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 (d) Additional precautions shall be taken to the extent necessary to protect adjacent ships,
buildings, and stores.
(2) Personnel in or near the blasting area shall be warned of blasting operations. In all
circumstances, close cooperation between ship and shipyard personnel is required.
(3) The entire area to be blasted shall be visually inspected. Heavily rusted or corroded areas,
damaged metal, and holes in the structure or piping shall be checked to determine if technical
examination is warranted, and for possible repair prior to blasting.
b. Protective Equipment. All blast operators shall wear hoods and airline respirators or air helmets of
the positive-pressure type. Other mandatory clothing includes rubber or leather gauntlet gloves, safety
shoes, and coveralls. The blast operator shall wear a safety belt or harness when working on staging or
other elevated places. Staging shall be stable and correctly positioned for the safety, convenience, and
comfort of the blast operator. Personnel other than blast operators, including machine operators and
personnel engaged in work near abrasive blasting operations, shall wear full eye protection and NIOSH-
approved dust respirators. Approved ear protection shall be worn wherever the airborne noise level is
above 85 dBA. Both earplugs and earmuffs (double protection) shall be worn if the noise level exceeds
108 dBA.
c. Operating Safety Precautions. The nozzle shall never be pointed in the direction or ricochet line of
another person, even with the air and abrasive stream shut off. The blast operator shall always keep
hands and other parts of the body away from the discharge and the nozzle, and shall never try to adjust
the nozzle while the abrasive stream is flowing.
(1) Hoses will be secured, leaving only enough free length to be handled safely by the blast operator.
All hoses, fittings, and so forth shall be inspected before blasting begins; worn parts shall be discarded.
secured to a strong support or to each other.
(2) Abrasive-blasting equipment shall be properly maintained because operation of damaged or
poorly maintained equipment at high pressures is dangerous.
(3) Whenever practical, hoppers and hopper tenders should be located on top of dry-dock walls
rather than in the basin. This improves housekeeping and permits grit flow to be aided by gravity.
Minimizing the number of people who must be in the dock basin reduces the risk of injury if a hose or
connection should break, causing the hoses to whip.
3-14. Abrasive Materials. Metal or synthetic shot, grit, or similar abrasives are used where recovery of
the abrasive is possible. Sand or other low-cost materials are used when the abrasive agent is
expendable, but the use of sand is costly. The abrasive grit must be of a size sufficient to remove surface
contamination without working the surface to excess. Overworking creates extreme peaks and valleys on
the surface, which require an additional buildup of the applied paint film for adequate protection. The
peaks, if too high, represent possible areas of premature failure in coating systems with less than five mils
dry film thickness.
a. Conventional Blasting. Conventional blast cleaning is a term used to designate the usual method of
field blasting, in which no effort is made to alleviate the dust hazard or recycle the blasting abrasive.
Conventional blasting does not require special rinsing, as is required for wet blasting, but it does require
that health precautions be taken to protect the operator and other personnel in the area from the fine,
abrasive dust. Machinery in the vicinity must also be shielded from the dust. After blasting, the surface
must be brushed, vacuumed, or air cleaned to remove residues or trapped grit.
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