Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea
Abstract
:1. Introduction
2. Materials and Methods
2.1. Selection of Study Subjects
2.2. Data Collection
2.3. Classification of Job and Subtasks
2.4. Occupational Exposure Assessment
2.5. Statistical Analysis
3. Results
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Characteristics | Description |
---|---|
Work environment | |
Outside | Job tasks performed outside the workplace (e.g., hull assembly, outfitting, hull painting, sea trial) |
Inside | Job tasks performed inside the workplace (e.g., subassembly, panel assembly, unit assembly, pre-outfitting, pre-painting) |
Combined | Job tasks performed both outside and inside the workplace (e.g., sub-departments) |
Department | |
Hull assembly | The completed larger units are then moved to the graving dock, shipway or final assembly area. Here, the larger units are joined together to form the vessel |
Hull painting | Hull surface preparation and painting on repair ships is normally performed when the ship is fully drydocked (i.e., on the graving dock of a floating drydock). |
Sea trial | After completion of the outfitting phase, the ship undergoes both dock and sea trials, during which all the ship’s systems are proved to be fully functional and operational. |
Outfitting | The process of installing parts and various subassemblies (e.g., piping systems, ventilation equipment, electrical components) on the block prior to joining the blocks together at erections. After the ship is launched, it enters the outfitting phase. A large amount of time and equipment are required. The work includes the fitting of cabling and piping, the furnishing of galleys and accommodations, insulation work, installation of electronic equipment and navigation aids, and installation of propulsion and ancillary machinery. |
Subassembly | The basic component of shipbuilding is steel plate. The plates are cut, shaped, bent or otherwise manufactured to the desired configuration specified by the design. |
Panel assembly | The plates are joined into various units and subassemblies. At this juncture, piping, electrical, and other utility systems are assembled and integrated into the units. The units are assembled using automatic or manual welding or a combination of the two. |
Unit assembly | The units or subassemblies are usually then transferred to an open-air platen or lay down area where erection, or joining of assemblies, occurs to form even larger units or blocks |
Block painting | blasted to ensure proper profiling, and painted |
