54 °C
Uses
http://upload.wikimedia.org/wikipedia/commons/thumb/1/14/FinishedEPDMcoveredRoof.jpg/150px-FinishedEPDMcoveredRoof.jpg
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An EPDM rubber roof
EPDM rubber is used in seals (for example it is used in cold-room doors since it's an insulator, as well as in the face seals of industrial respirators in automotive paint spray environments, where silicone must be avoided). EPDM is also used in glass-run channels, radiators, garden and appliance hose, tubing, pond liners, washers, belts, electrical insulation, vibrators, O-rings, solar panel heat collectors and speaker cone surrounds. It is also used as a medium for water resistance in electrical cable-jointing, roofing membranes (since it does not pollute the run-off rainwater, which is of vital importance for rainwater harvesting), geomembranes, rubber mechanical goods, plastic impact modification, thermoplastic, vulcanizates, and many other applications.[6][7] Colored EPDM granules are mixed with polyurethane binders and troweled or sprayed onto concrete, asphalt, screenings, interlocking brick, wood etc. to create a non-slip, soft, porous safety surface for wet-deck areas such as pool decks and as safety surfacing under playground play equipment (designed to help lessen fall injury).
The most common use however is probably in vehicles. It is used in door seals, window seals, trunk seals, and sometimes hood seals. Frequently these seals are the source of noise due to movement of the door against the car body and the resulting friction between the EPDM rubber and the mating surface (car painted sheet metal or glass). This can be alleviated using specialty coatings that are applied at the time of manufacture of the weather seal. Such coatings can also greatly increase the chemical resistance of EPDM rubber. Some vehicle manufacturers also recommend a light application of silicone dielectric grease to weatherstripping to reduce noise. Other uses in vehicles include cooling system circuit hoses where water pumps, thermostats, EGR valves, EGR coolers, heaters, oil coolers, radiators and degas bottles are connected with EPDM hoses; as well as charge air tubing on turbo charged engines to connect the cold side of the charge air cooler (intercooler) to the intake manifold.
References
1.      Jump up ^ Ravishankar, P.S. (2012). "Treatise on EPDM". Rubber Chemistry and Technology 85. p. 327-349.
2.      Jump up ^ Green, Mark M.; Wittcoff, Harold A. (July 2003). Organic Chemistry Principles and Industrial Practice. Weinheim, Germany: Wiley. p. 170. ISBN 978-3-527-30289-5. "In addition to natural rubber, many synthetic rubbers…such as…ethylene-propylene-diene monomer rubber…"
3.      Jump up ^ Louie, Douglas K. (2005). "Elastomers". Handbook of sulphuric acid manufacturing. Richmond Hill, Canada: DKL Engineering, Inc. pp. 16–116. ISBN 978-0-9738992-0-7. "EPDM (Ethylene Propylene Diene Monomer is a M class Rubber containing a saturated chain of the polyethylene type."
4.      Jump up ^ "Designing with Rubber", Technical Documentation Orings, Eriks, p. 33

1 comment:

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