Our first question this month asks for information regarding the correct installation of Splices and our second enquires about the use of floor bolts.
Splicing Query
Q. I checked the technical documentation given with our splice pack and there is no mention of max/min gap for splices
Do we just mount them as close as possible to each other as long as the fixing holes are lined up?
A. The SEMA recommendations with respect to splicing are given in clause 11.7 of the SEMA Code of Practice for the design of adjustable pallet racking as given below.
Upright Splices
In any type of compression joint, where the ends of the members are square cut for bearing over the whole of the cut area, they shall be spliced to hold the connected members accurately in place and alignment and to resist any tension where bending is present.
Where such members are not in bearing over the whole of the cut area the joint shall be designed to transmit all the forces and moments to which the joint is subjected. It is not recommended to splice an upright below the lowest beam level on the front face of a rack, unless the splice is designed by the manufacturer to have a strength and stiffness at least equal to the continuous upright member.”
Some splices will have a gap between the uprights prior to being loaded for the first time and, in the absence of any specific information from the Designer, a SEMA Approved Rack Inspector (SARI) will normally apply a check limit of 1.5mm.
It is, of course, quite possible that the Designer of this particular product might have designed the splice to function with a gap between the uprights and you would need to contact the Designer for confirmation of their particular design requirements. If this splice is simply a replacement of an existing splice, then the structural design of the rack should already have been checked when the original splice was fitted. Nevertheless, it is always wise to contact your supplier to make sure that the position of the splice does not alter the structural behaviour of the racking and, if this splice is not a replacement of an existing splice, then contacting the supplier is essential so that a design check can be done.
Securing Bolts
Q. I was wondering if you could answer a question I have. How many bolts are needed to secure racking to the floor?
A. According to the current SEMA code of practice for the design of adjustable pallet racking all uprights in racking for use with mechanical handling equipment shall be floor fixed. Each upright to floor connection should be able to transfer a minimum un-factored force of 3kN tension and 5kN shear; this can normally be achieved by a single bolt and, therefore, the current code will typically require a single floor fixing per baseplate.
Prior to 2008 the SEMA code had slightly different provisions and, under certain conditions, some baseplates did not need to be fixed to the floor; this was known as “perimeter fixing”. The conditions that allowed perimeter fixing to be done are a little complex and are given in the SEMA code of practice for the design of adjustable pallet racking (1992). Perimeter fixing could only be done for double-entry racks that had a height to width ratio (H:W) of less than 6:1 and when the frames were tied together with sufficient run-spacers.
The requirement for the run spacers joining the frames together was that they should be at not more than 2.5m centres vertically. If the runs spacers satisfied this criterion then the ‘depth’ could be taken as the overall depth of the two frames plus the space between the two frames. The ‘height’ is height to the top of the top-most beam. So, if the double entry rack satisfied these criteria and had H:W less than 6:1 then only the uprights on the perimeter of the rack needed to be floor fixed and, again, the minimum requirement was that the upright to floor connection should be able to transfer a minimum un-factored force of 3kN tension and 5kN shear. Putting this another way the interior baseplates did not necessarily need to be fixed.
A further slight complication is that the recommendations given in the SEMA codes are not retrospective i.e. if a rack was installed with perimeter fixing according to the provisions of the “old” code then there is no requirement to bring that “old” rack into line with the provisions of the “new” code.
Of course, if the rack design identifies that the forces at the baseplate are greater than the minima specified above then more floor anchors may be required and these will be specified by the rack designer; this often happens if the racks are installed outside or if the rack supports cranes, live storage etc.
Drive-In racking has its own rules and will normally have at least two anchors per baseplate.
Cantilever racking has its own rules and requires that the floor fixings must be designed to adequately transfer the forces from the base to the concrete slab; this must include a check on overturning effects. As cantilever racking can sometimes be installed outside the applied forces can be significant leading to more and bigger floor fixings.
SEMA Rack Safety Awareness Inspection Courses
SEMA runs a one-day safety course on Rack Safety Awareness and Inspection. These courses are aimed at end users, giving an in-depth look at the need for inspections, how to conduct an assessment and what actions to take when this is completed. These courses are held at the SEMA headquarters in Burntwood, Staffordshire, but arrangements can be made to hold them at the delegates’ premises.
SEMA Approved Rack Inspectors Qualification
This qualification is aimed at professionals who conduct rack surveys as an integral and significant part of their duties. It involves delegates in undertaking an in-depth SEMA Course, together with an examination and practical assessment. CPD will be an important part of the qualification, demonstrating to end users that SEMA Approved Inspectors maintain a high professional standard.
SEMA Publications
SEMA has 26 publications in stock – Codes of Practice, ‘Guides’ and European documents – all of which are available to purchase online. For further information on these documents contact SEMA or visit our website, www.sema.org.uk.
SEMA
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