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Sunday, August 6, 2017

Surface Preparation- SSPC Standard

Dear Readers,

SSPC is a short form of Steel Structure Painting Council.
SSPC: The Society for Protective Coatings was founded in 1950 as the Steel Structures Painting Council, a non-profit professional society concerned with the use of coatings to protect industrial steel structures. SSPC creates, publishes and maintain standards for coatings that protect and preserve concrete, steel and other industrial and marine structures and surfaces. These standards address surface preparation, coating selection, coating application, environmental regulations and industry health and safety issues to the coating industry.
 
SP1 - Solvent Cleaning: The method of solvent cleaning is intended to remove “all visible oil, grease, soil, drawing and cutting compounds, and all other soluble contaminants from steel surfaces.” by cleaning with solvent, vapour, alkali, emulsion or steam.


SP2 - Hand Tools Cleaning: This standard covers the removal of loose mill scale, loose rust, loose paint, and other loose detrimental foreign matter from surfaces with the use of non-powered hand tools. Cleaning by chipping, scraping, sanding and wire brushing to a specific degree. Equivalent to ISO St2 Grade.

SP3 - Power tool cleaning: A mechanical method of surface preparation widely used in industry and involving the use of power sanders or wire brushes, power chipping hammers, abrasive grinding wheels, needle guns etc. Although usually more effective than hand tool cleaning, it is not considered adequate for use under severe exposure conditions or for immersion applications. Equivalent to ISO St3 Grade.

SP4 - Flame Clean: Removal of all loose scale, rust and other detrimental foreign matter by passing high temperature, high velocity oxy-acetylene flames over the entire surface, followed by wire brushing. Surface should also be free of oil, grease, dirt, soil, salts and other contaminants.

SP5 - White Metal Blast Cleaning: The removal of all visible rust, mill scale, paint and contaminants, leaving the metal uniformly white or grey in appearance. This is the ultimate in blast cleaning. Use where maximum performance of protective coatings is necessary due to exceptionally severe conditions such as constant immersion in water or liquid chemicals. Equivalent to ISO Sa3 Grade and NACE #1 Definition.

SP6 - Commercial Blast Cleaning: All oil, grease, dirt, rust scale and foreign matter are completely removed from the surface and all rust, mill scale and old paint are completely removed by abrasive blasting except for slight shadows, streaks or discolorations caused by rust stain, mill scale oxides or slight, tight resides of paint or coating that remain.
 If the surface is pitted, slight residue of rust or paint may be found in the bottom of pits; at least two-thirds of each square inch of surface area shall be free of all visible residues and the remainder shall be limited to the light residues mentioned above. Equivalent to ISO Sa2 Grade and NACE #3 Definition.

SP7 - Brush Off Blast Cleaning: A method in which all oil, grease, dirt, rust scale, loose mill scale, loose rust and loose paint or coatings are removed completely. Tight mill scale and tightly-adhered rust, paint and coatings are permitted to remain. However all mill scale and rust must have been exposed to the abrasive blast pattern sufficiently to expose numerous flecks of the underlying metal fairly uniformly distributed over the entire surface. Equivalent to ISO Sa1 Grade and NACE #4 Definition.

SP8 – Pickling: Complete removal of rust and mill scale by acid pickling, duplex pickling or electrolytic pickling.

SP9 - Weather and Blast: Weathering to remove all or part of the mill scale followed by one of the blast cleaning standards.

SP10 - Near White Blast Cleaning: In this method, all oil, grease, dirt, mill scale, rust, corrosion products, oxides, paint or other foreign matter have been completely removed from the surface by abrasive blasting, except for very light shadows, very slight streaks or slight discolorations caused by rust stain, mill scale oxides or slight, tight residues of paint or coating. Blast cleaning nearly to “White Metal” cleanliness, until at least 95% of the surface area is free of all visible residues. Equivalent to ISO Sa2.5 Grade and NACE #2.

SP11 - Power Tool Cleaning to Bare Metal: Utilizing same equipment as Power Tool Cleaning to remove all visible coatings and contaminants to bare metal substrate. It will be applicable where abrasive blasting is not feasible or permissible.

