The core idea
Tissue, vane meters and balancing instruments answer different airflow questions and should not be treated as interchangeable.
How the mechanism works
Velocity at one point, total volume flow and pressure relationships describe different aspects of ventilation.
When it becomes relevant
Typical trigger: Fan operation, door changes or commissioning.
Evidence that supports this interpretation
- Method matches the question
- Multiple points show a consistent pattern
- System state is recorded
Evidence that weakens it
- A point velocity is used as total flow
- Grille geometry is ignored
- Fans change during testing
What this concept cannot prove alone
A single observation, image or meter reading cannot confirm the complete failure pathway. Use this concept to form better questions, compare alternatives and decide which safe observation would be most informative next.
Safety and professional boundary
Combustion and pressure safety must be addressed before altering ventilation flows.
Primary references for this topic family
These references ground the general building-science or safety context. They do not diagnose a specific house, replace local requirements or certify a repair.
