The high strength, smooth surfaces and inherent stability of MDF are desirable attributes for shelves and other load bearing surfaces. The shelves may form part of a fully integrated wall storage system designed and custom built to fit a particular room configuration. They may be assembled using standard size shelf and end panels forming part of a self assembly system using mechanical fittings.
Some manufacturers are supplying individual shelf panels for use with adjustable metal support brackets. On a smaller scale, individual shelves complete with MDF brackets can be manufactured to give the customer more freedom in fitting position.
The selection of the grade and thickness of MDF for a particular application depends upon the expected load on the shelf and the geometry of the shelf itself The initial deflection of a simply supported MDF shelf can be calculated from the applied load, the span and thickness of the shelf and the modulus of elasticity of the shelving material using the standard load/deflection equation.
|5 W L3|
|d =||----------||x 9.81|
where d = centre deflection (mm)
W = total load uniformly distributed (kg)
L = distance between supports (mm)
t = panel thickness (mm)
E = modulus of elasticity (N/mm2)
b = panel width (mm)
Using this equation, the likely deflections of MDF shelves of back to front width 300 mm and span 600, 800 and 1000 mm are presented graphically. The MDF for these examples is assumed to have a modulus of elasticity of 2500 N/mm2 and the total load W is assumed to be distributed uniformly over the whole area of the shelf.
These centre deflections relate to MDF shelves which have been surfaced by direct painting or the application of thin decorative foils. Creep effects occurring during long term loading could result in an increase of these initial deflections by up to 50%
Considerably lower initial deflection and less creep would be expected when using MDF panels surfaced on both faces with wood veneer or decorative plastics laminate.