ABRASIVE SAND-BLASTING PROCEDURE DOC. NO. : PR/TSE/005A
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Workshop :
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Jl. Kawasan Industri Millenium Blok E.2 No. 15 Tiga Raksa, Banten Phone : +62-21-2900 7059 Fax : +62-21-2900 7059 Email :
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ABRASIVE SAND-BLASTING PROCEDURE
TABLE OF CONTENTS 1. INTRODUCTION 2. SCOPE 3. APPLICATION 4. STANDAR OF MEASUREMENTS 5. TOOLS AND EQUIPMENTS 6. PERSONAL PROTECTIVE EQUIPMENT 7. PREPARATION 8. SAND-BLASTING MATERIALS 9. AIR SUPPLY AND AIR COMPRESSORS 10. DUST ACCUMULATION CONTROL 11. MANUAL VALVE OF ABRASIVE BLASTING NOZZLE 12. GENERAL SAFETY CONSIDERATIONS
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ABRASIVE SAND-BLASTING PROCEDURE
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1.
INTRODUCTION Sandblasting is the process of spraying abrasive material is usually a silica sand or steel grit with a high pressure on a surface in order to eliminate contamination of materials such as rust, paint, salt, oil, etc.. It also aims to create a profile (roughness) on the surface of the metal so the paint adhere better. There are 3 (three) type sandblasting process: Sandblasting usual, namely to remove paint primer coating. Sweep blast remove paint to paint the outer base layer. Sweep, just clean, without removing the paint.
2.
SCOPE This procedure is specific to applicable for all applications regarding the operation of any sand-blasting activities.
3.
APPLICATION Sand-blasting activities commonly used. Recognizes the hazards associated with working in close proximity of such operations and in order to ensure the safety of it’s sand-blasting, and will inform to be aware of the conditions that could cause them to be injured.
4.
STANDARD OF MEASUREMENTS There are 3 (three) standard roughness commonly used : SA 2 Thorough blast cleaning: Commercial finish 65% cleanthe surface shall be free from visible oil, dirt and grease, from poorly adhering mill scale, rust,paint coatings and foreign matter. Any residual contamination should be firmly adhering. SA 2.5 Very thorough blast cleaning: Near white metal 85% cleanThe surface shall be free from visible oil, dirt and grease, from poorly adhering mill scale, rust,paint coatings and foreign matter. The metal has a grayish color. Any traces of contaminationshall be visible only as slight stains in the form of spots or stripes. SA 3 Blast cleaning to pure metal: White metal 100% cleanthe surface shall be free from visible oil, dirt and grease, from poorly adhering mill scale, rust,paint coatings and foreign matter. The blasted surface must have a uniform metallic color.
5.
TOOLS AND EQUIPMENT Air Compressor Minimum 390 CFM, High Pressure Air Supply Hose, Hard Hat, Safety Shoes, Airline Respirator, Blasting Hood, Gloves,Ear Muffs, Coverall, Apron, Blasting Gun, Regulator, Filter, Dust Mask and Surface Profile Comparator to see the level of surface roughness after sandblasting.
6.
PERSONAL PROTECTIVE EQUIPMENT Equipment for protection of the eyes and face shall be supplied to the operator when the
ABRASIVE SAND-BLASTING PROCEDURE
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respirator design does not provide such protection and to any other personnel working in the vicinity of abrasive blasting operations. Appropriate personal protective equipment includes the use of a full sandblast outfit consisting of a rigid blasting helmet with air-flow control valves and filters approved for such use (example: Bullard supplied-air hood), disposable full-body protective clothing, steel-toed leather boots, and leather gloves. Stand-by persons shall wear dust hazard protection consisting of goggles and a proper dust-control respirator, standing upwind of the operation. Workers shall discard disposable clothing and change into clean clothing before leaving the work site. 7.
PREPARATION Irregular surfaces such as sediment, dirt welding, porous surfaces, sharp edges, layers of sediment, and the crust, diper should be discarded or repaired. Areas where the grinding process is required after blasting, must be cleared in order to obtain the appropriate profile. The process of dry cleaning by blasting is not permitted for the surface to be wet from the blasting and before painting, or a surface that is less than 5 degrees above the dew point or relative humidity of the air when it is greater than 85%. Metal surface is clean after blasting process to be coated is not. be allowed to stand for over 2 hours. Highly specialized treatment and cares should be applied to the work of blasting near the surface of the flange and the like. Surfaces should be given protection during the blasting and coating (coating)
8.
SAND-BLASTING MATERIALS Grit sizes of solid particles with 18-40 silica sand or steel grit. The materials used as abrasive (abrasive) in blasting shall be free of dust and other impurities. Such materials may only contain a maximum of 100 ppm chlorine (Cl).
9.
AIR SUPPLY AND AIR COMPRESSORS Air supply and air compressors are in minimum 390 CFM to create a steady air pressure of at least 100 PSI to blast the sand fastenough. Air for abrasive-blasting respirators must be free of harmful quantities of dusts, mists, or noxious gases, and must meet the requirements for supplied-air quality.
10.
DUST ACCUMULATION CONTROL Dust shall not be permitted to accumulate on the floor or on ledges outside of an abrasive-blasting enclosure, and dust spills shall be cleaned up promptly. Aisles and walkways shall be kept clear of steel shot or similar abrasive which may create a slipping hazard.
ABRASIVE SAND-BLASTING PROCEDURE
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11.
MANUAL VALVE OF ABRASIVE BLASTING NOZZLE The blast cleaning nozzles shall be equipped with an operating valve which must be held open manually. A support shall be provided on which the nozzle may be mounted when it is not in use.
12.
GENERAL SAFETY CONSIDERATIONS The identified sand-blasting unit and all accessory equipment shall be inspected prior to use, including any blast hose, the lock-pin for the crow’s foot connection to the sandblast pot, the spray nozzle condition, and the remote control “dead-man” valve on the nozzle. Any observed signs of excessive wear will be reason for replacement before use. (Hose joints or extra connections are not allowed at this time.) The flanged “pop-up” valve shall be in the “up” position before the blast tank can be pressurized. After use, do not shut off the air compressor until the blast pot is depressurized. Appropriately worded safety signs shall be posted to warn unauthorized personnel of the sandblast area of operation, and that proper personal protective equipment is required to be worn in this designated work area. The blower shall not be positioned where it will recycle sand or other particles from the blasting process. Used blasting agents shall be removed from the work area at the end of the blasting period, and in such a manner as to avoid dust dispersal (vacuum pick-up or wet-down and shovel), followed by proper disposal of spent abrasives. (Blasting agents are used to prepare the newly fabricated metal surfaces for primer and finish-coat enameled paints.) All personnels subject to silica exposure from sand-blasting operations shall be provided with information about the adverse health effects, safe work practices, hazard communication, and proper use and care of all PPE. Engineering control methods can be used to decrease exposure to silica dust, by using alternate blasting media, containment methods such as blast cleaning machines & cabinets, blasting rooms or portable equipment.
