Rolling margin of steel rod which is used for construction?

Rolling Margin is the deviation of actual unit weight to that of Standard unit weight as per IS Standards.

Rolling Margin is calculated as :

Sectional weight = Weight of Steel Bars dia wise / length of the bars.

As per IS Standards unit weight of the Bars is calculated as dia x dia / 162

Rolling Margin is deviation of actual sectional weight to that of IS Standard unit weight.

Standard Rolling Margin for different dia reinforcement bars used for construction purposes:

8mm to 10mm +- 7%

12mm to 16mm +- 5%

20mm & Above +- 3%