Incident pressure
The pressure wave propagating through free air before a major obstruction stops or redirects it. Think of it as the incoming wave condition at a location.
Reflected pressure
When the wave strikes a substantial surface, the flow is decelerated and the pressure at that surface can be amplified. The amplification depends on the wave intensity and the angle at which it meets the surface.
Why architecture cares
A wall, roof, opening or other surface does not necessarily experience the same pressure condition as the unobstructed air nearby. Orientation and geometry influence how a pressure wave meets surfaces, while openings and structural systems introduce further response questions. Those are specialist design topics; the portfolio point is simply that terminology and interfaces matter.
Important Finland note
Finnish Decree 408/2011 specifies pressure-wave design loads of 100 kPa for S1 reinforced-concrete shelters, 200 kPa for S2 and 300 kPa for rock shelters. The cited clause itself does not label those statutory loads as “incident” or “reflected”. This page therefore does not equate them with either term.
Technical-commercial takeaway
When a requirement, quotation or product document contains a pressure value, the reference condition and source should be clear. A bare number can be misleading if different documents use different pressure conventions.