SP12 - Surface Preparation and Cleaning of Metals by Water jetting Prior to Recoating: Water jetting is the use of standard jetting from a nozzle at high pressures (10,000 psi or higher) to prepare a surface for coating. Intended primarily for carbon steel, but applicable on other metals, water jetting does not create a profile on the metal substrate. However, metals with an existing profile acceptable for painting can be cleaned with water jetting to expose the existing profile. Water jetting will remove all loose rust, loose mill scale, and loose coatings uniformly.

SP13 - Surface Preparation of Concrete: Describes requirements for mechanical, chemical and thermal methods of concrete surface preparation to improve the adhesion and longevity of coating systems. This standard applies to all types of cementitious surfaces including cast-in-place concrete floors and walls, precast slabs, masonry walls, and shotcrete surfaces.

SP14 - Industrial Blast Cleaning

SP15 - Commercial Grade Power-Tool Cleaning

SP16 - Brush-Off Blast Cleaning of Coated and Uncoated Galvanized Steel, Stainless Steels, and Non-Ferrous Metals.

Sunday, July 23, 2017

Unit Weight of Chinese I Beam

Dear Readers,
 
For Chinese Steel section Beams are mentioned as “I “or “H " followed by number. To find out the size of section is, shown number multiple by 10 is the size of member.

For Example I20 means I section 200 mm depth. Simultaneously the beam sizes are same but width or flange size is different then suffix a, b, c is shown.

For example I20a & I20b, both are 200 beam. However width of flange is 100 and 102 mm respectively, also thickness of web also changes. While designating the beam Depth and width only mentioned. I20a means Beam 200 X 100 and I20b means Beam 200 X 102. Unit Weight of I Beam section is below.

Generally Chinese Steel Grades are Q195, Q215, Q235, Q255 and Q275 is used for Structural works. steel grades by the yield point of the letter on behalf of (Q) and yield point value is mentioned and sub grade A, B, C & D are used for further classification. For Example Q235A means, it is a carbon steel and having maximum yield strength of 235 Mpa.
For More Details about Chinese Channel Click Here
For More Details about Chinese Steel Standards Click Here

Sunday, July 2, 2017

Concreting Precautions

Dear Readers,

No construction activities will be taken without concreting, Let us see the precaution works before concreting. Proper concreting of RCC Columns, pedestals and footings is needed to ensure desired strength and durability of these structural members. Improper method of concreting may lead to corrosion of steel reinforcement due to pores, cracks in concrete and concrete may not achieve its target strength on setting. This may also lead to failure of columns, pedestals or footings on during occupancy of the structure.

Things to keep in mind before starting concrete works at site are:

1. Formwork inspection for strength, leakage and surface finish.

2. Reinforcement inspection as per drawing, lap length, correct lapping guidelines as per code,

3. Inspection for concrete cover to reinforcement

4. Inspection for alignment of structural member as per drawing

5. Availability of sufficient construction material at site

6. Availability of concrete vibrators,

7. Proper safety PPEs and safety measures,

8. Proper ratio of concrete mix should be confirmed,

9. Availability of slump testing equipment,

10. Availability of cube casting equipment.

After the above inspection is done and found satisfactory, concreting work should start. 

Concreting of RCC columns, pedestals and footings should start from the center of vertical bars and go towards the ends. After placement of sufficient quantity, concrete should be vibrated at regular intervals so that the concrete spreads evenly on all sides. Over vibration of concrete should be avoided. Over vibration of concrete leads to segregation of coarse aggregates which settles at the bottom making the mix weak.

Proper keys should be provided in the center of column reinforcement and walls. if the concreting has to be stopped for the day, all upper surfaces of column and walls should be made rough by wire brush after initial setting of concrete for joints with later pour of concrete.
 
This is required to provide a proper grip between concrete of stem part with footing and walls and foundations. Cement and sand slurry of 1:1 mix should be applied on the footing and foundations before column stem and wall concreting is started, to avoid separation of stem/ wall where a cold joint may be formed.

