Specification guide & definitions

PSA v BSEN specification guide

In order to assist specifiers in determining the actual performance specification that is appropriate the Access Flooring Association (AFA) has issued a Specification Guide which attempts to show a comparison between the PSA & BSEN12825. It should be noted however that these two standards are not equivalent.

PSA Spec Grade
Static loadings
Concentrated loads (Min) Uniformly distributed load (Min)
Typical uses Comparable (not equivalent) BS EN 12825 classification
Extra Heavy Grade 4.5 kN over 25 mm square† 12.0 kN/m² Main frame computer rooms with heavy equipment; Other special applications No comparable classification
Heavy Grade 4.5 kN over 25 mm square 12.0 kN/m² Computer rooms; Telephone exchanges; Public areas; Control rooms Class 6/3/A/2
Medium Grade 4.5 kN over 300 mm square 3.0 kN over 25 mm square* *8.0 kN/m² General office use with heavy equipment; Educational accommodation; Public areas Class 5/3/A/2
Light Grade 2.7 kN over 300 mm square; 1.5 kN over 25 mm square 6.7 kN/m² General office use; no heavy equipment Class 3/3/A/2 (minimum)
No comparable grade Small offices with low occupancy levels; limited use of filing cabinets, etc. Class 1/3/A/2 or Class 2/3/A/2 (minimum)


Raised access floors are rated according to the following load carrying capabilities:

Point load

Uniformly distributed load

Ultimate load

Rolling load

† this grade must also sustain a total load of 11 kN applied equally on four points, each point 25 mm square on a 200 mm x 200 mm square configuration at any point on
the system.
* British Council for Offices Guide to Specification 2014
Consideration should be taken regarding use of the raised floor as a working platform during construction, pedestrian traffic in escape routes, main thoroughfares etc. & how furniture / filing cabinets and other heavy equipment etc. will be taken into the building (across the floor) especially if the lower classification is being considered.
Classification by grade is based upon a complete system i.e. panels & under structure supplied by the same manufacturer.
Performance verification for PSA MUST be by an “approved independent laboratory”.
The Access Flooring Association (AFA) suggests that any independent test certificate should be no more than 5 years old.