Hi Have you tried the fire risk assessment guide for offices and shops. You may find more information on page 70. Ian

As SBH has indicated, you need to maintain the level of detection coverage as determined by your FRA (and not your fire alarm installers!). You may well need additional heads in carving up an existing larger area - whether they are fire resisting or otherwise to prevent a reduction in coverage. One option which may reduce costs in to stop the partition walls short of the ceiling, similar to what is permitted with an inner room situation. I could only imagine this would be possible for low risk premises, say offices with more than one MOE