ARDHI UNIVERSITY

SCHOOL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY

BSc. IN MUNICIPAL AND INDUSTRIAL SERVICES ENGINEERING

INDUSTRIAL UTILITIES AND SAFETY SERVICES REPORT

CASE STUDY: PLASTIC INDUSTRY

STUDENT’S NAME: PROSPEROUS FRANK

REG. # 4730/T.2012

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ACKNOWLEDGEMENT

I would like to give special thanks firstly to almighty God for giving me life and strength;

indeed, it is worth to convey sincere thanks to all who have supported in one way or another to

prepare this report.

Special thanks go to course instructor, Dr. MBULIGWE for his good instruction, supervision,

and assistance during the whole period of study and report preparation, his instruction and

supervision were of great help to widen the knowledge and understanding of different utilities

and safely services to be incorporated in different industries.

Moreover great thanks to class mates for their suggestions, comments during presentation; also

their assistance and collaboration were much useful on the whole process of learning and in fact

preparation of this report document.

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ABSTRACT

Environmental programs centered upon widespread analysis of air, water, and land pollution is

becoming an important supplement to traditional single media methodologies to environmental

protection. Environmental regulatory agencies are beginning to embrace comprehensive,

multistate solutions to facility permitting, compliance assurance, education/outreach, research,

and regulatory development issues. The central concepts driving the new policy direction are that

pollutant releases to each environmental medium from plastic industry affect each other and that

environmental strategies must actively identify and address these interrelationships by designing

policies for the "whole" facility. One way to achieve a whole facility focus is to design an

industrial utilities and safety services measures to reduce the amount of waste emissions to the

environment, systems involved in this manner are; ventilation system design, water supply

system, Solid waste management system, waste water treatment system as well as safety

services.

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LIST OF FIGURES

Figure 1 Extrusion process………………………………………………………………………...6

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TABLE OF CONTENTS

1.0 INTRODUCTION .................................................................................................................................. 1

1.1 BACKGROUND .................................................................................................................................... 1

1.2 OBJECTIVES ......................................................................................................................................... 2

1.2.1. Main objective ................................................................................................................................ 2

1.2.2. Specific objectives .......................................................................................................................... 2

1.3 SCOPE ................................................................................................................................................ 2

1.4 METHODOLOGY ............................................................................................................................. 2

1.4.1 Literature review; ............................................................................................................................. 2

1.4.2 Observation; ..................................................................................................................................... 3

1.4.3 Consultation; .................................................................................................................................... 3

2.0 MANUFACTURING PROCESSESS AND WASTES .......................................................................... 4

2.1 PLASTIC MANUFACTURING PROCESSESS ................................................................................... 4

2.1.1 Injection Molding; ........................................................................................................................... 5

2.1.2 Reaction Injection Molding: ............................................................................................................ 5

2.1.3 Extrusion: ......................................................................................................................................... 6

2.1.4 Blow Molding: ................................................................................................................................. 7

2.1.5 Thermoforming: ............................................................................................................................... 7

2.1.6 Rotational Molding; ......................................................................................................................... 7

2.1.7 Compression and Transfer Molding: ............................................................................................... 7

2.1.8 Casting and Encapsulation: .............................................................................................................. 8

2.1.9 Calendering: ..................................................................................................................................... 8

2.1.10 Foamed Plastic: .............................................................................................................................. 8

2.1.11 Thermoset Resin: ........................................................................................................................... 8

2.2 WASTE GENERATED FROM PLASTIC INDUSTRY ....................................................................... 9

2.2.1 Fugitive and stack air ....................................................................................................................... 9

2.2.2 Solid waste (Container residue) ....................................................................................................... 9

2.2.3 Waste water/slurries ....................................................................................................................... 10

2.2.4 Plastic pellets spills ........................................................................................................................ 10

3.0 INDUSTRIAL UTILITIES INFRASTRUCTURES AND SAFETY SERVICES ............................... 11

3.1 INDUSTRIAL UTILITIES INFRSTRUCTURES ............................................................................... 11

3.1.1 Waste water Treatment system ...................................................................................................... 11

3.1.1.1 Settling Unit ............................................................................................................................ 11

