Hanging sculpture commission with load and fire constraints
Year 11 student Luke has been asked by the student council to make a hanging sculpture for the school foyer. The space is 2.5 m wide, 1.8 m deep and 4.2 m high, with two ceiling anchor points rated at 15 kg each. The brief is 'a colourful sea-creature made from recycled plastic bottles and fishing nets', with a budget of €80, installed for six weeks in spring above a bench used by students. The school's fire officer will only approve materials that are non-combustible or documented as fire-retardant, and suspended loads must not exceed the anchor rating. Luke's first maquette, made from bottles, netting and hot glue, collapsed when 1.5 kg was hung from it. He has four weeks and one adult technician available for two afternoons. He wants to use spray paint and expanded polystyrene for the eyes.
1. Assess whether Luke's brief is feasible as described. Identify the critical safety and material constraints and state what must change.
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It is not feasible as described. The two anchors are rated at 15 kg each, but that is a static rating; a hanging sculpture needs a safety factor for dynamic loads, hardware and movement, so the working load should be well below 30 kg total. Luke's maquette already failed under 1.5 kg, showing that hot glue and netting are not a structural system. The fire officer requires non-combustible or documented fire-retardant materials: expanded polystyrene is unsuitable, spray paint adds flammable solvent and fumes, and untreated fishing net is doubtful. The bench beneath creates a fall zone and head-contact risk. The four-week timetable with two technician afternoons is tight but possible only if the piece is modular and prefabricated. Changes: reduce span or weight, build a rigid lightweight frame, use mechanical fixings and steel cable, replace polystyrene with a non-combustible core, use water-based paint, and obtain material documentation. A load test and risk assessment must precede installation.
2. Propose a revised construction and testing plan that keeps the sea-creature idea but meets the constraints.
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Keep the concept but change the structure. Build a central welded steel or aluminium frame, or a timber frame treated to the required standard, sized so the complete piece stays below about 10 kg-roughly one-third of the combined anchor rating. Form the creature's body from HDPE bottles threaded on stainless steel wire and fixed with cable ties, not hot glue; bottles are hollow and light, and mechanical connections can be inspected. Use offcuts of fire-retardant-treated fabric or painted aluminium mesh for fins instead of untreated net. Make the eyes from painted lightweight board or foil-covered spheres, not polystyrene. Paint with water-based acrylic and allow full curing. Test progressively: weigh each module, hang it from a test rig, then test the assembled piece at 1.5 times its working weight with the technician present. Record every test. Install with secondary safety cables, keep the bench area clear during installation, and have the fire officer approve samples before painting.
3. What should Luke document in his portfolio so the project counts as sustained coursework rather than a one-off commission?
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The portfolio should show the project as an investigation, not just a finished object. Include the brief and constraints, the failed maquette with an annotated explanation of why it collapsed, alternative sketches, material samples, and the fire documentation. Record load calculations and test results, including the weight of each module and the safety factor used. Photograph the construction stages, especially the mechanical fixings and any changes forced by safety advice. Add a risk assessment and the installation plan. Most importantly, reflect on the trade-offs: scale versus weight, recycled plastic versus fire performance, visual impact versus the bench below. Show the negotiation with the fire officer and technician. Label the final photos with dimensions, materials and location. This evidence maps onto assessment criteria for research, experimentation, problem-solving and realisation, and it distinguishes Luke's design decisions from the technician's fabrication.