Understand the components, installation language, and performance terms used in raised floor systems. This glossary explains raised access floor panels, understructure, finishes, and the services below a computer floor or data center floor. Select a letter to jump to its terms.
Panel names and ratings vary by manufacturer. Use the specified system details when selecting components, reviewing equipment loads, or planning changes to an existing access floor.
A
A/F (Access Floor)
An installation abbreviation for the access floor, including its panels, supporting pedestals, and accessories.
Access Flooring / Access Flooring Systems
Removable floor panels and their supports that create accessible space for building services below the walking surface. Also called raised access flooring.
Acclimation
Allowing flooring materials to adjust to the installation environment before use, following the manufacturer's storage and environmental requirements.
Air Diffuser
An outlet that delivers air from an underfloor supply space into the occupied room. Diffuser selection and placement affect air distribution.
Airflow Panel
A perforated panel or open grate that lets supply air pass through a raised floor to the space above.
All-Steel Panel
An access floor panel with a steel structural body rather than a wood or concrete-filled core. Construction and performance vary by product.
Anti Static Flooring for Server Room
A common search phrase for flooring intended to reduce static buildup around IT equipment. Specify the required electrical performance; the phrase alone does not establish an ESD rating.
Attic Stock
Extra panels and components retained for future repairs or alterations. Matching replacement stock helps preserve the original floor system.
B
B/M (Bill of Material)
An itemized list of panels, pedestals, stringers, hardware, and accessories required for a project.
Bare Panel
An access floor panel supplied without a factory-applied decorative finish, often used beneath compatible carpet tiles or another specified covering.
Bolted Stringer System
An understructure with horizontal stringers secured to pedestal heads using bolts or screws. Panels may remain removable without unbolting the stringers.
C
C/L (Center Line)
A reference line used to locate and align the floor layout or its components. Its meaning should be confirmed against the project drawings.
Cable Cutout
An opening in an access floor panel for cables or other services. Cut edges require suitable protection, and the panel may need additional support.
Cable Management
Organizing and routing power and communications cables so they remain accessible without obstructing other underfloor services.
Calcium Sulphate Panel
An access floor panel with a dense calcium sulphate core. Also spelled calcium sulfate; finishes, edge treatments, and load capacities depend on the product.
Carpet Tile
A modular carpet covering used over compatible access floor panels. Layout and attachment should preserve the required panel access.
Computer Floor
A common name for raised flooring used in computer rooms to provide access to cabling and, where designed for it, cooling services.
Concentrated Load
A force applied over a small area, such as an equipment foot. A panel rating must be read with its test conditions.
Concrete-Filled Steel Panel
A steel access floor panel containing a cementitious fill. Commonly used in commercial and equipment-room raised floor systems.
Cornerlock System
A system that fastens panel corners to pedestal heads. Access requires releasing the applicable fasteners.
Cut Panel
A panel trimmed to fit a wall, column, or opening. Full-panel load ratings do not automatically apply after cutting; support details must be reviewed.
D
Damping / Damper
A damper adjusts airflow through an outlet. Damping describes reduction of movement or vibration; these terms have different meanings.
Data Center Floor
The floor supporting data center equipment. When built as raised flooring, it can provide underfloor space for cables, piping, and air distribution.
Dead Load
The weight of permanently installed construction, including the floor system itself. It is distinct from loads associated with occupancy or movable equipment.
Deflection
Movement of a panel or support under load. It differs from deformation that remains after the load is removed.
Dry Line
A taut string used as a temporary alignment reference without depositing chalk on the floor.
Dynamic Load
A load that changes as equipment moves or an impact occurs, rather than remaining stationary.
E
Edge Trim
Material protecting or finishing the perimeter of a panel. Its fit and condition can affect panel spacing and handling.
ELL (Starting L)
Initial rows laid along perpendicular control lines to establish a square starting layout for the floor.
ESD (Electrostatic Discharge)
A transfer of static charge between objects. Flooring can be one part of a coordinated ESD control program.
