Glass Fibre Reinforced Plastic (GRP) Panel Type Door Shutters for Internal Use
2000 Edition

Per IS 14856:2000, the GRP laminate for door shutters must meet specified minimum material parameters, including: a fiberglass content of at least 25% by weight (Annex B); Barcol hardness of no less than 30 BHU (Annex C); tensile strength minimum of 100 MPa (Annex D); bending strength at least 120 MPa (Annex E); elastic modulus in bending no less than 1500 MPa (Annex F); water absorption limited to a maximum of 0.5% by weight (Annex G); and fire retardancy demonstrated by a 100 mm specimen not burning for more than 60 seconds (Annex H). These criteria collectively ensure durability, structural integrity, moisture resistance, and fire safety for internal GRP door shutters.

IS 14856 specifies the following dimensional tolerances for GRP panel door shutters: a minimum laminate thickness of 5 mm; width and height dimensions permitted a tolerance of plus or minus 5 mm; squareness deviation limited to 1 mm over any 500 mm length; and thickness uniformity variation not exceeding 0.8 mm between any two points on the shutter. These limits guarantee proper fit, consistent quality, and structural soundness of the door shutters.

IS 14856 recognizes several manufacturing techniques for producing glass-reinforced polyester door and window frames. Notably, the Resin Transfer Moulding (RTM) process—including resin injection, resin infusion, vacuum infusion, and vacuum press moulding—is specified as performed within a closed mould under differential pressure (Clause 3.1.13). While not exhaustively detailed here, other common methods for FRP composites such as hand lay-up, spray-up, compression moulding, and pultrusion are generally applicable under the standard’s scope.

Under IS 14856, GRP door shutters must fulfill rigorous mechanical and fire performance criteria. Mechanical tests include ensuring fiberglass content of at least 25%, Barcol hardness above 30 BHU, tensile strength surpassing 100 MPa, bending strength exceeding 120 MPa, elastic modulus in bending over 1500 MPa, and water absorption below 0.5%. Fire performance requires a 100 mm specimen to resist burning for at least 60 seconds (Annex H). Additional door shutter tests as per IS 4020 parts 1-16 include dimensions, squareness, flatness, impact indentation (five impacts on both sides without damage), edge loading, shock resistance, and slamming tests, ensuring comprehensive durability and safety.

IS 14856 mandates that door shutters be fitted with three hinges: one positioned centrally and two others placed 200 mm from the top and bottom edges, respectively. These hinges are mounted exclusively at locations where internal blocks are provided within the shutter frame, with these block positions indicated by depressions in the profile (Clause 8.2, Fig. 1). Other fixings such as locks and handles must also be installed only where blocks have been pre-positioned to ensure secure anchorage and structural integrity (Clause 8.3). The design and sizing of these blocks are standardized to prevent weakening the shutter.