Applications Of Plastics In Civil Engineering - How To Reuse Plastics

Applications of plastics in civil engineering building construction are many. The prime reason for this is the property of plastics which makes it durable, non-corrosive, low cost and many others.

There are two types of Plastics, namely Thermoplastic and Thermosetting plastics distinguished by the physical property.

Thermoplastics:

This type can be softened by heating after they have been cured and remoulding cycle can in theory be repeated an indefinite number of times but in practice some defects may eventually take place. The curing process is that by which the shape is moulded by heat and pressure to form the hard shape.

Thermosetting Plastics:

The shape is first prepared by softening under heat and then cured with the use of further heat. After this stage, no further heat will deform the moulded shape once chemical decomposition has occurred. In general these plastics have giant three dimensional molecules.

APPLICATIONS OF PLASTICS IN CIVIL ENGINEERING:

Plastics are manufactured in different forms such as moulding pipes, sheets and films. They are formed or expanded to produce materials of low density. Dissolved in solvents or dispersed as emulsions, they are used in paints, varnishes and adhesives. At present, plastics find use in buildings mainly in thin coverings, panels, sheets, foams, pipes etc. skilful use of plastics will expand the usefulness and life of conventional building materials and help them to function more efficiently and economically.

A wide range of applications of plastics in buildings are given below:

APPLICATIONS OF PLASTICS IN FAÇADE PANELS, EXTERIOR COVERING, CARPENTRY ETC.

Façade Panels:

1. Sandwich panels covering with PVC (polyvinyl Chloride), plasticized plates and polyurethane foams.

2. Sandwich panels – asbestos cement covering and polyurethane foam core

3. Sandwich panel – polystyrene foam core and various coverings

4. Sandwich panel – covering with polyester laminated sheet and polyurethane foam core

5. Sandwich panel – enameled iron covering and polyurethane foam core.

6. Sandwich panel – covering with polyester laminated sheet glued to asbestos cement and polyesterene foam core.

Exterior covering:

1. Polyester coated concrete by moulding from an existing plates.

2. Sprayed polyurethane with sand and gravel agglomeration.

3. Epoxy resins and polyesters on various supporting media

4. PVC plasticized plates (spraying, coating or adhesive films)

5. Polyester epidermis available as permanent shuttering

Weather Boarding

1. Polyester

2. PVC

3. Polymethyl methacrylate

Windows:

i. PVC casing on metal moulding

ii. Polyester laminated sheet on wooden moulding

iii. PVC – chlorinated polyethylene compound

iv. Methyl polymethacrylate

v. Polyester glass fibre and phenolic foam core

vi. PVC/ wood

Rolling Shutters

i. Plasticized PVC extruded sections

ii. Rigid PVC extruded sections

iii. Polyamide winding gear

Blinds and sun screens

Polyester, PVC

INTERIOR COVERING, FLOORS, WALLS, CEILINGS, DOORS, PARTITIONS ETC

Interior Covering

a) Wall Lining

i. Adhering films – vinyl coated fabrics or paper vinyl sheet doubling on fabric or paper etc.

ii. Sprayed lining polyurethane

iii. Laminabee – Molamine and phenolic plastics – polyester

iv. Wall tiles – polystyrene, PVC – tiles or mosaic

v. Coating – polyvinyl acetate

b) Floor Covering

i. Asbestos plastic slabs (asphalt tile type)

ii. Vinyl asbestos slabs

iii. Homogeneous semi-flexible vinyl slabs

iv. Flexible, homogeneous or multi-layered vinyl slabs.

v. Homogeneous vinyl carpets (a) stuck, (b) laid

vi. Vinyl carpets on felt (applied or coating)

vii. Multi-layered coating with cellular structure on fabrics

(a) Multilayered coating on cork structure

(b) Vinyl carpets on jute cloth.

viii. Thermosetting resin based covering

ix. Rubber covering

x. Synthetic fibre tensile covering (polyamides, viscose etc.)

