Wendes HVAC Estimating Blog

HVAC Sheet Metal Labor Calculations Are The Cornerstone

  

  

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                     Wendes HVAC Sheet Metal  Labor Calculation

The labor hours contained  in the Wendes  HVAC Sheet Metal Estimating Software labor tables are based on 20 years of detailed time and motion studies conducted by Herbert Wendes. Wendes labor estimating hours  have been refined and validated by feed back from many contractors across the nation. The Wendes HVAC labor hours are an accurate representation of industry average labor.

Wendes labor hours are based on a detailed  ‘Per Piece’ fabrication  methodology rather  than  ‘Lbs per Hour’. The  Per Piece  labor estimating process eliminates labor inaccuracy resulting from variations in  the  mix of individual types and sizes of ductwork contained in a project. The cost "per pound"  for individual pieces of ductwork changes based on variations in fitting types, straight duct  and  duct sizes contained in a project. Accurate labor hour calculations cannot effectively be correlated to actual time studies, cost records or labor rate mixtures when using  per pound methodology. Calculating labor hours using  per piece ductwork estimating  reduces  variations in cost per pound by calculating the detailed cost for labor associated with each size and type of ductwork in a  project.

The labor hours calculated in the Wendes estimating software are based on the production rate for a typical mechanic, of average competence and training, under average conditions, using standard equipment, tools,   motivation and supervision. In instances where variations in typical working conditions are experienced, Wendes labor correction factors or adjustments may be applied, at the estimators discretion.

Shop fabrication labor included Wendes  software includes  calculations for the following  additional labor. Shop  fabrication labor inc ludes labor for  unloading raw materials, blanking sheet stock, preparing shop lists, duct labeling,  fitting layout,manual or automated plasma cutting, seaming, forming, assembling, reinforcing and connections. A typical  12% labor hour idle time is applied to the total labor hours.

Field or installation labor includes distribution of ductwork,erection of scaffolds,handling of tools, layout of duct runs, cutting duct hangers and cleats, ductwork hanging time (including straight duct and fitting connections), labor time to remove  erection equipment,  clean up.A typical 15% labor idle time is applied to the total labor hours. Installation hours are based on the time it takes to erect complete duct runs as a batch and not as single pieces. Material handling labor and supervision labor are included with the shop and field hours.

Labor hours in the WenDuct program include all of the following operations in the percentages indicated:

Fabrication Time              Installation

Material Handling                         10%                                 12%  

Set Up                                              5% to 10%                    5% to 10%

Layout Time                                20% to 50%                    5% to10%

Actual Fabrication Time         5%  to 35%                          ------

Actual Installation Time              ----                              30% to50%

Idle Time (Non Productive)        12%                                 15%

Supervision                                         12%                             ------- 

Clean Up                                               5%                                    5%