01 May 1999
British thermal unit (BTU)--Heat energy
required to raise the temperature of one pound
copolymer in which there are repeated
of water by 10F (= 1055 joules).
sequences of polymeric segments of different
Brooming--Embedding a ply by using a broom
to smooth it out and ensure contact with the
Block or board thermal insulation--Rigid or
adhesive under the ply.
semi-rigid thermal insulation preformed into
Btuh--Btu per hour.
Blocking--(1) wood built into a roofing system
Building code--Published regulations and
above the deck and below the membrane and
ordinances established by a recognized agency
flashing to (a) stiffen the deck around an
describing design loads, procedures, and
opening, (b) act as a stop for insulation, (c)
construction details for structures. Usually
serve as a nailer for attachment of the
applying to designated political jurisdiction (city,
membrane or flashing. (2) Wood cross-members
county, state, etc.). Building codes control
installed between rafters or joists to provide
design, construction, and quality of materials,
support at cross-joints between deck panels. (3)
use and occupancy, location and maintenance
Cohesion or adhesion between similar or
of buildings and structures within the area for
dissimilar materials in roll or sheet form that may
which the code was adopted. (See Model
interfere with the satisfactory and efficient use of
Built-up roofing (BUR)--A continuous, semi-
Blocking, wood--Treated wood members
flexible membrane consisting of plies of
designed to help prevent movement of
saturated felts, coated felts, fabrics or mats
assembled in place with alternate layers of
bitumen, and surfaced with mineral aggregate,
Blowing agent--A compounding ingredient used
bituminous material, or a granule surfaced sheet
to produce gas by chemical or thermal action, or
both, in manufacture of hollow or cellular
Bull--Roofer's term for flashing or plastic
Blueberry--A small bubble or blister in the flood
coating of a gravel-surfaced membrane.
Butyl rubber--A synthetic rubber based on
isobutylene and a minor amount of isoprene. It is
vulcanizable and features low permeability to
consisting of a solution of the membrane
compound in solvent used in the seaming of
aging, chemicals and weathering.
Calender--A machine with two or more rolls,
Bond--The adhesive and cohesive forces
operating at selected surface speeds and
holding two roofing components in intimate
laminating, skim coating (topping) and a friction
coating to a controlled thickness or surface
Boot--A bellows type covering to exclude dust,
characteristic, or both.
dirt, moisture, etc., forming a flexible closure.
Camber--A predetermined curvature designed
Breaking strain--% elongation at which a sheet
into a structural member to offset the anticipated
or other tested component ruptures under
deflection under design load.
Canopy--Any overhanging or projecting roof
Breaking stress--Stress (in force per linear or
structure with the extreme end usually
area units) at which sheet, or other tested
component, ruptures under tensile force.