What is mezzanine floor fire protection and why is it necessary?
So called ‘fire protection’ is effectively insulation of the mezzanine floor steelwork to prevent it from heating up quickly in a fire. Unprotected steelwork heats up quickly and can suddenly break. Fire protection is specified for a certain period of time such as ‘half hour’, ‘1 hour’, ‘2 hour’ or ‘4 hour’. The time period làm gác xép refers to the time that the protected elements remain structurally sound in the event of a fire. The fire protection required for different parts of buildings is specified within the Building Regulations part B.
Fire protecting building elements as outlined by the regulations is a statutory requirement, protecting lives and property and enabling the fire brigade to assess how long they can safely fight a fire before a risk of break.
Providing fire protection to mezzanine floors is also known as ‘fire rating’ them, and a mezzanine floor fitted with fire protection may be referred to as ‘fire rated’.
Do mezzanine floors always need to be fire protected?
The requirement for fire protection depends upon the employment, size and extent of the mezzanine floor. Mezzanine flooring that is less than 10m x 10m in size, and occupying less than 50% of the area of the building in which it is located and which is not permanently occupied and occasionally accessed (used for storage) does not need to be fire rated.
Mezzanine flooring that is less than 20m x 20m in size, and occupying less than 50% of the area of the building in which it is located and which is not permanently occupied and occasionally accessed (used for storage) does not need to be fire rated as long as it is fitted with an appropriate fire diagnosis and security alarm.
Any mezzanine floors that are permanently occupied regardless of size will need to be fire protected such as office areas, assembly and manufacturing, loading, canteen space or areas such as retail space with public access. Also mezzanines larger than 10m x 10m without an appropriate fire diagnosis and security alarm, all mezzanines larger than 20m x 20m and all mezzanines whoever size is much greater than 50% of the area within which they are generally. It can be seen that only in the smallest storage applications can fire protection be omitted.
How is most mezzanine flooring fire protected?
The most common means of fire protecting mezzanine floors is making use of four important components of insulation, column casings, a hung hallway, bulkheads/fascias and cavity barriers. This means of fire protecting mezzanine floors is used for its speed of installation and low cost.
Column casings comprise a two part published metal case lined with ‘Promalit’ or similar board bonded to the inside of the cased characters. The published metal case usually has a galvanized or white ‘plastisol’ finish to suit the approval, but can be metal or tinted ‘plastisol’, and the two parts have an unobtrusive locking seam enabling them to be quickly and neatly fitted with a few taps from a plastic mallet.
Hung ceilings comprise wires put up vertically on video from the second beams of the mezzanine supporting length of hallway runner. The runners clip together and are joined in turn by intermediate programs of hallway runner to create a hallway grid. Minaboard tiles are then inserted to fill the grid. The grid is commonly and most economically based around 1200mm x 600mm hallway tiles, however by adding further intermediate 600mm hallway runners, 600mm x 600mm tiles can be used. The tiles fitted must be certificated to provide the essential level of fire protection when used in the grid under a mezzanine floor. This confines the available choice of tiles and finishes.
Bulkheads or fascias (vertical barriers to close off hallway cavities to exposed perimeters at mezzanine floor edges or voids) are achieved by creating a framework from galvanized section and cladding the framework with plasterboard to see the required level of fire protection as outlined by the manufacturers specifications. Our bulkheads/fascias are then emblazoned.
Cavity barriers are vertical barriers within the hallway void created with mineral made of wool insulation to subdivide the void into sections as outlined by the Building Regulations in order to prevent smoke or flare traveling through the hallway void.
Alternative means of fire protecting mezzanine floors
Sometimes aesthetic or other considerations such as positive pressure fire extinguishing systems preclude the use of hung ceilings. Alternatives include taped, jointed and emblazoned plasterboard ceilings on a metal furring (MF) hallway framework and similarly boxed in columns providing flush finishes or intumescent painting of hot thrown columns and beams.
All the components of fire protection should be certified to provide the desired degree of protection in the application in which they are being used. For example it is not acceptable to use any old hung hallway below a mezzanine floor; the hallway tile and grid system must have certification specifically providing the essential level of protection under a steel joist type mezzanine construction, which significantly confines backyard of manufacturers able to give a suitable product.
This general information relates to mezzanine flooring fire protection in Great britain and is intended for guidance only. Each application needs to be tested untreated merits.
It is always prudent to discuss your specific project with an approved inspector or building control representative prior to starting out work, a task with which your mezzanine floor contractor will anticipate to assist.