painting consumables calculation details.pdf

How to calculate how much paint required for defined surface area

1. Paint School
JPS-E / Calculat / ‹#›
Calculations

2. Paint School
JPS-E / Calculat / ‹#›
Calculations : Paint
Abbreviations
WFT =Wet Film Thickness
DFT =Dry Film Thickness
% VS=Percent Volume Solids
LF =Loss Factor
DV =Dead Volume

3. Paint School
JPS-E / Calculat / ‹#›
WFT =250 microns
% VS =50 %
DFT =
DFT= =125 microns
WFT x % VS
100
250 x 50
100
Formula for Determining the DFT

4. Paint School
JPS-E / Calculat / ‹#›
Formula for Determining the WFT
DFT =100 microns
% VS =65 %
WFT =
WFT = =154 microns
DFT x 100 %
% VS
100 x 100 %
65 %

5. Paint School
JPS-E / Calculat / ‹#›
DFT = 100 microns
% VS = 65 %
Added thinner= 20 %
WFT =
WFT = =185 microns
DFT x (100 % + % thinner)
% VS
100 x (100 % + 20 %)
65 %
Formula for Determining the WFT
after thinning (Method 1)

6. Paint School
JPS-E / Calculat / ‹#›
Formula for Determining the WFT
after thinning (Method 2).
DFT = 100 microns
% VS = 65 %
Added thinner= 20 %
Volume of paint= 1 litreNew % VS: = 54 %
Volume of thinner= 0,2 litre
New volume = 1,2 litre
WFT = =185 microns
65
1,2
100 % x 100 microns
54 %

7. Paint School
JPS-E / Calculat / ‹#›
Theoretical spreading rate
DFT =100 microns
% VS =65
10 = Factor
=m
2
/litre
=6,5m
2
/litre
% VS x 10
DFT
65 x 10
100

8. Paint School
JPS-E / Calculat / ‹#›
Consumption of Paint
Paint DFT % VS
Epoxy mastic 200 microns85 %
Polyurethane topcoat50 “ 50 %
Consumption= =litre
Area (m
2
) x DFT
10 x % VS
To be painted: Tank, area of 500 m
2

9. Paint School
JPS-E / Calculat / ‹#›
Consumption of Paint with no loss
Epoxy mastic =117,7 litre
Polyurethane topcoat =50,0 litre
500 x 200
10 x 85
500 x 50
10 x 50
To be painted: Tank, area of 500 m
2
Formula:
Area, m
2
x DFT
10 x % VS

10. Paint School
JPS-E / Calculat / ‹#›
Consumption of Paint with loss
Epoxy mastic =196 litre
Polyurethane topcoat = 83 litre
500 x 200
10 x 85 x 0,6
500 x 50
10 x 50 x 0,6
To be painted: Tank, area of 500 m
2
, 40 % loss
40 % loss implies that only 60 % will remain on the surface.
The correction factor, Loss factor , will be 0.6
Formula:
Area, m
2
x DFT
10 x % VS x loss factor

11. Paint School
JPS-E / Calculat / ‹#›
Consumption of Paint with Loss
including Dead Volume (1 of 2)
Total Dead volume, litre =
Area (m
2
) x DV x 100
% VS x LF
Roughness, microns
30
45
60
75
90
105
Dead volume, l/ m
2
0.02
0.03
0.04
0.05
0.06
0.07
A certain roughness will give a certain dead volume

12. Paint School
JPS-E / Calculat / ‹#›
DFT % VS
Epoxy mastic 200 85
Polyurethane topcoat 50 50
Litre dead volume = = 39 litre (EM)
Epoxy mastic (EM) = 196 litre (EM
Polyurethane topcoat = 83 litre (EM)
500 x 0,04 x 100
85 x 0,6
500 x 200
10 x 85 x 0,6
Consumption of Paint with Loss
including Dead Volume (2 of 2)
500 x 50 10 x 50 x 0,6
Tank area 500 m
2
, 40 % loss, surface roughness 60 microns

13. Paint School
JPS-E / Calculat / ‹#›
How Much Paint Should We Order ?
Calculation of Paint Consumption With Loss
Example: 100 litre is needed, loss is 40 %
We have to order
= = 167 litre
Not100 litre + 40 % extra = 140 litre
100 x 100
60
100
0,6 (loss factor)
A loss of 40 % means that only 60 %
will be applied on the surface