diff --git a/app/models/ticket.rb b/app/models/ticket.rb
index 521fd3604..137e272ef 100644
--- a/app/models/ticket.rb
+++ b/app/models/ticket.rb
@@ -505,25 +505,11 @@ class Ticket < ApplicationModel
 
     # get and set calendar settings
     if sla_selected
-      BusinessTime::Config.beginning_of_workday = sla_selected.data['beginning_of_workday']
-      BusinessTime::Config.end_of_workday       = sla_selected.data['end_of_workday']
-      days = []
-      ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'].each {|day|
-        if sla_selected.data[day]
-          days.push day.downcase.to_sym
-        end
-      }
-      BusinessTime::Config.work_week = days
+      TimeCalculation.config( sla_selected.data )
     end
     return sla_selected
   end
 
-  def _escalation_calculation_dest_time(start_time, diff_min)
-    start_time = Time.parse( start_time.to_s )
-    dest_time = (diff_min / 60).round.business_hour.after( start_time )
-    return dest_time
-  end
-
   def _escalation_calculation_higher_time(escalation_time, check_time, done_time)
     return escalation_time if done_time
     return check_time if !escalation_time
@@ -532,13 +518,6 @@ class Ticket < ApplicationModel
     return escalation_time
   end
 
-  def _escalation_calculation_business_time_diff(start_time, end_time)
-    start_time  = Time.parse(start_time.to_s)
-    end_time    = Time.parse(end_time.to_s)
-    diff = start_time.business_time_until(end_time) / 60
-    diff.round
-  end
-
   def escalation_calculation
 
     # set escalation off if ticket is already closed
@@ -574,13 +553,13 @@ class Ticket < ApplicationModel
 
     # first response
     if sla_selected.first_response_time
-      self.first_response_escal_date = self._escalation_calculation_dest_time( created_at, sla_selected.first_response_time )
+      self.first_response_escal_date = TimeCalculation.dest_time( created_at, sla_selected.first_response_time )
 
       # set ticket escalation
       self.escalation_time = self._escalation_calculation_higher_time( self.escalation_time, self.first_response_escal_date, self.first_response )
     end
     if self.first_response# && !self.first_response_in_min
-      self.first_response_in_min = self._escalation_calculation_business_time_diff( self.created_at, self.first_response )
+      self.first_response_in_min = TimeCalculation.business_time_diff( self.created_at, self.first_response )
 
     end
     # set sla time
@@ -595,13 +574,13 @@ class Ticket < ApplicationModel
       last_update = self.created_at
     end
     if sla_selected.update_time
-      self.update_time_escal_date = self._escalation_calculation_dest_time( last_update, sla_selected.update_time )
+      self.update_time_escal_date = TimeCalculation.dest_time( last_update, sla_selected.update_time )
 
       # set ticket escalation
       self.escalation_time = self._escalation_calculation_higher_time( self.escalation_time, self.update_time_escal_date, false )
     end
     if self.last_contact_agent
-      self.update_time_in_min = self._escalation_calculation_business_time_diff( self.created_at, self.last_contact_agent )
+      self.update_time_in_min = TimeCalculation.business_time_diff( self.created_at, self.last_contact_agent )
     end
 
     # set sla time
@@ -612,13 +591,13 @@ class Ticket < ApplicationModel
 
     # close time
     if sla_selected.close_time
-      self.close_time_escal_date = self._escalation_calculation_dest_time( self.created_at, sla_selected.close_time )
+      self.close_time_escal_date = TimeCalculation.dest_time( self.created_at, sla_selected.close_time )
 
       # set ticket escalation
       self.escalation_time = self._escalation_calculation_higher_time( self.escalation_time, self.close_time_escal_date, self.close_time )
     end
     if self.close_time# && !self.close_time_in_min
-      self.close_time_in_min = self._escalation_calculation_business_time_diff( self.created_at, self.close_time )
+      self.close_time_in_min = TimeCalculation.business_time_diff( self.created_at, self.close_time )
     end
     # set sla time
     if sla_selected.close_time && self.close_time_in_min