Siniat will assume a default 200Pa internal pressure when specifying systems. If an internal space has a greater internal pressure this must be communicated as it will effect the system design.

Partitions, shaftwalls and linings are limited to the lateral deflection that may occur within the system and a higher pressure will increase this deflection. To keep the system within its acceptable lateral deflection window, the maximum height of the system will reduce as internal pressure increases. 

Situations where internal pressure may increase beyond the default allowance are large spaces, cinema auditoria for example, areas with roller shutter doors to external  which are in constant use, multistory risers.