Safety Tips: Mezzanine lift safety

To maximize the use of overhead space, facilities often install a second-level mezzanine platform for a more efficient cube. Mezzanine scissor lifts offer a mechanical means to transport goods and personnel up to that second level. Like all equipment, it’s critical to follow guidelines both for configuration and for regular inspections of the lifts to ensure safe operation and protection of workers.

The safest mezzanine scissor lifts include the following elements:
Platform guarding: The platform should be equipped with bevel toe guards and 42-inch high guardrails with mid rails and 4-inch toe plates. Electrically interlocked gates should prevent platform movement unless the gates are closed.

Operation switches: Proximity or limit switches should function for each level. For lifts that transport riders (as well as materials), movement control must be a constant pressure pushbutton. An emergency down valve on the power unit lowers the lift if a power failure occurs.

Smooth fascia: To eliminate shear points, the entire surface of the mezzanine—adjacent to the lift from ground level to the top of the guardrail on the upper level—must be equipped with a smooth face (such as wallboard, polycarbonate sheets, fine mesh, or interlocked doors and windows).

Enclosure system: Sides not adjacent to the mezzanine must be enclosed from ground to the height of the topmost guardrail when the lift is fully raised. The mezzanine guardrail and the enclosure access gates must be electrically interlocked to prevent movement when gates or doors are opened, and mechanically locked so as to not open unless the lift platform is present. Maximum gap between the platform and the mezzanine should be 1 inch, and the gap between the platform and other three enclosure sides should be 3 to 4 inches.

ANSI MH29.1 is the governing code for industrial scissor lifts. A checklist of inspection items developed in alignment with these standards is below.

Inspection checklist for industrial scissors lifts for mezzanines
For use with inspection of both:
• Rider mezzanine lifts
• Non-rider (material only) mezzanine lifts

Prior to beginning inspection, refer to the American National Standard ANSI MH29.1 Safety Requirements for Industrial Scissor Lifts; items on this checklist meet or exceed this standard.
Areas for Inspection
1. General
A. The entire base frame of the scissors lift is sitting on a flat and level surface, shimmed and grouted if necessary for continuous support

2. Controls
A. Shall be clearly marked as to direction and function
B. Shall be protected from inadvertent operation
C. If pushbutton is momentary contact type (touch and release to start), then the lift shall be clearly marked “No riders allowed”
D. If momentary contact pushbutton, then it shall have an emergency stop button
E. Controls shall prevent lift movement when any gate is open
F. For rider lifts the control must be constant pressure style and located on lift platform

3. System protection
A. Hydraulic systems shall be equipped with flow controls or velocity fuses for hose failure protection
B. If electromechanically actuated, the design shall prevent movement if there is a power failure

4. Platform guarding (shear point protection)
A. Automatic operations with momentary contact controls shall be guarded with skirts, enclosures or other means of personnel
protection
B. Pit mounted installations shall have one or more of the following:
a) 8-inch bevel toe guards
b) Solid skirts
c) Suspended indicator bar
d) Electronic toe sensor
e) Solid or mesh enclosure 8 feet high, or full height of platform rise plus top of guardrail, whichever is less
C. Above floor installations must have one of the following:
a) 4-inch bevel toe guards
b) 3-inch vertical toe clearance
c) Electronic toe sensor
D. For all installations with more than 5.5 feet between the landing and the bottom edge of the fully raised platform, the following items are required:
a) Upper landings shall be equipped with enclosures and an automatic landing gate or a landing gate with interlock that prevents opening the gate unless the lift is present
b) The entire surface of the mezzanine adjacent to the lift from ground level to top of the mezzanine guardrail shall be equipped with a smooth surface to eliminate shear points
c) Sides used for loading at lower landings shall be equipped with an automatic landing gate or a landing gate with interlock. These gates shall be 84 inches, or the full height of the lift, whichever is less
d) Sides at lower landings not used for loading shall be provided with solid or mesh enclosures 8 feet high, or to the full height of the lift rise plus guardrail, whichever is less
e) Gates and enclosures will be positioned no more than 6 inches from the lift platform
f) Mesh for enclosures shall reject a 2-inch ball and a smooth surface shall be a solid surface or a flattened mesh that will reject a 0.325-inch ball

5. Hinged bridges shall conform to the following:
A. At raised position, slant bridge back toward platform approximately 20 degrees or lie back flat on the platform or provide chain, latch or other means of security
B. At lowered position, bridge angle can not hang more than 45 degrees below horizontal unless shear risk is eliminated
C. Bridge purchase on truck beds shall be at least 4 inches
D. Split bridge sections shall have 0.75 to 1-inch clearance between sections

6. Guardrail system
A. All rider lifts must have guardrails on all sides with interlocked access gates that prevent lift movement when a gate is open
B. Non-rider lifts shall have guardrails and chains or gates across load access sides
C. Guardrails shall be 42 inches high ±3 inches with mid-rail and 4-inch toe board

7. Maintenance device
A. A securely attached maintenance device to hold the empty lift open for maintenance is present

8. Markings
A. Manufacturer’s nameplate with name of manufacturer, model number serial number, lifting capacity and edge or axle load ratings is present
B. Warning labels in compliance with ANSI Z535.4

9. There shall be an operating/maintenance manual that contains:
A. Special warnings, cautions or restrictions for safe operations
B. Manufacturer’s name and contact information
C. Installation and start up information
D. Operating instructions
E. Maintenance recommendations and instructions
F. Replacement parts information
G. Owner’s/user’s responsibilities clearly defined

10. Capacity verification
A. The lift capacity shall be clearly visible to operators
B. Maximum system pressure with lift fully raised and cylinders fully extended against internal cylinder stops (may require overriding electrical limits) is ±150 psi of pressure labeled on the hydraulic pump and/or listed in owner’s manual
-OR-
C. From fully lowered position, lift is demonstrated to lift rated capacity

SOURCE: Advance Lifts Inc. (800-843-3625, http://www.advancelifts.com). A copy of this checklist (“AL-1020 REV1: Inspection Checklist for Industrial Scissors Lifts At Mezzanines”) may be obtained at: advancelifts.com/SiteFiles/PDFs/WhitePaper/MezzChecklist.pdf