Design Solution · HVAC & Energy
Design Solution · Dream about it
Plant sized to a quantified high-leakage tent envelope.
Air-permeability and thermal-gain modelling (CIBSE TM23 leakage rates, ~2 air changes/hour) sizes plant for a tent whose envelope cannot be sealed like a permanent building. Accepting and quantifying the leakage, rather than fighting it, sets realistic set-points and avoids over-sizing.
Engineering the HVAC for a temporary or semi-permanent tent structure requires accepting that the envelope will never behave like a conventional building, and the correct response is to quantify the leakage and model the plant around it rather than to assume air-tightness that will never be achieved. CIBSE TM23 leakage testing and empirical air-change rates for tent and tensile structures give the designer a defensible basis for load calculation, and the result — typically two or more air changes per hour from fabric infiltration — significantly changes the heating and cooling demand compared with a permanent building of the same floor area. The record carries no provided evidence, but the approach is sound engineering judgment rather than a novel claim. The practical value is in the word 'realistic': plants sized against a leaky envelope will be larger than a comparable permanent structure, running costs will be higher in cold or hot conditions, and set-point temperatures need to be set to what the plant can actually deliver rather than what occupants might expect from a well-insulated building. The risk is principally financial and occupant-expectation rather than technical — document the leakage assumptions in the brief so any future operator or tenant understands why the energy consumption profile looks the way it does.
#air permeability #tent #load modelling