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3.1.1.2 Activated Carbon process ....................................................................................................... 12

3.1.2 Solid waste management ................................................................................................................ 12

3.1.3 Turbine roof Ventilation system .................................................................................................... 12

3.1.3.1 Components of Turbine roof Ventilator:................................................................................. 13

3.1.3.2 Installation procedures; ........................................................................................................... 13

3.1.4 Air pollution Control ...................................................................................................................... 13

3.1 PUBLIC AND OCCUPATIONAL HEALTH AND SEFETY ............................................................ 14

3.2.1 Fire escaping routes ....................................................................................................................... 14

3.2.1 Personal Protective Equipment ...................................................................................................... 14

3.2.2 Assembly Point Design .................................................................................................................. 15

4.0 CONLUSION AND RECCOMMENDATION .................................................................................... 16

4.1 CONCLUSION ..................................................................................................................................... 16

4.2 RECOMMENDATION ........................................................................................................................ 16

LIST OF REFERENCES ............................................................................................................................ 17

APPENDIXES

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CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND

Environmental conditions impact dramatically on the life-expectancy of plastic objects.

Appropriate environmental conditions are therefore vital. What follows is good practice for the

majority of plastic Industries.

The clue to which manufacturing process has been used can lie in the number of the particular

product being made. Some processes can be used at home and others involve high tooling

investment. Low investment processes tend to be craft based and thus slower than high

investment ones. Injection moulding is only economically viable if a very high output is

required. For example an injection moulding machine can convert plastic granules to a safety

helmet in 40 seconds that is 2160 in 24 hours, 15,120 in a week and 786,240 in a year. The

sharing of the tooling cost across so many units results in a relatively low unit price. It is not,

however, cost efficient to injection mould small runs (e.g. 5000) of products. On the other hand,

casting, fabrication and rotational moulding cost less to set up but are slower in the making.

Currently, excluding plastic bags, far more plastic objects are made by injection molding than by

any other process.

Certain processes leave marks behind on the finished product. The most frequently encountered

are the marks left by what is now the most widely used process: injection moulding. There are

two kinds of marks: that left by the ‘sprue’, the tail of plastic that is broken off at the point it

enters the mould, and the ejector pin marks, smooth and circular, which assist with the removal

of the moulding from the mould.

As certain plastics are only used with certain processes, identifying the process can assist in the

identification of the particular utilities and safety services measures to increase productivity

while creating the industrial image through minimizing environmental problems by the use of the

best technology.

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1.2 OBJECTIVES

Objectives of this project report are categorized in to aspect; the main objective to which this

project was conducted for and the specific objectives which support the succession of the main

objective of this project.

1.2.1. Main objective

The main objective of this project is assessing the industrial utilities of the Plastic industries so as

to come up with the best solutions for proper utilities arrangement which are environmentally

friendly.

1.2.2. Specific objectives

To explore and assess the industrial utilities i.e. water supply, waste water treatment

facility, ventilation, firefighting Equipment, telecommunication and solid waste

management facilities provision in Plastic Industries.

To assess safety services provision in Plastic Industries.

To assess the implementation and practices of occupational health and safety services.

To assess the rain water harvesting system and storm water drainage.

To assess the alternative use of treated waste water in Plastic Industries

1.3 SCOPE

The scope of our project based on Plastic facilities manufacturing industries in Tanzania

focusing on utilities and safety services provision assessment.

1.4 METHODOLOGY

Methods used to conduct this project were; Literature review, observation, and Consultation.

1.4.1 Literature review;

This involved reading of various different books found in library and from internet services that

are related to Plastic Industries in terms of utilities provision and safety services. These provided

the baseline of this project through understanding on what is done in the field compared to that

of the literary works.

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1.4.2 Observation;

Through observing the existing situations on the present industrial utilities and safety measures

taking place at NABAKI AFRICA industry I came up with the specific solutions to the specified

problems.

1.4.3 Consultation;

Through consulting our supervisor, and our fellow students, especially continuous students, the

objectives of the study were reached to a maximum since the knowledge of Industrial Utilities

and Safety Services Engineering was shared without any biasness in order to fulfill this project.

