ANSI MH 16.1-2012 Related Excerpts
The recognized expert resource in the United States regarding pallet racking is the Rack Manufacturer’s Institute (RMI). Mac Rak Incorporated is a proud Associate Member of this prestigious organization. RMI represents suppliers of Industrial Steel Storage Racks and Related Structural Systems. RMI’s main engineering document ANSI MH16.1: 2012 Specification for the design, testing, and utilization of Industrial Steel Storage Racks addresses the topic of pallet rack repair and general safe pallet rack operations. All following RMI applicable excerpts and reference materials have been reproduced with expressed written permission of RMI.
Please Note: The use of ANSI MH16.1: 2012 is permissive, and not mandatory. The RMI has no legal authority to require or enforce compliance with the Specification. This advisory Specification provides technical guidelines to the user. Following the Specification does not assure compliance with applicable federal, state, or local regulations and codes. This Specification is not binding on any person and does not have the effect of law.
1.4 INTEGRITY OF RACK INSTALLATION
1.4.1 Owner Maintenance
The owner shall maintain the structural integrity of the installed rack system by assuring proper operational, housekeeping, and maintenance procedures including but not limited to:
Regularly inspect for damage. If the damage is found, immediately isolate the affected area. Have a storage rack design professional evaluate the damage, and unload, replace or repair if directed by the professional, any damaged columns, beams, or other structural components to restore the system to at least its original design capacity.
Require all pallets to be maintained in good safe operating condition.
Ensure that pallets are properly placed onto pallet load support members in a properly stacked and stable position.
Ensure that all goods stored on each pallet be properly stacked and stable.
Prohibit double-stacking on any pallet position, including the top-most position unless the rack system is specifically designed for such loading.
Ensure that the racks are not modified or rearranged in a manner, not within the original design configurations per 1.4.4 or as might invalidate the plaque information per 1.4.2.
1.4.2 Plaque: The owner is responsible for displaying in one or more conspicuous locations a permanent plaque (s). Each plaque shall have an area of not less than 50 square inches. Plaques shall show in clear, legible print (a) the maximum permissible unit load and/or maximum uniformly distributed load per level, (b) the average unit load (Average, see Section 2.6.2) if applicable and (c) maximum total load per bay. The unit load is usually a single pallet or container and its contents that is mechanically transported. Storage levels having multiple stacking of unit loads shall be so identified. It is the responsibility of the owner to ensure that the rack system is not altered in a manner that the plaque information is invalidated.
1.4.3 Conformance: All rack installations produced in conformity with this Specification shall be so identified by a plaque having the same characteristics as specified in Section 1.4.2. The same plaque may be used to show permissible unit loads.
1.4.5 Multiple Configurations: If a pallet rack or stacker rack system is designed for more than one shelf configuration or profile the drawings (Section 1.4.4) are to include either (a) all the permissible configurations or (b) limitations as to the maximum number of shelves, the maximum distance between shelves and the maximum distance from the floor to the bottom shelf. This information is best furnished in table form on the drawings. A notice is to be included in the conspicuous text on the drawings stating that deviations from the limitations must be evaluated by a storage rack design professional or the deviation may impair the safety of the rack installation. American National Standard ANSI MH16.1: 2012 (a revision of MH16.1: 2008) Specification for the Design, Testing Utilization of Industrial Steel Storage Racks V12a 3 If a change is approved, it shall be added as a permissible configuration on the drawings. 1.4.6
1.4.7 Column Base Plates and Anchors: The bottom of all columns shall be furnished with column base plates, as specified in Section 7.1. All rack columns shall be anchored to the floor with anchor bolts, which shall be designed in accordance with Section 7.3, to resist all applicable forces as described in Section 2.1 or Section 2.2
1.4.8 Small Installations: For installations not exceeding 12 feet (3.65 m) in height to the top shelf, covering floor area less than 3,000 square feet (278.7 m2) (not including aisles), having a unit load not exceeding 2,500 pounds (1134 kg), and having no multiple stacking on the top shelf, the provisions given in Sections 1.4.4 and 1.4.5 may be waived.
1.4.9 Rack Damage: Upon any visible damage, the pertinent portions of the rack shall be immediately isolated by the user until the damaged portions evaluated by a storage rack design professional. Before allowing the rack to be placed back into service the design professional must certify that the rack system and/or the repaired components have been restored to at least their original design capacity.
