HVAC Sheet Metal Labor Calculations Are The Cornerstone

Posted by joseph damelio on Thu, Apr 15, 2010
                     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 feedback 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 includes 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%                                                                                                                                                                             



Topics: Accurate HVAC Sheet Metal Labor Calculation, Estimating Labor Cost, HVAC Sheet Metal Estimating Software

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