Calculating the total surface area of insulation on pipe

Multiply outside diameter of insulation by itself X Pi/4 X length of the pipe.

Area = (O.D.) X (O.D.) X Pi/4 X L.

Suppose :

4" pipe + 4" insulation = 4 + 4 + 4 = 12" x 3.142/12 = 3.142 sft x total length of pipe = Total Sft.

6" pipe + 4" insulation = 6 + 4 + 4 = 14" x 3.142/12 = 3.67 sft x total length of pipe = Total Sft.

6" pipe + 2" insulation = 6 + 2 + 2= 10" x 3.142/12 = 2.62 sft x total length of pipe = Total Sft.

ducon Disregard Post #1. SS

The Diameter of the 4" pipe + 4" of insulation is 12" or 1.'

The Circumference of the 1' diamenter is therefore C = Pi X D = 3.14159 ft.

or simply 3.1459 Sq.Ft. per Ft. of length of pipe.

My apologies for prior erroneous figures.

Thanks Stirling Stan . No apology required.

I just gave the same lay-man formula I give to my workers since easier to calculate & understand. Further simplified as : 4+4+4 x .26= Sft. x total length in Rft. = Total Sft

Dear sir, i am new to insulations Field so please guide me .How can i measure the surface area of a pipe section for example: NB is 4 inches n thickness is 25 mm.considering 1 linear meter of pipe.

Also i want to do insulations to a pump,its dimension is 0.8m×1.2m ,while the insulations thickness is 25mm.. ?

For Pipes: 4" dia x 1 metre(3'-3") with 1" insulation

4 +1+1 = 6 x 3.142/12=1.6 Sft x 3.3 =5.2 Sft

For Pipes: 4" dia x 1 metre(3'-3") with 4" insulation

4 +4+4= 12 x 3.142/12=3.14 Sft x 3.3 =10.4 Sft

For Flange/Valve Boxes we take a lump sum amount per sizes x Qty.

Why? Because the time it takes to fabricate these boxes does not justify running Sft rates.

Commercial pipe insulation is sold by unit length for a given diameter. The calculation, while simple as indicated above, is usually unnecessary.