Automatic bill of materials from the P&ID: eight requirements
The bill of materials is the bridge between engineering and procurement. It must be complete, current, and traceable. The eight requirements a tool must meet so that the bill of materials does not become a source of errors.
A P&ID without a bill of materials is only an attractive drawing. It is the bill of materials—the link from a symbol to a specific component, including manufacturer, material, and data sheet—that turns the diagram into engineering information. What a tool must provide:
1. One line per placed symbol
Every pump, every valve, and every item of equipment appears exactly once in the bill of materials. No duplicates and no forgotten components. What is drawn in the diagram is represented in the bill of materials.
2. Tag number as the primary key
The bill-of-materials line carries the tag number from the diagram. This makes it possible to locate every component in the diagram—and, conversely, to move from the diagram to the corresponding bill-of-materials line.
3. Any attributes for each symbol type
A pump needs different fields from a vessel. A heat exchanger needs different fields from a valve. The tool must allow appropriate attributes to be maintained for each symbol type: material, manufacturer, nominal diameter, pressure rating, and data-sheet reference.
4. Media and materials in a single source of truth
Stainless steel 1.4404, PTFE, FKM—anyone entering these manually in every data field will eventually mistype them. A central list of media and materials from which each component is selected prevents exactly that.
5. Synchronisation between the diagram and bill of materials
When you change the diagram, the bill of materials must follow immediately. Deleted components disappear, new ones appear, and tag numbers remain stable. No click on “regenerate bill of materials”, no waiting, and no outdated list in circulation.
6. Filterable views for equipment, valves, and measuring points
Procurement needs a different view from installation. The auditor, in turn, needs a different one from the process engineer. Filters by symbol type, plant section, or material make it possible to produce different lists from the same data base—without sending Excel copies around.
7. Exports that arrive usable
The bill of materials must move into the recipient’s systems without loss. CSV for ERP, Excel for procurement, PDF for acceptance documentation. With the column headings the recipient expects—not cryptic field names.
8. Versioning and history
Bills of materials change dozens of times over the course of a project. It must remain traceable who added or replaced which component and when. A history per line is not bureaucracy—it is a prerequisite for every serious acceptance process.
piblaster keeps the bill of materials live alongside the diagram. Each placed symbol creates a line, and every change to the diagram updates the bill of materials. Export as CSV, Excel, or PDF—ready for procurement, installation, and audit.
Conclusion
A bill of materials derived from the diagram is not a bonus feature. It is what turns a P&ID into an engineering document in the first place. Tools that cannot do this—and there are many—shift the work into Excel spreadsheets and thus create the error sources that every standard is intended to prevent.
