There are many different types of service support clips available in today’s market. When fixing either to Z-sections or C-sections, the most common types of purlin clips and clamps and their application are shown.
The maximum recommended safe working loads given in the table below are intended for guidance only. They are for roof pitches less than 12° and will be conservative for some of the more innovative or heavy duty clips available. Please refer to the clip manufacturer for advice.
Note: beware of published clip load capacities as these may be for the clip only. Unacceptable movement of the purlin flange, particularly on steep slopes, may cause slip or failure of the fixings.
An equivalent service load used for the design of the purlins may be calculated as follows:
Point loads from services = 25kg at 1.2m spacing
Purlin centres = 1.8m
Equivalent service load = 25 x 9.81 x 10-3 / 1.2 x 1.8 = 0.114kN/m2
By using a Metstrut channel fixed between purlin lines, loads can be evenly distributed as shown on below.
Using standard gauge line holes, a channel or angle trimmer can be fitted and used to carry heavier or large pieces of equipment as shown below.
An allowance should be made when selecting sections from the design load tables if services are to be hung from the purlins, either as a uniformly distributed load for a small service load, or a point load if the load is of a large magnitude. Our engineers are available to advise on purlin selection for unusual cases.
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