1 Scope
This process standard applies to indoor and outdoor pipeline, equipment and container corrosion protection project.
2 Construction Preparation
2.1 Material Requirements
2.1.1 Antirust paint, top coat, asphalt, etc. should have factory certificates.
2.1.2 Thinner: gasoline, kerosene, alkyd thinner, rosin, alcohol and so on.
2.1.3 Other materials: kaolin, seven asbestos, limestone powder or talcum powder, glass cloth, mineral wool paper, linoleum, kraft paper, plastic sheeting and so on.
2.2 Main machines and tools:
2.2.1 Machines and tools: spray gun, air compressor, golden steel wheel, emery cloth, sandpaper, brush, cotton wool, asphalt pots and so on.
2.2.2 Tools: scraper, file, wire brush, emery cloth, sandpaper, brush, cotton wool, asphalt pot and so on.
2.3 Operating conditions:
2.3.1 Yardage of pipes, equipment, containers and anticorrosive operation of the site
2.3.2 construction environment temperature above 5 ℃, and well ventilated, no soot, dust and water vapor. Temperature below 5 ℃ construction to take winter construction measures.
3 operation process
3.1 process:
Piping, equipment and container cleaning → piping, equipment and container anti-corrosion oil brushing
3.2 Piping, equipment and container cleaning, rust removal:
3.2.1 manual descaling:
Scraping, filing will be used to remove the surface of the pipeline, equipment and containers of the oxidized skin, casting sand, and then use a wire brush to remove the surface of the pipeline, equipment and container. Remove, and then use wire brush to remove floating rust on the surface of pipes, equipment and containers, then use sandpaper to polish, and finally use cotton wool to wipe it clean.
3.2.2 Mechanical descaling:
First, remove the oxide skin and cast sand on the surface of pipeline with scraper and file. Then one person in front of the descaling machine, one person after the descaling machine, the pipe will be placed in the descaling machine repeatedly descaling until the original color of the metal is exposed. Before brushing the oil, use the cotton wool to rub it again, and remove the floating ash on its surface.
3.3 Pipeline, equipment and container anticorrosive oil:
3.3.1 Pipeline, equipment and container anticorrosive oil, generally according to the design requirements for anticorrosive oil, when the design does not require, it should be carried out in accordance with the following provisions:
3.3.1.1 The surface installation of pipelines, equipment and containers must be brushed with an antirust paint, to be handed over to the work of the two topcoats before brushing. If there are insulation and anti-condensation requirements should be brushed two anti-corrosion paint.
3.3.1.2 Concealed pipelines, equipment and containers shall be painted with two anti-corrosion paints, and the second anti-corrosion paint shall be brushed after the first paint is dry. And the consistency of antirust paint should be appropriate.
3.3.1.3 Buried pipeline to do corrosion protection layer, the practice of the outer wall of the anti-corrosion layer can be in accordance with the provisions of Table 1-39.
1. Use glass cloth as reinforcement wrapping layer, shall be coated with a cold primer oil sealing layer;
2. Do anti-corrosion inner wrapping layer, joint lap length of 30~50mm, outside the protective layer, lap length of 10~20mm;
3. Unconnected interfaces or construction of interruptions should be made into a contraction of each layer of 80~100mm of the stepped stubble;
4.
4. Paint anti-corrosion cold primer should be uniform, the thickness is generally 0.1~0.15mm;
5. Cold primer weight ratio: asphalt: gasoline = 1:2.25.
3.3.2 Anti-corrosion paint method has two kinds of:
3.3.2.1 Hand painting: hand painting: manual painting should be painted in layers, each layer should be reciprocated, vertical and horizontal crisscrossing, and each layer should be painted in layers, each layer should be painted in layers. should be reciprocated, crisscrossed, and keep the coating uniform, no leakage of paint or run-off.
3.3.2.2 Mechanical spraying: the paint stream should be vertical to the spraying surface, when the spraying surface is flat, the nozzle and the spraying surface should be 250~350mm apart, and when the spraying surface is rounded, the distance between the nozzle and the spraying surface should be about 400mm. Spraying, the nozzle should move evenly, the speed should be kept at 10 ~ 18m/min, spray paint using compressed air pressure of 0.2 ~ 0.4MPa.
3.3.3 buried pipeline corrosion:
Buried pipeline anticorrosion layer is mainly composed of cold substrate oil, petroleum asphalt Mardi grease, waterproofing membrane and kraft paper, etc..
3.3.3.1 The composition of cold bottom oil is shown in Table 1-40.
Modulation of cold bottom oil of asphalt, is the grade 30 A construction petroleum asphalt. Before boiling, the asphalt into more than 1.5kg of small pieces, into a clean asphalt pot, gradually warming and stirring, and keep the temperature within the range of 180 ~ 200 ℃ (up to 200 ℃), generally should be simmered at this temperature for 1.5 ~ 2.5 hours, until no bubbles, that is, said dehydration is complete. According to the proportion of cooling to 100 ~ 120 ℃ of dehydrated asphalt slowly poured into the measured unleaded gasoline, and constantly stirring until completely homogeneous mixture.
