Report on Heat, Light, and Sound Principles in Local Authority Buildings
Assignment Brief
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Learning Outcomes |
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LO1: Understand scientific principles relating to heat, light and sound. |
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LO2: Use a range of equipment designed to illustrate each scientific principle. |
Project Brief:
Background Scenario
You are currently working for a Local Authority in the technical services department offering a range of services to support the local authority in relation to their building stock. Your work covers a range of technical issues associated with existing and new buildings that come under the local authority ownership. You have been asked to produce a report for the Technical Director relating to the following tasks.
Task 1
The local authority are considering upgrading some of their domestic housing stock by retro fitting an insulation system to houses built in 1950 consisting of 112mm clay common brick inner leaf 50mm cavity and 112mm clay facing brick outer leaf.
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Calculate the U Value of the existing wall if the clay bricks have a thermal conductivity for external skin of brick 0.84 W/ m K and internal skin of brick 0.62 W/ m K. The plaster is 16mm thick with a thermal conductivity of 0.16 W/ m K. The internal surface resistance is 0.123 m2 K/W external surface resistance is 0.055 m2 K/W, the cavity has a resistance of 0.18 m2 K/W.
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Calculate the additional thickness of insulation required to improve the U value of the wall to 0.3 W/m2 K. The insulation will have a thermal conductivity value of 0.025 W/ m K.
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Describe what instrument could be used to assess the existing thermal performance of the wall.
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Using annotated section diagram show how you could improve the thermal performance of this wall using suitable insulation materials
Task 2
The local authority have received a complaint from one of its tenants regarding dampness in the property and you have been called on to investigate the situation.
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Explain how you could differentiate between rising damp and surface condensation.
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Describe with the aid of sketches the type of instrument used to determine the relative humidity of the room in the damp building.
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Using the Psychometric chart determine the relative humidity of the room if the dry bulb temperature is 21degree’s centigrade and the wet bulb temperature is 19 degree’s centigrade. Comment on your result in relation to the damp problem suggesting remedial action to cure the problem.
Task 3
The local authority have taken over an existing building to use for offices of their technical services department. The current lighting system in place is very poor and needs to be replaced with new lighting system.
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Describe the type of instrument that you would use to determine the current lighting levels in the building.
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Determine the number of lamps for a new lighting system for seminar room in the building that has the following dimensions 20m length, 10m width, 2.7m high. The new lamps will be 65W with luminous efficiency of 80 lm/W. Luminaires will be recessed Louvre 50% down light output ratio. Reflectance value of ceiling to be 0.7 and walls 0.5. Assumed Maintenance Factor or Light Loss Factor of 0.85. The required service illuminance will be 500 lx for the room. The table surface will be 800 mm above the floor level.
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Check the spacing for the lamps and suggest a suitable layout for the lighting system. Draw this to a suitable scales
Task 4
The sound quality in the room used in task 3 above needs improvement in relation to new partition work between offices and the acoustic performance of a proposed seminar room.
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Describe the basic principle of good sound insulation in partition used between two rooms in relation to its construction.
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Describe the type of instrument used to measure sound.
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Determine the combined sound reduction of a partition if the wall has a sound reduction index of 40db and the door has a sound reduction index of 25db. The overall dimensions of the wall are 20m in length and 2.7m high. The dimensions of the door are 2100mm high by 900m wide.
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Determine the ideal reverberation time of a seminar room. Briefly explain what measures could be adopted to control the actual reverberation time of the room to obtain the ideal reverberation time.
The above should be presented in report format with introduction, conclusion and recommendations. You should use number referencing system 1.0 1.1 - 2.0 2.1 etc with headings. Drawing should be hand drawn using ruler and annotated but not to scale unless stated in the task and should be put in the appendix at the rear making reference to them in the main body of report. The report should be submitted as a PDF file via Turn IT IN.
Sample Answer
Introduction
This report explores the practical application of scientific principles relating to heat, light, and sound within the context of a local authority’s building management. The aim is to assess thermal performance, lighting design, and acoustic quality in residential and office buildings. Each section applies scientific theory to real-world scenarios, with calculations and recommendations for improving building efficiency and comfort.
Task 1 – Heat and Insulation
Calculation of U-Value for Existing Wall
The U-value represents the rate of heat transfer through a building element. It is calculated using the formula:
U = 1 / (Rsi + R1 + Rcavity + R2 + Rplaster + Rse)
Where:
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Rsi = internal surface resistance = 0.123 m²K/W
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R1 = internal brick resistance = thickness / thermal conductivity = 0.112 / 0.62 = 0.181 m²K/W
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Rcavity = 0.18 m²K/W
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R2 = external brick resistance = 0.112 / 0.84 = 0.133 m²K/W
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Rplaster = 0.016 / 0.16 = 0.1 m²K/W
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Rse = 0.055 m²K/W
Total resistance Rtotal = 0.123 + 0.181 + 0.18 + 0.133 + 0.1 + 0.055 = 0.772 m²K/W
U = 1 / 0.772 = 1.295 W/m²K
So, the existing wall has a U-value of approximately 1.30 W/m²K, which is quite poor for thermal performance.
Additional Insulation Thickness Required
We need to improve the U-value to 0.3 W/m²K.
First, find the required total resistance:
Rrequired = 1 / 0.3 = 3.33 m²K/W
Additional resistance needed = Rrequired - Rexisting = 3.33 - 0.772 = 2.558 m²K/W
Thickness of insulation = required resistance * thermal conductivity = 2.558 * 0.025 = 0.064 m
Therefore, an insulation thickness of about 64 mm is required to achieve a U-value of 0.3 W/m²K.
Instrument to Assess Thermal Performance
A thermal imaging camera can be used to detect heat loss areas and assess insulation performance. It identifies temperature variations on the surface of walls, allowing detection of cold bridges or areas with poor insulation.
Improving Wall Performance
The best approach would be to install external wall insulation using rigid polyurethane boards or expanded polystyrene sheets. These materials offer high insulation value for minimal thickness. An annotated section diagram would show the insulation layer fixed externally, finished with a render coat for weather protection.
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