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IS 8419:2000 (Part 2) is the Indian Standard (BIS) for requirements for rapid sand gravity filtration equipment, part 2: under drainage system. This standard specifies the requirements for the underdrainage system of rapid sand gravity filters used in water treatment. It covers pipe-and-nozzle grid systems and false bottom with nozzle systems, outlining design criteria, material specifications, and construction requirements to ensure uniform collection of filtered water and efficient distribution of backwash water.
Requirements for rapid sand gravity filtration equipment, Part 2: Under drainage system
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Proper leveling of the underdrain system is critical to ensure uniform filtration and backwashing; even minor deviations can lead to channeling and poor filter performance.
! The choice between a pipe grid and a false bottom system depends on the plant scale, cost, and maintenance. False bottom systems generally provide better backwash distribution but can be more expensive.
! Clogging of orifices or nozzles is a common operational issue. Ensure the design facilitates easy inspection and cleaning where possible.
AWWA B100-22American Water Works Association (AWWA), USA
HighCurrent
Granular Filter Material
Covers physical, chemical, and testing requirements for granular media used in water filters.
EN 12904:2005European Committee for Standardization (CEN), Europe
HighCurrent
Products used for treatment of water intended for human consumption - Sand and gravel
Specifies characteristics and requirements for sand and gravel in drinking water treatment.
JWWA A 103:2020Japan Water Works Association (JWWA), Japan
HighCurrent
Filter Materials for Water Works
Defines quality standards for sand, gravel, and anthracite used in Japanese water treatment plants.
ASTM E11 - 22ASTM International, USA
LowCurrent
Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
Does not specify filter media properties, but is a referenced standard for the sieve analysis method used by all.
Key Differences
≠IS 8419 defines three specific grades of sand (Fine, Medium, Coarse) and three sizes of gravel, whereas AWWA B100 and EN 12904 provide a framework for the purchaser to specify any custom Effective Size (ES) and Uniformity Coefficient (UC) required by the filter design.
≠EN 12904 includes specific requirements for testing the release of hazardous substances (e.g., heavy metals, arsenic) from the media into the water, a requirement not explicitly quantified in IS 8419.
≠IS 8419 specifies a qualitative requirement for media to be 'free from clay, loam...', while international standards like AWWA B100 and EN 12904 often impose a quantitative limit, such as 'less than 1% material passing the 75-micron sieve'.
≠While all standards specify acid solubility tests, the exact procedure, type of acid, and temperature can vary slightly, potentially leading to different results for the same material.
Key Similarities
≈All standards use Effective Size (ES) and Uniformity Coefficient (UC) as the fundamental parameters to define the grading and performance characteristics of the filter sand.
≈There is a common requirement for the filter media to be hard, durable, and siliceous (quartz-based), with limits on the content of soft or soluble materials like limestone or shale.
≈All include a requirement for an acid solubility test to limit the amount of carbonate material that could dissolve and adversely affect the pH and hardness of the treated water.
≈The underlying methodology for determining the particle size distribution, using a standardized set of laboratory test sieves (sieve analysis), is a common foundation across all standards.
Parameter Comparison
Parameter
IS Value
International
Source
Effective Size (Sand)
Prescribed ranges for 3 Grades (e.g., Grade 1: 0.45-0.70 mm)
Not prescribed; specified by purchaser based on filter design. Common range 0.45-0.55 mm.
AWWA B100-22
Uniformity Coefficient (Sand)
≤ 1.6 for all grades
Generally specified as < 1.7, with < 1.5 often preferred
AWWA B100-22
Acid Solubility
≤ 5.0% by weight
≤ 5.0% by weight (though purchasers may specify lower values like ≤ 2.0%)
AWWA B100-22
Specific Gravity (Sand & Gravel)
≥ 2.50
≥ 2.5
AWWA B100-22
Gravel Sizing
Defined in three fixed sizes (e.g., Size I: 3-6 mm)
Specified in multiple layers with defined size ranges (e.g., 3 mm x 6 mm, 6 mm x 12 mm, etc.)
EN 12904:2005
Fines / Clay Content
Qualitative: 'shall be free from clay, loam...'
Quantitative: 'Material passing 0.063 mm sieve shall not exceed 1% by weight'
EN 12904:2005
Hardness
Not explicitly quantified with a value.
Mohs hardness scale value of not less than 6 (often specified as 7).
AWWA B100-22
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Ratio of total orifice area to filter area0.2 to 0.3 percent
Maximum head loss during backwash1.0 m of water
Maximum velocity in manifold1.8 m/s
Maximum velocity in laterals2.4 m/s
Centre to centre spacing of laterals15 to 30 cm
Centre to centre spacing of nozzles on false bottom15 to 30 cm