Raised Floor System (Access Floor) - An Overview

What is Raised Floor? 

Also referred to as raised access computer floor, access floor, false floor, elevated floor or raised flooring, a raised floor offers an elevated structural floor over a solid substrate. It is beneficial in developing a hidden void so that the electrical and mechanical services can pass easily. 

These raised floors systems are used on a wide scale in the modern office buildings, as well as in different specialized areas like computer rooms, IT data center, command center, where you need to install mechanical, electrical, wiring and cable services. 

It is possible to install this kind of flooring at different heights, ranging from 2 inches to 4 ft, catering to your needs. If the raised floor has the prerequisite height for walking underneath or crawling, lighting and structural support are also provided in it.

In the United States, air distribution beneath the floor is considered to be a vital option for cooling the building where the void, present under the raised floor is used as the plenum chamber for the distribution of the conditioned air. 

Raised access floors in data centers are known to be interlinked with the air-conditioned zones. Perforated tiles are installed under the computer systems for directing the conditioned air towards them directly. The computing equipment features a unique design for withdrawing cool air from underneath and exhausting the same in the room. The AC unit will be extracting air from the room and cool the same after which it will be forced under the raised floor, thereby executing the circle.

After several decades, an optional approach to these floors was introduced for the management of the distribution of the underfloor cable for a bunch of applications in which there is no use of the distribution of the under floor air.

It was in the year of 2009 when a different category of this floor was launched by CSC (Construction Specifications Canada) or CSI (Construction Specifications Institute) for separating the different, yet same approach to the access floor.

In such cases, the raised floor comes with a low profile and fixed height access flooring. It is a prerequisite to installing the floor plan configuration and alterations in technology in Studios, museums, retail spaces, conference rooms, classrooms, and offices in no time without any hassles.

Raised Floor Design & Specification

The regular floor comprises of gridded metal framework or pedestals, the substructure of different adjustable height support which offers the prerequisite support for the liftable floor panels. The volume of the cables as well as the services, offered underneath regulates the height of the pedestals or legs. 

However, they are known to be arranged typically for the clearance of 15 cm or 6 inches along with the height, in the range of 24-48 inches. Such panels are composed of steel panel or steel-clad particleboard along with the cementations internal core. 

However, few of the titles are known to possess hollow cores. The raised floor panels are covered with a bunch of flooring finishes, as per the requirements of the application. For instance, antistatic, stone, marble, high-pressure laminate, and carpet tiles are used for the laboratories and computer rooms.

As a panel is used with the cement top surface, it is left stained or bare at times for providing a tile appearance, thereby saving an ample amount of money. Such bare applications find extensive usage in the hallways, office areas, casinos, museums, and lobbies.

Raised Floor Panel Lifter

For the removal of the panels, a specific tool - Access Floor Panel Lifter that is equipped with the suction cup towards the end is known to be used. For the carpeted panels, the hook and loop lifter is used. Gravity holds the access flooring of fixed height and low profile without the use of fasteners or glue. Here, no tools are necessary for introducing the changes.

Raised Floor Features & Advantages

Adaptive Management of Cables

A low profile and contemporary cable management raised floor or fixed type is different from the regular access floors as they need reduced ramping floor space at the transitions of the floor height. They can be removed in the current construction with the installation of slab depressions.

The primary benefits include easy handling and lightweight panels. Hence, no tools are necessary for making the changes where the organized cable channel pathways are recognized to be crucial for the system. Thus, there is a significant reduction in the expense and time during the installation as well as during the time, when changes are introduced in the building. 

As such kind of floor does not have an attachment to the structure, they are recognized to be a fixture, furnishing, equipment that can be leased or depreciated expense. As the under floor cabling is not present in the plenum, there is no need to spend on the plenum rated cable.

Cooling the Load Implications

As the raised floor systems are installed, it might bring a change in the thermal behavior of the building by reducing the interaction, present between the thermally massive concrete slab and the heat gains. The raised floor is known to act as the separation area between the slab and the room.

The energy simulation of the office building, present in San Francisco revealed that the mere presence of the raised floor has an impact on the zone cooling load profile, resulting in the rise of the peak cooling load. With the presence of the carpet, the negative effect of the raised floor on the specific zone cooling gets decreased.

Raised Floor Applications

Common Application

Raised access flooring has found extensive usage in the retail spaces, office accommodation, control rooms, and computer rooms. Primarily two benchmarks are present for performance testing in the United Kingdom which includes BS/EN12825 and PSA MOB PF2 PS (spu) 1992. They stand out of the ordinary in setting out the defined static loading criteria which should be accomplished by the raised access floor.

As the raised access flooring is used for the general office, it offers a uniformly distributed load of 8 kn m2 UDL as well as the point load of 3.0kn. In addition to this, it comes with an extra 3 x safety factor, which applies to the loadings.