Misc. | The rest of the departments |
Employment type | |
Full-time worker | Directly employed by the shipbuilding company |
Contractor worker | Affiliated to several vendor companies |
Occupation (job task) | |
Blasting | Removing and cleaning substances, including scale, rust, etc., on the surface of the block |
Power | Removing paint, rust, etc. applied to parts requiring modification outside of a ship |
Spray | Spraying paint using a compressed air gun |
Touch up | Touching up paint using a small brush and pulley |
Heating | Bending an iron plate by heating |
Grinder | Cutting and grinding scales of weld metal parts |
Sea trial | Sea trial commander responsible for managing the vessel and all personnel on board |
Signal | Signaling for crane, forklift truck, etc. |
Welding | Joining and welding between the steel plates by heating and melting |
Material classification | Preparation and classification of raw materials |
Cutting | Cutting steel plates into desired shapes and sizes |
Fit-up | Fitting up steel plates prior to pre-welding |
Misc. | The rest of job tasks |
Methodology | Including Entire Break Time 1 (9 h) | Excluding Entire Break Time 2 (8 h) | ||||
---|---|---|---|---|---|---|
Time (1 h) | DOSE (%) | OEL | Time (1 h) | DOSE (%) | OEL | |
OSHA method | Included | Included | 89.2 dBA | Excluded | Excluded | 90 dBA |
KOSHA guide | Included | Included | 90 dBA | Excluded | Included | 90 dBA |
Characteristics | Preparation Time | Lunch Break | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
N 1 | Time (h) 2 | DOSE (%) 3 | Max | LAVG 4 | N 1 | Time (h) 2 | DOSE (%) 3 | Max | LAVG 4 | |
Overall | 1432 | 0.4 | 0.9 | 110.0 | 77.6 | 1359 | 1 | 6.1 | 125.9 | 84.8 |
Work environment | ||||||||||
Outside | 583 | 0.4 | 0.4 | 91.4 | 71.8 | 548 | 1 | 5.1 | 125.9 | 83.5 |
Inside | 635 | 0.3 | 1.2 | 110.0 | 81.8 | 617 | 1 | 2.2 | 114.2 | 77.5 |
Outside/Inside | 214 | 0.4 | 0.7 | 96.2 | 75.8 | 194 | 1 | 0.9 | 89.5 | 71.0 |
Department | ||||||||||
Hull assembly | 250 | 0.4 | 0.5 | 91.4 | 73.4 | 233 | 1 | 1.8 | 106.0 | 76.0 |
Hull painting | 72 | 0.4 | 0.4 | 80.8 | 71.8 | 67 | 1 | 28.5 | 125.9 | 95.9 |
Sea trial | 47 | 0.4 | 0.3 | 75.6 | 69.7 | 48 | 1 | 0.6 | 81.8 | 68.1 |
Outfitting | 214 | 0.4 | 0.4 | 90.9 | 71.8 | 200 | 1 | 2.3 | 106.3 | 77.8 |
Subassembly | 173 | 0.2 | 0.7 | 101.5 | 80.8 | 175 | 1 | 1.7 | 100.1 | 75.6 |
Panel assembly | 186 | 0.3 | 0.9 | 101.1 | 79.7 | 173 | 1 | 1.0 | 88.4 | 71.8 |
Unit assembly | 195 | 0.4 | 0.5 | 100.6 | 73.4 | 188 | 1 | 0.9 | 91.1 | 71.0 |
