How to calculate weight of Cladding?

Cw = ((Pie () x (D + 2 x Th))/1000) x RMT x Wc x Co.

Where:

Cw = Cladding Weight 

D = Pipe outer diameter.

Th = Insulation Thickness

RMT = Insulation running meter 

Wc = Weight of cladding in one Sq. meter

Co = Cladding overlap/ wastage 

 Normally we have considered 15-20% quantities for overlap & wattage.

Now 

Cw = ((Pie () x (D + 2 x Th))/1000) x RMT x Wc x 1.15

For Example: 

A 4" pipe having length is 120m, 1st layer insulation thickness is 50mm, 2nd layer insulation thickness is 25mm & cladding material is 24G aluminum cladding. Calculate Cladding weight? 

Solution: 

Pipe Size = 4"

Pipe OD (D) = 114.3NB

1st Layer Insulation Thickness (Th1) = 50mm

2nd Layer Insulation Thickness (Th2) = 25mm

Cladding Weight (Wc) = 1.52 Kg/m2

Insulation Running meter  (RMT) = 120 

Calculation of RMT is as per Insulation Material Calculation.

Now we putting all values in formula: 

Cw = ((Pie () x (D + 2 x Th))/1000) x RMT x Wc x Co.

Cw = (((Pie () x (114.3 + (2 x (50+25))))/1000) x 120 x 1.52 x 1.15

  = 0.830 x 120 x 1.52 x 1.15

  = 174.17 kg