The CFD models JASMINE and SOFIE have been used to simulate the convection currents and thermal conditions inside one steel compartment due to a fire in an adjacent compartment. The impact, on the thermal environment inside the steel compartment, of the positioning of the adjacent fire in both 'side-heated' and 'bottom-heated' configurations has been examined. For the side-heated configuration, the predicted thermal conditions inside the steel compartment, based on a standard 'hydrocarbon' specification for the fire source in the adjacent compartment, have been compared with a full-scale experiment using a liquid fuel spray burner as the fire source. For the bottom-heated configuration, since there were no experimental data available, the predicted flow patterns inside the steel compartment were supported by additional two-dimensional steady-state CFD simulations in a 3m high rectangular geometry for aspect ratios ranging from 1: 1 to 1:8 by enforcing both horizontal and vertical temperature gradients.