Block painting | 81 | 0.4 | 4.3 | 110.0 | 88.9 | 81 | 1 | 9.0 | 114.2 | 87.6 |
Misc. | 214 | 0.4 | 0.7 | 96.2 | 75.8 | 194 | 1 | 0.9 | 89.5 | 71.0 |
Employment type | ||||||||||
Full-time worker | 591 | 0.3 | 0.4 | 100.6 | 73.9 | 542 | 1 | 0.8 | 87.4 | 70.2 |
Contractor worker | 841 | 0.4 | 1.1 | 110.0 | 79.1 | 817 | 1 | 4.8 | 125.9 | 83.1 |
Occupation (job task) | ||||||||||
Blasting | 18 | 0.5 | 3.1 | 96.0 | 84.9 | 16 | 1 | 5.8 | 98.3 | 84.5 |
Power | 41 | 0.4 | 0.6 | 85.0 | 74.7 | 37 | 1 | 56.4 | 125.9 | 100.9 |
Spray | 57 | 0.4 | 0.4 | 81.8 | 71.8 | 56 | 1 | 1.0 | 87.1 | 71.8 |
Touch up | 24 | 0.5 | 1.1 | 87.2 | 77.5 | 22 | 1 | 1.6 | 84.8 | 75.2 |
Heating | 28 | 0.3 | 0.6 | 86.5 | 76.8 | 28 | 1 | 1.6 | 91.1 | 75.2 |
Grinder | 159 | 0.4 | 2.4 | 110.0 | 84.7 | 154 | 1 | 6.0 | 114.2 | 84.7 |
Sea trial | 23 | 0.4 | 0.4 | 75.6 | 71.8 | 24 | 1 | 0.8 | 81.8 | 70.2 |
Signal | 27 | 0.4 | 0.6 | 85.3 | 74.7 | 25 | 1 | 0.6 | 77.9 | 68.1 |
Welding | 318 | 0.3 | 0.5 | 100.6 | 75.5 | 281 | 1 | 1.1 | 86.8 | 72.5 |
Material classification | 93 | 0.3 | 0.6 | 89.5 | 76.8 | 85 | 1 | 0.9 | 81.4 | 71.0 |
Cutting | 43 | 0.2 | 0.3 | 83.9 | 74.7 | 44 | 1 | 1.2 | 85.5 | 73.1 |
Fit-up | 390 | 0.4 | 0.6 | 101.5 | 74.7 | 376 | 1 | 1.2 | 100.1 | 73.1 |
Misc. | 211 | 0.4 | 0.5 | 96.2 | 73.4 | 211 | 1 | 0.8 | 89.5 | 70.2 |
Characteristics | N | Mean Levels of Occupational Noise Exposure [Average of LAVG (Standard Deviation), Unit: dBA] | p-Value 1 | |
---|---|---|---|---|
Excluding Entire Break Time (8 h) | Including Entire Break Time (9 h) | |||
Overall | 1575 | 88.3 (8.0) | 87.3 (7.9) | <0.001 |
Work environment | ||||
Outside | 658 | 87.5 (7.7) | 86.5 (7.6) | <0.001 |
Inside | 679 | 90.6 (7.6) | 89.6 (7.5) | <0.001 |
Outside/Inside | 238 | 84.0 (7.8) | 83.0 (7.6) | <0.001 |
Department | ||||
Hull assembly | 291 | 89.7 (7.6) | 88.6 (7.5) | <0.001 |
Hull painting | 77 | 87.5 (8.0) | 86.6 (8.0) | <0.001 |
Sea trial | 54 | 81.4 (6.1) | 80.4 (6.0) | <0.001 |
Outfitting | 236 | 86.1 (7.0) | 85.1 (7.0) | <0.001 |
Subassembly | 188 | 90.7 (7.9) | 89.7 (7.8) | <0.001 |
Panel assembly | 191 | 90.0 (7.1) | 88.9 (7.0) | <0.001 |
Unit assembly | 213 | 92.0 (6.7) | 90.9 (6.6) | <0.001 |
Block painting | 87 | 88.6 (8.9) | 87.8 (9.0) | <0.001 |
Misc. | 238 | 84.0 (7.8) | 83.0 (7.6) | <0.001 |
Employment type | ||||
Full-time worker | 667 | 86.3 (7.4) | 85.3 (7.3) | <0.001 |
Contractor worker | 908 | 89.8 (8.1) | 88.8 (8.0) | <0.001 |
Occupation (job task) | ||||
Blasting | 18 | 90.6 (7.5) | 89.6 (7.5) | <0.001 |
Power | 45 | 93.7 (7.4) | 92.8 (7.7) | <0.001 |
