building science plastics

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BUILDING SCIENCE 

PART (1)

Dr f Dejahang (BSc CEng, BSc (Hons) Construction Mgmt, MSc, MCIOB, PhD)

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Building scienceBuilding science and buildingengineering are fields ofstudy concerned with: the technical performance

of buildingsbuilding materialsbuilding systems

Building scienceThe area is broad enough toinclude:construction technologymaterial scienceurban designArchitectureheat and mass transport

physics

Building sciencedesignconstructionmaintenance of buildings and

StructuresBuilding and Civil Engineering

represent a significant portion of the gross domestic product for countries of the developed world.

Building scienceOperating costs (energy,

maintenance, cleaning and repairs) are also multi-billion pounds expenditure.

Building scientists and engineers seek to improve the manner in which buildings are constructed and maintained to ensure:

Building sciencelong building lifeto improve building performance throughout the expected service life

to allow demolitionReuserecycling

Building scienceBuildings and Climate ChangeThe buildings we live and work in

could be very different in the future if our climate does change as predicted.

Changes in the weather, such as with rainfall, wind and the frequency of storms will affect the way our homes and offices are designed and constructed.

Building scienceAdapting Buildings for Climate Change There is now a clear and overwhelming

opinion that the earth’s climate is being affected by human activities, which is largely due to burning fossil fuels. 

Even the most optimistic projections indicate that some climate change is inevitable. 

The UK Climate Impacts Programme (UKCIP) anticipates that by 2080

Building science Summer temperatures will rise by 1 to

5ºC. Winter storms and heavier winter

precipitation will be more frequent. Summer precipitation will decrease by up

to 60 per cent. Impacts of climate change on the built environment may include increased risks of flooding, overheating, storm damage and subsidence.

Building science

At the current rate of new andReplacement building by2050, it has been estimatedthat around 70 per cent ofbuilding stock will consist ofexisting buildings.

Building scienceAreas for consideration are asfollows:-Heat gain reductionEffective thermal massVentilation strategyActive coolingEnable future adaptabilityProject Learning

Building scienceFig-1

Natural air ventilation-Natural cooling system

Building scienceHeat gain reduction Cooling requirements for buildings are

largely affected by heat gained from solar radiation.

Reduction of solar heat gain can very effectively decrease the energy consumption of buildings. Some areas for consideration in building design in order to minimise solar heat gain are as follows:

Building science Glazing - extent, orientation and specification of

glazing Use of solar shading Ventilation – use of natural cooling Building footprint – use of narrow building

footprints to allow passive cooling and heating and prevent deep floor plans

Thermal Mass – consideration of building materials, radiant barriers, green roofs etc. to keep heat in building where require and to prevent excessive heat gain through fabric

Building sciencePlastics-Building & Construction residential homes to commercial buildings hospitals to schools architects and designers rely on plastics to help

maximize: energy efficiency durability and performance.In addition to potentially lightening a structure’senvironmental footprint properly installed plastic building products can

help reduce energy and maintenance costs over many years.

Building scienceEnergy Savings A one-year study1 found that the use of plastic

building and construction materials saved 467.2 trillion Btu of energy over alternative construction materials.

That’s enough energy saved over the course of a year to meet the average annual energy needs of 4.6 million U.S. households.

Following are some examples of plastic building products that promote the efficient use of energy and other resources:

Building scienceRoofingRoofing systems made with spray

polyurethane foam (SPF) offer durability, energy savings and moisture control.

This foam can be used to cover an existing roof, helping to reduce the amount of building materials sent to landfills.

Building scienceWalls In walls, the use of structural insulated

panels (SIPs) made with expanded polystyrene (EPS) can help homeowners save hundreds of pounds annually on heating and cooling bills.

Savings vary by material and products. EPS starts out as a plastic pellet and ends

up as nearly 95 percent air, a very effective insulator.

Building science Vinyl is increasingly found in durable, easy-to-clean vinyl

wall coverings It requires only half as much energy to manufacture as

the same amount of paper wall coverings. Windows Plastics also rival traditional materials for windows and

frames. For example, polycarbonate—a material also used in

eyeglasses—is used in windows. These lightweight, shatter-resistant plastic products have

low thermal conductivity, which can help to reduce heating and cooling costs.

Building scienceVinyl window frames save the nearly

2 trillion thermal units of energy per year (USA)

helping reduce the greenhouse gas emissions associated with energy generation—all the while cutting maintenance time, materials and costs.

Building sciencePipingPolyolefin, polyvinyl chloride (PVC),

and acrylonitrile butadiene styrene (ABS) pipes and fittings, offer excellent fusion integrity for continuous pipeline systems

helping to eliminate potential leak points where water could be wasted.

