Abstarct: Free convection from horizontal pipes or tubes placed over a floor carrying cold fluid encounters in many refrigeration, air-conditioning and freezing equipments. Heat gain by such cylinders which have different boundary conditions from a horizontal cylinder surrounded by an infinite medium is not the same. Accurate thermal exchanges with environment for such cylinders are important for any design simulation. Heat transfer form a single horizontal cylinder surrounded by infinite fluid has been studied extensively but for a single cylinder close over a floor or an angle is not analyzed yet. In the present analysis, steady state two-dimensional laminar free convection heat transfer from a single horizontal, isothermal cylinder located above a nearly adiabatic floor and inclosed between two flat adiabatic walls is studied experimentally and numerically. For experimental measurements effects of cylinder distance from horizontal floor to its diameter (L/D) changes from 0.1 to 1.5 and vertical distance to its diameter (S/D) changes from 0.1 to 1, on heat transfer coefficient from cylinder are investigated for Rayleigh numbers 3×105 and 6×105.Cylinder diameter of 8 cm are tested in a control room for various cylinder surface temperature and room conditions