Spray | 61 | 82.7 (6.1) | 81.8 (6.1) | <0.001 |
Touch up | 25 | 81.8 (3.7) | 81.1 (3.7) | <0.001 |
Heating | 30 | 100.8 (5.4) | 99.6 (5.3) | <0.001 |
Grinder | 172 | 97.3 (6.5) | 96.2 (6.4) | <0.001 |
Sea trial | 24 | 80.7 (6.8) | 79.8 (6.6) | <0.001 |
Signal | 30 | 81.9 (4.6) | 80.9 (4.5) | <0.001 |
Welding | 349 | 89.1 (5.2) | 88.1 (5.2) | <0.001 |
Material classification | 100 | 80.6 (6.4) | 79.9 (6.2) | <0.001 |
Cutting | 46 | 90.6 (3.8) | 89.6 (3.8) | <0.001 |
Fit-up | 434 | 89.3 (7.1) | 88.2 (7.1) | <0.001 |
Misc. | 241 | 82.6 (6.0) | 81.4 (1.1) | <0.001 |
Characteristics | N | KOSHA Guide | OSHA Method | p-Value 2 | p-Value 3 | ||
---|---|---|---|---|---|---|---|
Mean (SD) 1 | >90 dBA [N (%)] | Mean (SD)1 | >90 dBA [N (%)] | ||||
Overall | 1575 | 87.4 (8.5) | 597 (37.9) | 88.3 (8.0) | 629 (39.9) | <0.001 | <0.001 |
Work environment | |||||||
Outside | 658 | 86.5 (8.3) | 220 (33.4) | 87.5 (7.7) | 231 (35.1) | <0.001 | 0.005 |
Inside | 679 | 89.9 (7.9) | 336 (49.5) | 90.6 (7.6) | 354 (52.1) | <0.001 | <0.001 |
Outside/Inside | 238 | 82.8 (8.2) | 41 (17.2) | 84.0 (7.8) | 44 (18.5) | <0.001 | 0.083 |
Department | |||||||
Hull assembly | 291 | 88.9 (8.1) | 128 (44.0) | 89.7 (7.6) | 133 (45.7) | <0.001 | 0.059 |
Hull painting | 77 | 86.6 (8.6) | 24 (31.2) | 87.5 (8.0) | 26 (33.8) | <0.001 | 0.157 |
Sea trial | 54 | 80.0 (6.7) | 3 (5.6) | 81.4 (6.1) | 3 (5.6) | <0.001 | 1.000 |
Outfitting | 236 | 85.1 (7.5) | 65 (27.5) | 86.1 (7.0) | 69 (29.2) | <0.001 | 0.102 |
Subassembly | 188 | 90.1 (8.3) | 103 (54.8) | 90.7 (7.9) | 106 (56.4) | <0.001 | 0.083 |
Panel assembly | 191 | 89.1 (7.7) | 82 (42.9) | 90.0 (7.1) | 92 (48.2) | <0.001 | 0.002 |
Unit assembly | 213 | 91.3 (6.8) | 118 (55.4) | 92.0 (6.7) | 123 (57.7) | <0.001 | 0.025 |
Block painting | 87 | 87.8 (9.4) | 33 (37.9) | 88.6 (8.9) | 33 (37.9) | <0.001 | 1.000 |
Misc. | 238 | 82.8 (8.2) | 41 (17.2) | 84.0 (7.8) | 44 (18.5) | <0.001 | 0.083 |
Employment type | |||||||
Full-time worker | 667 | 85.3 (8.1) | 187 (28.0) | 86.3 (7.4) | 204 (30.6) | <0.001 | <0.001 |
Contractor worker | 908 | 89.0 (8.4) | 410 (45.2) | 89.8 (8.1) | 425 (46.8) | <0.001 | 0.001 |
Occupation (job task) | |||||||
Blasting | 18 | 89.8 (7.7) | 8 (44.4) | 90.6 (7.5) | 8 (44.4) | <0.001 | 1.000 |
Power | 45 | 93.2 (8.0) | 33 (73.3) | 93.7 (7.4) | 33 (73.3) | <0.001 | 1.000 |
Spray | 61 | 81.5 (6.7) | 6 (9.8) | 82.7 (6.1) | 6 (9.8) | <0.001 | 1.000 |
Touch up | 25 | 80.7 (4.0) | 1 (4.0) | 81.8 (3.7) | 1 (4.0) | <0.001 | 1.000 |
Heating | 30 | 100.3 (5.4) | 29 (96.7) | 100.8 (5.4) | 29 (96.7) | <0.001 | 1.000 |
