The introduction of a European truss standard

Aluminium truss, one of the most applied structural elements in temporary structures, now finally has a common European EN standard (DS/EN 17115:2018), which hopefully will be adapted in its full contexts by manufacturers; increasing comparable structural information and not least aid to an increase in safety of the entire industry. For the non-industry reader, a list of abbreviations used in this post is posted at the end.

What to expect from EN 17115 compliant truss´?

A key demand of EN 17115 is (but not limited to) the creation and maintenance of engineering documentation, including mandatory structural calculations - reducing the role of physical testing to the purpose of verification and support of calculations.

As an end-user you should at least expect to find manufacturers provide

• A technical datasheet at least including information about material specifications, sizes and dimensions of all members (main chords, bracing, end frames, etc.) and connection elements (internal tubes, couplers, bolts, pins, etc.). Provide the maximum loads for givens spans in UDL, CPL, TPL and QPL and maximum loads for givens lengths to cantilevers in UDL and EPL and not least the design resistance of the full truss and its members.
• User documentation containing vital information about at least the safe usage when suspending, supporting and loading the truss, including the correct orientation of the truss, recommended tools and electrical potential equalization. The documentation shall also include maintenance instructions of the truss system and not least provide guidance of periodical inspections and discard criteria.

How, and how often, should truss´ be inspected?

The current version of EN 17115 does not give guidance to the inspection process, leaving the manufacturer to provide guidance to the process, and the end user to interpret the demands of local legislation for minimum intervals and the inspection process. This will hopefully be sorted in a revision, while waiting for this, the approach given by the American standard ANSI E1.2-2012 Entertainment Technology — Design, Manufacture and Use of Aluminum Trusses and Towers could in conjunction with the information provided by the manufacturer, and local applicable legislation be applied in an effort to establish minimum guidelines.

As part of a general update to a suite of truss calculation sheets, I´m currently drafting an inspection report template including general guidance on the process based upon the ANSI E1.2-2012, EN 17115:2018 and other applicable standards to aid in the process of documenting initial, periodic and frequent truss inspections.

Definition of abbreviations used in this post:

UDL - Uniformly Distributed Load; CPL - Centre Point Load; TPL - Third Point Load; QPL - Quarter Point Load; EPL - End Point Load.