A detection system for measuring the presence of one or more conditions in a predetermined area, comprising: a fiber harness having at least one fiber optic cable for transmitting light (21, 23), the at least one fiber optic cable defining a node arranged to measure the one or more conditions, wherein the node is arranged such that light scattered by an atmosphere adjacent the node is received by at least one core (40, 42) of the fiber optic cable; a control system operably connected to the fiber harness, the control system including: at least one light source for transmitting light to the node and at least one light sensitive device configured to receive scattered light associated with the node; wherein the control system is configured to analyze more than one signal corresponding to more than one wavelength of the scattered light associated with the node to determine at least one of a presence and magnitude of the one or more conditions at the node; characterised in that the control system is further configured to analyze the more than one signal corresponding to the more than one wavelength of the light reflected back down the at least one core of the fiber optic cable at the interface between said at least one core and the ambient atmosphere to determine a temperature near the node. a fiber harness having at least one fiber optic cable for transmitting light (21, 23), the at least one fiber optic cable defining a node arranged to measure the one or more conditions, wherein the node is arranged such that light scattered by an atmosphere adjacent the node is received by at least one core (40, 42) of the fiber optic cable; a control system operably connected to the fiber harness, the control system including: at least one light source for transmitting light to the node and at least one light sensitive device configured to receive scattered light associated with the node; wherein the control system is configured to analyze more than one signal corresponding to more than one wavelength of the scattered light associated with the node to determine at least one of a presence and magnitude of the one or more conditions at the node; characterised in that the control system is further configured to analyze the more than one signal corresponding to the more than one wavelength of the light reflected back down the at least one core of the fiber optic cable at the interface between said at least one core and the ambient atmosphere to determine a temperature near the node. at least one light source for transmitting light to the node and at least one light sensitive device configured to receive scattered light associated with the node; wherein the control system is configured to analyze more than one signal corresponding to more than one wavelength of the scattered light associated with the node to determine at least one of a presence and magnitude of the one or more conditions at the node; characterised in that the control system is further configured to analyze the more than one signal corresponding to the more than one wavelength of the light reflected back down the at least one core of the fiber optic cable at the interface between said at least one core and the ambient atmosphere to determine a temperature near the node.