Ceilings and Counter Ceilings

i. Translucent – polyester, PVC, polyamides, polyurethanes

ii. Opaque, extruded polyesterene or vinuyl co-polymers, impact type polystyrene

iii. Lighting – PVC, polymethylmethacrylate

ROOF COVERINGS, TIGHTNESS, DOMES AND LIGHTING ELEMENTS

Roof Covering

i. Flat or corrugated sheets – polyester, PVC, polymethylmethacrylate

ii. Curved sheets – reinforced polymer

iii. Domes – polyester, polymethylmethacrylate

iv. Casements – polymethylmethacrylate, reinforced polyester

v. Troughs – class / polyester

vi. Gutters – Rigid PVC polyester

vii. Downpipes – PVC

Roof Tightness

i. Polybutylene with or without glass cloth armature

ii. Butyl rubber

iii. Multilayered bitumen with PVC film screens and armatures

iv. PVC sheets

v. Welded polyester

SANITARY EQUIPMENT AND PIPING

Sanitary Equiment

i. Appliances

(a) Sinks – polymethylmethacrylate, polyester, polyamides

(b) Basins – polyester, polymethylmethacrylate – polyester / glass fibre

(c) Baths – polyester, polymethylmethacrylate

(d) Showers – polymethylmethacrylate, polyester

ii. Pipe works – PVC, phenolics, ABS – terpolymer

iii. Fittings – PVC and ABS – terpolymer – phenolic plastics

iv. Traps – polyamides

v. Water – finishings – polysterene and copolymers, polymer and copolymers, polyethylene

Insulation

Insulation materials and application of foams

i. Polystyrene

ii. PVC

iii. Phenolic

iv. Formaldehyde urea

v. Polyurethane

OTHER PROSPECTS

Some noteworthy trends in use of plastics are given below:

i. Concrete and mortar with thermosetting resin bending agents

ii. Thermoplastic and thermosetting resin covering applicable to facades and concrete epidermis

iii. New roof covering and roof tightening materials (accessory covering materials, tightness network), easy to place and standing up well to normal to wear

iv. Large foam component units and new shaping techniques

v. Developing techniques for quick shaping of plastic into large components

vi. Assembling and fixing processes more suitable for plastics

vii. New developments in sanitary equipment and piping, applying thermoplastic and thermosetting resins.

viii. New developments in the way of shuttering and of elements in permanent shuttering

USES OF PLASTICS IN BUILDINGS

No.	Material	Use	Form in which it is commonly used	Normal colour
1	Expanded polystyrene	Thermal insulation	Thin sheets in slabs 12mm thick	White
2	Expanded polyvinyl chloride (PVC)	Thermal insulation	Boards 20 to 50 mm thick	Yellow brown
3	Foamed urea formaldehyde	Thermal insulation	Foamed in situ	White
4	Foamed phenol formaldehyde	Thermal insulation	Sheets and blocks	Deep red
5	Foamed polyurethane	Thermal insulation	Sheets and blocks or foamed in situ	Brown
6	Expanded ebonite	Thermal insulation	Sheets	Brown or black
7	Polythene	Damp-proofing, plumbing	Thin sheets, pipes, cisterns	Transparent to black
8	Poly propylene	Domestic drainage, but water overflow tanks
9	Unplasticised PVC	Rainwater goods, ventilation, ducts, pipes of water mains
10	Acrylic resins	Sinks and baths		Various
11	Nylon	Cold water fittings, window furniture		Various
12	Phenolic resins	Adhesives for laminates		Dark
13	Melamine	Laminates	Sheets	Many

Low Cost Building Materials For Construction Of Low Cost Buildings

Construction of low cost housing by using the low cost building materials increases the access to buildings by low income group peoples. Low cost housing can be achieved by use of efficiet plannng and project management, low cost materials, economical construction technologies and use of alternate construction methods availabe. The profit gained from use of such methods can decrease the cost of construction and make the low cost housing accessible to all.

Materials for low cost housing

The use of low cost alternate building materials also prevents the rise of construction cost due to use of scarce building materials which eventually increase the cost of the project.

Selection of Materials for Low Cost Housing:

The first step to low cost housing material selection is to select ecofriendly building materials. This also enhanaces the sustainable design principle. The life cycle of a building os pre-building, building and post-building stages. Each stage of building should be such that they help conserve the energy. These three stages indicate flow of building materials through different stages of a building. Pre-building stage mainly consists of manufacture which is subdivided in processing, packing and transport. The building phase mainly consists of construction, operation and maintenance whilst as the last stage would be disposal where the material can be recycled or reused.

