Fire resistance performance is based on complete ‘elements’ such as a partition, wall, ceiling membrane or floor, rather than the individual plasterboards that only form part of these constructions.
Building Regulations Approved Document B and supporting documentation (such as HTM05 and BB100) require these separate ‘elements’ of the building to provide minimum periods of fire resistance, expressed in minutes (usually 30, 60, 90 or 120). These required durations are generally based on the occupancy, use and size of the building and further details can be found in various tables in Approved Document B.
If we take a partition as an example of an ‘element’, in addition to the plasterboard linings themselves the system will also consist of metal studs, head and base channels and screw fixings. Since it is not possible to build a plasterboard partition without a supporting framework all of these components are vital to the overall fire resistance performance of the partition, therefore the plasterboard cannot be considered on its own in terms of fire resistance.
Looking through the various GypWall partition sections of the WHITE BOOK you will see that different combinations of plasterboards and studs will provide different fire resistance durations. For example if we consider the GypWall CLASSIC system:
- Single layer 12.5mm Gyproc WallBoard each side of Gypframe 48 S 50 studs provides 30 minutes
- Single layer 15mm Gyproc FireLine each side of Gypframe 48 S 50 studs provides 60 minutes
- Double layer 15mm Gyproc WallBoard each side of Gypframe 48 S 50 studs provides 90 minutes
- Double layer 12.5mm Gyproc FireLine each side of Gypframe 48 S 50 studs provides 90 minutes
As you can see by varying the type of board and number of layers any of the commonly encountered fire resistance durations can be met. Partition fire testing is carried out in accordance with BS476: Part 22: 1987 and various factors will contribute to the overall fire resistance performance of a partition system in this test, such as:
- Partition height
- Board type, thickness and number of layers
- Staggered board joints
- Stud type, width and gauge
- Stud centres
- Screw fixing type, length and fixing centres
- Insulation type and thickness
- Jointing / plastering
- Fixing details at the partition head and base
Similar factors also exist for ceiling membranes and floor elements, therefore when considering any of our systems in terms of fire resistance reference should be made to the system performance tables for that type of construction in our WHITE BOOK. Each section of the WHITE BOOK organises our systems according to the fire resistance period and provides all of the vital construction and specification information for meeting that performance (such as stud type, centres, etc).
Further information about fire resistance performance can be found in WHITE BOOK Chapter 02 Section 01 Page 03 or refer to the FIRE BOOK.