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| ABRASION RESISTANCE |
The ability of the membrane
to resist mechanical abrasion such as foot
traffic and wind-blown particles which tend
to progressively remove materials from the
membrane's surface. |
| ADHESION |
The ability of the membrane
to remain adhered to the substrate or to itself
during its service life. |
| AGGREGATE |
Crushed stone or water-worn
gravel used for surfacing or ballasting. |
| ALUGATORING |
A term describing the defect
in an applied coating or mastic when it shrinks
or cracks into large segments. When the action
is fine and incomplete it is usually referred
to as "checking." |
| ALLOY |
A mixture or blend of similar
materials (thermoplastic) melted and reextruded
into a new material from which the original
materials cannot be separated. |
| AMBIENT TEMPERATURE |
Temperatures of the surrounding
air on all sides. |
| AMERICAN SOCIETY FOR TESTING
& MATERIALS (ASTM) |
A consensus standards-setting
organization, headquartered in Philadelphia. |
| APPLICATION TEMPERATURE
LIMITS |
Temperature between which it
is usually safe to apply finishes, adhesives
and sealants. |
| ASPHALT |
A brown to black bitumen found
in natural beds or obtained as a residue from
petroleums. |
| ASPHALT COATINGS |
Asphalt coatings fall within
three general categories: cutbacks, emulsions
and modified. Each has a different composition.
|
| ATACTIC |
A polymer in which there is
a random arrangement of pendent groups on
each side of the chain, as in Atactic Polypropylene
(APP). |
| BACKNAILING |
The practice of back nailing
in addition to hot-mopping all the plies to
a substrate to prevent slippage. |
| BASE SHEET |
Saturated or coated felt placed
as the first ply in a multi-ply built-up roofing
membrane. |
| BATTEN |
A strip of steel or aluminum
used to mechanically fasten a single-ply membrane
for the purpose of preventing wind uplift.
Type of metal roofing seam; raised rib in
a metal roof, or a separate part of formed
portion in a metal roofing panel. |
| BITUMEN |
An asphalt, various mixtures
of hydrocarbon material of natural or pyrogenous
origin (as coal tar), or combinations of both,
which may be liquid, semi-solid, or solid,
and which is completely soluble in carbon
disulfide. Any number of inflammable mineral
substances. |
| BLANKET INSULATION |
Fiberglass insulation in roll
form, used with a vapor retarder membrane
laminated to the inside face. |
| BLIND RIVET |
A rivet applied from one side,
incorporating a stem which pulls against material
on the blind side and "pops" off
when the rivet is fully formed. |
| BLOWING AGENT |
A gas or a substance capable
of producing a gas used in making formed materials.
|
| BOND |
The adhesive and cohesive forces
holding two roofing components in contact. |
| BUILDING CODE |
Any system of principles or
rules set to control, design and construct
buildings or materials. |
| BUILT-UP ROOF (BUR) |
A roofing membrane built up
on the job, made of several sections or layers
of bitumen fastened together with felts. The
top can be finished with crushed slag or gravel.
|
| BUTYL RUBBERS |
Butyl rubber is an elastomer
that has extremely low water vapor and gas
permeability. Having the lowest permeability
in comparison to other elastomers, it is especially
recommended in situations which have relatively
higher vapor drives, such as low-temperature
applications (water coolers, freezers, and
cryogenic storage) or water immersion (water
storage and ponding water). When exposed to
exterior weathering or in areas where mechanical
damage may occur, butyl rubbers should be
topcoated with tougher or more weatherable
coatings (see coating manufacturers for specific
recommendations). While most butyl rubbers
are two-component materials, some single-component
versions are available. |
| CALENDER |
A machine normally composed
of three counter-rotating steel rolls of large
diameter; a device used to produce film and
sheet goods that are normally wound up into
roll stock. |
| CANT STRIP |
A continuous strip of material
(triangular in cross-section) used as a transition
between the roof deck and a vertical surface;
normally has a 45° sloping surface. |
| CAP SHEET |
The top sheet of BUR forming
the finished surface of the roof. |
| CHLOITINATED POLYETHYLENE
(CPE) |
A thermoplastic sheet composed
of high molecular weight, low-density polyethylene
that has been chlorinated to a given level. |
| CHLOROSULFONATED POLYETHYLENE
(CSPE) |
Basically a chlorinated polyethylene
containing chloro-sulphonyl groups with a
high molecular weight, low-density polyethylene.
