General notes and installation guidance for pallet racking installation.

Rack Verticality

All uprights should be vertical and beams horizontal in accordance with the tolerances and guidelines laid down by SEMA in their guideline No 2 “Guide to erection tolerances for static racking” which states

For all pallet rack installations the out of verticality when loaded should not exceed 1:300.

Frames

Frames consist of pairs of uprights braced together, which are designed on the basis of complex rules, which govern both the strength and stability of the installation. 

Generally, manufacturers will state a maximum frame loading, which should not be exceeded, but this will be based on a specific beam and bay configuration.  The overall capacity of a frame can vary under a variety of conditions:

The vertical height of the first beam level

The vertical spacing of beam levels.  The greater the separation the lower the upright capacity

The beam size and number of levels in a bay

The number of bays in a rack length

Floor fixings

 

Thus, adjustment to, removal or additional of beams can significantly affect the load capacity of the structure and should not be undertaken without prior approval from the installer or manufacturer.  Where modifications are made, load notices must be revised to show the revised configuration and capacities.

 

Typically, increasing the clearance to the first beam level will reduce the load carrying capacity of the whole bay.  In addition, varying the beam pitch can reduce the loading capacity of the bay.

Floor fixings to pallet racking

Pallet racking should be installed on a solid stable base that provides adequate support and anchorage for the floor plate and fixings.

 

Single rows of racking should have suitable floor fixings to every foot plate (see below).

For back to back racks installed before 2010:

Where sufficient row spacers are present and a height to depth ratio does not exceed 6:1, only the perimeter uprights need be floor fixed.  See § 3.10 for further details on row spacers.

Where the height to depth ratio exceeds 6:1 but does not exceed 10:1 all uprights require floor fixings.

Where the height to depth ratio exceeds 10:1 but does not exceed 20:1 each frame should be restrained by connections to other substantial structures providing that they are capable of providing this support.  This condition will be satisfied if the rack is connected at the top to an adjacent double sided rack frame.

The 2010 SEMA guideline revises the requirement for floor fixings and now require floor fixings to all footplates.  This applies to racks installed from 2010 onward but is not retrospective.

Floor fixings should be designed to carry a shear force of 5Kn and a tensile force of 3Kn.  Providing that the fixings satisfy these criteria then they would satisfy the SEMA Code.

These fixings should be applied through the base plate of the upright and be capable of resisting the anticipated horizontal shear and vertical uplift forces.

Floor fixings to shelving.

Where materials handling equipment is present or there are other forces that may overturn the structure suitable fixings are required (SEMA COP Low Rise Shelving § 9)

The frequency of floor fixing depends upon the height to depth ratio of the shelving:

With a height to depth ratio of less than 4:1 the shelving can be free standing in the absence of materials handling equipment. 

With a height to depth ratio of between 4:1 and 6:1, only the perimeter uprights need be fixed by a bolt through the base plate. 

 

Floor fixings should be designed to carry a shear force of 3Kn and a tensile force of 2Kn.  Providing that the fixing satisfy these criteria then they would satisfy the SEMA Code.

 

These fixings should be applied through the base plate of the upright and be capable of resisting the anticipated horizontal shear and vertical uplift forces.

 

Where the height to depth ratio exceeds 6:1 additional restraints are required to other substantial structures providing that they are capable of providing this support.

Racking Protection - Back to back row spacers

SEMA guidelines & HSE (HSG76) recommend fitting row spacers to all back to back racks as they add greatly to the security and stability of the installation and provide greater stability and protection in the event of a rack collapse.

 

They should be fitted adjacent to the frame nodes starting at the first horizontal brace and thereafter at intervals not exceeding 2.5m with a final brace adjacent to the top node.

 

Racks installed from 2010 onward should comply with the updated 2010 SEMA guidelines § 7.17 with row spacers fitted at the top bracing node and at not more than every second node or 3.6m intervals adjacent to nodes (max 225mm from nodes).

 

This applies to racks installed from 2010 onward but is not retrospective.

Racking Inspection Services

1 Orc​hard Lane

Ironbridge, Telford, 

Shropshire, TF8 7PB

0560 370 5666

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