Fire Retardant Plywood -Specification
2000 Edition

IS 5509 identifies several categories of fire retardant chemicals for plywood treatment, including: Ammonium phosphates; Ammonium sulphate; Boron-based compounds; combinations of ammonium phosphate with boron compounds; and mixtures of ammonium sulphate with ammonium phosphate. The suggested chemical retention is approximately 50 kg per cubic meter for applications not exposed to leaching. Since these retardants can be leachable, usage in wet or rain-prone environments is discouraged. For treatments combining fire retardants with preservatives, IS 12120 provides relevant guidelines.

Per IS 5509, fire retardant treatment is applied after plywood manufacture, primarily via pressure impregnation. The plywood must be of BWR grade according to IS 303, clean, with moisture content not exceeding 15%, and free of contaminants. Decorative plywood requires solutions that do not alter surface coloration. The process includes vacuum application followed by pressure impregnation to achieve the required chemical absorption. After treatment, the plywood is conditioned to an equilibrium moisture content not exceeding 20%. Testing involves cutting samples at least 150 mm from edges for flammability and flame penetration assessments, ensuring compliance with dimensional and quality standards.

IS 5509 mandates that fire retardant plywood must withstand flame penetration for a minimum duration calculated as 15 minutes multiplied by the plywood thickness in millimeters. For example, a 6 mm thick panel must resist flame penetration for at least 90 minutes. The fire retardant chemical retention should be around 50 kg/m³, and moisture content post-treatment should not exceed 20%. Additionally, plywood used must be BWR grade as per IS 303 to ensure suitability for pressure impregnation and durability.

Yes, IS 5509 allows for the combined treatment of plywood with both fire retardants and preservatives provided that the fire resistance requirements are met. The purchaser must specify whether the plywood is to receive fire retardant treatment alone or in combination with preservative treatment. When both treatments are applied, preservative types and required retention levels must comply with IS 12120. It is important to note that fire retardants are generally leachable, so treated plywood should not be used in conditions where leaching could occur. The plywood must be BWR grade to withstand pressure impregnation.

Manufacturers must secure environmental clearance from the State Pollution Control Board under relevant water and air pollution legislations, including the Water (Prevention and Control of Pollution) Act 1974, Air (Prevention and Control of Pollution) Act 1981, and Water Cess Act 1977, plus authorization under the Environment (Protection) Act 1986 if applicable. Compliance with Forest Department regulations is also required. For ECO-Mark certification, plywood must conform to IS 5509 and ECO-Mark specifications within IS 303, and pass tests such as glue shear strength, fungal resistance, and water resistance. Documentation including certificates or declarations must be submitted to BIS during the ECO-Mark application process to demonstrate conformance.