General guidance for assessment of damage and other issues affecting pallet racking

 

1.1         Repairs

SEMA guidelines are that:

  • Heating, welding, general component repair or modification is not acceptable.

  • Straightening damaged structural components is not acceptable.

  • Damaged components cannot be repaired and must always be replaced

    • It is sometimes possible to straighten twisted uprights where no damage is present but this should only be undertaken by a qualified competent person

  • Only the correct manufacturers warranted parts should be fitted.

  • Different component makes should never be mixed on the same system

  • Repairs should only be undertaken by competent persons such as SEIRS registered installers as required by Health & Safety & SEMA guidelines. 

    • SEMA can provide details of approved installers in your area.  See § 3.13.2.

  • Repairs or installation undertaken internally should again only be undertaken by competent persons. 

    • To have your staff trained contact SEMA for details of SEIRS training courses.  See § 3.13.2.

 

1.2         Damage to adjustable beam pallet racking uprights and bracing members
  • Deviation is measured, based on a 1,000mm straight edge placed on the concave surface of the damaged member, such that it is as near to the centre of damage as possible.

  • For an upright bent in the direction of the rack beam (i.e. parallel to the aisle) the maximum gap should not exceed 5mm

  • For an upright bent in the plane of the frame, (i.e. at right angles to the aisle) the maximum gap should not exceed 3mm

  • An upright bent in both directions should be measured separately in each direction as above.

  • For bracing members bent in either plane, the gap should not exceed 10mm.

  • These guidelines only apply to overall bends. 

  • Members subject to significant dents, tears, buckles, and splits should be replaced.

 

 

 

 

 

 
 
1.3         Damage to beams or beam connectors on adjustable beam pallet racking
 

Beams will deflect naturally under normal loading conditions up to a maximum deflection of Span/200.  This deflection should almost disappear once the beams are offloaded and should not be confused with permanent deformation caused by overloading or impact damage

 

 

  • Residual vertical deformation when the beam is unloaded should not exceed span/1000 of the normal deflection under working load

  • Lateral deflection should not exceed 40% of the normal vertical deflection under working load

  • Residual lateral deformation when the beam is unloaded should not exceed span/500

  • Beam end connectors which show any clearly visible deformation should be unloaded and expert advice sought from the equipment supplier

  • Welded connections between the beam section and the beam end connector should show no signs of cracking

  • Physical alterations to beams are not permitted

  • Where any damage is noted seek immediate advice and if in doubt, offload immediately

  • Beams are designed for a UDL (uniform distributed load) and uneven or point loading should be avoided

Notes on above:

  • If any beams are bent vertically downward when loaded by more than the beam span divided by 200, the beams should be offloaded and the pallet weights checked.

    • E.g.  with a beam span of 2,700mm the bend when loaded should not exceed 13.5mm.

  • When offloaded the bending should disappear, if not DO NOT RELOAD.

    1. Damage to shelves

  • The deflection of shelf edges at working load shall not exceed 1000L/C where ‘L’ is the length of the shelf in metres and where C=167 for spans greater than 2.175 metres.  For spans less that 2.175 metres C=40(2+L).

  • If any shelf edges are bent vertically downward when loaded by more than these  measure they should be offloaded and the shelf loading checked.

  • When offloaded the bending should disappear, if not DO NOT RELOAD.

 

1.5         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 rack installations the out of verticality when loaded should not exceed 1/300.

 

1.6         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.

 

1.7         Floor fixings to pallet racking

SEMA guidelines:

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

  • For double entry racks with sufficient row spacers and a height to depth ratio of less than 6:1, only the perimeter uprights need be floor fixed.  See § 3.9 for further details on row spacers.

    • 2010 cop guidelines are for floor fixings to all footplates.

  • Single entry racks should have suitable floor fixings to every foot plate.

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

  • Floor fixings should be designed to carry a shear force of 5Kn and a tensile force of 3Kn.  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 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.

 

1.8         Floor fixings to shelving.  

SEMA guidelines:

  • The frequency of floor fixing depends upon the height to depth ratio of the shelving with a height to depth ratio of less then 4:1 the shelving can be free standing in the absence of materials handling equipment. 

  • Where materials handling equipment is present suitable fixings are required.

  • 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.

 

1.9         Back to back row spacers
  • SEMA guidelines 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 onwards should comply with the updated 2010 SEMA guidelines 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).

