What are the different classes of gratings defined in IS 5961?

Three classes: Light Duty (LD) for pedestrian areas, Medium Duty (MD) for areas with light vehicle traffic, and Heavy Duty (HD) for areas with heavy vehicle traffic (Clause 5).

What is the material specified for these gratings?

Grey cast iron conforming to Grade FG 200 as specified in IS 210 (Clause 3.1).

What is the load test requirement for a Heavy Duty (HD) grating?

It must withstand a central test load of 7.5 tonnes without breaking (Table 4).

What information should be marked on the grating?

The manufacturer's name or trademark, the standard number 'IS 5961', and the duty class (LD, MD, or HD) (Clause 7.1).

IS 5961

: 1970

cast iron gratings for drainage purposes

CurrentFrequently UsedSpecificationMEP · Sanitary Appliances and Water Fittings

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This standard specifies the requirements for materials, manufacture, dimensions, and testing of cast iron gratings intended for use in drainage systems. It classifies gratings into Light, Medium, and Heavy Duty based on their intended location and traffic load.

cast iron gratings for drainage purposes

Quick Reference Values

Material SpecificationGrey Iron Castings Grade FG 200 of IS 210

Light Duty (LD) Test Load2.0 tonnes

Medium Duty (MD) Test Load4.5 tonnes

Heavy Duty (HD) Test Load7.5 tonnes

HD-20 Grating Clear Opening200 mm

Coating SpecificationBlack bituminous composition

Practical Notes

Always select the duty class (LD, MD, HD) based on the expected traffic. Using a light-duty grating in a heavy traffic area will lead to failure.

Ensure the grating is properly seated in its frame to prevent rattling and uneven load distribution, which can cause premature cracking.

Verify manufacturer's test certificates to ensure compliance with the material (FG 200) and load testing requirements of the standard.