01 May 1999
Phased application--The installation of a roofing
cone vertically penetrates a sample of material
or waterproofing system during two or more
under specified conditions of loading, time, and
separate time intervals; a roofing system not
installed in a continuous operation.
Percent elongation--In tensile testing, the
Phenolic plastics--Plastics based on resins
increase in the gauge length, measured after
fracture of the specimen within the gauge length.
phenol and cresol, with aldehydes.
Percent water by volume--
Picture framing--A rectangular pattern of ridges
in a membrane over insulation or deck joints.
Volume of Water in Sample
Pig spout--A sheet metal flashing designed to
Volume of Sample
direct the flow of water out through the face of
the gutter rather than through a downspout.
Percent water by weight--
Pinhole--A tiny hole in a film, foil, or laminate
Sample Weight Wet-Sample Weight Dry
comparable in size to one made by a pin.
= ------------------------------------ x100
Sample Weight Dry
Pitch--See Incline; Coal Tar Pitch; or Petroleum
Perlite--An aggregate used in lightweight
insulating concrete and in preformed perlite
Pitch pocket--A flanged, open bottomed
insulating board, formed by heating and
container placed around a column or other roof
expanding siliceous volcanic glass.
penetration and filled with hot bitumen, flashing
cement or pourable sealer.
Perm--(vapor transmission) Unit to measure
water vapor transmission--one grain of water
Plastic--A material that contains as an essential
vapor per square foot per hour per inch of
ingredient one or more organic polymeric
mercury pressure difference. 1 Perm = 1
substances of large molecular weight. It is solid
grain/hft2in. Hg = 5.74 x 10-11 kg/Pasm2.
in its finished state and at some stage in its
manufacture or processing into finished articles
Permeability--(1) The capacity of a porous
can be shaped by flow.
medium to conduct or transmit fluids; (2) The
amount of liquid moving through a barrier in a
Plastic cement--See Flashing Cement.
unit time, unit area and unit pressure gradient
not normalized for but directly related to
Plasticizer--Material, frequently solvent-like,
thickness; (3) The product of vapor permeance
incorporated in a plastic or a rubber to increase
and thickness (for thin films, ASTM E96--over
its ease of workability, flexibility, or extensibility.
3.2 mm (1/8 in.), ASTM C355). Usually reported
Adding the plasticizer may lower the melt
in perm inches or grain/hft in. Hg per inch of
viscosity, the temperature of the second order
thickness. 1 perm inch = 1.46 x 10-12 kg/Pasm.
transition, or the elastic modulus of the polymer.
transmission per unit area at a steady state
(phthalate esters), low molecular weight liquid
through a membrane or assembly, expressed in
polymers (polyesters) or rubbery high polymers
ng/Pasm2 (grain/ft2hin. Hg).
(EVA). The most important use of plasticizers is
with PVC where the choice of plasticizer dictates
Petroleum pitch--A dark brown to black,
under what conditions the membrane may be
predominantly aromatic, solid cementitious
material obtained by the processing of
petroleum, petroleum fractions, or petroleum
Plastisols--Mixtures of resins and plasticizers
that can be cast or converted to continuous films