Building sciencePlastics in Building and Construction The Building and Construction sector -

currently the second largest user of plastics in Europe

is expected still to grow substantially in the future.

Plastics have over the years become a material of choice for achieving economic and environmental balance between technological challenges and functional design.

Building sciencePlastics in Building and Constructionapplications plastics for decorative laminates plastics for drainage and irrigation pipes plastics for drinking water pipes plastics for electrics and electronics plastics for fittings plastics for floor and wall coverings

Building scienceplastics for insulation materialsplastics for roofingplastics for sewer pipes and

ductsplastics for waterproofingplastics for window and door

profiles

Building sciencePlastics Features and Advantages in Buildingand Construction durability, corrosion resistant cold, heat sound insulation for energy saving noise reduction cost efficiency light weight

Building science maintenance free innovation applications with unlimited choice of

surface, colours and materials for creative design

recyclabilityThermoplastic and Thermosetting A thermoplastic (sometimes written as thermo

plastic) is a type of plastic made from polymer resins that becomes a homogenized liquid when heated and hard when cooled.

Building scienceWhen frozen thermoplastic  becomes glass-like and subject to

fracture.These characteristics, which lend

the material its name, are reversible.

That is, it can be reheated, reshaped, and frozen repeatedly.

This quality also makes thermoplastics recyclable.

Building science Thermoplastic Coaters Plastic Coatings - ISO 9001:2000 apply a

variety of thermoplastics  www.plasticcoatings.co.uk Sometimes, thermoplastics are confused

with thermosetting plastics. Although they may sound the same, they

actually possess very different properties. thermoplastics can be melted to a liquid

and cooled to a solid,

Building scienceThermosetting plastics chemicallydeteriorate when subjected to heat.

Building scienceThermoplastic molecules

Building science What is the difference between thermo

plastic and thermo-setting plastic?Answer A thermoplastic can be re-melted and reused. A Thermoset cannot. An analogy would be like cake and butter. The cake would be analogous to thermosets. Once it's baked (cured) you cannot re-bake it. Butter would be analogous to thermoplastic. Once it's melted, it can be re-melted and reused.

Building science Heat is used to raise the temperature of

both the Thermoset and thermoplastic until they become a fluid.

They can be injected, poured, transferred into a mould.

The hot thermoplastic is injected into a cold mould, where it then is cooled down into its final shape, then ejected out of the mould.

The Thermoset is injected into a hot mould, where it is cured, then ejected out of the mould. 

Building scienceWhat Is Plastic?  A plastic is a type of synthetic or man-made

polymer; similar in many ways to natural resins found in trees and other plants.

Webster's Dictionary defines polymers as: any of various complex organic compounds produced by polymerization

capable of being moulded Extruded cast into various shapes and films, or drawn into

filaments and then used as textile fibber.

Building scienceCharacteristics of Plastics Plastics can be very resistant to chemicals Plastics can be both thermal and electrical

insulators Generally, plastics are very light in weight

with varying degrees of strength Plastics can be processed in various ways

to produce thin fibbers' or very intricate parts

Building science Polymers are materials

with a seemingly limitless range of characteristics and colours

Polymers are usually made of petroleum, but not always

Building scienceWhat are the advantages anddisadvantages of plastic? ADVANTAGES  Plastic is very useful in the building and

construction electronics (laptops wouldn't work well if they

were made from glass) Packaging transportation industries. 

Building scienceVery easy to make - water bottles,

plastic bags, pens, cups etc.the main advantages of plastic

materials are also the reason why plastic is such a problem

It lasts forever and it is very cheap to make. 

Building science

Lightstrong and cheap to produceIt does not decompose but it can

instead be recycledThis is done more easily than

producing more plastic. 

Building science Unlike aluminium cans, plastic bottles can

be re-used and stored over and over again.

Plastic is usually not breakable and it is see-through

It's light-weight and odourless Plastic comes from a natural resource (oil)

but CAN'T be re-made into bottles (but they can be re-made into other items)

It takes a long time to break down. 

Building scienceDISADVANTAGESIt is a compound that is indestructible,

even when it is melted the compound gas that is gives off is very harmful to our health and environment; it weakens the ozone layer.

Most plastic is produced from oilThe world is gradually running out of

oil.

Building scienceScientists are now developing plastics

that are made from vegetable oil and other organic matter.

This means that the plastic is more likely to be degradable, so it will be less of a problem in future. 

Another Disadvantage is pollution-Plastic accumulation in the environment is a looming catastrophe. 

Building science

It is cheap but it is not easily disposable so it is in a lot of landfills

Plastic bags can kill the marine animals and destroy the soil.