Brush cold primer oil within 24 hours after cleaning the surface of the pipe, the coating should be uniform, the thickness of 0.1~0.15mm.
3.3.3.2 Asphalt Mardi grease ratio: asphalt: kaolin = 3:1.
Asphalt should be used No. 30 A construction petroleum asphalt or No. 30 A and the No. 10 construction petroleum asphalt mixtures. Dehydrated asphalt at a temperature of 180~200℃ is gradually added to kaolin which is dried and preheated to 120~140℃, and stirred constantly to make the mixture homogeneous. Then determine the softening point, elongation, needle penetration and other three technical indicators of asphalt Mardi grease, to meet the provisions of Table 1-41 is qualified.
When applying asphalt Mardi grease, its temperature should be maintained at 160 ~ 180 ℃, construction temperature higher than 30 ℃, the temperature can be reduced to 150 ℃. Hot asphalt Mardi grease should be coated on a dry and clean layer of cold substrate oil, the coating should be uniform. The innermost layer of asphalt Mardi grease such as manual or semi-mechanized coating, should be divided into two layers, each layer is 1.5 ~ 2mm thick.
3.3.3.3 waterproofing membrane is generally used in mineral wool paper linoleum or glass mesh cloth soaked in cold subsoil oil, a spiral wrap in the hot asphalt Mardi grease layer, between each circle is allowed to have a gap of not more than 5mm or overlap, before and after the two coils of the overlap length of 80 ~ 100mm, and with hot asphalt Mardi grease layer, the lap length of 80 ~ 100mm. 100mm, and bond the joints with hot asphalt Mattei fat.
3.3.3.4 When wrapping kraft paper, there should be 15-20mm lap between each circle, the lap length of the two volumes before and after should not be less than 100mm, and the joints should be bonded with hot asphalt matte grease or cold primer oil. Kraft paper can also be replaced by PVC plastic sheeting or glass mesh tape without cold primer oil.
3.3.3.5 When making extra-strong anticorrosion layer, two waterproofing roll-roofing winding direction is appropriate to phase batch.
3.3.3.6 Has done the anti-corrosion layer of the pipe in the lifting, should be used soft sling or do not damage the anti-corrosion layer of the rope, so as not to damage the anti-corrosion layer. Before the pipe is lowered into the trench, the trench should be cleaned so that the bottom of the trench is level and free of stones, masonry or other debris. If the upper layer is very hard, the bottom of the trench should be padded first 100mm loose fine soil, pipe down the trench, do not use the crowbar to move the pipe, not to mention directly push the pipe down the trench.
3.3.3.7 All the defects on the anti-corrosion layer, unqualified places and the parts broken during inspection and ditching should be repaired before backfilling the pipe trench, and when backfilling, it is preferable to manually backfill a layer of fine soil and bury it over the top of the pipe before backfilling it manually or mechanically.
4 quality standards
4.1 Basic items:
4.1.1 The anti-corrosion layer of buried pipelines should comply with the following provisions:
Materials and structure in accordance with the design requirements and construction specifications. Coil and pipe as well as between the layers of coil pasted firmly, the surface is flat, no wrinkles, hollowing, slipping and sealing defects such as laxity.
Inspection method: observation or cut the anticorrosion layer check.
4.1.2 Pipeline, box and metal support paint should be in accordance with the following provisions:
The type of paint and the number of brush strokes in accordance with the design requirements, good adhesion, no peeling, blistering and leakage of paint, uniform thickness of the paint film, uniform color and luster, without falling and pollution phenomenon.
Inspection method: observation and inspection.
5 Finished product protection
5.1 Have done a good job of corrosion-resistant layer of pipeline and equipment should be separated from each other, shall not be adhesive, so as not to damage the corrosion-resistant layer.
5.2 Clean up the surrounding environment before brushing the oil to prevent dust, keep clean, such as wind, rain, fog, snow shall not work in the open air.
5.3 Pipes, equipment and containers painted, the paint layer in the drying process should be prevented from freezing, impact, vibration and drastic changes in temperature.
6 Quality problems to be noted
6.1 Pipe surface peeling, rust. The main reason is that the pipe is not clean from rust.
6.2 Pipe, equipment and container surface paint is not uniform, there is a flow or there is a leakage of paint, mainly because the brush is too much paint and brush oil is not serious.
7 Quality records should be available
7.1 Materials such as antirust paint, top coat, asphalt and thinner should have factory certificates.
7.2 There should be acceptance records of incoming materials.
7.3 pipeline and timely equipment corrosion prevention before the pre-inspection records.
7.4 Acceptance records after completion.
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