The Siniat Independant Wall Lining systems maximum height is dependant on a number of factors such as the stud specification (size, gauge and centres) and board layers and type applied to the stud frame. 

The heights quoted in the Siniat literature for cold state are based upon L/240 which limits the mid height lateral deflection of the specified build up. Fire state heights where applicable may have a reduced maximum height from the cold state due to the effects of exposure to high temperatures and limitations and/or the tested height in the laboratory.

Example below from the Siniat Lining Section of the Drywall Manual:

In this case the maximum system height is 4800mm (mechanical capability if no fire resistance is required) but if you need to achieve the quoted fire resistance the height is limited to 4000mm.