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IS 7191:2018 is the Indian Standard (BIS) for bituminous felt for waterproofing and damp-proofing - specification. This standard specifies the requirements for manufacturing, performance, and testing of bituminous felts used for waterproofing and damp-proofing. It covers various types (jute or glass fibre base) and grades (self-finished or mineral-surfaced) intended for applications like roofing, basements, and other structures.
Specifies requirements for different types of bituminous felts used for waterproofing and damp-proofing.
! Ensure the correct grade of felt is used: self-finished (Grade 1) for underlying layers and mineral-surfaced (Grade 2) for exposed top layers to provide UV protection.
! Always check for the ISI certification mark on the product rolls to ensure compliance with the standard.
! Store rolls vertically on a clean, flat surface to prevent distortion and damage before application.
EN 13707:2013CEN (European Committee for Standardization), Europe
HighCurrent
Flexible sheets for waterproofing - Reinforced bitumen sheets for roof waterproofing - Definitions and characteristics
Covers reinforced bituminous sheets for roof waterproofing, overlapping significantly with IS 7191's application.
ASTM D226 / D226M - 17ASTM International, USA
MediumCurrent
Standard Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing
Specifies asphalt-saturated organic felts, similar to IS 7191 Type 1 (fibre base), but is for the base felt, not the finished coated product.
ASTM D2178 / D2178M - 15aASTM International, USA
HighCurrent
Standard Specification for Asphalt Glass Felt Used in Roofing and Waterproofing
Specifies requirements for asphalt-impregnated glass felts, directly comparable to IS 7191 Type 2 (glass fibre base).
BS 747:2000BSI (British Standards Institution), UK
HighWithdrawn
Reinforced bitumen sheets for roofing. Specification
Was the primary British standard for bitumen roofing felts, historically a direct counterpart to IS 7191.
Key Differences
≠IS 7191 prominently features hessian (jute fabric) as a reinforcement base (Type 3), a material not commonly specified in modern European (EN) or American (ASTM) standards, which favor glass fiber or polyester.
≠The classification system in IS 7191 is based on reinforcement Type (1, 2, 3) and finish Grade (1, 2). ASTM standards often classify by weight (e.g., No. 15, No. 30), while EN standards use a performance-based classification system.
≠EN standards increasingly focus on polymer-modified bitumen (APP, SBS) for enhanced flexibility and durability, whereas IS 7191 primarily specifies conventional bitumen conforming to IS 73 or IS 1580.
≠The test temperature for pliability in IS 7191 is fixed at 10°C, whereas for EN 13707, low-temperature flexibility is a declared value by the manufacturer, allowing for a range of performance levels.
Key Similarities
≈All standards cover the same fundamental product: a fibrous reinforcement (base) saturated and coated with bitumen to create a water-impermeable sheet for built-up roofing and waterproofing.
≈Core performance requirements like tensile strength (breaking strength), flexibility (pliability), and water impermeability are specified in all standards as they are critical for the material's function.
≈The intended application is consistent across the standards, focusing on use in multi-layer built-up roofing systems and for general damp-proofing and waterproofing below or above ground.
≈All standards specify requirements for mass per unit area and saturant content, as these are fundamental indicators of the product's quality and expected service life.
Parameter Comparison
Parameter
IS Value
International
Source
Reinforcement Type
Type 3: Hessian (Jute) Fabric, bitumen saturated.
Glass fleece or fabric, polyester mat, or a composite of these materials.
What is the difference between Type 2 and Type 3 felt?+
Type 2 has a jute-based hessian fabric, while Type 3 has a stronger, more durable glass fibre base (Clause 4).
What is the standard roll size for bituminous felt?+
Rolls are typically 1 metre in width and 10 or 20 metres in length (Clause 7.1).
How is the pliability of the felt tested?+
A strip of felt is bent 180° around a 25 mm mandrel at 10°C. It must not crack or show signs of detachment of the coating (Clause 10.7).
Which grade of felt is suitable for an exposed roof surface?+
Grade 2 (mineral surfaced) felt is required for exposed applications, as the mineral granules protect the bitumen from sunlight and weathering (Clause 4.1).