1) In Manufacturing of low cost building materials – Pollution prevention:

Manufacturing of building materials should be environment friendly. Efforts should be made to study and revise the technologies for producing good quality, efficient building materials and should improve the waste generation during manufacturing. These results in reduction of pollutants to environment.

2) Recycling of wastes in Manufacturing – The wastes which can be recycled can and used in masonries whilst as wooden wastes can be used in manufacture of plywood or soft boards. (Courtesy-BMTPC)

3) Reducing Energy Consumption and use of Natural materials – The total energy required to produce a material is called embodied energy. The greater a materials embodied energy; it requires a greater usage of non-renewable sources. It is therefore advantageous to use materials or composite materials prepared from the wastages. The natural materials such as stones, wood, lime, sand and bamboo can be used in ample where ever possible. The natural materials impact more sustainability to structures as well as they are friendlier to environment.

4) Use of Local material – The use of local materials reduces the dependence on transportation whose contribution to the building material cost is high for long distance. Use of locally available building materials not only reduces the construction cost but also are suitable for the local environmental conditions.

5) Energy Efficiency – Energy efficiently of a building material can be measured through various factors as its R value, shading coefficient, luminous efficiency or fuel efficiency. Energy efficient materials must reduce the amount of generated energy.

6)Use of non-toxic building materials: Use of toxic building materials can significantly impact the health of construction people and the occupants of the building. Thus it is advisable to use the non-toxic building materials for construction. There are several chemicals including formaldehydes, benzene, ammonia, resins, chemicals in insulations, ply boards which are present in furnishings and building material. The effect on health of these toxic materials must be considered while their selection and they should be used only where-ever required.

Higher air cycling is recommended while installation of materials having volatile organic compound such as several adhesives, paints, sealants, cleaners and so on.

7) Longitivity, durability and maintenance of building material: The use of durable cosntruction materials does not only enhance the life of the building but also reduces the cost of maintenance. The lower maintenance costs naturally save a lot of building operating cost. The materials used in building determine the long term costs of an operating.

8) Recyclability and reusability of building material: A material should be available in form which can be recyclable or reusable. Ex – the plastics waste can be used for recycling and producing newer materials. The scrap from steel can be used to manufacture the rcc bars, binding covers and other miscellaneous steel products in building construction.

9) Biodegrability –A material should be able to decompose naturally when discarded. Natural materials or organic materials would decompose very easily. It is also a very important consideration whether a material decomposes naturally or produces some toxic gases.

COMPOSITES AS BUILDING MATERIALS:

The composite building materials are made of composition of two or more materila which have enhanced property. Natural fiber materials are coming up as excellent substitutes for the prevailing building materials. Fibers likes jute, sisal coconut, ramie, banana are cheap and environmentally suited as they are made from natural fibers. They are also replacing the fiber reinforced plastics.

Composite building materials present immense opportunities to replace traditional materials as timber, steel, aluminum and concrete in buildings. They help in reduction of corrosion and their low weight has been proved useful in many low stress applications. Each type of composite has its own characteristic properties and thus useful for specific purpose.

Jute fiber reinforced polypropylene composites, coir fiber reinforced composites, sisal fiber and wollastonite jute pultruded composites are a few to be named. CBRI has developed MDF composite doors containing coir fiber, cashew nut, shell liquid (CNSL) as natural resin and Para formaldehyde as major constituents.

Many composite building materials are generated from glass fibres and industrial wastes. These materials are used for manufacturing of portable toiles, water storage tanks, outdoor furniture, bath tubs, interior decoration, basin, door, window frames etc. Thus the application of composite building materials in construction vary from cladding to internal furnishings and the owner highly benefits due to their application because of their light weight, resistance to corrosion and availability in different colours. Pultrusion is most cost effective method for producing composite profiles. It is commercially applicable for light weight corrosion free structures, electrical non conductive systems and so many other functions.

The pultruded items are recognized and recommended in the Global markets. Pultrated sections are well established alternative to steel, wood and aluminium in developed countries and catching fast in other parts of the world.

Plinth Area And Plinth Regulation Of The Building Construction

Plinth Area:

The minimum area of buildings of different classes shall be governed by the following:

In an industrial plot, the plinth area should not exceed 60% of the site area.