1.4.11 Out-of-plumb and Out-of-straight Limits: Out-of-plumb Limit The maximum top-to-bottom out-of-plumb ratio for a loaded rack column is 1/240 (for example 1/2 inches per 10 feet (12.5 mm per 3 m) of height). American National Standard ANSI MH16.1: 2012 (a revision of MH16.1: 2008) Specification for the Design, Testing and Utilization of Industrial Steel Storage Racks V12a 4 Columns whose out-of-plumb ratio exceeds this limit should be unloaded and replumbed. Any damaged parts must be repaired or replaced.
18.104.22.168 Out-of-straight Limit: The maximum out-of-straight ratio for a loaded rack column is 1/240 (0.05 inches per foot or 1/2 inches per 10 feet (12.5 mm per 3 m). Columns whose out-of-plumb ratio exceeds this limit should be unloaded and replumbed. Any damaged parts must be repaired or replaced.
2.6 Earthquake Loads: (see specification)
5.4.2 Beam Locking Device: Except for movable-shelf racks, beams subject to machine loading shall have connection locking devices (or bolts) capable of resisting an upward force of 1,000 pounds (453.6 kg) per connection without failure or disengagement.
5.6 Welded-Wire Rack Decking: Where Welded-Wire Rack Decking is utilized to support the load, it shall be designed in accordance with ANSI MH26.2 .
7.1.4 Shims: Shims may be used under the base plate to maintain the plumbness and/or levelness of the storage rack. The shims shall be made of a material that meets or exceeds the design bearing strength (LRFD) or allowable bearing strength (ASD) of the floor. The shim size and location under the base plate shall be equal to or greater than the required base plate size and location. In no case shall the total thickness of a shim stack under a base plate exceed six times the diameter of the largest anchor bolt used in that base. Shims stacks having a total thickness greater than two and less than or equal to six times the anchor bolt diameter under bases with only one anchor bolt shall be interlocked or welded together in a fashion that is capable of transferring all the shear forces at the base. Shims stacks having a total thickness of less than or equal to two times the anchor bolt diameter need not be interlocked or welded together. Bending in the anchor associated with shims or grout under the base plate shall be taken into account in the design of anchor bolts.
7.3 Anchor Bolts: Anchor Bolt Design The anchor bolt design shall be in accordance with the provisions of ACI 318 Appendix D. The redundancy factor in the load combinations in Section 2.1 and 2.2 shall be 1.0. 7.3.2 Periodic Inspection of Anchor Bolt Installation When periodic inspection of the anchor bolt installation is required, the owner, or the owner’s designated representative, shall retain a qualified inspector to conduct the inspection. Only the anchors in the main force-resisting system need to be inspected. See the commentary for a broader discussion of this topic.
8.1 Overturning Row Spacers: The height-to-depth ratio of a storage rack shall not exceed 6 to 1 measured to the top loaded shelf level unless the rack is anchored or braced externally to resist all forces. The height is measured from the floor to the top loaded shelf level and the depth from face to face of the upright column. Storage rack, which is loaded and unloaded by powered handling equipment, that exceeds the 6 to 1 ratio defined above, shall also be designed to resist a 350-pound (159 kg) side force applied to any single frame at the top loaded shelf level in a direction perpendicular to the aisle. For LRFD design method, the load factor applied to this force shall be 1.6. This force is to be applied to an empty frame and divided into as many frames as are interconnected in the direction of the force. Anchors and base plates will be designed to resist uplift forces from this force when applied to an empty frame. Frame columns need not be designed for the additional axial load from this force. Unless it can be shown to be unnecessary because of such factors as soil, slab and frame stiffness, single rows of rack exceeding a height-to-depth ratio of 8 to 1 must be tied externally to the building or cross-aisle to another rack. Stabilizing a single rack with an a height-to-depth ratio over 8 to 1 with anchoring alone is not recommended unless designed and certified by an engineer.
8.4.1 Posting of Design Loads: The design loads for the floor areas of the rack supported platforms and pick module walkways shall be shown on the rack configuration and load application drawings. These design loads shall also be displayed in one or more conspicuous locations within the structure, such as at the top of the access stairways