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Access Flooring operative measuring the levels of a raised floor system installation

A Guide to Raised Access Flooring

What is raised access flooring? As raised access flooring experts, in this knowledge article we will examine what raised access flooring is, what it is used for, how a raised access floor system is constructed and what the many advantages are of specifying access flooring.

What is Raised Access Flooring?

A raised access flooring system is an elevated floor that is laid above a sub floor, often a concrete floor slab, in order to leave an open space or void between.  Raised floor systems are sometimes referred to as access floors, raised access floors, platform floors, computer floors or suspended flooring.

The space created between the two floors is used to house cabling and pipework required to distribute services around a building. These services can include:

  • Electrical power
  • Network data and telecommunication cabling
  • CCTV
  • Water supply and drainage
  • Air conditioning, heating and ventilation
  • Security cabling
  • Environmental controls
  • Fire detection and suppression

Access floors are most commonly specified in newly constructed or refurbished buildings where there is a requirement for information and communications infrastructure and advanced fire and safety systems, such as commercial offices, data centres, airport lounges, shopping centres, department stores, supermarkets and hospitals.

They are also often specified as a refurbishment solution in historic or listed buildings where traditional methods of construction could damage period features and historically important artefacts or interior decoration.

Raised access flooring is an ideal alternative to suspended ceilings and is far more versatile and aesthetically appealing than dado trunking and pre-cast trunking.

What does a raised access flooring system look like?

Raised access floor systems comprise of removable panels that are laid in a grid formation on adjustable vertical pedestals.

cabling infrastructure concealed beneath a raised access flooring system

As the height of the pedestals can be determined, the gap between the solid floor and the raised access floor can be between 20mm and 1500mm in height depending on the services that need to be contained within the space. Greater depths can be achieved through the design of bespoke raised access floor systems.

The pedestals are bonded to the concrete floor using an epoxy resin adhesive and carefully adjusted to take into account any undulations in the sub floor so as to provide a level plane on which to lay the access flooring panel.

Stringers are employed either to increase the performance of the raised access floor system or to aid with lateral stability during installation of finished floor heights over 600mm high. Stringers are horizontal steel bars that connect the pedestal grid together and are either clipped on or bolted on depending on the type of access floor system

What are access floor panels made of?

Access flooring panels are usually manufactured from a chipboard core that is encased in steel.  They may also be pre-bonded with other materials such as vinyl, natural wood, granite, glass or marble for a high-quality aesthetic finish.

Diagram of a raised access flooring panel structure

They are uniform in size; a raised floor panel is usually 600mm by 600mm. In the USA, a typical access flooring panel size is slightly larger at 24” x 24” (around 610mm).

How are raised floor panels installed?

Raised floor systems can be designed and installed as gravity systems, also known as loose lay, where the floor panels are laid to rest loosely on the pedestal head. This makes them easy to remove in order to access the void below.  In some cases, where greater security is required, they can be fixed onto the pedestal head, known as lock-down or screw-down.

The raised floor system is designed according to the end user requirements and is dependent on the type of traffic and static or dynamic load it will have to bear.

How much weight can a raised floor panel hold?

The load bearing capability of a raised access flooring system is determined by the type of access flooring panel specified.

Access flooring panels are designed and manufactured in line with two industry standards; PSA MOB PF2 PS/SPU and BS EN 12825. 

Access Flooring, the access floors division of Raised Floor Solutions is a Tier 1 supplier and installer of Kingspan Access Flooring Products.  Kingspan manufactures access floor panels that comply with both sets of regulations and within each are different grades of access floor panel product.

PSA MOB PF2 PS/SPU Floor Systems

PSA MOB PF2 PS/SPU access floor panels meet a stringent specification set by the Property Services Agency (PSA), a Government body in existence between 1972 to 1993 which was established to provide and maintain all Government and state buildings.   They were the largest users of raised access floor systems at the time.

This specification consists of performance requirements that must be verified by standard testing procedures. Requirements include fire safety, moisture and thermal movement, electrical binding and continuity, dimensional accuracy and strength. The last edition of the specification was published in 1992. After the PSA disbanded, the custodian of the standard was transferred to the Access Flooring Association.

The specification puts raised floor panels into four structural standards determined by their load carrying capability: light, medium, heavy and extra heavy.  The light, medium and heavy grades all have three times safety factor and can tolerate load of between 1kN and 12kN depending on the grade and whether the load is centred to one point or evenly distributed.

The table below shows the correct Kingspan raised floor panel to use according to PSA MOB classification.

PSA MOB Specification Table for Raised Access Floor System

BS EN 12825 Floor Systems

In 2001, a new European standard for raised access flooring was introduced which classifies floor systems based on their safety factor, deflection under working load, dimensional tolerances and their ultimate load, i.e. the load at which failure occurs.

The ultimate load test involves punching a square load with an increasing weight at various places on the panel at a pre-determined rate until failure occurs, and recording the weight when the panel collapsed.

