Calculations for the painting work

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Calculation for painting work I. Painting of pipes and equipment cylinders 1. The painting of pipes and equipment cylinders is calculated in units of “m2”. 2. Formula for calculating the external surface area to be painted on pipes and equipment cylinders: S=π×D×L. Where: S—is the surface area, in m2 ； π—pi ； D—Outer diameter of pipes and equipment, m ； L—length of pipes and equipment, in m. 3. The rust removal and painting of various pipe fittings, valves, equipment manholes, and uneven parts of pipe ends are already included in the quota and are not calculated separately. II. Oiling of equipment heads 1. The oiling of equipment heads is calculated in units of “m2”. 2. Formula for calculating the painting area of equipment end caps: S=π×(D/2)2×1.6×N (17-3-2). Where: S is the surface area of the elliptical end cap, in m2 ； π—pi ； D—Outside diameter of the equipment, m ； N—Number of end caps ； 1.6—Adjustment coefficient. III. Painting of metal structures 1. The painting of metal structures is calculated in units of 100 kg. 2. Painting area for metal structures: (1) For various types of supports, ladders, platforms, railings, etc., 5.8 m2 is calculated per 100 kg of weight ； (2) For other steel structures such as ductwork, 3.8 m2 is calculated per 100 kg of weight ； (3) For large H-beams of 300×300×6×12 and above, 2.0 square meters is calculated per 100 kg of weight. IV. Examples of calculating the cost for oiling and installation work 【Example 1】One of the pipes in a chemical processing plant was coated with red lead anti-rust paint twice; the outer diameter of the pipe is Φ89 mm, and its length is 120 m. Calculate the cost for oiling this pipeline. Solution: As given in the problem, the length of the pipe is L = 120 m, and its outer diameter is D = 0.089 m. 1. To calculate the external surface area of the pipe: S = π × D × L = π × 0.089 × 120 = 33.55 (m2). It is also possible to determine the external surface area by referring to tables using the given values. Refer to Table 2, select the column for insulation thickness of zero, and the external surface area of the pipeline is 27.96 m2/100 m. S=27.96 m2/100 m×120 m=33.55 m2. 2. Calculation of the cost for pipeline painting: According to the \"Estimate Index for Petrochemical Installation Projects\", Chapter 9 \"Insulation, Painting, and Corrosion Protection\", Section 2 \"Painting Works\", the application of red lead anti-rust paint in two coats is used as a reference (9—2001). The estimated cost is 27 yuan per 10 m2, of which 21 yuan covers labor costs and 6 yuan covers material costs. The direct costs included in the pipeline painting installation fee = 27 yuan/10m2 × 33.55 m2 = 91 yuan. Among these, the labor cost = 21 yuan/10m2 × 33.55 m2 = 70 yuan. Note: ① Other direct costs, on-site expenses, indirect costs, planned profit, and taxes included in the installation fee shall be calculated separately in accordance with relevant regulations (the same applies hereafter). ② The pipeline greasing and installation cost does not include the cost of paint materials. 【Example 2】In a petrochemical plant, one pipeline was coated with an undercoat twice. The outer diameter of the pipeline is 114 mm and its length is 950 m. Calculate the area to be coated and the cost of the coating work. Solution: As given in the problem: the pipe length is L = 950 m, and the outer diameter of the pipe is D = 0.114 m. 1. Calculate the external surface area of the pipe by referring to a table. By looking up the column corresponding to a insulation thickness of zero in Appendix 2, the external surface area of the pipe is found to be 35.81 m²/100 m. Therefore, S = 35.81 m²/100 m × 950 m = 340.20 m². 2. Calculate the cost of painting the pipe. According to the “Estimate Index for Petrochemical Installation Projects”, Chapter 9 “Insulation, Painting, and Corrosion Protection Works”, Section 2 “Painting Works”, the procedure for painting pipes involves applying two coats of primer; this corresponds to item (9—2015). Estimated cost index: 41 yuan/10m2, of which labor costs amount to 16 yuan and material costs amount to 25 yuan. The direct cost in the pipeline painting installation fee = 41 yuan/10m2 × 340.20m2 = 1395 yuan. Of this, the labor cost = 16 yuan/10m2 × 340.20 = 544 yuan. Note: The cost of applying the primer is already included in the pipeline painting fee. 