SECTION A Question 1
a) The reverberation time of a hall is being measured using a loudspeaker to generate a steady noise level which is then switched off, allowing the sound to decay. Describe how you would calculate the reverberation time, T60, from the decay curve – add a sketch to aid your explanation [4 marks]. (Word limit: 150 words.)
b) When the loudspeaker is on, the broadband noise level is 100dB in the hall. When the loudspeaker is off, the background noise level of the hall is 50dB because there is a fairly noisy air conditioning system in operation. Can you still use the measured decay curve to calculate the reverberation time, and if you can, how would you do it? [2 marks]. (Word limit: 100 words.)
c) The acoustic quality of a concert hall for unamplified orchestral music depends on the design. In particular, the shape of the hall plays an important role in early lateral reflections; consequently, the spatial impressions of the music from the stage can be quite different in different halls. Focusing on spatial impression and early reflection, describe acoustic characteristics associated with (a) shoebox shaped halls and (b) halls where the audience surround the stage with vineyard seating on all sides [8 marks]. (Word limit: 300 words. Sketches may be added to aid your explanation)
d) Wood veneered panel is being considered as a finishing material of the concert hall to provide strong reflections and sufficient reverberation time; however, it must be installed with care. Describe a potential acoustic problem with the use of wooden panels in a concert hall and two (2) ways to avoid this problem [3 marks]. (Word limit: 120 words.)
e) Outside the hall there is a garden, however the nearby noisy roads mean that it is not particularly well-used. A re-design of the garden is being planned using the concept of Module Code: ARCH311 Page 3 of 5 Continued soundscape. Describe the advantages of using water sounds in the soundscape design [4 marks]. (Word limit: 120 words.)
f) Many countries have announced regional and national lockdowns to reduce the spread of COVID-19. Restrictions on the movement of people and transportation have brought several changes to the urban environment such as air quality and noise. Discuss possible changes in major indoor and outdoor noise sources and annoyance during the lockdown compared to before lockdown [4 marks]. (Word limit: 150 words.)
a)In a school classroom, what are typical acoustic design criteria to make sure that a teacher’s voice can be heard clearly above the background noise [2 marks] (Word limit: 30 words).
What are the sound pressure levels at a distance of 1m from a person’s mouth for a normal voice and a raised voice [2 marks]. (Word limit: 60 words)
If a teacher speaks with a raised voice, calculate the sound pressure level of the speech at a distance of (1) 2m and (2) 4m from the teacher’s mouth [2 marks].
A new secondary school building is being designed and there is a suggestion from the school governors that it should be open-plan with no walls between the classrooms and the main atrium. This means that noise will be transmitted between the classrooms and the atrium making them both noisy. The noise that enters an empty classroom from the atrium causes the background sound pressure level inside that classroom to be 58dB. Based on the above calculations for a teacher speaking, discuss the problems of speech intelligibility that would occur with this potential design [6 marks] and discuss design changes that could minimise these problems [5 marks]. (Word limit: 300 words. Use diagrams to illustrate your answers where appropriate)
b) A school has some old classrooms that were built in the 1970s using a prefabricated, portable construction. Two adjacent classrooms are separated by a moveable partition wall for which the airborne sound insulation is inadequate. The school wants to replace this partition with a permanent, fixed wall. Describe a suitable wall construction and give reasons for your choice of construction and materials as well as indicating any important detailing considerations at the floor and ceiling junctions [6 marks]. (Word limit: 250 words. Use diagrams to illustrate your answers where appropriate)
To maintain a physical link between the two classrooms, the school would like to know whether it would be possible to include a door without reducing the airborne sound insulation provided by your proposed wall construction. Give two reasons why the inclusion of a door would, or would not, reduce the airborne sound insulation of your particular choice of wall [2 marks]. (Word limit: 100 words.)
a) Using annotated diagrams, briefly explain three (3) types of natural ventilation strategies, including the limit of their effectiveness [6 marks].
b) Explain in detail what is meant by “mixed mode” ventilation [5 marks]. (Word limit: 100 words.)
c) With the aid of annotated diagrams, explain the basic working principles of a displacement ventilation (DV) system, clearly describing the vertical profiles of temperature and pollutants. Please comment on how this system may be more efficient to contain COVID-19 and other air-borne diseases. [14 marks] (Word limit: 200 words.)
a) Heat pumps can be used to remove heat from a relatively cold area to a hotter area. With the aid of an annotated diagram indicating the source of the heat, the sink of the heat, and an arrow for work required, explain the basic theory of a heat pump [5 marks].
b) For a reversible heat pump / refrigeration system, derive and explain the relationship between its COP in heating mode and its COP in refrigeration mode. Use diagrams and formulae to aid your explanation. [8 marks]
c) The UK government has pledged to install 600,000 heat pumps every year by 2028, with the aim of phasing out gas boilers in the future. Comment briefly about this plan, giving the rationale behind this strategy and potential obstacles that needs to be overcome [12 marks]. (Word limit: 250 words.)
Type Of Service: Academic paper writing
Type Of assignment: Coursework
Number of sources: 0
Academic Level: Senior(College 4th year)
Paper Format: Harvard
Line Spacing: Double
Language style: UK English