In a market area, the plinth area should not exceed 75% of the area of site, provided sufficient off-street parking facilities for loading and unloading of vehicles are provided on the same plot as the building.

In residential plots, the covered areas should be as given in the table 1.

S. No	Area of plot	Maximum permissible covered area
1	Less than 200 sq.m	66.66 % of the plot area on the ground and first floor and nothing on the second floor, except a barsati (garret) not exceeding 25% of the ground floor.
2	201 to 500 sq.m	50% of the plot area or 133 sq.m whichever is more.
3	501 to 1000 sq.m	40% of the plot area or 250 sq.m whichever is more.
4	More than 1000 sq.m	33.33 % of the plot area or 400 sq.m whichever is more.

Plinth Regulation:

a) Main Building: No plinth or any part of a building or outhouse should be less than 30cm above the determined level of

i. the central part of the abutting street,

ii. the footpath of the abutting street,

iii. the height part of a service lane which determines the drainage of the premises,

iv. any portion of the ground within 3m distance of such a building, and

v. undulating or sloping land 1.2 m above the drainage or country water level.

in cases where adequate drainage of the premises is not assured, the plinth should be of a height approved by the authority.

b) Interior courtyards: Every courtyard should be raised atleast 15cm above the level of centre of the nearest street and should be satisfactorily drained. Common courtyards should have independent access.

c) Plinth of garages, stables and warehouses: the plinths of such constructions should not be less than 15cm above the level determined in portion (a) above for main building.

Height And Size Regulations Of Rooms In Building Construction

Height Regulation:

Habitable rooms: The minimum height from the surface of the floor to the ceiling or bottom of slab should be not les than 2.75m. For air-conditioned rooms, a height of not less than 2.4 m measured from the top of the floor to the lowest point of the air-conditioning duct or the false ceiling should be provided.

Bathrooms, water closets and stores: The height of all such rooms measured from the floor in the ceiling should not be less than 2.4m. In the case of a passage under the landing, the minimum headway may be kept as 2.2m.

Kitchen: The height of the kitchen measured from the floor to the lowest point in the ceiling should not be less than 2.75m except for the portion to accommodate floor trap of the floor.

Ledge: It shall have a minimum head room of 2.2m.

Size Of Rooms:

Habitable rooms: The area of habitable rooms should not be less than 9.5 sq.m where there is only one room. Where there are two rooms, one of these should not be less than 9.5 sq.m and other be not less than 7.5 sq.m with a minimum width of 2.4m.

Kitchen: Minimum floor area required is not less than 5.5 sq.m. It should not be less than 1.8min width at any part. With a separate storeroom, the area may be reduced to 4.5 sq.m. A kitchen cum dining room should have a floor area not less than 9.5 sq.m with a minimum width of 2.4m. Each kitchen should be provided with a flue.

Bathrooms and water closets: The size of bathroom should not be less than 1.5m x 1.2m or 1.8 sq.m. If it is combined with water closet, its floor area should not be less than 2.8 sq.m. the minimum floor area of a water closet should be 1.1 sqm.

Ledge: A ledge in a habitable room shall not cover more than 25% of the floor area of the floor on which it is constructed and should not interfere with the ventilation of the room under any circumstances.

The minimum size of a mezzanine floor, if it is used as a living room, should not be less than 9.5 sq.m.

Lighting And Ventilation Requirements Of Rooms In Building Construction

Lighting And Ventilation Requirements Of Rooms In Building Construction

a) Rooms: Every habitable room which should have for the admission of air and light, one or more apertures such as windows and fanlights, opening directly to the external air or into an open verandah and of an aggregate area, inclusive of frames, of not les than

i. One-tenth of the floor area excluding doors for dry hot climate.

ii. One-sixth of the floor area excluding doors for wet/hot climate.

No portion of a room should be assumed as lighted if is more than 7.5m away from the door or window which is taken for calculation as ventilating that portion.

