insPIRe® U panel fastening — PM1 washer

Junction function

Concealed insPIRe® U + PM1 fastening = concealed fastening system. The steel PM1 washer transfers the load from the fastener to the joint geometry.

Vs visible fastening (S):

• Fewer fasteners (2 vs 3 across the width) — load distributed via PM1.
• PM1 = AISI 304 stainless steel or carbon steel with zinc coating >80 μm.
• PM1 works in shear (wind pressure) + compression.

Critical installation aspects

• Min. 2 fasteners per panel — catalogue minimum for heights up to 5 m + rail spacing ≤4 m.
• PM1 position along the joint axis, centred along its length between rails.
• Tightening torque 6-10 Nm — less than for S (PM1 distributes the load).
• PES tape continuation as in S — between the panel and the rail.

Documentation

Technical Catalogue insPIRe S/U + GS PIR D (Gór-Stal 2025), page 49 — U panel fastening + PM1. Scale 1:5.

Components in this junction