Grinder | 172 | 96.7 (6.6) | 147 (84.9) | 97.3 (6.5) | 149 (86.6) | <0.001 | 0.180 |
Sea trial | 24 | 79.1 (7.5) | 1 (4.2) | 80.7 (6.8) | 1 (4.2) | <0.001 | 1.000 |
Signal | 30 | 80.1 (6.0) | 1 (3.3) | 81.9 (4.6) | 2 (6.7) | <0.001 | 0.317 |
Welding | 349 | 88.5 (5.5) | 124 (35.5) | 89.1 (5.2) | 137 (39.3) | <0.001 | <0.001 |
Material classification | 100 | 78.9 (7.4) | 7 (7.0) | 80.6 (6.4) | 7 (7.0) | <0.001 | 1.000 |
Cutting | 46 | 90.2 (3.8) | 26 (56.5) | 90.6 (3.8) | 27 (58.7) | <0.001 | 0.317 |
Fit-up | 434 | 88.5 (7.4) | 190 (43.8) | 89.3 (7.1) | 200 (46.1) | <0.001 | 0.004 |
Misc. | 241 | 81.5 (6.4) | 25 (10.4) | 82.6 (6.0) | 29 (12.0) | <0.001 | 0.046 |
Characteristics | N | Mean (SD) 1 | KOSHA Guide | OSHA Method | p-Value 2 |
---|---|---|---|---|---|
>90 dBA [N (%)] | >89.2 dBA [N (%)] | ||||
Overall | 1575 | 87.3 (7.9) | 544 (34.5) | 608 (38.6) | <0.001 |
Work environment | |||||
Outside | 658 | 86.5 (7.6) | 203 (30.9) | 223 (33.9) | <0.001 |
Inside | 679 | 89.6 (7.5) | 302 (44.5) | 342 (50.4) | <0.001 |
Outside/Inside | 238 | 83.0 (7.6) | 39 (16.4) | 43 (18.1) | 0.046 |
Department | |||||
Hull assembly | 291 | 88.6 (7.5) | 117 (40.2) | 129 (44.3) | 0.001 |
Hull painting | 77 | 86.6 (8.0) | 23 (29.9) | 24 (31.2) | 0.317 |
Sea trial | 54 | 80.4 (6.0) | 3 (5.6) | 3 (5.6) | 1.000 |
Outfitting | 236 | 85.1 (7.0) | 60 (25.4) | 67 (28.4) | 0.008 |
Subassembly | 188 | 89.7 (7.8) | 86 (45.7) | 104 (55.3) | <0.001 |
Panel assembly | 191 | 88.9 (7.0) | 76 (39.8) | 85 (44.5) | 0.003 |
Unit assembly | 213 | 90.9 (6.6) | 109 (51.2) | 120 (56.3) | 0.001 |
Block painting | 87 | 87.8 (9.0) | 31 (35.6) | 33 (37.9) | 0.157 |
Misc. | 238 | 83.0 (7.6) | 39 (16.4) | 43 (18.1) | 0.046 |
Employment type | |||||
Full-time worker | 667 | 85.3 (7.3) | 165 (24.7) | 193 (28.9) | <0.001 |
Contractor worker | 908 | 88.8 (8.0) | 379 (41.7) | 415 (45.7) | <0.001 |
Occupation (job task) | |||||
Blasting | 18 | 89.6 (7.5) | 7 (38.9) | 8 (44.4) | 0.317 |
Power | 45 | 92.8 (7.7) | 32 (71.1) | 33 (73.3) | 0.317 |
Spray | 61 | 81.8 (6.1) | 6 (9.8) | 6 (9.8) | 1.000 |
Touch up | 25 | 81.1 (3.7) | 1 (4.0) | 1 (4.0) | 1.000 |
Heating | 30 | 99.6 (5.3) | 29 (96.7) | 29 (96.7) | 1.000 |
Grinder | 172 | 96.2 (6.4) | 143 (83.1) | 147 (85.5) | 0.046 |
Sea trial | 24 | 79.8 (6.6) | 1 (4.2) | 1 (4.2) | 1.000 |
Signal | 30 | 80.9 (4.5) | 1 (3.3) | 1 (3.3) | 1.000 |
Welding | 349 | 88.1 (5.2) | 100 (28.7) | 127 (36.4) | <0.001 |
Material classification | 100 | 79.9 (6.2) | 5 (5.0) | 7 (7.0) | 0.157 |
Cutting | 46 | 89.6 (3.8) | 17 (37.0) | 26 (56.5) | 0.003 |