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CHAPTER TWO

2.0 MANUFACTURING PROCESSESS AND WASTES

2.1 PLASTIC MANUFACTURING PROCESSESS

The production of plastics products, both solid and foam, is a relatively diverse industry. Simpler

processes consist of:

Imparting the appropriate characteristics to the plastic resin with chemical additives;

Converting plastic materials in the form of pellets, granules, powders, sheets, fluids, or

preforms into either intermediate or final formed plastic shapes or parts via molding

operations; and

Finishing the product.

There are also several methods of reacting plastic resin and catalyst materials to form a

thermoset plastic material into its final shape. Additives are often mixed with the plastic

materials to give the final product certain characteristics (some of these additives can also be

applied to the shaped product during the finishing process). These plastic additives and their

functions, in terms of their effect on the final product, are listed below.

Additive Lubricants assist in easing the flow of the plastic in the molding and extruding

processes by lubricating the metal surfaces that come into contact with the plastic.

Antioxidants inhibit the oxidation of plastic materials that are exposed to oxygen or air at

normal or high temperatures.

Antistats impart a minimal to moderate degree of electrical conductivity to the plastic

compound, preventing electrostatic charge accumulation on the finished product.

Blowing Agents (foaming agents) produce a cellular structure within the plastic mass and

can include compressed gases that expand upon pressure release, soluble solids that leach

out and leave pores, or liquids that change to gases and, in the process, develop cells.

Colorants impart color to the plastic resin.

Flame Retardants reduce the tendency of the plastic product to burn.

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Hat Stabilizers assist in maintaining the chemical and physical properties of the plastic

by protecting it from the effects of heat such as color changes, undesirable surface

changes, and decreases in electrical and mechanical properties.

Impact Modifiers prevent brittleness and increase the resistance of the plastic to cracking.

Organic Peroxides initiate or control the rate of polymerization in thermosets and many

thermoplastics.

Plasticizers increase the plastic product's flexibility and workability.

After adding the necessary additives to the plastic pellets, granules, powders, etc. the plastic

mixture is formed into intermediate or final plastics products. To form solid plastics products, a

variety of molding processes are used, including injection molding, reaction injection molding,

extrusion, blow molding, thermoforming, rotational molding, compression molding, transfer

molding, casting, encapsulation, and calendaring. Slightly different processes are used to make

foamed plastics products. The choice of which plastic forming process to use is influenced by

economic considerations, the number and size of finished parts, the adaptability of particular

plastic to a process (various plastic will mold, process, etc., differently), and the complexity of

the post-forming operations. Below are brief descriptions of the most common molding and

forming processes for creating solid plastics products.

2.1.1 Injection Molding;

In the injection molding process, plastic granules or pellets are heated and homogenized in a

cylinder until they are fluid enough to be injected (by pressure) into a relatively cold mold where

the plastic takes the shape of the mold as it solidifies. Advantages of this process include speed

of production, minimal post-molding requirements, and simultaneous multipart molding

2.1.2 Reaction Injection Molding:

In the reaction injection molding process, two liquid plastic components, polyols and

isocyanates, are mixed at relatively low temperatures (75 -140 degrees F) in a chamber and then

injected into a closed mold to form polyurethane products. The parts molded using this process

can be foams or solids, and they can range from being flexible to extremely rigid. Products

include large polyurethane foams for noise abatement and large panels for any indoor or outdoor

application. Polyurethane is also used to encapsulate items and protect them from the

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environment. Reaction injection molding requires far less energy than other injection molding

systems because an exothermic reaction occurs when the two liquids are mixed. Reaction

injection molding is a relatively new processing method that is quickly becoming common in the

industry. Reinforced reaction injection molding involves placing long fibers or fiber mats in the

mold before injection.

2.1.3 Extrusion:

In the extrusion process, plastic pellets or granules are fluidized, homogenized, and formed

continuously as the extrusion machine feeds them through a die. The result is a very long plastic

shape such as a tube, pipe, sheet, or coated wire. Extruding is often combined with post-

extruding processes such as blowing, thermoforming, or punching. Extrusion molding has an

extremely high rate of output (e.g., pipe can be formed at a rate of 2,000 lb/hr (900 kg/hr)).

