Transformable structures in architecture can adapt their shape or function offering dynamic answers to modern problems, such as deployement for creating temporary spaces, responsiveness to climatic influences and change of use, in a society which embraces the concept of sustainable design. Depending on how the transformation is carried out, transformable structures can be deployable or demountable, as a kit-parts system. According to their structural system, deployable structures can also be classified in four main groups: spatial bar structures; foldable plate structures; tensegrity structures; and membrane structures. In this paper, a review on the deployable structures based on foldable plate structures will be done.

HVAC system represent major source of buildings internal noise and therefore they are designed to provide a human acoustic comfort besides the thermal and air quality requirements. The paper experimentally investigates three types of commercial air handler units (AHU) with different ducts cross-section sizes and inlet-outlet configuration. The measurements are performed in an anechoic room. The measurements are carried out at different fan's speeds, ranging the power-charge from 30-100% while the duct air flow is slowly adjusted from full open to full closed, between 0-500 Pa. The sound pressure levels of the radiant units are rated using NR curves. Also, the supply and the outdoor ducts sound levels are compared in order to point the frequencies where the noise must be reduced. Third-octave band analysis of random noise of an air handling unit from a HVAC system is realized, using measurement procedures that agrees the requirements of the ISO 3744:2011 and ISO 5136:2010 standards. The comparatively results highlight the effects of the geometry, air flow pressure and power-charging dependencies upon the sound level. This is the start for a noise reduction strategy.