Primary and secondary steel structures are based on the requirements of anti-corrosion to sand paint, the amount of paint used to a large extent and dry film thickness, and construction methods and coating system also has a relationship (spray than the manual brush loss rate), the next data is the theoretical coating rate (for reference only), the actual amount multiplied by the coefficient of 1.5-1.8:
75 microns thick, about 8.5 square meters / liter;
125 microns thick, about 6.5 square meters / liter;
200 microns thick, about 4 square meters / liter.
It is generally measured using volumetric units.
Paint instructions there is a theoretical coating rate, that is coated with 1 square meters 100um (or 50um, etc. can convert their own) with the number of L paint. For example, this number is X%
Then the amount of paint used = x% * 25000 * paint thickness / 100
After this result you multiply by a loss factor, such as 1.3 This is generally related to the construction of the equipment.
The net weight of the weld on the steel structure is about 1.5 to 2% of the steel component. And then according to this to mention the electrode, because it is the net weight so the electrode weight increased, coupled with the left of the welding head, and the weight of the skin, the general need for electrode weight is 1.8 to 2.2 times.
Calculation method of dosage and loss coefficient of steel structure engineering
The theoretical coating rate of paint and the actual coating rate calculation formula
In a completely smooth and no pores of the glass surface, pour a liter of paint, forming a specified dry film thickness after the coverage of the area, called the paint the theoretical coating rate.
Theoretical coating rate = solid volume content * 10 / dry film thickness (microns) (m²/ liter)
In the actual construction, due to the surface shape of the workpiece, the required film thickness, construction methods, workers, construction conditions, weather and other factors, the actual use of paint must be greater than the construction area divided by the theoretical coating The calculated amount of "theoretical use".
Paint actual use / theoretical use (this ratio is defined as "loss factor" CF.)
Actual amount of engineering paint = construction area / actual coating rate = construction area * CF / theoretical coating rate = theoretical use ×CF
"Loss coefficient" CF analysis and estimation:
The paint loss caused by the surface roughness of the workpiece
When the surface of the sprayed surface is painted, the film thickness at the crest of the steel plate is smaller than the film thickness at the trough, in order to meet the corrosion resistance requirements at the crests (to avoid pitting), and the " Equivalent to being depleted, that is, "steel plate roughness loss." The following table shows the different spray patterns that cause paint loss (expressed in dry film thickness):
Paint film thickness distribution caused by uneven paint loss
After the construction of the film acceptance film thickness to meet or exceed the provisions of the film, technical service representatives, supervision or owners will be signed by normal qualified, but not meet the provisions of the film thickness will be required to make up, it will cause " loss. The main factors that lead to the uneven distribution of the thickness of the paint are: workers' proficiency, construction environment, simple construction (flat workpiece) or complex, construction method (no air spraying, air spraying, brushing, roller coating).
Construction waste means that the paint does not reach the surface of the construction work and lost to the surrounding environment or ground waste. If there is no air spray paint loss of about 10-20%, there are more than 50% of the air spray paint loss, roller coating about 5% loss, brush control is relatively less when the wind environment, bridge paint can cause more than 100% waste.
The residual paint in the container is wasted
Paint construction is completed, residual paint in the inner wall of the paint bucket and rubber hose, the average loss of about 5%.
In summary, the construction of the paint loss coefficient mainly by the workpiece surface roughness loss, film thickness distribution uneven loss, construction waste, container residual paint caused by waste.