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IS 6280:1971 is the Indian Standard (BIS) for sewage screens. This standard provides recommendations for materials, design criteria, construction, installation, and operation of sewage screens. It covers various classifications of screens (coarse, medium, fine) and outlines key hydraulic design parameters like flow velocities and head loss for both manually and mechanically cleaned screen types used in wastewater treatment.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Ensure the approach channel is straight for a sufficient length (typically 8-10 times the channel width) to ensure uniform flow velocity distribution before the screen.
! The design must account for the handling, drainage, and disposal of collected screenings, which is a critical operational aspect.
! For mechanically cleaned screens, redundancy (e.g., a standby unit or a manual bypass screen) is highly recommended to allow for maintenance and handle breakdowns.
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
steelcast ironstainless steel
International Equivalents
Similar International Standards
BS EN 12255-3:2000BSI (British Standards Institution) / CEN, UK/Europe
HighCurrent
Wastewater treatment plants - Part 3: Pre-treatment
Directly covers design principles and performance for screening systems in wastewater pre-treatment.
Ten States Standards (2014)Great Lakes-Upper Mississippi River Board (GLUMRB), USA
HighCurrent
Recommended Standards for Wastewater Facilities
Chapter 30 provides detailed design criteria for screens, serving as a functional equivalent to the IS code's scope.
WEF MOP 8, 6th Ed.Water Environment Federation (WEF), USA
MediumCurrent
Design of Municipal Wastewater Treatment Plants
Contains a comprehensive chapter on screens, but its overall scope covers the entire treatment plant.
DWA-A 207-1DWA (German Association for Water, Wastewater and Waste), Germany
HighCurrent
Design of Screening Plants
A highly detailed standard focused exclusively on the design and dimensioning of screening systems.
Key Differences
≠IS 6280:1971 is highly prescriptive and focuses on basic bar screens, while modern standards are more performance-based and cover a wider range of technologies like step screens, drum screens, and band screens.
≠Modern standards like WEF MOP 8 and BS EN 12255 provide detailed guidance for fine screening (<6 mm), essential for protecting technologies like MBRs, a category not addressed in the 1971 Indian standard.
≠IS 6280 specifies traditional materials like mild steel. International standards now strongly recommend or mandate corrosion-resistant materials like stainless steel (304L, 316L) and advanced polymers.
≠International standards include extensive sections on automation (SCADA integration), controls (level-based, timer-based), and operator safety (guarding, E-stops), which are largely absent in IS 6280.
Key Similarities
≈All standards acknowledge the fundamental purpose of screens: to remove large solid materials to protect downstream pumps, pipes, and processes.
≈The basic classification into manually and mechanically cleaned screens is a common principle across both the IS code and international guidelines.
≈Core hydraulic design parameters, such as approach velocity and the calculation of head loss across the screen, are a fundamental consideration in all standards.
≈The principle of inclining the screen from the horizontal to increase the effective screening area and aid in the cleaning process is a shared design concept.
Parameter Comparison
Parameter
IS Value
International
Source
Bar Spacing (Medium Screen)
15 - 40 mm
10 - 25 mm
WEF MOP 8
Bar Spacing (Coarse Screen)
40 - 100 mm
> 40 mm (typically 50-150 mm)
BS EN 12255-3:2000
Approach Channel Velocity (Average Flow)
0.6 - 0.9 m/s
0.4 - 0.9 m/s
Ten States Standards
Velocity Through Bars (Peak Flow)
Not to exceed 1.2 m/s
Should not exceed 1.2 m/s
WEF MOP 8
Inclination Angle (Mechanically Cleaned)
60 - 75° from horizontal
75 - 85° from horizontal
Ten States Standards
Primary Material of Construction
Mild steel, cast iron
Stainless steel (304L or 316L)
Ten States Standards / WEF MOP 8
Bar Shape
Rectangular section
Rectangular, teardrop, or other profiles to optimize hydraulics
General practice in WEF MOP 8
⚠ Verify details from original standards before use
Key Values8
Quick Reference Values
Velocity through screen bars at average flow0.6 to 1.0 m/s
Velocity through screen bars at maximum flowNot exceeding 1.2 m/s
Velocity in approach channel (min)0.45 m/s
Velocity in approach channel (max)0.9 m/s
Inclination of manually cleaned bar screens30 to 60 degrees from horizontal
Inclination of mechanically cleaned bar screens0 to 30 degrees from vertical
Clear spacing for coarse screens50 mm and above
Clear spacing for medium screens20 to 50 mm
Key Formulas
h = (V² - v²) / (2g * C) — Head loss through screen, where V is velocity through screen, v is approach velocity, and C is a coefficient of discharge.
Tables & Referenced Sections
Key Tables
Table 1 - Classification of Screens Based on Size of Openings
Table 2 - Design Velocities for Flow Through Screens
What are the recommended flow velocities for sewage screens?+
Velocity through the screen openings should be 0.6-1.0 m/s at average flow, while the approach channel velocity should be 0.45-0.9 m/s (Clause 5.2.1 and Table 2).
What is the difference between a coarse and a medium screen?+
Coarse screens have clear openings of 50 mm or more, while medium screens have clear openings between 20 mm and 50 mm (Table 1).
What is the typical inclination for a manually cleaned bar screen?+
Manually cleaned screens are typically installed at an inclination of 30 to 60 degrees with the horizontal to facilitate raking (Clause 5.4.1).
What formula is used to calculate head loss through a screen?+
The head loss (h) can be calculated using the formula h = (V² - v²) / (2g * C), where V and v are velocities through the screen and channel respectively, and C is an empirical coefficient (Clause 5.3.1).