Control rooms and computers which are equipped with the Data centers are known to have a higher requirement of static loading and hence it is essential to employ PSA Heavy Grade. Thus, they offer a uniformly distributed load of 12 kn m2 UDL along with a 4.5 kn point load after which an additional 3 x safety factor is applied again.

Residential Use

Though the major wiring might not be the object of attention, the residential usage of the split levels and raised floors in the Manhattan apartments, featuring 12 ft ceiling offer high-performance elements along with extra functionality.

Computer Centers Applications

There is a plethora of modern equipment and computer rooms which make use of under floor air distribution so that the room cools evenly and there is the least wastage of energy. Now, conditioned air is conferred beneath the floor, after which it is dispersed in the room in the upward direction via the blowers, diffuser tiles or ducts that are directed into certain equipment. 

The shutdown of the automated fire protection might be necessary for performing under floor ventilation. If any under floor fire occurs, extra suppression systems might be installed. 

Office Buildings Applications

There is a wide assortment of office buildings that make use of access flooring for the creation of sustainable and flexible spaces. A large corporation might have more than twenty thousand miles of cabling in one facility.

As the under floor air is transformed into a specific building from the beginning of the particular project, you can be ensured that it takes a lesser amount of money for the development and operation of the building.

Under floor air needs reduced space for every floor, and it decreases the height of the whole building, resulting in the reduction of the price of the building facade. The air handlers and blowers which are necessary for the under floor air is known to be smaller and need less energy as the hot air advance through space naturally while coming in contact with equipment and people, which will be warming the air after which it will accelerate towards the ceiling.

In addition to this, as buildings get designed with the combination of access floor, modular walls, modular electrical, it is possible to reconfigure the space in the interior of the building within few hours, in comparison to the historical techniques of drilling wells within the floor and removing the walls for giving passage for electrical as well as other services.

As a plethora of companies renovates or construct the buildings for achieving Leadership in Energy & Environmental Design or LEED, the use of access floor and under floor air will enhance manifolds. According to the United States Green Building Council or USGBC, almost forty to forty-eight percent of the latest nonresidential construction is known to be green.

Telecommunications Data Center Applications

The raised floors which are feasible for general use do not address the specialized requirements, which are necessary for the telecommunication application. The generalized type of raised floors, which are used in the telecommunication data centers, is inclusive of structural, stringed and stringerless platforms.

The telecommunication facility comprises of consistent lineups of different equipment cabinets. The installation configuration which is known to be densely populated comprises rows of consistent equipment cabinets of 2 ft wide along with aisles which brings a separation in the adjacent rows of 2 ft. 

The lineup configuration contributes to being the most densely populated sq. ft area and thus it has the largest floor load for the raised floor system. A single equipment cabinet is capable of occupying the floor area of sq. ft. 

It is possible to install the data center in the remote locations and it is known to be subjected to different electrical and physical stresses from different sources like from the electrical faults and the fires. The environment leads to the installation techniques for the raised floors, which include grounding, bonding, cable racking, site preparation, fire resistance. You, however, need to remember that the actual installation should be done according to customer’s practices.

Computer Rooms and IT Data Centers Applications

The raised floors for the data centers, primarily the rooms boast of history along with the specific set of the specifications.

Telcordia GR-2930

Telcordia GR-2930 offers generic engineering needs for the raised floors which will be included in the strict NEBS guidelines.

Metal Whiskers

Raised floors, as well as metal structures like ventilation ducts and cable trays, might lead to several issues with the zinc whiskers, previously. The installation of the cable for the maintenance on the raised floor might result in dislodging the whiskers, entering the airflow, and short-circuiting the power supplies, server components. Such a phenomenon is not unique to the data center and results in destructive failure of military hardware and satellite.

Raised Floor Structure

Structural Issues

Structural issues like the gaps and rocking panels might be present between the panels which results in extensive damage to the specific equipment. In addition to this, it also causes injury to the personnel. As regular inspections are done for maintaining the structural integrity of the raised floor, it helps in identifying as well as mitigating the issues. 

Damage to the floor and equipment might occur as the used flooring does not accomplish the load requirements. The load ratings are known to have the range between 1,000-25,000 lbs. It is possible to use higher panels on the bulk areas of the floor whereas you can consider using the lower panels for the lighter areas.

There are a bunch of similar issues that are associated with the sub-par installation. During the installation, it is necessary to pay attention to the subfloor condition and hence it is essential to clean the debris and level it.

The walls which are present around the raised floor must be square for reducing the requirements to cut the access floor panels and diminish rocking panels as well as gaps. The fixed height system of low profile can accommodate the rooms of irregular size, having adjustable border components that reduce the cutting of the panels.

Other Issues

The flooring tiles are removed rarely with the installation of the equipment owing to which the space beneath them is cleaned rarely. Thus, the fluff and other debris are known to settle owing to which working on the cabling under the floor is considered to be dirty work. At times, workers trigger the smoke detectors, which were installed beneath the raised floor, causing the ringing of false alarms.