The spread rate of paint paint refers to the construction area that can be painted by a unit weight of paint paint. The spread rate of paint is a key factor in calculating the amount and cost of paint for users. Therefore, the coating spread rate is one of the issues that users are very concerned about. There are two kinds of spreading rates of paints and paints , which are theoretical spreading rate and actual spreading rate. The calculation formulas of the two spreading rates are explained below.
Theoretical spreading rate
Theoretical spreading rate refers to the area (square meter or square foot) that paint can be applied per liter of paint on a smooth surface without loss, and the unit is square meter/liter (㎡/L). Due to different uses, different types of coatings, and different dry film thicknesses of coatings, the theoretical spreading rate will also change accordingly. The calculation formula is:
Theoretical spreading rate = (volume solids × 10) / dry film thickness
Theoretical coverage is derived based on 100% coating volume solids, see table below. If the volume solids of the paint is 100%, and the dry film thickness of 1 μm per liter of paint is applied, the coating area is l000㎡, then the problem arises: if the volume solids of the coating is not 100%, the coating area is how much? "The volume solids of the coating is less than 100%, and the "spreading rate" when the coating thickness is 1 μm is calculated by multiplying 1000 by the actual volume solids percentage of the coating used, expressed as a decimal.
Volume solids 100% | 1L | 1μm | 1000㎡ |
Volume solids 40% | 1L | 1μm | 400㎡ |
Volume solids 40% | 1L | 100μm | 4㎡ |
Table: Relationship between Volume Solids and Paint Coating Coverage
Actual spread rate
The actual spreading rate will be different from the theoretical spreading rate due to many factors such as construction method, worker's technology, construction surface structure and shape, surface roughness, working environment, wind speed, and the distribution of paint film, etc. .
Under normal circumstances, the loss of paint is 25% to 40%, but it may be as high as 50% or more. When calculating the amount of paint, especially when making an actual order, it is necessary to calculate this part of the paint loss.
The actual spreading rate is calculated by multiplying the theoretical spreading rate by the estimated loss factor, the calculation formula is:
Actual spreading rate = theoretical spreading rate × (1- loss %)
The above is the description of the two calculation formulas for the coating rate of paint.
