description of each master activity, it will be clear to all where each work element falls. A good narrative description reduces the chance of omitting any work items from the estimate. Master activities for a typical building might look like the following: 10XX Sitework 20XX Underslab  Utilities 30XX Foundation  and  Slab 40XX Walls 50XX Roof 60XX Rough  Utilities 70XX Interior Finish 80XX Finish  Utilities 90XX Exterior  Finish Construction  Activities As the crew leader, you must break the master activities  into  construction  activities.  The  work element  checklist  contained  in  appendix  A  to  the NAVFAC  P-405,  Seabee  Planner’s  and  Estimator’s Handbook,  is  a  good  guide  for  the  development  of  the construction  activity  list.  A  typical  Naval  Mobile Construction  Battalion  (NMCB)  project  might  contain between 15 and 50 construction activities. Construc- tion 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  “Pull Wire”  numbered  6025.  The  number  60  represents master activity “Rough Utilities” and 25 distinguishes “Pull Wire” from other construction activities in that same master activity. and reporting are always done in 8-hour man-days, regardless of the length of the workday. 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? (See page 4-78 of the P-405.) 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  2-1  has  listed  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  such.  You  need  to  assign  a  production  factor between 25 (low production) and 100 (high produc- tion) 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. 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 2-1.) Using the delay factor of 1.05 you now can adjust the original man-day estimate. 66 x 1.05 = 69.3 or 70 MD MAN-DAY ESTIMATES AND DURATIONS You need to know how to calculate mandays and duration 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, This mathematical procedure has limitations. If for example you are working outside in extremely bad weather,  and  all  other  factors  are  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. 2-10