Firstly, let me outline exactly what a 'mezzanine' floor is. The word mezzanine derives from the Italian word mezzano, meaning simply 'middle'. With this in mind the mezzanine acts as a middle or extra floor. Although architects use this term to explain additional levels in domestic buildings, a 'mezzanine', for the purpose of this topic, relates to additional floors in commercial or industrial applications.
When looking at an area to add additional floor space to, it is important to ensure that the space meets the design criteria requirements. Generally a ceiling height which exceeds 4.5m is acceptable to insert an intermediate floor, however, the physical construction depth of the system should be taken into account. ie 2m clear headroom above and below the mezzanine floor should ideally remain so a construction depth in excess of 0.5m could cause issues. The construction depth consistors of all materials required to suspend the mezzanine. Typically, a main beam combined with the decking creates the overall dimension. I will come back to these components later in the article.
In addition to the height, the sub floor should also be considered, for example, the floor of which the mezzanine shall be built. This should be strong enough to accept the load of the mezzanine columns. In most cases mezzanine floors are bolted on top of concrete slab floors. Structural calculations that the slab will take the point loads should be transported out prior to the installation and are required as part of the local authority building regulations submission. In order to determine the physical strength of the concrete when construction details are not available, core samples can be taken from the slab and 'crush' tested.
Once these two elements are suitable, you can then begin to design a mezzanine floor for your area. The first thing to decide is how far apart the columns (supporting pillows) are. This is large dependent on the results of the slab calculation which would tell you the maximum permissible load down a column, as well as any obstacles in the way, ie floor joints, machinery, doors etc. If the area is completely clear of obstruction it may be an idea to design the mezzanine floor from an economic point of view and make sure that the columns are set out in the most cost saving manner. The typical size of an economic design can vary between manufacturers, however, as an example, a 4 meter grid pattern in both directions is very common.
There are various types of flooring material available to use on mezzanine floors, however, the most common by far is chipboard. There are a few environments where chipboard is unsuitable such as damp or wet workspaces as well as areas that have very high point loads on them. Other examples of flooring types are durbar or chequer plate, which are very strong but can be noisy and expensive. Open grates are good for letting light through but again noisy and also difficult to use with picking trolleys.
Any open edges of the mezzanine, ie sides of the floor not buttting up to a wall, should be protected. The most common way to do this is by means of installing handrails. In addition to a handrail, a knee rail must be added and usually a toe rail to avoid kicking anything of the floor. There are regulations surrounding handrail and these should be adhered to.
Access for personnel to the mezzanine level can be achieved in several ways such as lifts or ramps, however, in most cases, people access the lifts via staircases. Stairs are designed either under Part K (Fire escape) or Part M (Ambulant) of the building regulations and one access point should be in close proximity to a fire escape stair. Staircases can include landings to change direction or to split the flight if the floor level is particularly high.