Cross-ventilation by means of windows and ventilators or both shall be effected in at least living room of tenement either by means of windows in opposite walls or if this is not possible or advisable, then atleast in the adjoining walls.

b) Bathrooms and water closets: The rooms should be provided with natural light and permanent ventilation by one of the following means:

i. Windows having an area of not less than 10% of the floor area and located in an exterior wall facing a street alley, yard or an air shaft whose dimensions in the direction perpendicular to the window is not less than one-third the height of the building on which the window is located, subject to a minimum limit of 1m and maximum 6m.

ii. Skylights, the construction of which shall provide light and ventilation required in (i) above.

iii. Ventilation ducts: Provided such ducts have 130 square cm of area for each square meter of area with a minimum total area of 300 square cm and least dimension of 9cm.

c) Stores, backrooms: These will have atleast half the ventilation required for living room.

d) Basement and floors: Basements and rooms located therein except room shall be lighten and ventilated by windows in exterior walls having a ventilating area of not less than 2.5% of the floor area.

e) Kitchen shall be ventilated according to standards prescribed for habitable rooms near the ceiling as far as possible.

f) Stairways: every staircase should be lighted and ventilated from an open air space of not less than 3m depth measured horizontally in case of ground and one upper floor structure, 4.5 m in case of ground and two upper and in higher structure than this, the open air space shall not be less than 6m, provided that the lighting area shall not be less than 1 sq.m per floor height. Every staircase shall be ventilated properly.

Requirements Of Staircase And Bathrooms In Building Constructions

Requirements of staircase and bathrooms other than lighting and ventilation are given here.

Other Requirements Of Staircase:

The minimum clear width of staircase in case of residential buildings shall not be less than 1m. In case of a public building, a staircase not less than 1.2m in width should be provided for 600 persons or thereof, expected to use the building and the farthest corner of the building shall not be more than 30m distant from the staircase. The maximum riser and minimum width of tread of staircase should be as given in the table 2.

Type of Building	Maximum riser	Minimum tread width
Public buildings	15 cm	30 cm
Domestic buildings	19 cm	25 cm

Other Requirements In The Construction Of Bathrooms And Water Closets:

1. Every water closets or bathroom should
2. Be so situated that at least one of its walls shall be open to external air.
3. Not be directly over or under any room other than another latrine, washing place, bath or terrace, unless it has a water tight floor.
4. Have the platform or seat either plastered with cement or be made of some water tight non-absorbent materials,
5. Be enclosed by walls or partitions of bricks. Surface of every such wall or partitions should be finished with a smooth impervious material, such as cement plaster, 1.3cm thick of glass glazed tiles or polished marbles or any suitable material to a height of not less than 1m above the floor of such a room.
6. Be provided with an impervious floor covering sloping towards the drain and not towards varnishes or any other room.
7. Have a floor level of such a height as to ensure suitable grade towards the sewage drain.

Building Construction Regulations For Projections From Buildings

Projections from Buildings

No projections of any sort what so ever extending more than 23 cm below a height of 4.3m, such as projection on the level of chajja, cornice, water spouts, drains, pipes, advertisement boards and the like shall project over the land of the road or over any drain of the vertical part of the rain water spouts projecting at the road level or the water pipe may be permitted in accordance with the drainage plan.

a) Sunshade over windows and ventilators: Projections of sunshades over windows or ventilators when permitted by the authority shall fulfill the following conditions:

i. Notwithstanding anything contained in these bye-laws, no projection of any sort shall be permitted over the land and the road or over any drain or over any portion outside the boundaries of the site below a height of 2.8 m from the road level.

ii. Sunshades provided above a height of 2.8 m from the ground level shall be permitted to project upto a maximum width of 60 cm if the road over which they project exceeds 9m in width.

iii. No projection of any sort whatever shall be permitted on roads less than 9m in width or on roads having no footpaths.

b) Porticos in existing developed areas: Porticos may be allowed in such roads as can leave a minimum clear space of 18m between kerbs or if a stipulation has been made for such construction in the lease deed or in such cases where its construction would completely fall in a gap in the existing arcade, provided that these shall be constructed as follows:

i. It shall not be less than 3m wide and is either cantilevered or supported on thin steel or RCC pillars.

ii. Nothing shall be allowed to be constructed on the portion which shall be used as an open terrace.

iii. Nothing shall be allowed to project beyond the line of arcades.

iv. The space under the portion shall be paved and channeled according to the directions of the authority.

