Prolyte Campus blog: Best practices - Truss Inspection

Speaking about best practices in rigging it’s best to start at the basics.

One of the basics is to work with checked and proper materials. After all, you send your car to a regular check up – so why not your truss?

Truss is an important element in a great number of show designs, so we better make sure that it remains in the condition it originally had. Furthermore, truss is a far more complex element than many people realise. It is composed of individual types of components, like chords, connection parts, diagonals, vertical and horizontal braces, internal diagonals etc.

Trusses can be part of a (temporary) building structure or – more critical – a (temporary) lifting structure.  Obviously, if one of the modules is damaged or faulty, the risk of failure becomes greater if such a module is incorporated in the structure.

The manufacturer is responsible to avoid faulty modules to leave the plant, normally we can rely on the fact that manufacturers won’t allow that to happen. But manufactures can make mistakes, modules might leave the plant undetected. Users should therefore do a check on all new incoming goods, as well as trusses that are already in use and go out on a project.

So previous to each use a visual check is to be made by the user, making sure there is no visual defect and the specific item can safely handle the amount of load it will meet in that position. On top of all that a periodic inspection is to be made on a specific list of parts or details in accordance to the specs of the manufacturer (e.g. Prolyte BlackBook, chapter 18). The results of such a periodic inspection shall be documented in a log.

Prolyte BlackBook, chapter 18


Best practices - Truss Inspection

Some examples of details and criteria

Main Chords:

  • No (visual) cracks anywhere along the round tube, in or near the weld area
  • No bending out of the axis by more than 1 degree
  • No holes except to made by the manufacturer for connection system purposes
  • Dents or other types of distortion of the cross section shall be less than 10% of change (dents in a 50mm chord shall be no deeper than 5mm).

Bracing:

  • No (visual) cracks anywhere along the round tube, in or near the weld area
  • No bending out of the axis by more than 5 degrees
  • No holes except to made by the manufacturer for connection system purposes
  • Dents shall be of a depth of less than 10% of the diameter.

Connection parts:

  • No dents, burrs, cracks or deformation. Parts need to be clean and without apparent corrosion
  • Bolts shall be of the size and tensile strength as specified by the manufacturer
  • Spigot pins shall be manufacturer originals and free of burrs etc.

So, for all of you truss owners out there, please add this to your working practice and make the entertainment business a safe place to work! I’m sure there is some work to do…

For further reading: Prolyte BlackBook, chapter 18.

This training has had a major impact. The training was very good and highly important, because people in our region do not have a sufficient basic knowledge of safety, rigging etc

Vinko Perinic Perinic Sistemi, Croatia