This classification system creates six classes with ultimate loads ranging from 4kN to over 12kN. The higher the number, the more strength the access floor panel will have.   The ultimate load is then divided by the safety factor to create the ‘working load’. The working load is then applied to the panel and the deflection is measured and classified as following:

A – 2.5mm

B – 3.0mm

C – 4.0mm

The tolerances determined during the access floor panel’s manufacture then provide the final element within the classification. There are two tolerances with ‘1’ being the superior.

This process creates the classification for each type of panel, as seen in this example:

Ultimate load above 12kN – 6

Deflection under working load 2.5mm – A

Safety factor – 3

Class of tolerance – 1

Kingspan’s range of PSA MOB PF2 PS/SPU compliant access floor panels remain the most frequently specified, however its BS EN panels provide designers with alternative options when there is not a suitable PSA MOB access floor solution.

Download data sheets for all of Kingspan’s PSA MOB access flooring panels here.

Download data sheets for all of Kingspan’s BS EN access flooring panels here.

You can read more about access flooring specifications and request a copy of the PSA specification guide at the Access Flooring Association website.

What are the benefits of specifying access floors?

Access flooring systems are extremely versatile. As the access floor panels are removable, a raised access floor system will allow easy access to maintain, reconfigure or upgrade wiring and pipework with minimum disruption to a business.  

When combined with modular wall and electrical systems, it allows the reconfiguration of an entire office or building in a fraction of the time it could take if other solutions had been employed. This is particularly beneficial as companies look to adjust their office layouts and working practices in line with Covid-19 guidelines.

Raised Access Floors are a superior economic and aesthetic solution to chiselling cable channels in walls or installing unsightly plastic casing for pipes and wires.

Raised access floor systems can also be employed to create even floor levels and to eliminate steps or ramps creating more usable or accessible space.  This makes them a popular flooring solution when updating or repurposing historic or listed buildings.

There are huge benefits to installing raised access flooring in data centres and this is a large sector of the access flooring market.

How beneficial is it to install a raised floor system in a data centre?

Raised access floor systems are the most commonly specified type of flooring for data centres, and hyperscale data centres (see below).

There are many reasons why access floor systems are beneficial to data centres but the two core benefits are:

  • Data centres require huge volumes of cabling which needs to be stored safely and somewhere where it can be regularly access for upgrades, reconfiguration and maintenance. The service voids and easy accessibility offered by loose lay access flooring solve this problem.
  • Data servers emit a high volume of heat through their operation yet overheating can cause equipment failure.  Raised access floor systems can be used as a way of distributing cold air around a space. Having the access floor system in place means that less energy is required to maintain an even temperature across the cabinets, some statistics show that a 40% reduction in cooling load can be achieved.
Graphic showing the composition of a raised floor system for a data centre

What are the acoustic benefits of raised floor systems?

The nature of raised floor systems means that reducing airborne sound seepage between spaces needs full consideration at specification stage.

The construction of the floor panel and its edge profile become important, as does the level of gap between panels. These factors are all influenced by the quality of the manufactured access floor panel and the competence of the access flooring installer.

During the design of the raised access floor system, laboratory tests have been conducted to provide the acoustic ratings given on the data sheets that the system could potentially achieve when installed in accordance with the manufacturer guidelines.  Acoustic barriers and rubberised/cork acoustic adhesives are often specified to dampen noise in sound sensitive areas, such as hospitals, libraries or office meeting rooms.

How much does a raised floor system cost?

Raised floor systems are designed bespoke to meet end user requirements and therefore every project is priced individually. Contact our Access Floors team for a no obligation discussion about your access flooring requirement.  

How long does a raised floor system last?

High quality raised floor systems installed by skilled access flooring contractors should last for several decades but the expected life span is dependent on the specification.

Access floor systems compliant with PSA MOB PF2 PS / SPU are expected to last for up to 25 years for the floor panels and up to 50 years for the components. Kingspan Access Floors offer a 25 year lifespan guaranty on their access floor panels when installed as part of a Kingspan access floor system.

Whilst there is no guaranteed lifespan attributed to access flooring complying to BS EN 12815 standard, we usually provide a 10 year warranty upon completion.

The Rising Demand for Raised Access Flooring Systems

In 2020, market analysts Artizon published a report that predicted the global raised access flooring market would reach revenues of $903million (£650million) over the period 2020 – 2025.

Whilst the stats were published pre-Covid, one of the key catalysts cited for this growth was a rising demand for hyperscale data centres, with the UK named as one of seven preferred locations.  Other contributors included:

  • Rise of ‘Industry 4.0
  • 5G deployment
  • Growth in infrastructure at airports
  • Growth in the Construction sector

Whilst Covid-19 has slowed the accelerated growth of many markets, our reliance on fast and efficient technology and data access in order to function in every area of our lives is at an all-time high. Couple this with an access floor system’s cost efficiency, flexibility and versatility as a retro-fit commercial office solution and it is no surprise that raised floor systems remain as much in demand as ever.

Access Flooring Installers

Access Flooring is a specialist access flooring contractor division within Raised Floor Solutions that designs, supplies and installs raised floor systems. Access Flooring is a Tier 1 installer of Kingspan Access Flooring Products.

For a no obligation confidential discussion about our raised access floors design, supply and installation services or to discuss the suitability of access flooring for your next project contact our team on 01695 555070 or email us.