Factories And Industrial Buildings Construction Regulations

Notwithstanding any provisions provided, in any one of these bye-laws, every factory building or part thereof shall comply with the following additional regulations:

a) Site: The location of every factory site shall be governed by the provisions of the development plan. For cities having no development plans, the factory site shall have to be approved by the authority.

b) Means of escape in case of fire: In the case of factories constructed or converted to use as a factory after the date of enforcement of the these regulations the following additional requirements shall apply:

i. At least two of the stairways provided should be of the fire resisting materials.

ii. No stairway shall be less than 1.2m in width.

iii. All the stairs shall have an unobstructed head room of at least 2.1 m measured vertically above the tread in line with the face of the riser.

iv. In straight treads, the run of the treads shall not be less than 25 cm wide and the rise shall not be more than 18cm high. The width of the tread including nosing shall not be less than 27 cm.

v. No part of a factory building shall be farther than 15 m from any one of the fire escapes.

vi. Every staircase provided above shall be lighted and ventilated from an air space of not less than 3m depth, measured horizontally in case of ground and one upper floor structure, 4.5m in case of ground and two upper and higher structures than this shall not have an air space of less than 6m, provided that the lighting and ventilating area shall not be less than 1 sq.m per floor height.

vii. Every person who undertakes construction of a factory building shall construct lobby, landing corridor or passage included in such work that it shall in no part be less than 1.2 m in width free from encroachment of any kind and its floor shall be of fire-resisting materials and supported by fire-resisting materials.

viii. Every hoist-way or lift-way inside a factory building shall be completely enclosed with fire-resisting materials and means of access to that hoist or lift, shall be fitted with doors of fire-resisting materials, provided that such hoist-way or lift-way shall be enclosed only at the top by some material easily broken by fire or be provided a vent at the top. Escape arrangements should be fully in terms of section 38(7) of the Indian Factories Act,1948.

Abutment of over crowding:

These should be provided at all times for each person employed in any room of the factory at least 3.4 sq.m f the floor space exclusively of that occupied by the machinery and a breathing space of atleast 14 cubic meter.

Height of work Rooms

The internal heights of a work room shall not be less than 4.5 m measured from the floor level to the lowest point in the ceiling.

Percentage of Coverage:

Not more than three-fifths area of the site may be covered subjected to the mandatory open spaces specified as above:

Front area – 7.5 m

Side yard – 3.0 m

Rear yard – 7.5 m

Miscellaneous

Unfinished buildings: No building should be left with unfinished portions including projecting reinforcing bars, which in the opinion of the authority are unsightly unless within the permission prescribing conditions with respect to the structure and the period for which such permissions remain valid.

Clearing of site: As soon as any building is completed, all rubbish, refuse or debris of any description shall be removed by the owner from the site or sites on which building operations have been carried out or from any adjoining land which may have been used for deposition of debris.

Building Construction Miscellaneous Regulations

Distance Of Buildings From Electric Lines

No verandah, balcony, saiban or the like be allowed to be erected or re-erected or any additions or alterations made to a building with the distances (quoted below) as per the current Indian Electricity Rules and its amendments from time to time between the buildings and any overhead electric supply line.

Voltage line	Vertically (meters)	Horizontally (meters)
(a) Low and medium voltage lines and service lines.	2.4 m	1.22 m
(b) High voltage lines upto and including 33000 V.	3.66 m	1.83 m
(c) Extra high voltage lines beyond 33000 V	3.66 m (plus 0.3 m for every additional 33000 V or part thereof)	1.83 m (plus 0.3 m for every additional 33000 V or part thereof)

Minimum thickness of load bearing walls excluding plaster for residential or business masonry walled buildings:

The strength of masonry walls depends on a number of factors such as the quality of bricks, mortar, method of bonding, unsupported height and length, eccentricity in loading, the position and amount of openings in the wall, the location of longitudinal and cross-wall and combination of various external loads to which the walls are subjected. The walls should be designed taking into account the various factors discussed above, such that the stresses in the walls do not exceed the safe permissible limits.

Requirements For Specific Uses (Regulations For Building Construction):

Parking spaces:

Parking spaces for cars required for cinemas, shopping centres and offices in central areas shall be as given below:

Shopping areas: One car for 440 square meter of plinth area of shops.

Offices: One car for 600 square meter plinth area of offices.

Scales of areas required for parking cars, scooters, motor cycles and bicycles shall be as below:

Cars – 24 sq.m

Scooter / motor cycles – 2.8 sq.m

Bicycles – 1.4 sq.m