Expansion Joint
A joint accommodating building movement. Raised floor details must account for the joint without restricting its intended movement.
F
Fascia
A vertical closure covering an exposed raised floor edge, ramp side, or step face.
Field
The main floor area occupied by full panels, excluding the cut perimeter areas.
Finished Floor Height (FFH)
The distance from the supporting subfloor surface to the top of the access floor panel. Confirm how an added finish is treated in project dimensions.
Floor Access Panel
In raised flooring, a removable load-bearing panel that opens access to the services below. The term can also describe a separate hatch in another floor type.
Floor Finish
The exposed covering on an access floor panel, such as HPL, carpet, or vinyl. Finish choice affects maintenance, appearance, and electrical performance.
Floor Panel Lifter
A tool used to lift removable panels. Suction lifters suit compatible smooth surfaces; carpet surfaces require an appropriate carpet lifter.
Freestanding System
A pedestal-supported arrangement in which panels rest on their supports without corner fasteners or connecting stringers, where permitted by the system design.
G
Gasket
A strip or pad at a support interface that can cushion panel contact and reduce noise. Electrical and sealing properties depend on the specified material.
Grid Line
A line formed by the joints between adjacent panels, used to check the floor layout and alignment.
Grommet
A fitting protecting cables where they pass through a panel. Brush or sealed versions can also reduce unwanted airflow through the opening.
Grounding and Bonding
Electrical measures providing the required connection to ground and continuity between conductive parts. Details must follow the project electrical design and applicable requirements.
H
High-Pressure Laminate (HPL)
A durable factory-applied panel finish commonly used in computer rooms. Static-control characteristics must be confirmed for the selected product.
HVAC
Heating, ventilation, and air conditioning. A raised floor may form part of the air distribution arrangement when designed for that purpose.
I
Impact Load
A sudden force, for example from a dropped object. Its effect depends on the object, contact area, and drop height.
Interchangeability
The ability to exchange panels within a compatible floor system. Matching nominal size alone does not confirm compatibility with existing supports.
J
Joint / Panel Joint
The meeting line between adjacent panels. Consistent joint spacing supports proper fit and panel removal.
L
Laser Level
An instrument establishing an elevation reference for setting pedestal heights and checking the floor plane.
Leveling Bar
A straightedge used across pedestal heads to establish consistent elevations during installation.
Live Load
A load associated with use and occupancy. Building live-load requirements and access floor panel test ratings describe different things.
Load Rating
A stated load performance under defined test conditions. Concentrated, rolling, uniform, and ultimate ratings are not interchangeable.
Low-Profile Raised Floor
A shallow access floor arrangement primarily used for cable distribution. Support configuration and height vary by manufacturer.
M
Maintenance
Inspection, cleaning, and correction of panel or support problems to retain usable access and the intended floor performance.
Modular Power, Voice, and Data
Service distribution components arranged for connection and relocation beneath an access floor.
N
Nosing
A protective or transition profile at the edge of a step, ramp, or floor opening.
O
Open Area
The portion of an airflow panel that is open to air passage, commonly expressed as a percentage. It is not a direct measure of delivered airflow.
P
Panel
A removable structural unit forming the raised floor surface. Its size, thickness, core, and support interfaces determine system compatibility.
Pedestal
The vertical support beneath raised floor panels, normally comprising a base, an adjustable stem or tube, and a head.
Pedestal Adhesive
A manufacturer-specified adhesive used to secure pedestal bases to the supporting subfloor. Surface preparation and curing affect the connection.
Pedestal Base
The bottom portion of a pedestal that bears on and attaches to the supporting slab or subfloor.
Pedestal Head
The top portion of a pedestal supporting panel corners and, when applicable, connecting to stringers or panel fasteners.
Perforated Panel
A floor panel with a pattern of openings for airflow. Its load capacity must be checked separately from that of solid panels.
Perimeter Panel
A panel at the boundary of the raised floor, often cut to fit a wall or column and supported according to the perimeter detail.