After the concreting of footing is complete, immediately in a day or two starters for column and wall should be casted with proper alignment and again the upper surface of starter should be made rough. This can be easily achieved simply by spreading and light pressing coarse aggregates particles when concrete is still green in such a way that part of coarse aggregate is outside and part goes inside.

This method of making top surface rough is to be adopted along with providing key at all places in columns, pedestals, vertical walls which are always concreted after concreting of footing and rafts concreting is over (approximately two or three days letter). These measures provide a proper grip between the surfaces. In addition to above dowels in between outer main bars of wall and column are inserted when concrete is wet to provide further grip between old and new concrete surfaces.

 These dowels are 600 to 800 mm cut pieces of reinforcement bars, which are inserted in green/wet concrete such a way that half length is projecting and half length is inside concrete.
 
Wish you all the best for excellent concreting. Have a Nice Day.
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Abbreviations (16) Acre (2) ANSI (1) Anti friction bearing (2) Apothecaries Mass (1) Avoirdupois Mass (1) AWG (4) AWS (1) BCR 295 (2) Beam (19) Bearings (5) Blasting & Painting (4) Blogoversary (2) Bolt (4) CAR A/C (1) Cartoon (2) Cent (2) CHANNEL (7) Chequered Plate (1) Chinese (3) Civil (2) Classification (1) Cleaning (3) Cold Rolled Steel (2) Column Section (1) Computer (1) Concrete (1) Construction Industry (4) Conversion Table (2) Crane Rail (2) Density (1) Drill bit (1) Drill gauge (1) Drilling (1) EHS (1) Ellipcon Steel (1) Elliptical Hollow Section (1) EN 10083-3 (1) EN 10219 (1) Engineer Day (5) Engineering Miracle (2) European Steel (3) Fibre Rope (3) Fire (1) FLAT (1) floating crane (1) Flood (1) GAUGE (9) General (20) Greetings (4) H-beam (4) Handrail (1) Heavy Weight Beam (1) Helmet (1) HEXAGOAN (1) Hollow Rectangle (3) Hollow Square (5) Hollow Steel (10) Hot rolled Steel (26) HSS (9) I-Beam (2) Information (5) Informations (4) Introduce (4) IPE (3) IS 1173 (5) IS 1786 (1) IS 3443 (2) IS 4923 (2) IS 808 (15) ISA (2) ISCR (1) ISHB (3) ISJB (4) ISJC (2) ISLB (3) ISLC (2) ISMB (4) ISMC (2) ISMCP (1) ISNT (2) ISSC (2) ISWB (3) JIS G3466 (1) Junior Beam (2) Junior Channel (3) Labour Law (2) Land Measurement (2) Light Beam (1) Light Channel (3) LPG Cylinder (1) Mass (2) Measurement (3) Metals (4) Mile Stone (2) Music Wire (4) MWG (6) Numbers (3) OCTOGAN (1) Painting (4) Parallel Flange Channel (1) PFC (1) PIPE (1) Plastics (2) PPE (1) Precautions (2) Rain (1) Rebar (1) Reinforcement Rod (1) Reinforcemnt Steel (1) Reo (1) Rigging (7) River on River (1) Rope (6) ROUND (1) Safety (9) Scale (1) Self Explanatory (4) SEP (4) Short cut key (1) Sling (1) Slit Tee (1) Specific Gravity (3) SQUARE (1) SSPC (1) Steel (18) Steel Beam (7) Steel Section (6) Steel Section Type (5) Structural Steel (52) Surface Preparation (4) SWG (4) SWL (1) Technical (5) Tee Section (5) Thanks (6) Tools & Tackles (2) Torque (5) Troy Mass (1) TUBE (1) Turnbuckle (1) UB (2) UC (2) Unit of Mass (1) UNIT WEIGHT (45) Universal Beam (1) universal Column (2) Water (2) Weight (8) Welding (3) Wide Flange Beam (2) Wind (6) Wind Speed (4) Wire Rope (2) Wishes (11) WWD (1)

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