Laminated Gypsum Boards (PYL): Types and Properties

• The text regards laminated gypsum boards, or PYL

Laminated Gypsum Boards

• This unit defines the different types and main properties of PYL.
• Laminated gypsum boards are manufactured, with a continuous lamination process and presented as a rectangular board, smooth, and with variable thicknesses and dimensions.
• The boards contain a core of natural gypsum surrounded by two sheets of cellulose (cardboard).
• All PYL products must have the N certificate and the CE marking.
• Standards include UNE-EN-520+A1, UNE-EN-14190, UNE-EN-13950, UNE-EN-13915, and UNE-EN-15283-1.

Types of PYL

• Type A boards are standard PYL, where a decorative finish can be applied to one of their faces.
• Type H boards have reduced water absorption capacity and contain additives to decrease moisture absorption, and are intended for humid rooms.
• Type E boards are for exteriors and are used in exterior wall coverings. They aren't made of gypsum, so this material can't stay outside and is constructed of cement.
• Type F boards have improved core cohesion for high temperatures and add mineral fibers to improve their capacity.
• Type P boards are a base gypsum board with a face prepared to receive a gypsum plaster.
• Type D boards have controlled density to improve performance, with a minimum density of 0.8 x 103 Kg/m³.
• Type R boards have improved resistance and are used in applications where superior resistance is required against breaking loads, both longitudinally and transversally.
• Type I boards have improved surface hardness, where the footprint produced by a surface impact (according to standard UNE-EN 520+A1) does not exceed 15 mm.

Modified Boards from Secondary Processes

• Type BV boards are normally type A and incorporate a special sheet on their back that acts as a vapor barrier.
• Type RX boards are normally type A and incorporate a lead plate on their back for radiological protection.
• Type Perforated boards are normally type A, with perforations or grooves to improve the acoustic conditioning.
• Type SS boards are a special PYL modification to make dry floors.
• Type VTR boards are normally type A, and incorporate a decorative sheet for suspended ceiling units.
• Type PVP boards are normally type A or F, and incorporate a decorative sheet for vertical wall or partition units.

Modified Boards with Thermal and/or Acoustic Insulation

• Type EPS boards are normally type A and incorporate a sheet of expanded polystyrene (EPS) of different thicknesses on their back.
• Type XPS boards are normally type A, to which a sheet of extruded polystyrene (XPS) of different thicknesses is incorporated on their back.
• Type MW boards are normally type A, to which a mineral wool (MW) sheet of different thicknesses is incorporated on their back. The wool can be rock (LR) or glass (LV).

Grid Type Modifications

• Grid boards are modified and formed by two type A PYL, normally 9.5 mm thick, and a cardboard core in the shape of a honeycomb pattern and are used for shelves and/or decoration.

Modified Boards with Fiberglass Veil

• Type GM-F boards are reinforced with fibers and normally have the fire classification of A1 non-combustible.

General Characteristics

• The "face" part (the surface to be decorated) must not have stains, efflorescence, mildew, dents, erosion, scratches, or detachments in the cardboard.
• Dimensions:
  • Length varies from 2000-3000 mm.
  • Width varies from 600-800-900-1200 mm.
  • Thickness varies from 6, 9.5, 12.5, 15, 18, to 20 mm.
• Edges: different types of longitudinal edges depending on the purpose or finish they have in the work. The transverse edges are always presented as BCO or BCT, except in the boards with the four refined edges 4BA.
• Flexural strength: the average breaking load through testing must not be less than the following values:
  • For type A, D, E, F, H, and I boards: depends on thickness and direction.
  • For type R boards or their combination: depends on thickness and direction.
• Impact resistance: in boards with reinforced type I hardness, the footprint produced by the impact of 2.5 J will not exceed 15 mm.
• Thermal conductivity: the capacity of a material to transmit heat must not be greater than λ = 0.25 W/mK
• Hygroscopicity: the board has the capacity to absorb moisture when the environment is very humid and expel moisture when the environment is dry.
• Curvature: depending on the thickness and type, the boards have a natural radius of curvature that ranges between 600 and 1500 mm, and smaller curvature radii can be obtained by following the manufacturers' instructions.
• Dimensional stability: PYLs are practically inert at ambient temperatures (up to 200 °C) and slightly sensitive to variations in air humidity between 15% and 90% relative humidity.
• Air permeability: the ability of the material to let air pass through which must be 1.4 x 10 m³/h•m².
• Water vapor resistance factor: 10μ
• Fire classification: A2-s1, d0