 

1.10     Cantilever racking
  • Column deflection.  The maximum allowable column deflection under full working load is H/150 up to 5m and H/200 for columns over 10m where H=the total column height from ground as shown in the following diagram.  Lengths in between may be interpolated.

  • Arm deflection.  The maximum allowable deflection is L/180 where L=the arm length as shown in the following diagram.

  • Under full working load the arm should not deflect below the horizontal.

 

Cantilever racking is designed for uniformly distributed loads, and the same applies to load overhang as in the following diagram:

 

 

 

1.11     Display of Information.

The supplier should provide Safe Load Notices to A3 landscape size.  They should be displayed prominently throughout the warehouse.

 

Adjustable beam pallet racking and shelving notices should display:

i                 Date supplied and contract reference

ii               Supplier

iii             Maximum permissible unit load or loads per level

iv              Maximum bay load

v                Number of levels per bay

vi              Height to first beam level

vii            Beam pitch thereafter (beam to beam dimension)

viii          Required safety information

 

 

Drive in racking notices should display:

i                 Date supplied and contract reference

ii               Supplier

iii             Maximum permissible unit load per location

iv              Maximum lane load

v                Height to first beam level

vi              Beam pitch thereafter (beam to beam dimension)

vii            Pallet width and depth

viii          Load width

ix              Required safety information

 

 

Cantilever racking notices should display:

i                 Date supplied and contract reference

ii               Supplier

iii             Max load per arm

iv              Max load per column side

v                Height to first beam level

vi              Arm pitch thereafter (beam to beam dimension)

vii            Max height to top arm

viii          Arm length

ix              Required safety information

 

 

Gravity live and push back racking notices should display:

i                 Date supplied and contract reference

ii               Supplier

iii             Maximum permissible unit load or loads per level

iv              Minimum pallet load

v                Maximum bay load

vi              Height to first beam level

vii            Beam pitch thereafter (beam to beam dimension)

viii          Pallet width and depth

ix              Required safety information

 

SEMA compliant notices are available from the equipment installers or via the web.  Please specify that the updated SEMA notice format is required.  Full details are available directly from SEMA. 

 

 

 

1.12     Pallet, load, and upright clearances

Beam height

All dimensions in mm

a

pallet/upright

b

pallet/pallet

c

lift off

Up to 3,000

75

75

75

3,000 – 6,000

75

75

100

6,000 – 9,000

100*

100*

125*

9,000 – 12,000

100*

100*

150*

* These dimensions may be reduced in certain circumstances, such as where man aloft trucks are employed

 

 

 
 
1.12.1    Standard adjustable beam pallet racking

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.12.2    Drive in racking
i                 Clearances

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ii               Loading & unloading sequence

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.13     Advisory bodies

1.13.1    SEMA is the Storage Equipment Manufacturers Association and are an invaluable source of help and advice on storage related matters.  They can also advise on suitably accredited installers in your area.  See following note on SEIRS installers.

SEMA

6th Floor

The National Metalforming Centre

47 Birmingham Road

West Bromwich B70 6PY

Tel: 0121 601 6350

www.sema.org.uk

 

1.13.2    SEIRS is the Storage Equipment Installers Registration Scheme, an initiative run by SEMA.  You should ensure that all storage equipment is installed and maintained by a SEIRS registered installer.  On successful completion of a SEIRS Category “A” safety training course, an individual installer is awarded a SEIRS ID Card.  This is normally valid for a period of three years and demonstrates that the installer has been trained in safe and best practice.  Contact details as above for SEMA.  Insisting on a SEIRS registered installer ensures:

  • Installation by professionals

  • A means of verifying qualifications.

  • Adherence to SEMA Guidelines and Codes of practice.

i                 SEMA can provide details of accredited installers in your area.

ii               Where you intend to undertake maintenance in house you should contact SEMA for details of SEIRS training courses and eligibility requirements.

 

1.13.3    HSE

Infoline is HSE's public enquiry contact centre.  Infoline provides access to workplace health and safety information, guidance and expert advice.

0845 345 0055

www.hse.gov.uk

 

1.13.4    Useful publications:

i                 “Warehousing and Storage - A guide to health and safety” (HSG76) an HSE publication.

ii               “A user’s guide to pallet racking Safety.  Guideline no 2”, a CIOLT publication (Chartered Institute of Logistics & Transport)

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