As the crew leader, you must break the master activities into construction activities. The work element checklist, contained in appendix A in the NAVFAC P-405 and the Seabee Crewleader's Handbook, are an excellent reference for the development of the construction activity list. A typical Naval Mobile Construction Battalion (NMCB) project might contain between 15 and 50 construction activities. Construction activity numbers are usually four digits. The first two digits identify the master activity and the second two digits show a specific construction activity within a master activity. The number also includes a prefix assigned by OPS that identifies the specific project. Looking at the list of master activities example, this project could have a construction activity for "pre-fab forms" numbered 0312. The number 03 represents master activity "concrete construction" and the "1X" distinguishes "concrete formwork" and the "2" represents "pre-fab forms" from the order of precedence in that master activity. Refer to the Seabee Crewleader's Handbook for the construction activities listing.
MAN-DAY ESTIMATES AND DURATIONS. - You need to know how to calculate man-days and duration days for each construction activity. The P-405 is the primary reference for Seabee man-day estimates. The P-405 lists how many man-hours it takes to do one unit of work. The size of the unit is also given. The quantity of work is divided by the unit size and multiplied by the man-hours required to do one unit. You then divide by 8 man-hours per man-day and multiply by a delay factor (DF). Tasking, estimating, and reporting are always done in 8-hour man-days, regardless of the length of the workday. Note the following formula:
MDs = QTY Of WORK ÷ UNIT SIZE X MHRS
PER UNIT ÷ 8 x DF
For example, to install 16,000 sf of 1/2-inch drywall over wall studs would require how many man-days? The equation should be as follows:
MDs = 16,000 SF ÷ 1000 SF x 33 MHRS ÷ 8 = 66 x DF
PRODUCTION EFFICIENCY FACTORS. - Production efficiency factors are the first step in adjusting man-day estimates based on your unique circumstances. The intent of a production efficiency factor is to adjust for factors that will make you more or less productive than the average Seabee. In calculating a production efficiency factor, consider only those factors that affect the crew while on the job. Table 2-4 lists eight production elements in the far-left column. You need to consider the impact of each of these production elements on each activity given a specific crew, location, equipment condition, and so on. Then assign a production factor between 25 (low production) and 100 (high production) for each element. A production factor of 67 is considered average. Average these eight factors to figure your production efficiency factor (PEF).
DELAY FACTORS. - Before you can adjust the man-day estimate, you must convert the production efficiency factor to a delay factor according to the graph shown in figure 2-14. You can find the delay factor by dividing 67 (the average production factor) by the production efficiency factor (DF = 67/63.6 = 1.05). (See table 2-4.) Using the delay factor of 1.05 you now can adjust the original man-day estimate as shown in the following equation:
66 x 1.05 = 69.3 or 70 MD
This mathematical procedure has limitations. If, for example, you were working outside in extremely bad weather and all other factors were considered average (weather = 25, all others = 67), you would obtain a production efficiency factor of 62 and a delay factor of 1.08. This 8 percent increase in the man-day estimate would not adequately compensate for working in extreme weather. You are not limited to the method of delay factors in the P-405. Use common sense when impacted by extreme circumstances. Come up with what you feel is a reasonable delay factor and discuss it with your chain of command. You are not bound by either the delay factors or the production rates in the P-405. To figure man-day estimates, you can use your experience to determine the logical production rates to use. Keep in mind that the delay factor is only used to determine the man-day estimate for a particular construction activity. Each activity will have a different delay factor. All other calculations use the availability factor.
AVAILABILITY FACTORS. - Availability factors take into account that Seabees assigned as direct labor are not available 100 percent of the time. Each Naval Construction Brigade provides the availability y factors for planning purposes. Availability y factors are sometimes still referred to as site efficiency factors. These factors vary between 0.75 for main body sites to 0.85 for detail sites. Using the following equation, you can determine the man-day capability (MC) for the main body and each detail.Continue Reading