Mezzanine floors: Telecommunications

August 24, 2010

Fenland floors on stilts

Mezzanine floors
Mezzanine floors

Reliability is fundamental to the operation of telecommunications networks as maintaining communications is vital to the function of emergency services.

The potentially disruptive effects of flooding to a fenland telecommunication centre mezzanine was overcome by raising the mezzanine floor by an extra metre and introducing a reinforced concrete slab on corrugated shuttering at a 1m height above floor level.

By effectively mounting our mezzanine floor on stilts, the risk of flooding affecting this switchroom in a fenland location was minimised.

The remainder of the structure generally followed our standard pattern for switchroom mezzanine flooring. These mezzanine floors are used to provide a framework around which perimeter walls can be constructed  to enclose switchrooms whilst providing a structure capable of  support ceilings, extensive services and air handling equipment.

Apart from the provision of ‘stilts’ this mezzanine floor was of standard design with the exception of extra large baseplates being provided to distribute load over the slab due to the poor bearing capacity of the fenland soil below.

Access to the raised switchroom itself was provided by ramps from the floor slab to the raised 1m slab of the switchroom, and a catladder was provided for maintenance access to the plant located on top of the switchroom.

Internal services were slung on cable trays suspended from the flanges of the main steels of the mezzanine floor.

The mezzanine flooring was erected within a week with the ground floor concrete slab being completed within a further week.

This is one mezzanine floor that we hope is never fully subjected to its design parameters.

 

 

 

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Mezzanine floors: Fire protection

August 12, 2010

What is fire protection and why is it necessary?

Fire protectionSo 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 collapse. Fire protection is specified for a certain period of time such as ‘half hour’, ‘1 hour’, ‘2 hour’ or ‘4 hour’. The time period 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 in accordance with 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 collapse.

Providing fire protection to mezzanine floors is also referred to 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 use, 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 infrequently 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 infrequently accessed (used for storage) does not need to be fire rated as long as it is fitted with an appropriate fire detection and alarm system.

Any mezzanine floors that are permanently occupied regardless of size will need to be fire protected such as office areas, assembly and manufacturing, packing, canteen space or areas such as retail space with public access. Also mezzanines larger than 10m x 10m without an appropriate fire detection and alarm system, all mezzanines larger than 20m x 20m and all mezzanines whose size exceeds 50% of the area within which they are located.

It can be seen that only in the smallest storage applications can fire protection be omitted.

How do we fire protect our mezzanine flooring?

The most common means of fire protecting mezzanine floors is through the use of four key elements of insulation, column casings, a suspended ceiling, bulkheads/fascias and cavity barriers. This means of fire protecting mezzanine floors is used because of its speed of installation and low cost.

Column casings comprise a two part sheet metal case lined with ‘Promalit’ or similar board bonded to the inside of the casing. The sheet metal case usually has a galvanized or white ‘plastisol’ finish to suit the application, but can be stainless steel or coloured ‘plastisol’, and the two parts have an unobtrusive locking seam enabling them to be quickly and neatly fitted with a few taps from a rubber mallet.

Suspended ceilings comprise wires hung vertically on clips from the secondary beams of the mezzanine supporting  length of ceiling runner. The runners clip together and are joined in turn by intermediate lengths of ceiling runner to create a ceiling grid. Minaboard tiles are then inserted to fill the grid. The grid is commonly and most economically based around 1200mm x 600mm ceiling tiles, however by adding further intermediate 600mm ceiling runners,  600mm x 600mm tiles can be used. The tiles fitted must be certificated to provide the necessary level of fire protection when used in the grid under a mezzanine floor. This restricts the available choice of tiles and finishes.

Bulkheads or fascias (vertical barriers to close off ceiling 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 obtain the required level of fire protection in accordance with the manufacturers specifications. Our bulkheads/fascias are then decorated.

Cavity barriers are vertical barriers within the ceiling void created with mineral wool insulation to subdivide the void into compartments in accordance with the Building Regulations in order to prevent smoke or flame traveling through the ceiling void.

Alternative means of fire protecting mezzanine floors

Sometimes aesthetic or other considerations such as positive pressure fire extinguishing systems preclude the use of suspended ceilings. Alternatives include taped, jointed and decorated plasterboard ceilings on a metal furring (MF) ceiling framework and similarly boxed in columns providing flush finishes or intumescent painting of hot rolled columns and beams.

Certification

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 suspended ceiling below a mezzanine floor; the ceiling tile and grid system must have certification specifically providing the required level of protection under a steel joist type mezzanine construction, which significantly restricts the range of manufacturers able to offer a suitable product.

Get advice

This general information relates to mezzanine flooring fire protection and is intended for guidance only. Each application needs to be assessed on its own merits.

It is always prudent to discuss your specific project with an approved inspector or building control officer prior to commencing work, a task with which your mezzanine floor contractor will be prepared to assist.

Mezzanine floor advice and support

If you would like advice regarding the specific requirements for your project, someone to liaise with building control on your behalf, or a quotation for your project call Llonsson Ltd on 01883 622068.

 

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Mezzanine floors: New Budget range

August 12, 2010

We are pleased to announce the launch of our economy range of mezzanine floors.

