Guide · Trussing
Truss loads & D8 basics
How much does truss really carry? A short intro to loads, spans and hoist classes — enough to specify correctly and know when to involve an engineer.
1. Load types
- UDL (uniformly distributed) — lighting spread along the beam.
- Point load — a line array, LED wall or hoist at one point; the same truss carries far less than under UDL.
2. Span and deflection
Capacity drops sharply with span: a beam that carries e.g. 500 kg UDL at 6 m carries only a fraction at 12 m. Always read the manufacturer tables (in our range: GUIL TQN290, TQN400XL…) for the exact span and load type, and keep deflection within L/200.
3. What D8 / D8+ / C1 mean
- D8 — standard electric chain hoist; loads must not hang above people without secondary safety.
- D8+ — doubled safety factor and brakes; may hold loads above people (no moving during the show).
- C1 — stage machinery for moving loads above people during the performance (strictest requirements).
In practice: for most events a D8+ hoist with the right safety factor and a secondary steel is sufficient — ask for certificates with every hoist.
4. When to call an engineer
- Spans over 10 m or cantilevers
- Roof systems and outdoor events (wind!)
- Loads suspended above the audience
- Anything outside the manufacturer tables
Build your portal or roof in 3D — the configurator prints elements and corners for your enquiry.