|
| CLOSURE STRIP |
A pre-formed shape used to
fill the space between ribs on a metal panel. |
| COAL TAR PITCH |
Dark brown to black solid hydrocarbon
obtained from the residuum of the distillation
of coke-oven tar, used as the water-proofing
agent of dead-level or low-slope built-up
roofs. It comes in a narrow range of softening
points - from 129° to 144°F. |
| COATED BASE SHEET |
Roofing felt that is coated
with asphalt, usually on both sides, then
(or Felt) surfaced with an anti-stick material. |
| DISPERSION |
A heterogeneous system in which
a finely divided material is distributed in
another material. Note: dispersion is usually
the distribution of a finely divided solid
in a liquid or a solid; for example, pigments
or fillers in coatings. A dispersion of a
liquid in another liquid is an emulsion. |
| DUCTILITY |
The property of the material
to withstand deformation by stretching without
recovery of shape upon removal of the stretching
force. |
| EAVE |
The low edge of a sloping roof. |
| EDGE VENTING |
The practice of providing regularly
spaced openings at a roof perimeter to relieve
the pressure of water vapor entrapped in the
insulation. |
| ELASTOMER |
Any of several elastic substances
that, at room temperature, resemble and display
the qualities of rubber. |
| EUSTOPUSTIC |
A substance that exhibits a
greater or lesser resiliency and will return
to, or almost return to, its original size
and shape if deformed to some extent below
its elastic limit, as opposed to a brittle
substance. A trade description used to identify
elastomeric and plastomeric types of singleply
roof membranes. |
| ELONGATION (STRETCH) |
Lengthening or stretching ability
to accommodate movement. |
| EQUIVISCOUS TEMPERATURE |
The optimum temperature for
applying bitumen. At this temperature, the
bitumen will be about as fluid as 20-weight
oil. (Approximately 125 Centistokes.) When
asphalt is mopped between felts, it yields
approximately 23 lbs. when applied at the
equiviscous temperature. |
| ETHYLENE INTERPOLYMER ALLOY
(EIP) |
Generic term for Elvaloy (a
registered trademark of E.I. Du Pont de Nemours
& Co.), a very dense molecular resin with
exceptional fire-resistant and chemical-resistant
properties. |
| ETHYLENE MONOMER (EPDM) |
Material synthesized from ethylene,
propylene and small amounts of PROPYLENE DIENE
diene monomer. |
| EXPANSION JOINT |
A joint where movement is allowed
to take place, usually in response to thermal
stress. |
| EXTRUSION |
Process of extruding or forcing
a material (under heat and pressure) through
a die of specified shape. Plastic and aluminum
materials may be extruded into various shapes
by this process. |
| FACTORY MUTUAL ENGINEERING
& RESEARCH CORP. |
Organization located in Norwood,
MA, that classifies roof assemblies on their
fire characteristics and wind uplift resistance
for insurance companies in the United States. |
| FIRE RESISTANCE |
The property of a material
or assembly to withstand fire or give protection
from it. As applied to elements of buildings,
it is characterized by the ability to confine
a fire or to continue to perform a given structural
function, or both. |
| FISHMOUTH |
An opening formed by an edge
wrinkle in the felt. |
| FLAME SPREAD |
(1) The rate of flame movement
across an exposed deck. (2) The measurement
of how much product contributes to the fire
spread (determined under controlled and standardized
test conditions). Refer to ASTM Designations
E84 or El 62. |
| FLASHING |
Sheet metal, felts or elastomeric
sheet used in waterproofing roofvalleys or
hips or the angle between a wall and roof
and ail joints. |
| FLASHING CEMENT |
A trowelable, plastic mixture
of bitumen and asbestos (or other inorganic)
reinforcing fibers, and a solvent. |
| FLOOD COAT |
The top layer of bitumen in
an aggregate-surfaced, built-up roofing membrane.
Correctly applied, it's poured, not mopped,
to a weight of 60 lbs. per square for asphalt
and 75 lbs. per square for coal tar pitch.
|
| FLUTTER FATIGUE |
The fatigue action a single-ply
membrane may experience in a high wind situation,
causing a complete stress reversal to occur
rapidly; temperature may influence the flutter
fatigue resistance of the membrane material.
|
| GABLE |
Same as rake; also, the triangle
formed by two sloping roof edges and the horizontal
line connecting them. |
| GAGE, GAUGE |
A designation of metal thickness. |
| GALVANIZED |
Zinc coating on steel for corrosion
resistance. |
| GRAVEL STOP |
Flanged device, normally metallic,
designed to prevent loose aggregate from washing
off the roof and to provide a finished edge
detail for the built-up roofing assembly.
|
| GUTTER |
Drainage trough at the low
edge of a sloping roof. |
| HEAT AGING |
Submitting a membrane to prolonged
elevated temperatures to determine if its
physical properties are adversely affected.
|
| "HOT STUFF" OR
HOT |
Roofers term for hot bitumen. |
| HYPALON COATINGS |
Hypalons (a registered trademark
of E.I. DuPont de Nemours & Co.) are elastomeric
coatings based on chlorosulfonated polyethylene
rubbers. They are fast-drying single-package
materials that have exceptional fire retardancy,
chemical resistance, weathering properties,
and moisture vapor transmission resistance.
