A storage system is described where goods are stored in containers (10) and the containers (10) are stored in stacks (12). Above the stacks (12) runs a grid network of tracks on which load handling devices (30) run. The load handling (30) devices take containers (10) from the stacks (12) and deposit then at alternative locations in the stacks or deposit then at stations where goods may be picked out. The framework (14) may be provided with one or more of the following services: power, power control, heating, lighting, cooling, sensing means, and data logging means. The system describes a method of partitioning the storage system to prevent the spread of fire or prevent damage caused by sprinkler activation.