Facility Managers are contacting material handling dealers and purchasing mezzanines for projects when in fact they should be purchasing work platforms. What is the difference you may ask?
Mezzanines are elevated steel structures typically built between two main stories of a building. They are primarily used for storage of goods and have personnel walking on top of them frequently to access the product. They support pallet racking, industrial shelving, cantilever racks, and generally any type of racking system in addition to general floor storage. They may also act as a second floor office if modular offices are installed on them. Typically, they have a pound per square foot requirement of 125 PSF. As such, mezzanines have certain codes designed just for them.
Work platforms are typically built to hold equipment in a manufacturing environment. This equipment is typically above the ground level. Some examples of these are broaching machine platforms, conveyor platforms, etc. Typically a person would access this platform for repair or cleaning purposes only. They are not accessed on a daily basis and their main purpose is to support equipment above ground level.
While mezzanines have specific minimum height clearances and stair width/length regulations, work platforms have clear exemptions from most of these. For example, a mezzanine requires 7 feet 6 inches clear underneath if people are working under it, and the same above it for people walking on it. Also, when installing any type of plastic shelving, gondola shelving or steel shelving, most fire marshals require a 12 inch chase between every 48 inch deep shelving unit.
In the case of a platform being used to support equipment, vessels, etc., the clear height above the equipment may be such that it clears the equipment and has sufficient clearance to accommodate repair or maintenance activities. There is no minimum requirement. The same applies to the clear height above the platform as long as the equipment has sufficient clearance to accommodate repair or maintenance activities. Platforms need not be 125 PSF if a lesser amount will suffice. (Less PSF, less steel, less cost).
One stairway is needed for platforms unless the common path of egress exceeds 75 feet, then a second one is needed. However, you can use spiral stairway, alternating tread stairways or an industrial ladder to achieve egress. Also, stairways for platforms need not be designed for handicap accessibility. When designing and building mezzanines for general storage, International Building Code (IBC) 2006 requires continuous handrails, extended handrails and a 3-rail handrail/kickplate system. Thus, typically it is less expensive to purchase a work platform than a mezzanine of the same size.
There are other smaller differences, but the bottom line is this: define the use of the space you plan on adding to your building, then work with a mezzanine professional to determine the right type of mezzanine or work platform. This would include the weight capacities, footings required (if needed), stairways, work surfaces, access gates and railings.