In order to determinate the appropriate slinging method of technical aspects need to be considered:

1. The position of the support points within the truss
A. Trusses are calculated as single spans, suspended or supported at both ends at the position of the end braces. You can attach a sling to either the upper chords or lower chords in or very close to the node points without losing strength. All truss members help to transfer the forces, which are caused by the pay loads, to the suspension/support points. Forces in diagonals are alternating, they can be subject to tension or compression, depending in aluminium truss the allowable force in tension and compression is equal. However, if overloaded to the point of failure, a diagonal loaded in tension will snap, while one in compression will buckle as the failure mechanism. Therefore if is advised to have the first diagonal under compression, because if failure occurs, the consequences are less fatal.

B. Slinging shall be applied in the node points. if slinging is applied within 10 cm from the node the full load a maximum of 2000kg for TD-Q29S,TD-Q39S-series

C. Trusses without vertical end braces must be treated with utmost care. These trusses must always be supported at a node point.

2. Stabilisation of the suspended truss
A. Trusses can rotate due to eccentric loading, e.g. hanging lamps on one side at one chord only. The truss must be prevented from rotating at all time since it is not calculated for rotated positions. A common method is to wrap a sling around all chords and thus increase friction to prevent the truss from rotating. Raising the wraps elevation increases stability and reduced horizontal stresses in truss cross section.

B. In a closed grid or a ground supp0rt, trusses can rotate much more difficult. a corner block or sleeve block prevents them from doing so. In those situations other slinging methods can be used as used as well.

C. In case of tilting trusses or truss grids. suspensions are subject to changing forces due to the shift of the point of gravity of the load. For these applications we advice to wrap all chords

3. Arrangement of diagonals
A. For trusses, such as the TRINITY 101.102. and 112series (except folding trusses), with diagonals running parallel at two opposite sides, slinging can be applied in a node at the top or bottom chords, since the node points are laterally connected by cross bracing, which bears compression forces within the truss caused by slinging.

B. For trusses with an alternating diag0nal pattern such as the TRINITY TD-Q29S.TD-Q39Sseries, a slinging method where all chords are wrapped - 1 quarter the full node to node distance - fulfils all demands. This method guarantees that the slinging is never attached between node points.

4. Position of the suspension or support in a span
A. At the end of a span, at its support points, a truss is only subject to shear forces in the main chords and normal forces the diagonals The bending moment is assumed to absent.

B. At intermediate supports of a multiple supported truss, the truss subject to bending moments as well shear forces. Suspending the truss on that position by only slinging two of the main chords (e.g. a lifting bracket), adds an additional bending moment to the main chords. Furthermore the support reaction in these intermediate points is much higher. this shall all be minimised in its possible effect. therefore we advise a slinging method which wraps chords.

with literally hundreds of possibilities to sling the trusses, and over 10 parameters to judge them on safety, it is beyond the scope of this Black Book to discuss them allin detail. the methods below are those approved and advised by TRINITY.

Slinging of truss may only be applied in - or close to - the node points
TRINITY points out that using 2 similar slinging devices for each suspension point is advised due to redundancy . In case of full loading main chords should supported

preferable support should be at the lower chords as a result of risk reduction actions taken.