Fit-up | 434 | 88.2 (7.1) | 179 (41.2) | 195 (44.9) | <0.001 |
Misc. | 241 | 81.4 (1.1) | 24 (10.0) | 27 (11.2) | 0.083 |
LAVG (N = 1575) | Mean (SD) 1 | ICC 2 | >90 dBA (8 h) | p-Value 3 | |
---|---|---|---|---|---|
N | % | ||||
Reference value | 88.3 (8.0) | - | 629 | 39.9 | - |
More than 6 h | |||||
<08:00~15:00 | 88.0 (8.1) | 0.994 | 616 | 39.1 | 0.085 |
08:00~15:00 | 88.3 (8.1) | 0.994 | 644 | 40.8 | 0.063 |
09:00~16:00 | 88.3 (8.2) | 0.995 | 629 | 39.9 | 1.000 |
More than 5 h | |||||
<08:00~14:00 | 87.7 (8.2) | 0.984 | 594 | 37.7 | 0.001 |
08:00~14:00 | 88.1 (8.3) | 0.984 | 628 | 39.8 | 0.922 |
09:00~15:00 | 88.2 (8.3) | 0.989 | 635 | 40.3 | 0.508 |
10:00~16:00 | 87.9 (8.4) | 0.984 | 597 | 37.9 | 0.001 |
More than 4 h | |||||
<08:00~12:00 | 87.6 (8.3) | 0.967 | 574 | 36.4 | <0.001 |
08:00~12:00 | 88.0 (8.4) | 0.967 | 616 | 39.1 | 0.256 |
09:00~14:00 | 88.0 (8.5) | 0.978 | 614 | 38.9 | 0.166 |
10:00~15:00 | 87.8 (8.6) | 0.978 | 607 | 38.5 | 0.036 |
11:00~16:00 | 87.4 (8.7) | 0.958 | 581 | 36.8 | 0.000 |
LAVG (N = 1575) | Mean (SD) 1 | ICC 2 | >89.2 dBA (9 h) | p-Value 3 | |
---|---|---|---|---|---|
N | % | ||||
Reference value | 87.3 (7.9) | - | 608 | 38.6 | - |
More than 7 h | |||||
<08:00~15:00 | 87.1 (8.0) | 0.994 | 598 | 38.0 | 0.140 |
08:00~15:00 | 87.4 (8.1) | 0.994 | 627 | 39.8 | 0.018 |
09:00~16:00 | 87.3 (8.1) | 0.994 | 612 | 38.9 | 0.579 |
More than 6 h | |||||
<08:00~14:00 | 86.7 (8.1) | 0.985 | 567 | 36.0 | <0.001 |
08:00~14:00 | 87.0 (8.2) | 0.984 | 593 | 37.7 | 0.128 |
09:00~15:00 | 87.1 (8.3) | 0.989 | 610 | 38.7 | 0.816 |
10:00~16:00 | 86.8 (8.3) | 0.984 | 570 | 36.2 | <0.001 |
More than 5 h | |||||
09:00~14:00 | 86.6 (8.4) | 0.978 | 565 | 35.9 | <0.001 |
10:00~15:00 | 86.5 (8.5) | 0.978 | 553 | 35.1 | <0.001 |
11:00~16:00 | 86.1 (8.6) | 0.958 | 522 | 33.1 | <0.001 |
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Shin, J.; Lee, S.; Lee, K.; Kim, H. Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea. Int. J. Environ. Res. Public Health 2021, 18, 8847. https://doi.org/10.3390/ijerph18168847
Shin J, Lee S, Lee K, Kim H. Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea. International Journal of Environmental Research and Public Health. 2021; 18(16):8847. https://doi.org/10.3390/ijerph18168847
Chicago/Turabian StyleShin, Jaewoo, Seokwon Lee, Kyoungho Lee, and Hyunwook Kim. 2021. "Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea" International Journal of Environmental Research and Public Health 18, no. 16: 8847. https://doi.org/10.3390/ijerph18168847