The document provides formulas and calculations for determining wet film thickness (WFT) and dry film thickness (DFT) in paint applications, including adjustments for thinning and loss factors. It details how to calculate paint consumption for different paint types, factoring in surface area, volume solids, and potential losses due to application inefficiencies. Additionally, it guides on how much paint to order by accounting for anticipated losses.

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 litre New % 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
= m2/litre
= 6,5m2/litre
% VS x 10
DFT
65 x 10
100

8. Paint School
JPS-E / Calculat / ‹#›
Consumption of Paint
Paint DFT % VS
Epoxy mastic 200 microns 85 %
Polyurethane topcoat 50 “ 50 %
Consumption = = litre
Area (m2) x DFT
10 x % VS
To be painted: Tank, area of 500 m2

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 m2
Formula: Area, m2 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 m2 , 40 % loss
40 % loss implies that only 60 % will remain on the surface.
The correction factor, Loss factor, will be 0.6
Formula: Area, m2 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 (m2) x DV x 100
% VS x LF
Roughness, microns
30
45
60
75
90
105
Dead volume, l/ m2
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 m2, 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
Not 100 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