Change Order Processor
Business Case
Problem Statement
Change orders cause project disruption:
- Delayed processing affects cash flow
- Unclear cost impact
- Lost documentation
- Schedule impacts not tracked
Solution
Streamlined change order processing with cost analysis, approval workflow, and impact tracking.
Business Value
- Faster processing - Reduce approval cycle time
- Cost control - Accurate change pricing
- Documentation - Complete audit trail
- Impact visibility - Schedule and budget effects
Technical Implementation
pythonimport pandas as pd from datetime import datetime, date, timedelta from typing import Dict, Any, List, Optional from dataclasses import dataclass, field from enum import Enum class ChangeOrderStatus(Enum): """Change order status.""" DRAFT = "draft" PENDING_REVIEW = "pending_review" PENDING_APPROVAL = "pending_approval" APPROVED = "approved" REJECTED = "rejected" VOID = "void" class ChangeType(Enum): """Type of change.""" OWNER_REQUESTED = "owner_requested" DESIGN_CHANGE = "design_change" FIELD_CONDITION = "field_condition" CODE_COMPLIANCE = "code_compliance" VALUE_ENGINEERING = "value_engineering" ERROR_OMISSION = "error_omission" class ImpactType(Enum): """Impact categories.""" COST_INCREASE = "cost_increase" COST_DECREASE = "cost_decrease" TIME_INCREASE = "time_increase" TIME_DECREASE = "time_decrease" NO_IMPACT = "no_impact" @dataclass class CostItem: """Change order cost item.""" description: str quantity: float unit: str unit_cost: float total_cost: float category: str # labor, material, equipment, subcontractor markup_percent: float = 0.0 @dataclass class ApprovalRecord: """Approval workflow record.""" approver_name: str approver_role: str action: str # approved, rejected, returned action_date: datetime comments: str = "" @dataclass class ChangeOrder: """Change order record.""" co_number: str title: str description: str change_type: ChangeType status: ChangeOrderStatus created_date: date created_by: str # Cost cost_items: List[CostItem] = field(default_factory=list) direct_cost: float = 0.0 overhead_cost: float = 0.0 profit_cost: float = 0.0 total_cost: float = 0.0 # Schedule schedule_impact_days: int = 0 affected_activities: List[str] = field(default_factory=list) # Workflow approvals: List[ApprovalRecord] = field(default_factory=list) approved_date: Optional[date] = None approved_by: str = "" # References rfi_reference: str = "" spec_section: str = "" drawing_reference: str = "" location: str = "" def to_dict(self) -> Dict[str, Any]: return { 'co_number': self.co_number, 'title': self.title, 'change_type': self.change_type.value, 'status': self.status.value, 'created_date': self.created_date.isoformat(), 'direct_cost': self.direct_cost, 'overhead_cost': self.overhead_cost, 'profit_cost': self.profit_cost, 'total_cost': self.total_cost, 'schedule_impact': self.schedule_impact_days, 'approved_date': self.approved_date.isoformat() if self.approved_date else None } class ChangeOrderProcessor: """Process and manage change orders.""" DEFAULT_OVERHEAD_RATE = 0.10 DEFAULT_PROFIT_RATE = 0.10 def __init__(self, project_name: str, original_contract: float, overhead_rate: float = None, profit_rate: float = None): self.project_name = project_name self.original_contract = original_contract self.overhead_rate = overhead_rate or self.DEFAULT_OVERHEAD_RATE self.profit_rate = profit_rate or self.DEFAULT_PROFIT_RATE self.change_orders: Dict[str, ChangeOrder] = {} self._co_counter = 0 def create_change_order(self, title: str, description: str, change_type: ChangeType, created_by: str, rfi_reference: str = "", location: str = "") -> ChangeOrder: """Create new change order.""" self._co_counter += 1 co_number = f"CO-{self._co_counter:04d}" co = ChangeOrder( co_number=co_number, title=title, description=description, change_type=change_type, status=ChangeOrderStatus.DRAFT, created_date=date.today(), created_by=created_by, rfi_reference=rfi_reference, location=location ) self.change_orders[co_number] = co return co def add_cost_item(self, co_number: str, description: str, quantity: float, unit: str, unit_cost: float, category: str, markup_percent: float = 0.0): """Add cost item to change order.""" if co_number not in self.change_orders: raise ValueError(f"Change order {co_number} not found") co = self.change_orders[co_number] total = quantity * unit_cost * (1 + markup_percent) item = CostItem( description=description, quantity=quantity, unit=unit, unit_cost=unit_cost, total_cost=total, category=category, markup_percent=markup_percent ) co.cost_items.append(item) self._recalculate_totals(co) def _recalculate_totals(self, co: ChangeOrder): """Recalculate change order totals.""" co.direct_cost = sum(item.total_cost for item in co.cost_items) co.overhead_cost = co.direct_cost * self.overhead_rate co.profit_cost = (co.direct_cost + co.overhead_cost) * self.profit_rate co.total_cost = co.direct_cost + co.overhead_cost + co.profit_cost def set_schedule_impact(self, co_number: str, days: int, affected_activities: List[str] = None): """Set schedule impact.""" if co_number not in self.change_orders: raise ValueError(f"Change order {co_number} not found") co = self.change_orders[co_number] co.schedule_impact_days = days co.affected_activities = affected_activities or [] def submit_for_review(self, co_number: str): """Submit change order for review.""" if co_number not in self.change_orders: raise ValueError(f"Change order {co_number} not found") co = self.change_orders[co_number] if co.status != ChangeOrderStatus.DRAFT: raise