indicate that some factors with negative impact on productivity in construction and maintenance projects are: design errors and lack of specifications, design modifications during project implementation, lack of supervision on workers, grouping workers in confined spaces (overcrowding at work), high labor turnover, poor industrial safety conditions; which generate high rates of accidents, improper composition of work crews, inadequate distribution of materials on site, lack of materials required, failure to provide equipment and tools, adverse climate and conditions on site as shown on sample Table 1.