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IS 5509:2000 is the Indian Standard (BIS) for fire retardant plywood - specification. This standard specifies the requirements for fire retardant plywood used in building interiors, railway coaches, and other applications. It covers material composition, manufacturing, dimensions, and performance characteristics, particularly focusing on fire resistance tests like flammability and rate of burning.
Specifies the requirements for plywood treated to have fire retardant properties, including test methods and performance criteria.
BS 476-7:1997British Standards Institution (BSI), United Kingdom
HighCurrent
Fire tests on building materials and structures. Method of test to determine the classification of the surface spread of flame of products
IS 5509 explicitly uses the test method from BS 476-7 for its flammability classification.
ASTM E84-23aAmerican Society for Testing and Materials (ASTM), USA
MediumCurrent
Standard Test Method for Surface Burning Characteristics of Building Materials
Provides the primary North American method (Steiner Tunnel Test) for classifying surface flame spread and smoke development.
BS EN 13501-1:2018BSI / European Committee for Standardization (CEN), Europe
MediumCurrent
Fire classification of construction products and building elements - Part 1: Classification using data from reaction to fire tests
The modern European standard for classifying reaction-to-fire performance, superseding older national standards.
BS 476-6:1989+A1:2009British Standards Institution (BSI), United Kingdom
HighWithdrawn
Fire tests on building materials and structures. Method of test for fire propagation for products
IS 5509 specifies a fire propagation index limit based on the test method from this standard.
Key Differences
≠IS 5509 is a complete product specification for plywood, including glue adhesion and strength requirements, whereas standards like ASTM E84 and BS EN 13501-1 are primarily classification systems based on reaction-to-fire test methods applicable to many materials.
≠The classification systems differ significantly. IS 5509 gives a single 'Fire Retardant' classification, ASTM E84 uses a Flame Spread Index (FSI) to define Classes (A, B, C), and BS EN 13501-1 uses Euroclasses (e.g., B, C) with added smoke (s) and flaming droplet (d) ratings.
≠The primary test apparatus and methodology are different. IS 5509/BS 476-7 use a radiant panel, ASTM E84 uses a 25-foot horizontal 'Steiner Tunnel', and BS EN 13501-1 primarily relies on the 'Single Burning Item' (SBI) test which simulates a corner fire.
Key Similarities
≈The core objective of all standards is to evaluate and classify the surface flammability of materials to control the spread of fire in its initial stages.
≈IS 5509 directly adopts test methodologies from British Standards (BS 476 Parts 6 and 7), making its fire performance criteria very similar to the UK's 'Class 1' and 'Class 0' requirements.
≈All standards involve subjecting a specimen to a calibrated ignition source (flame or radiant heat) and measuring the subsequent fire behavior over time.
≈IS 5509 includes a 'Resistance to Leaching' test, which is conceptually similar to the practice of testing treated wood under standards like ASTM E84 after accelerated weathering to ensure the durability of the fire-retardant treatment.
Parameter Comparison
Parameter
IS Value
International
Source
Surface Flammability Test
Test as per Annex B of IS 5509, which is based on BS 476 Part 7.
Surface spread of flame test using a radiant heat panel.
BS 476-7:1997
Flammability Requirement
Time for flame front to reach 275 mm mark shall not be less than 10 minutes.
For Class 1: Final flame spread must not exceed 165 mm.
BS 476-7:1997
Fire Propagation Index (I)
Shall not exceed 15 when tested as per BS 476 Part 6.
To achieve 'Class 0', the material must be Class 1 (per Part 7) and have I ≤ 12 and i1 ≤ 6.
BS 476-6:1989+A1:2009
Equivalent US Classification
Not specified. Plywood meeting IS 5509 would likely be tested separately.
Class A requires a Flame Spread Index (FSI) of 0-25 and Smoke Developed Index (SDI) < 450.
ASTM E84
Equivalent European Classification
Not specified.
Typically achieves Euroclass B or C, with smoke and droplet classification (e.g., B-s1, d0).
BS EN 13501-1:2018
Durability of Treatment
Must pass flammability test after leaching (72 hours immersion in water at 27±2°C).
Exterior rated FRT wood is often tested after accelerated weathering per ASTM D2898 before E84 testing.
ASTM E84 / D2898
Glue Shear Strength (72h Boil Test)
Specifies minimum average failing loads, e.g., >1000 N for plywood up to 6.5mm thick.
Not specified in fire test standards; defined in plywood product standards like BS EN 636.
BS EN 636
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Rate of Burning Test Minimum Time20 minutes (for weight loss from 30% to 70%)
Flammability Test Duration30 minutes
Minimum Glue Shear Strength (WBP Dry State)1350 N
Minimum Glue Shear Strength (WBP after 72h boil)1000 N
Maximum Moisture Content15 percent
Thickness Tolerance (Sanded)±5 percent
Tables & Referenced Sections
Key Tables
Table 1 - Thickness of Veneers for Different Thickness of Plywood
Table 2 - Tolerances on Nominal Thickness of Plywood
The plywood must be marked with 'Type FR', the manufacturer's name, thickness, and the ISI Certification Mark (Clause 9).
What is the key fire safety test for this plywood?+
Two main tests are specified: a 30-minute flammability test (Annex A) and a rate of burning test where weight loss duration must be at least 20 minutes (Annex B).
Can this plywood be used in a kitchen or bathroom?+
Yes, provided it uses WBP (Weather and Boil Proof) adhesive. Check the product marking for 'WBP' type.
Does the fire retardant treatment weaken the plywood?+
No, the standard requires the treated plywood to still meet glue shear strength and other physical requirements as specified in Table 3.