01 May 1999
(ECO). These rubbers are vulcanized with a
caused by free alkalies leached from mortar,
variety of reagents that react difunctionally with
grout, or adjacent concrete.
the chloromethyl group, including diamines,
urea, thioureas, 2-mercaptoimidazoline, and
ammonium salts. This rubber offers excellent oil
which it regains its original size and shape after
removal of stress.
Elastomer--A macromolecular material that
content of a material stabilized at a given
returns rapidly to its approximate initial
temperature and relative humidity, expressed as
dimensions and shape after subsequent release
percent moisture by weight; (2) The typical
moisture content of a material in any given geo-
Embedment--(1) the process of pressing a felt,
aggregate, fabric, mat, or panel uniformly and
EVA--Family of copolymers of ethylene and
completely into hot bitumen or adhesive to
vinyl acetate used for adhesives and
ensure intimate contact at all points; (2) the
thermoplastic modifiers. They possess a wide
process of pressing granules into coating in the
range of melt indexes.
manufacture of factory prepared roofing, such as
EVT (Equiviscous Temperature)--Temperature
at which the viscosity of an asphalt is
appropriate for application. Viscosity units are
globules of a liquid in a liquid. Asphalt emulsions
generally expressed in centipoise or centistokes.
consist of asphalt globules, an emulsifying agent
Tolerance on EVT is usually 1400 ( 25 F).
such as bentonite clay and water.
Endlap--The overlap where one panel or felt
nests on top of the end of the underlying panel
between two building elements that allows free
Envelope--A continuous edge seal formed by
movement (expansion or contraction) between
extending one ply of felt beyond the edge of the
elements without damage to the roofing or
assembly. After other plies or insulation are in
place, the extended ply is turned back and
Exposure--(1) The transverse dimension of a
roofing element not overlapped by an adjacent
EIP (Elastoplastic)--pertaining to polymeric
element in any roofing system. The exposure
overlapped by an adjacent element in any
roofing system. The exposure of any ply in a
membrane may be computed by dividing the felt
EPDM--A synthetic elastomer based on
width minus 51 mm (2 in.), by the number of
ethylene, propylene, and a small amount of a
shingled plies; thus, the exposure of 914 mm (36
non-conjugated diene to provide sites for
in.) wide felt in a shingled, four ply membrane
vulcanization. EPDM features excellent heat,
should be 216 mm (8-1/2 in.); (2) The time
during which a portion of a roofing element is
exposed to the weather.
Extra steep asphalt--See Super Steep Asphalt.
Epichlorohydrin rubber--A synthetic rubber that
includes two epichlorohydrin-based elastomers
of saturated high molecular weight, aliphatic
removable from a solid or liquid mixture by
polyethers with chloro-methyl side chains. The
means of an appropriate solvent.
two types include a homopolymer (CO) and a
copolymer of epichlorohydrin and ethylene oxide