Plenum
A space used for air distribution. The void below a raised floor is a plenum only when it serves that function.
Plenum Divider
A partition below the raised floor that separates underfloor spaces or air distribution zones.
Plenum Seal
A seal at an opening or interface that helps limit unwanted air loss from an underfloor air distribution space.
Plumb
Vertical alignment, perpendicular to a level horizontal plane.
R
Raised Access Floor
An elevated assembly of removable load-bearing panels and supports that allows access to services beneath the floor.
Raised Access Floor Tiles / Raised Floor Tiles
Common names for removable structural access floor panels. They are different from decorative tiles installed on top of those panels.
Raised Floor / Raised Flooring
An elevated floor surface creating usable space above the supporting subfloor. In access flooring, removable panels provide entry to that space.
Raised Floor Systems
Complete assemblies of compatible panels, understructure, and accessories selected for the required use, height, and loads.
Raised Flooring for Wet Basements
A phrase describing interest in an elevated basement floor. Raising the walking surface does not stop water intrusion; moisture control and suitability of the materials must be addressed first.
Ramp Assembly
An inclined transition between floor elevations using compatible panels, supports, and edge details. Slope and dimensions must suit the project's accessibility requirements.
Ramp Shoe
The transition component at the lower end of a raised floor ramp where it meets the adjacent floor.
Replacement Panel
A panel supplied to replace an existing unit. Check its dimensions, thickness, finish, load performance, and fit with the existing understructure.
Rocker / Rocking Panel
A panel that moves diagonally or rocks on its supports. Causes can include debris, uneven support elevations, or an incorrect fit.
Rolling Load
A moving wheel load. Evaluate wheel characteristics, passes, and the actual assembled floor, rather than relying only on a stationary-load rating.
S
Seismic Bracing
Braces, anchors, or other reinforcement designed to resist earthquake forces as part of a project-specific floor support arrangement.
Service Outlet Box
An assembly providing access to electrical, communications, or other service connections through the floor.
Shoot In / Sight In
Establishing floor elevation reference points using a laser or surveying instrument before leveling the supports.
Shop Drawings
Project drawings showing the floor layout, elevations, support configuration, openings, and accessory details for coordination and review.
Spreading
Distributing pedestal assemblies and other understructure components across the work area before final positioning and attachment.
Stanchion
Another term sometimes used for an access floor pedestal.
Starting Point
The selected location from which the floor layout and initial panel rows are established.
Static Load
A load that stays substantially constant during evaluation, unlike a moving or impact load.
Stringer
A horizontal member connecting pedestal heads, forming part of the supporting framework.
Stringerless System
An access floor system without connecting stringers. Depending on the design, panels may be corner-fastened or rest freely on pedestal heads.
Subfloor
The supporting surface below the raised floor, commonly a concrete slab. Its condition influences support attachment and installation.
Swivel Pedestal Head
An adjustable-angle head used to support panels on an inclined surface such as a ramp.
T
Threshold
A transition at a doorway or between floor surfaces, coordinated with the access floor height and finish.
Transit
A surveying instrument used to establish elevations or angles for floor layout and leveling.
Trim Angle
An angled profile used to finish or support an exposed edge, depending on the manufacturer's detail.
U
Underfloor Air Distribution (UFAD)
A system supplying conditioned air through outlets in a raised floor from an underfloor air space.
Understructure
The supporting assembly beneath the panels, including pedestals, stringers where used, and related attachment hardware.
Uniform Load
A load spread across an area, usually expressed per square foot or square meter. It differs from a small-area point load.
V
Vertical Clearance
The usable space below the panels. It can be less than FFH because panel depth, stringers, and services occupy part of that height.
Void
The space between the supporting subfloor and the underside of the raised flooring; it may contain services without functioning as an air plenum.
W
Woodcore Panel
An access floor panel with an engineered wood core, often enclosed or faced with other materials. Moisture resistance and structural performance depend on its construction.
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