ValueError("Can only submit draft change orders") co.status = ChangeOrderStatus.PENDING_REVIEW def submit_for_approval(self, co_number: str, reviewer: str, comments: str = ""): """Submit for approval after review.""" if co_number not in self.change_orders: raise ValueError(f"Change order {co_number} not found") co = self.change_orders[co_number] if co.status != ChangeOrderStatus.PENDING_REVIEW: raise ValueError("Must be in review status") co.approvals.append(ApprovalRecord( approver_name=reviewer, approver_role="Reviewer", action="reviewed", action_date=datetime.now(), comments=comments )) co.status = ChangeOrderStatus.PENDING_APPROVAL def approve_change_order(self, co_number: str, approver: str, approver_role: str, comments: str = ""): """Approve change order.""" if co_number not in self.change_orders: raise ValueError(f"Change order {co_number} not found") co = self.change_orders[co_number] co.approvals.append(ApprovalRecord( approver_name=approver, approver_role=approver_role, action="approved", action_date=datetime.now(), comments=comments )) co.status = ChangeOrderStatus.APPROVED co.approved_date = date.today() co.approved_by = approver def reject_change_order(self, co_number: str, rejector: str, reason: str): """Reject change order.""" if co_number not in self.change_orders: raise ValueError(f"Change order {co_number} not found") co = self.change_orders[co_number] co.approvals.append(ApprovalRecord( approver_name=rejector, approver_role="Approver", action="rejected", action_date=datetime.now(), comments=reason )) co.status = ChangeOrderStatus.REJECTED def get_summary(self) -> Dict[str, Any]: """Generate change order summary.""" cos = list(self.change_orders.values()) by_status = {} by_type = {} total_approved = 0 total_pending = 0 total_schedule_impact = 0 for co in cos: # By status status = co.status.value by_status[status] = by_status.get(status, 0) + 1 # By type change_type = co.change_type.value by_type[change_type] = by_type.get(change_type, 0) + co.total_cost # Totals if co.status == ChangeOrderStatus.APPROVED: total_approved += co.total_cost total_schedule_impact += co.schedule_impact_days elif co.status in [ChangeOrderStatus.PENDING_REVIEW, ChangeOrderStatus.PENDING_APPROVAL]: total_pending += co.total_cost current_contract = self.original_contract + total_approved return { 'project': self.project_name, 'original_contract': self.original_contract, 'approved_changes': total_approved, 'current_contract': current_contract, 'pending_changes': total_pending, 'potential_contract': current_contract + total_pending, 'total_change_orders': len(cos), 'by_status': by_status, 'by_type': by_type, 'total_schedule_impact_days': total_schedule_impact, 'change_percent': round(total_approved / self.original_contract * 100, 1) if self.original_contract > 0 else 0 } def get_pending_approvals(self) -> List[ChangeOrder]: """Get change orders pending approval.""" return [co for co in self.change_orders.values() if co.status in [ChangeOrderStatus.PENDING_REVIEW, ChangeOrderStatus.PENDING_APPROVAL]] def export_log(self, output_path: str): """Export change order log to Excel.""" with pd.ExcelWriter(output_path, engine='openpyxl') as writer: # Summary summary = self.get_summary() summary_df = pd.DataFrame([ {'Metric': 'Original Contract', 'Value': summary['original_contract']}, {'Metric': 'Approved Changes', 'Value': summary['approved_changes']}, {'Metric': 'Current Contract', 'Value': summary['current_contract']}, {'Metric': 'Pending Changes', 'Value': summary['pending_changes']}, {'Metric': 'Change %', 'Value': f"{summary['change_percent']}%"}, {'Metric': 'Schedule Impact (days)', 'Value': summary['total_schedule_impact_days']} ]) summary_df.to_excel(writer, sheet_name='Summary', index=False) # Change order list co_data = [co.to_dict() for co in self.change_orders.values()] pd.DataFrame(co_data).to_excel(writer, sheet_name='Change Orders', index=False) # Cost details cost_data = [] for co in self.change_orders.values(): for item in co.cost_items: cost_data.append({ 'CO Number': co.co_number, 'Description': item.description, 'Quantity': item.quantity, 'Unit': item.unit, 'Unit Cost': item.unit_cost, 'Total': item.total_cost, 'Category': item.category }) if cost_data: pd.DataFrame(cost_data).to_excel(writer, sheet_name='Cost Details', index=False) return output_path
Quick Start
python# Initialize processor processor = ChangeOrderProcessor( project_name="Office Tower", original_contract=50000000 ) # Create change order co = processor.create_change_order( title="Additional Electrical Outlets", description="Add 50 electrical outlets per owner request", change_type=ChangeType.OWNER_REQUESTED, created_by="Project Manager" ) # Add cost items processor.add_cost_item(co.co_number, "Electrical outlets", 50, "EA", 150, "material") processor.add_cost_item(co.co_number, "Installation labor", 25, "HR", 85, "labor") # Set schedule impact processor.set_schedule_impact(co.co_number, days=5) # Submit for approval processor.submit_for_review(co.co_number)
Common Use Cases
1. Process Approval
pythonprocessor.submit_for_approval(co.co_number, "Reviewer", "Cost verified") processor.approve_change_order(co.co_number, "Owner Rep", "Owner", "Approved per request")
2. Get Summary
pythonsummary = processor.get_summary() print(f"Contract value: ${summary['current_contract']:,.0f}") print(f"Change %: {summary['change_percent']}%")
3. Export Log
pythonprocessor.export_log("change_order_log.xlsx")
Resources
- DDC Book: Chapter 3.1 - Cost Management
- Reference: AIA Document G701
