The invention relates to a system and method for determining and visualizing force flows in a bar supporting structure (1), which is preferably in the form of scaffolding, comprising a plurality of ladder or strut elements (5a-5c) which extend vertically and are set up in a disputed manner relative to one another and which are detachably connected via scaffolding couplings (7) to strut elements (6a-6d) extending diagonally and/or horizontally transversely thereto, wherein at least a load-critical part of the support elements (5a-5c) and/or strut elements (6a-6d) and/or scaffold couplings (7) of the bar structure (1) are provided with load sensors (8a-8c) for detecting static operating load values, the measured values of which are analysed in real time by a downstream analysis unit (9) for evaluating current load situations.

An indoor safety shelter appearing to be one file cabinet or a set of file cabinets is disclosed constructed with bullet-proof armor plates mounted on an interior support frame which protects one or more persons inside the shelter both from being discovered by and being harmed by an armed intruder in the case of a home or office invasion. The shelter can be assembled and disassembled on site providing for the ability of one or more persons protected inside the shelter to detach a plate or plates from one or more sides of the shelter if a bullet-proof door to the shelter, which is locked from the inside, becomes obstructed.

A safety system (1) for scaffolding on a construction site having a plurality of elongate scaffolding elements (5) connected together by a plurality of couplers (7) to form a scaffolding structure (2). One or more elements connected to one or more base plates supporting the structure on a surface. At least two safety monitors (10) spaced apart about said structure. Each said monitor having a power source, a sensor and a transmitter. The sensor sensing movement in said structure and transmitting a signal to a receiver to indicate movement in the structure.