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IS 4016:1984 Part 2 is the Indian Standard (BIS) for methods of test for fire retardant properties of treated timber - surface spread of flame test. This standard specifies the testing method to determine the surface spread of flame characteristics of fire-retardant treated timber. It provides a classification system based on the distance and rate at which flames travel across the wood surface when exposed to a radiant heat source.
Specifies the procedure for conducting a surface spread of flame test to evaluate the fire retardant properties of treated timber.
! Ensure timber moisture content is properly conditioned (typically to equilibrium at 65% RH) before testing, as moisture significantly affects flame spread.
! Do not confuse surface spread of flame with structural fire resistance; this test does not evaluate the load-bearing capacity of the timber under fire conditions.
Standard Test Method for Combustible Properties of Treated Wood by the Crib Test
Directly equivalent method for evaluating combustibility of treated wood using a crib assembly.
ASTM E1354ASTM International, USA
LowCurrent
Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter
Modern replacement in purpose, assessing reaction-to-fire properties (like heat release) but using a different methodology (cone calorimeter).
EN 13823CEN (European Committee for Standardization), Europe
LowCurrent
Reaction to fire tests for building products — Building products excluding floorings exposed to the thermal attack by a single burning item
A large-scale test (Single Burning Item - SBI) used for European classification; assesses similar fire properties but is methodologically and dimensionally different.
Key Differences
≠The Indian Standard uses a fixed volume of alcohol (9 ml) as the ignition source. The most direct equivalent, ASTM E160, specified a variable amount of alcohol based on the specimen's weight.
≠IS 4016 provides a classification system (Type 1 and Type 2) based on test results. In contrast, ASTM E160 was primarily a test method to generate data, with classification being outside its direct scope.
≠Modern international standards like ASTM E1354 and EN 13823 measure dynamic properties like Heat Release Rate (HRR) and Smoke Production Rate (SPR), which IS 4016 does not. The IS code relies on more basic terminal measurements like total mass loss and duration of combustion.
≠The specimen stick dimensions differ slightly. IS 4016 specifies 19 mm x 19 mm x 75 mm, whereas ASTM E160 specified 1/2 in. x 1/2 in. x 3 in. (12.7 mm x 12.7 mm x 76.2 mm), resulting in a less dense crib.
Key Similarities
≈Both IS 4016 and ASTM E160 are based on the same 'crib test' principle, where small wooden sticks are assembled into a lattice structure to be tested.
≈The fundamental measurements are analogous, focusing on mass loss due to combustion and the duration of flaming and glowing after the ignition source is removed.
≈All standards, including IS 4016 and its international counterparts, mandate pre-test conditioning of specimens to a constant weight at a specified temperature and relative humidity.
≈The overall purpose is identical: to assess and classify the fire-retardant effectiveness of chemical treatments applied to timber on a small scale.
Parameter Comparison
Parameter
IS Value
International
Source
Crib Specimen Construction
24 sticks, 19x19x75 mm, assembled in 12 layers
24 sticks, 12.7x12.7x76.2 mm (1/2"x1/2"x3"), assembled in 12 layers
ASTM E160-50
Ignition Source
9 ml of absolute alcohol
1 ml of 95% ethyl alcohol per 10g of specimen weight (min 5ml, max 15ml)
ASTM E160-50
Duration of Flame Application
Until alcohol is consumed (approx. 3.5 minutes)
3 minutes
ASTM E160-50
Primary Measured Property
Final mass loss (%), flaming duration (s), glowing duration (s)
Heat Release Rate (kW/m²), Smoke Production Rate (m²/s)
ASTM E1354
Specimen Conditioning (Temp / RH)
27 ± 2 °C / 65 ± 5% RH
21 ± 1.7 °C (70 ± 3 °F) / 65 ± 2% RH
ASTM E160-50
High-Performance Criteria (Example)
Type 1: Mass loss ≤ 20%, flaming ≤ 10s, glowing ≤ 20s
No classification within the standard; results are reported for comparison.
ASTM E160-50
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
Conditioning temperature27 ± 2°C
Conditioning relative humidity65 ± 5%
Specimen length900 mm
Specimen width230 mm
Test observation duration10 minutes
Tables & Referenced Sections
Key Tables
Table 1 - Limits for Classification of Spread of Flame
Key Clauses
Clause 3 - Test Specimens
Clause 4 - Conditioning of Specimens
Clause 5 - Apparatus
Clause 6 - Procedure
Clause 7 - Classification of Surface Spread of Flame