They may be used as the entire coating system
or as a topcoat over other generic coatings. |
| ICBO |
International Conference of
Building Officials. Uniform Building Code. |
| IMPACT |
Capability to withstand mechanical
or physical abuse under severe RESISTANCE
service conditions. Resistance to blows, bumps
and shocks incident to use. |
| INCLINE |
The slope of a roof, expressed
in the number of vertical units of rise per
horizontal units of run, or in percent. (See
Slope; Pitch). |
| INORGANIC |
Being or composed of material
other than hydrocarbons and their derivatives;
not of plant or animal origin. |
| INSTRON |
Brand of instrument utilized
in the stress-strain testing of materials. |
| INTERIOR GUTTER |
A gutter hidden behind an outside
wall or located inside a building. |
| LAMINATION |
Process of joining thin layers
of material together under heat and pressure
(with an adhesive) into a finished product.
|
| LAP |
The part of a roofing membrane
that covers the preceding course in any overlapping
situation. |
| LEADER |
Same as downspout. |
| LIVE LOADS |
Moving or non-permanent loads
such as wind, snow, ice, rain or portable
equipment. |
| LOW-TEMPERATURE |
Lowest temperature at which
a material can withstand a bending FLEXIBILITY
test around a mandrel of specified shape. |
| MANSARD |
A nearly vertical roof, typically
a fascia. |
| MEMBRANE |
Continuous flexible (or semi-flexible)
roof covering that forms the water control
element of a roofing system. It is normally
assembled on site from single or multiple
plies of material, e.g., polyvinyl chloride
roofing in single-ply systems and bituminous
felt roofing in multiple-ply systems. |
| MEMBRANE |
Woven or non-woven fabrics
used for saturation and embedment in REINFORCEMENT
mastic and coating applications to provide
strength, continuity and impact resistance.
|
| MIL |
A unit used in measuring thickness,
being 0.001 inch. (British equivalent: Thou.)
(Metric equivalent 0.0254.) |
| MODIFIED BITUMEN |
A broad class of materials
(and blends) that can be used to change the
performance characteristics of a roofing grade
asphalt. |
| MODULUS OF ELASTICITY |
The ratio of stress corresponding
to strain (within the elastic limit of a material);
it is a measure of the stiffness of a material.
|
| MONOUTHIC |
Single form or single piece;
formed or composed of material without joints
or seams. |
| MOPPING |
An installation of bitumen
applied with a mop or mechanical device to
the substrate or to the felts of a built-up
roofing membrane. |
| NEOPRENE RUBBER |
A synthetic rubber having physical
properties closely resembling those of natural
rubber, but not requiring sulphur for vulcanization.
It is made by polymerizing chloroprenes, produced
from acetylene and hydrogen chloride. |
| SBS |
Styrene-butadiene-styrene block
copolymer, with domains having the properties
of the pure homopolymers but contained in
the same molecule. |
| SCRIM |
A thin reinforcing mat usually
non-woven and normally made of glass or polyester
fiber. |
| SEAM |
A lap or area of juncture for
two separate sheets |
| SELF-IGNITION |
The minimum temperature at
which the self-heating properties TEMPERATURE
of a material lead to ignition in the absence
of an outside ignition source. It is dependent
upon specimen size, heat loss conditions and
possible other variables, such as moisture
content. |
| SELVAGE |
A sheet edge or edging which
differs from the main part of the finished
roof sheet. |
| SELVAGE EDGE |
A lapped joint detail for mineral-surfaced
cap sheets, in which the main surfacing is
omitted for 2 in. of the 36-in.-width, so
that the overlapping side will get better
adhesion. |
| SERVICE TEMPERATURE LIMITS |
The limiting temperatures at
a coated surface within which limits the applied
coating will have satisfactory performance.
|
| SQUARE |
Measure of roofing materials
equaling 100 square feet. |
| TENSILE STRENGTH |
The force per unit of the original
cross sectional area (of an unstretched specimen)
which is applied at the time of rupture of
the specimen. It is calculated by dividing
the breaking force in pounds by the cross
section of the unstretched specimen in square
inches. |
| THF |
Abbreviation for tetrahydrofuran,
a solvent used to weld together some thermoplastic
materials, such as PVC. |
| THERMAL BARRIER |
An insulated separation between
hot and cold air masses. |
| THERMAL MOVEMENT AND SHOCK
RESISTANCE |
The roofing system shall withstand
sudden and frequent changes in temperature. |
| THERMALSHOCK |
The stress-producing phenomenon
resulting from sudden temperature changes
in a roof membrane. |
| THERMAL (HOT-AIR) WELDING |
The joining of two, clean,
separate surfaces by applying heat from an
electric heat gun. Used with thermoplastic
materials like PVC, CPE and CSPE. |
| THERMOPLASTIC |
Capable of being repeatedly
softened by increase of temperature and hardened
by decrease of temperature. Note: Thermoplastic
applies to those materials whose change upon
heating is substantially physical. |
| THERMOSETTING |
Material which cannot be reshaped
or formed by heating; cured synthetic rubber
sheet materials (EPDM, Butyl, etc.) are thermosets.
|
| WATER VAPOR PERMEANCE |
The water vapor transmission
of a material under unit vapor pressure difference
between two specific surfaces. An acceptable
unit of permeance is the perm. |
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