Glassary - P

P1A:
BS EN 356 classification for manual attack.

P2A:
BS EN 356 classification for manual attack.

P3A:
BS EN 356 classification for manual attack.

P4A:
BS EN 356 classification for manual attack.

P5A:
BS EN 356 classification for manual attack.

P6A:
BS EN 356 classification for manual attack.

P7A:
BS EN 356 classification for manual attack.

P8A:
BS EN 356 classification for manual attack.

Pack:
a bulk quantity of glass, around 1-1.5 tonnes in weight often used to describe an end cap. The number of sheets in a pack will depend upon the thickness and size of the glass. 55 sheets for 4mm SSS, 35 Sheets for 6.4mm Laminated SSS. LES sizes are also sold in packs but typically 20-30 sheets depending on thickness.

Pallet:
a packaging method for transporting and storing glass. See also rack and stillage.

Pane:
a piece of glass.

P.A.R.:
Polished All Round. All the edges of a piece of glass are polished for decorative effect.

Part #:
Part # refers to one of the many building regulations. Part N for example refers to safety glazing in England and Wales. A full list of them is summarised at the rear of this guide.

Parry Moon range:
the part of electromagnetic radiation, which is UV light according to the Parry Moon definition (between 300 and 400nm). This is a stricter definition of UV light than the ISO range. In order to meet Parry Moon it is necessary to use products from the Pilkington Anti-Fade™ range (see Product Data Sheet).

Partial Insulation:
Fire resistant glass that does not achieve give 30 minutes insulation required in BS 476 is often referred to as a partial insulation product. Pilkington Pyrodur™ is an example of this. European Standard EN 357 will have a partial insulation category for products that give 15 minutes insulation or more. This will be referred to as reduced heat radiation or EW

Patent glazing:
a system of drained glazing which is formed from lightweight framing sections incorporating a built-in gutter in the rebate, commonly used for roof glazing.

Patterned glass:
glass manufactured by passing between two rollers (hence it used to be called rolled glass), one of which rollers forms an impression or pattern into the glass. It is known as Pilkington Texture Glass™.

Peg:
regional term for a pack or end cap of glass.

Pelerine™:
Pilkington Pelerine™ is the brand name for one of the Pilkington Texture Glass™ range (see consumer leaflet Pilkington Texture Glass™) of patterned glass. Pilkington Pelerine™ has an obscuration level of 5.

Photovoltaic:
literally producing electricity from light. Sometimes also called solar panels. These are special panels designed to convert light into electricity. A solar powered calculator has a photovoltaic panel, the 'A' Weighting Curve.

Pinhole:
a small defect where part of a coating, enamel or backing paint is missing. Acceptable standards are defined in relevant Product Data Sheets.

Pitch:
the frequency of a sound.

Planar™:
Pilkington Planar™ is our brand name for a range of frameless glazing solutions. See Pilkington Planar™ Product Data Sheets.

Planarclad™:
Pilkington Planarclad™ is our brand name for a high performance cladding system incorporating the well known features of the Pilkington Planar™ concept. See Pilkington Planarclad™ Product Data Sheet.

Planitherm:
Soft coated, Low emissivity glass, produced by St Gobain. We would offer Pilkington Optitherm™ as a substitute. Planitherm II is sold as a soft coated glass that can be toughened, we don't have a substitute for this product at present.

Plateau:
Simply, extremely flat glass. This is the brand name for specially toleranced glass for use in the cast-acrylic industry. It is available in annealed and toughened forms.

Polarised light:
light waves which are vibrating in a specific orientation, either after passing through a polarising filter, or after being reflected from a surface or from the sky.

Polished Edge:
the edge of a piece of glass that has been first flat ground and is then polished to a high lustre. If all of the edges are polished it may be described as P.A.R. (Polished all round).

Polished wired glass:
a generic name for Pilkington Pyroshield™ Clear (see Product Data Sheet). Wired cast glass which has subsequently been ground and polished on both surfaces to make it transparent, i.e. Pilkington Pyroshield™ Clear and Pilkington Pyroshield™ Safety Clear.

Pyran:
Competitors brand name for a Borosilicate glass, which is a clear, fire resistant glass. This product is produced by Schott glass; we have no direct substitute available.

Pyrobel:
Clear, Insulation, fire resistant glass made by Glaverbel. Pilkington Pyrostop™ should be offered as a substitute.

Pyrobelite:
Clear, Partial Insulation, fire resistant glass made by Glaverbel. Pilkington Pyrodur™ should be offered as a substitute.

Pyrodur™:
Pilkington Pyrodur™ (see Product Data Sheet) is the brand name for our clear (without wires), partial insulation, fire resistant glass.

Pyroshield™:
Pilkington Pyroshield™ (see Product Data Sheet) is the brand name for a range of fire resistant glass with a welded steel mesh incorporated within the body of the semi-molten glass and formed by passing between two rollers, one of which forms an impression or pattern into the glass. This product is translucent and is called Pilkington Pyroshield™ Textured. The surface can be polished to make it transparent: this is called Pilkington Pyroshield™ Clear. It is sometimes referred to as Georgian wired. It is an integrity only glass. A safety version to meet BS 6206 Class C is also available.

Pyrostop™:
Pilkington Pyrostop™ (see Product Data Sheet) is the brand name for our range of high performance, clear fire resistant glass. The products in this range all give insulation for a minimum of 30 minutes.

Polyvinylbutyral (PVB):
a type of interlayer used in the manufacture of laminated glass, by placing a sheet of the material between two panes of glass and curing under heat and pressure. This is the interlayer used in most laminated glass. In its unprocessed form PVB is opaque. It becomes tr4ansparent in the autoclave due to heat and pressure used, driving moisture from the interlayer.

Positive Image:
a term used in sand blasting and acid etching. It refers to the area of glass that has not been eroded by the sand or acid.

P.P.E.:
Personal Protective Equipment. The amount and type of P.P.E. required will depend upon the hazards likely to be encountered.

Primary seal:
see dual seal system.

Private side:
the side of a one-way vision glass from which the other, public side is clearly visible.

Profile:
a term used by window manufacturers to describe bar lengths of P.V.C. window section.

Public side:
the side of a one-way vision glass from which the other, private side is not visible.

PV:
an abbreviation for photovoltaic.

PVB:
see polyvinylbutyral.

Pyrolitic:
applied at high temperature. In relation to glass, this term describes coatings applied on-line when the ribbon of float glass is around 500 to 600ºC. Pilkington K Glass™ and Pilkington Eclipse™ are examples.