When you design a mezzanine floor you are controlled by a set of regulations called the “Building Regulations”. Each area of the building regulations is covered by an “Approved Document”. For example “Approved Document , Part B” covers fire safety and specifies how your premises should be fire protected, i.e compartment walls, fire door specification.
These documents can be purchased from the government planning department, but few people realise that these are available as PDF files, downloadable from the Planning Portal website at http://www.planningportal.gov.uk/buildingregulations/approveddocuments/
So anyone planning on making any changes to their premises then stay ahead of your supplier when tendering and study what you actually require rather than what your supplier is trying to sell you !