Windows are essential for ensuring efficient ventilation in our rooms. Properly designed and well-placed windows serve best to ward off rainwater from intruding into the living spaces as well as direct sunshine during summers. However, the safety and security of the living should not be jeopardized too. Hence, it becomes imperative to install window grills to ward off the intrusion of humans and animals from the window opening in the wall. Usually, window grills made of Mild Steels are installed. Let us analyze the rate for installation of a simple window grill. The figure below illustrates a simple MS window frame of 1500x1200mm consisting of solid angle (25x25x3mm), solid square bar(12x12mm) and hole fast.
Length of Angle= (2×1200) +(2×1500) = 5400mm= 5.4m
Volume of 1m length of angle= (0.25×0.03×1) +(0.22×0.03×1)
= 0.000141 cum
There are a total of 4 numbers of hole fast made of same Mild Steel angle of length 150mm are being installed so as to fix the Grill frame in the walls.
Total length of hole fast= (4×0.150) =0.6m
Total length of angle= 5.4+0.6=6m
Volume of 6m length of angle= (0.000141×6) = 0.000846 cum
Density of Mild Steel id 7850kg/cum
Hence, weight of angle= (0.000846×7850) =6.641kg ==> 7kg
No. of square bars placed horizontally spaced at distance of150mm, each of length 1200mm= 9
No. of horizontal bars of 1500mm length placed vertically=4
Total length of bars= (9×1200) + (4×1500) = 16800mm = 16.8m
Total volume of MS Bars= 0.012×0.012×16.8 = 0.00241cum
Hence, weight of MS Bars= (0.00241×7850) =18.9==>19kg
Usually, the average rate of Mild Steel is INR60/Kg. This rate varies with company to company and whether or not the material is ISI marked and also with respect to the thickness of the product. But for our analysis we will assume the average rate to be INR 60/kg for both the angle and MS bar.
Price of angle= (7×60) = 420
Price of MS bar= (19×60)= 1140
Labour charge= (7+19)x30= 780
Total è420+1140+780= 2340
Transportation & consumables charges @3%= 70.2 ==> 70
Total Cost= 2340+70= 2410
Final cost per Kg= (2410+241)/(26)= 101.96 ==>INR 102/kg
Thus, our final costing may vary between INR 95-110/kg depending upon factors like- material availability, transportation, labour expertise and volume of work.
Please note, this range is strictly valid only if the work is sourced directly from the vendor. However, the range may further increase if our selected vendor further subcontracts the work.