【Example 3】In a petrochemical plant, the cost of painting includes 28 tons for ladders and platforms, and 45 tons for the steel structures in the pipe galleries; two coats of alkyd enamel are applied. Calculate the cost of this painting work. Solution: As given in the problem: ladder + platform 28t = 280 (100 kg) ； Pipeline corridor steel structure 45t=450 (100kg). According to the \"Budget Index for Petrochemical Installation Projects\", for the painting of metal structures in Section 2 \"Painting Works\" of Chapter 9 \"Insulation, Painting, and Anti-corrosion Works\", two coats of alkyd enamel are applied, under sub-item (9—2043). Estimated cost index: 36 yuan/100kg, of which labor costs amount to 11 yuan, auxiliary material costs are 1 yuan, and machinery usage costs are 24 yuan. The direct costs in the installation fee for painting metal structures = 36 yuan/100kg × 280 (100kg) + 36 yuan/100kg × 450 (100kg) × 0.66 = 10,080 yuan + 10,692 yuan = 20,772 yuan. Among these, the labor cost = 11 yuan/100kg × 280 (100kg) + 11 yuan/100kg × 450 (100kg) × 0.66 = 6,347 yuan. The value 0.66 is the conversion factor for the surface area of the steel structure in the pipe gallery relative to that of ladders and platforms. Note: The cost for painting metal structures does not include the cost of paint materials. 【Example 4】In a petrochemical plant, asphalt glass cloth is used as an additional anti-corrosion layer for the buried water supply and drainage pipes (three layers of cloth and four layers of oil). One of these pipes has an outer diameter of 406 mm and a length of 150 m; calculate the cost of anti-corrosion treatment for this pipe. Solution: As given in the problem, the outer diameter of the pipe is D=406 mm, and the length of the pipe is L=150 m. 1. Calculate the external surface area of the pipeline by referring to Table 2: 127.55 m2/100 m. Therefore, S = 127.55 m2/100 m × 150 m = 191.33 m2. 2. Calculate the cost for anti-corrosion coating application on the pipeline. According to the “Budgeting Indicators for Petrochemical Installation Projects”, Chapter 9 “Insulation, Coating, and Anti-Corrosion Works”, Section 2 “Coating Works”, the materials used include asphalt felt, asphalt glass cloth, and epoxy coal tar pitch. Apply the sub-items 9—2091 (one fabric and two oils) and 9—2092 (one additional fabric and one oil). (9—2091) Estimated cost index: 230 yuan/10m2, of which labor costs amount to 42 yuan, material costs to 152 yuan, and machinery usage costs to 36 yuan. (9—2092) Estimated cost index: 167 yuan/10m2, of which labor costs amount to 38 yuan, material costs to 93 yuan, and machinery usage costs to 36 yuan. The direct cost in the installation fee for pipeline anti-corrosion coating is equal to (230 yuan/10m2 + 167 yuan/10m2 × 2) × 191.33m2 = 564 yuan/10m2 × 191.33m2 = 10,791 yuan. The labor cost is (42 yuan/10m2 + 38 yuan/10m2 × 2) × 191.33m2 = 2,258 yuan. Note: ① The estimated index (9—2092) applies per layer of fabric and coating; multiplying by 2 indicates the addition of two layers of fabric and two layers of coating ； ② The cost for anti-corrosion construction using pipeline asphalt and glass cloth includes the costs of asphalt and glass cloth materials. 【Example 5】A vertical unit has a diameter (outer diameter) of 1.6 m, a cylinder length of 5.5 m, and one top head; it is protected against corrosion using inorganic zinc-rich paint. The surface area required for corrosion protection is calculated, and the cost of carrying out this corrosion protection work is determined by applying the \"Estimate Indexes for Petrochemical Installation Projects\". Solution: As given in the problem: the outer diameter of the equipment is D = 1.6 m, the length of the cylinder is L = 5.5 m, and the number of end caps is N = 1.
1. Calculate the surface area of the equipment’s cylinder, S1. By substituting the known values into formula (17-3-1), we obtain S1 = π × D × L = π × 1.6 × 5.5 = 27.65 m².
2. Calculate the surface area of the equipment’s end caps, S2. By substituting the known values into formula (17-3-2), we get S2 = π × (D/2)² × 1.6 × N = π × (1.6/2)² × 1.6 × 1 = 3.22 m².
3. The total surface area of the equipment is S = S1 + S2 = 27.65 + 3.22 = 30.89 m².
4. Calculate the cost for corrosion protection measures on the equipment. According to the “Estimate Index for Petrochemical Installation Projects”, Chapter 9 “Insulation, Coating, and Corrosion Protection”, Section 3 “Corrosion-Protective Coating Works”, the sub-item for inorganic zinc-rich paint (9—3024) should be used for the corrosion protection of metal surfaces. Estimated cost index: 431 yuan/10m2, of which labor costs amount to 133 yuan, material costs amount to 152 yuan, and machinery usage costs amount to 146 yuan. The direct costs related to equipment corrosion prevention installation are calculated as 431 yuan/10m2 × 30.89m2 = 1331 yuan; among these, the labor costs equal 133 yuan/10m2 × 30.89m2 = 411 yuan. Note: ① The cost of equipment corrosion prevention work does not include the cost of corrosion prevention materials. ② The equipment anti-corrosion construction cost includes processes such as sandblasting for rust removal and sealing of pipe ends.