Mezzanine floors colleges 150x150 Mezzanine floors: New Budget range

Budget mezzanine floors

In addition to Llonsson’s range of standard specification and specialist mezzanine floors, we are now able to offer an economical ‘no frills’ range of mezzanine floors to suit applications where low price is a primary factor in product selection.

The budget range complies with all minimum statutory requirements for mezzanine floors, and is suited to simple mezzanine flooring applications such as storage and warehousing in modern portal frame ‘sheds’.

Smaller spans between mezzanine floor columns enables columns to be kept small and light, main sections shallow and light weight, and baseplate loads low. Baseplates are typically 300mm x 300m x 12mm. Secondary steel sections are still of inset construction, but utilize a low cost simple ‘C’ profile section with pressed ‘L’ shaped cleats.

For a functional solution to undemanding mezzanine flooring applications, that can offer up to 20% cost saving compared to our standard mezzanine floor range, and will even give preowned mezzanine floors a run for their money, ask for a quotation for one of our excellent value budget mezzanine floors from Llonsson Ltd.

Standard mezzanine floors from Llonsson Ltd

Alongside the new budget mezzanine floor range we continue to offer our standard mezzanine floor range with full design and  technical support, offering top quality mezzanine floor components and finishes as well as the flexibility to integrate specialised components and finishes and to provide higher levels of performance specification for more demanding applications.

Mezzanine flooring advice and support

If you would like advice regarding the most appropriate solution for your project, someone to liaise with building control on your behalf, or a quotation for your mezzanine floor project call Llonsson Ltd on 01883 622068.

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Mezzanine floors: Talking about baseplates…

August 5, 2010

Circular mezzanine floor base plate

Surface mounted mezzanine floor base plate

Dealing with mezzanine floors every day we get a bit blasé about specifications, however each floor is bespoke, and different customers have different needs, so here is a bit about the baseplate options available.

In common with most mezzanine flooring suppliers we quote for standard surface mounted mezzanine floor baseplates which are assumed to be 300mm x 300mm square in the absence of slab or subsoil data.

Our mezzanine floor baseplates are always fitted with countersunk fixings to eliminate a potential trip hazard.

When subsoil, slab and load conditions dictate, mezzanine floor plates that are oversized beyond our standard may be necessary and can be provided.

Surface mounted mezzanine floor base plate

Sometimes we are asked to provide circular columns for aesthetics, in which case a circular surface mounted mezzanine floor baseplate looks much smarter than a rectangular plate.

Chamfering the top arrises of surface mounted mezzanine floor baseplates makes it less likely that they will present a trip hazard. This can be offered if the budget doesn’t stretch to recessed plates but tripping is considered a potential risk.

Mezzanine floor base plates can be offset to enable columns to be positioned closer walls or to keep them out of racking aisles. Plates may sometimes need to be slightly thicker or larger in these circumstances.

Rectangular mezzanine floor baseplates can be used in similar circumstances as offset plates with the same provisos.

Mezzanine floors recessed baseplate in pocket

Mezzanine floors recessed baseplate

Mezzanine floors recessed baseplate in pocket

To eliminate the further potential trip hazard of a mezzanine floor baseplate, particularly in areas where there is no equipment under which baseplates can be positioned, or in offices where plates could interfere with the positioning of desks or furniture, we can offer recessed plates. Columns are extended to allow for this and a pocket detail is agreed to suit the necessary baseplate sizes which we can arrange to cut or can be undertaken by the clients builder. Fixings are still recessed so that they do not project above the finished floor surface. The plates are positioned with shims below them to level them and the pockets are finished off with a high performance non shrinking self levelling grout which is trowelled off flush with the surrounding floor surface. This is also a popular option for food production areas where potential dirt traps are avoided.

An alternative to recessed plates is standard plates with a full floor screed. The cost needs to be evaluated and the implications of raising the floor level need to be conside such as door alterations and introducing changes of levels. In our view recessed plates offer the better solution.

The concealed construction partition plate is a special type of rectangular mezzanine floor baseplate with gussets that can be surface mounted but remains concealed when used within a jumbo stud wall system, enabling mezzanine floor columns and baseplates to be completely concealed within the walls of an office layout whilst offering neat flush wall finishes.

Sometimes when the slab or subsoil is poor, rather than using mezzanine floor baseplates a ground beam can be used which creates a line load. This is an extreme form of surface mounted rectangular plate which does prevent doors being located along its length in one plane, but leaves the other plane unobstructed.

This general information relates to mezzanine floor base plates and is intended for guidance only. Each application needs to be assessed on its own merits.

It is always prudent to discuss your specific project with an approved inspector or building control officer prior to commencing work, a task with which your mezzanine floor contractor will be prepared to assist.

If you would like advice regarding the specific requirements for your project, someone to liaise with building control on your behalf, or a quotation for your project call Llonsson Ltd on 01883 622068.

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Llonsson Ltd

49 Court Farm Road,
Warlingham,
Surrey,
CR6 9BL United Kingdom

T: 01883 622068 F: 01883 623280

Registered No: 2389444

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