- Question 25 Marks A The Following Table Gives Details Of The Structure Of A Ceiling Type Commonly Encountered In Many D 1 (60.5 KiB) Viewed 51 times
- Question 25 Marks A The Following Table Gives Details Of The Structure Of A Ceiling Type Commonly Encountered In Many D 2 (60.5 KiB) Viewed 51 times
- Question 25 Marks A The Following Table Gives Details Of The Structure Of A Ceiling Type Commonly Encountered In Many D 3 (43.31 KiB) Viewed 51 times
Question 25 Marks a) The following table gives details of the structure of a ceiling type commonly encountered in many domestic houses. Taking into account the effects of thermal bridging, calculate the 'U' value for this structure. (15 Marks) Elements ( From Inside out) Internal surface thermal resistance R=0.1 m KW 13mm Plasterboard k = 0.25 W/mK 100mm high by 44mm wide timber joists at 500mm k (timber) = 0.13 W/mK centres with 100mm insulation between Jolsts k (insulation) = 0.04 W/mk Roof space thermal resistance 0.2 m KW External surface resistance R=0.04 m K/W b) Estimate the additional thickness of insulation, laid on top of the joists, required to bring the 'U' value to 0.2W/m²K. Assume a 'k' value for the insulation of 0.04W/mK, (10 Marks)
Question 1 25 Marks - (a) The exterior wall of a timber-framed house is constructed as follows from the inside out • Internal surface convective coefficient 8 W/m²K. • 13mm plasterboard k = 0.25 W/mK • 150 mm insulation (k = 0.04 W/mK), making up 87% of the area between 150 mm timber studs (k = 0.13 W/mK).. • 12 mm sheathing plywood (k = 0.13 W/mK). • A 75mm air cavity of thermal resistance 0.18 m²K/W. • 102mm brick outer leaf (k = 0.77 W/mK). • External surface convective coefficient 25 W/m²K Taking into account the bridging of the insulation by the timber studs, calculate the overall heat transfer coefficient for the wall. (15 marks) (b) Calculate the minimum thickness of insulation with a thermal conductivity of 0.027 W/mK, required to give the floor of a building, with a perimeter to area ratio of 0.4, an overall "U" value of 0.2 W/m²K (10 marks)