Masonry Magazine May 2001 Page. 29
PRODUCTIVITY / continued from page 11
Figure 2
MINOR, MODERATE AND SEVERE FIELD CONDITIONS
| No. | Field Factors | Minor | Standard Field Conditions Moderate | Severe |
| --- | --- | --- | --- | --- |
| 1 | Congestion | An additional crew/contractor working in the same area 1 day/week | Additional crews/contractors workingin the same area 2-3 days/week | Additional crews/contractors working in the same area everyday |
| 2 | Morale and Attitude | Less than 3 inspections/ week, average 1 hour each | Daily inspection, 1-2 hours each | Full time inspection |
| 3 | Labor Reassignment | Crews move once a week between job areas | Crews move 2-3 times/week between job areas | Crews move almost daily between jobs |
| 4 | Crew Size Change | Crew size changes once/week | Crew size changes 2-3 times/week | Crew size changes almost daily |
| 5 | Added Operations | Work disrupted once/week | Work disrupted 2-3 times/week | Work disrupted almost daily |
| 6 | Diverted Supervision | 2 times/week, 1-2 hours | Daily, 1-2 hours | Daily, 4 hours or more |
| 7 | Learning Curve | Once a week | 2-3 times/week | Daily |
| 8 | Errors and Omissions | Every 2 weeks or more | Every week | Every 1 or 2 day(s) |
| 9 | Beneficial Occupancy | Punch list work | Punch list and new work one week prior to the original completion date | Many crews and overtime a few days prior to the original completion date |
| 10 | Joint Occupancy | Facility partly occupied, one trade working | Facility partly occupied, 2-3 trades working in the same area | Facility in operation, work on limited shifts |
| 11 | Site Access | 4 days/week, < 25 yards to materials storage | 2-3 days/week, 25-50 yards to materials storage | Once/week, > 50 yards to materials storage |
| 12 | Logistics | 1 re-handling lifting, 4 days/ week material availability | 2 re-handling lifting, 2-3 days/ week material availability | > 3 re-handling lifting, limited time |
| 13 | Fatigue | Once/week | 2-3 times/week | Every day for more than 1 week |
| 14 | Work Sequence | One trade/ one change/week | 2 trades/ 2-3 changes/week | Multiple trades, many changes |
| 15 | Overtime | < 5 hours/week, 1-2 con secutive weeks | 5-10 hours/week, 3-5 consecutive weeks | > 10 hours/week, > 5 consecutive weeks |
| 16 | Weather or Environment | Expected Temp. +5F in summer or-5F in winter | Expected Temp. +10F in summer or-10F in winter | Expected Temp. +15F in summer or -15F in winter |
CONCLUSIONS AND RECOMMENDATIONS
This study explores field factors affecting masonry productivity for building construction, and also quantifies the productivity loss caused by these factors. The results include percentages of productivity loss employed to compute additional man-hours required to perform the work in the field conditions that differ from the original expectations. This study indicates that field factors that are beyond the control of the mason contractor can initiate productivity loss resulting in an increase in required man-hours. General contractors and owners may not recognize the additional man-hours due to differing field conditions, and this can cause a major concern to mason contractors due to the fact that mason contractors usually cannot control the field conditions.
Mason contractors, however, can take certain actions to minimize impacts of the factors, as well as to improve their position in negotiation and litigation. Firstly, mason contractors may include a clause in their contracts to cover uncertainty of field factors. Secondly, before or during experiencing of field factors, the mason contractor can discuss impacts of the field factors with the general contractor, and insist on coverage of additional man-hours. Additionally, referring to the study results, field factors usually accumulate, which causes high productivity loss. The mason contractor can schedule the work or manage the crews to minimize some field factors. For instance, the contractor may rearrange work time among bricklayers to reduce the necessity of working overtime for long consecutive weeks. Lastly and most importantly, sound documentation usually supports the contractor in negotiating with the general contractor and owner. The mason contractor, therefore, should maintain appropriately current records and orderly historical files of all documents.
REFERENCE
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5. Mechanical Contractors Association of America (1976). "Factors Affecting Productivity." Management Methods Bulletis, No. CO1, 31-34.
6. National Electrical Contractors Association (1989). "Overtime and Productivity in Electrical Construction." NECA, Washington, DC.
7. Ovararin, N., and Popescu, C. M. (2001). "Field Factors Affecting Masonry Productivity." The 45th Annual Meeting of AACE International, Association for the Advancement of Cost Engineering, June 17-20, 2001.
8. Sanders, S. R., and Thomas, R. T. (1991). "Factors Affecting Masonry-Labor Productivity." Journal of Construction Engineering and Management, ASCE. 117(4), 626-644.
9. Thomas, H. R., and Oloufa A. A. (1995). "Labor Productivity, Disruptions, and The Ripple Effect." Cost Engineering, 37(12), 49-54.