Access Floor Glossary

Parete Access Floor Systems 

Steel/concrete composite access floors with different coverings

Access Floor 

A rigid floor surface raised above the sub-floor comprising of load-bearing removable panels. The access floor creates an underfloor plenum suitable for the provision of building services.


An access floor panel (sometimes called a 'Tile'), of standard size 600mm x 600mm.

'Bare' Panel 

The panel has a 'bare' surface finish ready to accept on-site floor covering supplied by others.

'High Pressure Laminate' (HPL) Panel

The panel has a factory bonded, anti-static 'high pressure laminate' (HPL) surface finish ready for installation and immediate use.

Finished Floor Height (FFH)

The nominal vertical dimension measured from the sub-floor to the top surface of the installed access floor (excluding floor coverings).


Available space between the underside of the panels of the access floor and the sub-floor.

Plenum Height

Distance between the highest point of the sub floor and the lowest point of the underside of the access floor.



The assembled array of underfloor structure including pedestals, stringers, gaskets, and screws etc used to provide a rigid panel support system.


A rectangular steel tube connecting pedestals in a horizontal plane to form a rigid understructure grid. The stringers provide edge support for the panels and additional bracing for the understructure.

Stringer Gasket

Attaches to the top of a stringer – Stringer gasket provide a conductive path for static dissipation, increased sound absorption, and also act as a plenum seal.

Stringered Understructure

The corner pedestals are connected by bolted-stringers to form a rigid understructure grid.

Stringerless Understructure

As the name implies, the understructure does not include any stringers and uses only corner-support pedestals to support the panels.


The vertical support component of the understructure. Assembly of an adjustable pedestal head and pedestal base.

Adjustable Pedestal Head

Top section of the Pedestal - Assembly of head plate, threaded stud and locking nut used to provide an adjustable range for the pedestal.

Pedestal Base

Bottom section of the Pedestal - Assembly of base plate and steel tube or, base plate and threaded stud in low finished floor height applications.

'Field' Freelay Gasket

Attaches to top of the Unifix pedestal - Self-locating plastic gasket used for laying Freelay Access Floor panels.

'Perimeter' Pedestal Gasket

Attaches to top of the perimeter pedestal - Self-locating plastic gasket with 2 dividing nibs used to provide support for panels at perimeter regions.

Test methods

Concentrated Load

The load applied to the centre of a panel through a 25 x 25mm square indentor under test conditions (sometimes called the 'design load').

Ultimate Load

The load applied to the centre of a panel through a 25 x 25mm square indenter in various locations (under test conditions) which will cause failure.

Uniformly Distributed Load

The load applied to the access floor system over a 1 square metre surface area under test conditions.

Rolling Load

The load applied through a wheel mounted on 3 adjoining panels under test conditions. The wheel traverses at least one full panel to provide an indication of performance under dynamic loads.

Impact Load

The load applied by dropping a bag of a specific weight onto a spreader under which is located a 25 x 25mm square indenter.

Working Load

Load given by dividing the ultimate load by the safety factor (ultimate load is sometimes called failure load and working load is sometimes called design load as well as nominal load)

Electrostatic Resistance

A test result measuring the surface and bulk resistance in a panel and understructure system to determine how the system will provide a path for dissipation of electricity to earth.


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