Figure 2 Extrusion process

Source: McGraw-Hill Encyclopedia of Science and Technology

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2.1.4 Blow Molding:

Blow molding describes any forming process in which air is used to stretch and form plastic

materials. In one method of blow molding, a tube is formed (usually by extrusion molding) and

then made into a free-blown hollow object by injecting air or gas into the tube. Blow molding

can also consist of putting a thermoplastic material in the rough Shape of the desired finished

product into a mold and then blowing air into the plastic until it takes the shape of the mold,

similar to blowing up a balloon. Examples of products include a wide variety of beverage and

food containers.

2.1.5 Thermoforming:

In the thermoforming process, heat and pressure are applied to plastic sheets, which are then

placed over molds and formed into various shapes. The pressure can be in the form of air,

compression, or a vacuum. This process is popular because compression is relatively

inexpensive. Products include clam shells and blister packaging for the shipping industry as well

as thin plastic components for retail packaging.

2.1.6 Rotational Molding;

In the rotational molding process, finely ground plastic powders are heated in a rotating mold to

the point of either melting and/or fusion. The inner surface of the rotating mold is then evenly

coated by the melted resin. The final product is hollow and produced scrap-free. Products include

fuel tanks, side paneling for vehicles, and carrier cases.

2.1.7 Compression and Transfer Molding:

In the compression molding process, plastic powder or a preformed plastic part is plugged into a

mold cavity and compressed with pressure and heat until it takes the shape of the cavity. Transfer

molding is similar, except that the plastic is liquefied in one chamber and then injected into a

closed mold cavity by a hydraulically operated plunger. Transfer molding was developed to

facilitate the molding of intricate plastics products that contain small deep holes or metal inserts

because compression molding often ruins the position of the pins that form the holes and the

metal inserts.

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2.1.8 Casting and Encapsulation:

In the casting process, liquid plastic is poured into a mold until it hardens and takes the shape of

the mold. In the encapsulation or potting process, an object is encased in plastic and then

hardened by fusion or a chemical reaction, as shown in

2.1.9 Calendering:

In the calendering process, plastic parts are squeezed between two rolls to form a thin,

continuous film.

2.1.10 Foamed Plastic:

Manufacturing foamed plastics products involves slightly different forming processes than those

described above. The three types of foam plastic are blown, syntactic, and structural. Blown

foam is an expanded matrix, similar to a natural sponge; syntactic foam is the encapsulation of

hollow organic or inorganic micro spheres in the plastic matrix; and structural foam is a foamed

core surrounded by a solid outer skin. All three types of foam plastic can be produced using

processes such as injection, extrusion, and compression molding to create foam products in many

of the same shapes as solid plastics products. The difference is that creating foam products

requires processes such as chemical blowing agent addition, different mixing processes that add

air to the plastic matrix, or a unique injection molding process used to make structural plastic.

2.1.11 Thermoset Resin:

To produce a thermoset plastic material, liquid resins are combined with a catalyst. Resins used

for thermoset plastic products include urethane resins, epoxy resins, polyester resins, and acrylic

resins. Fillers are often added to the resin-catalyst mixture prior to molding to increase product

strength and performance and to reduce cost. Most thermoset plastic products contain large

amounts of fillers (up to 70 percent by weight). Commonly used fillers include mineral fibers,

clay, glass fibers, wood fibers, and carbon black. After the thermoset material is created, a final

or intermediate product can be molded.

Various molding options can be used to create the intermediate or final thermoset product. These

processes include vacuum molding, press molding, rotational molding, hand lamination, casting

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and encapsulation, spray-up lamination, resin transfer molding, filament winding, injection

molding, reaction injection molding, and pultrusion.

2.2 WASTE GENERATED FROM PLASTIC INDUSTRY

There are various wastes produced during the entire process of plastic manufacturing and these

will help in determining what type of the industrial utilities to be encapsulated in the industry as

well as safety measures to account. The following are the wastes produced;

2.2.1 Fugitive and stack air

All air emissions from industry activity. Point emissions occur through confined air streams as

found in stacks, ducts, or pipes. Fugitive emissions include losses from equipment leaks or

evaporative losses from impoundments, spills, or leaks. This occurs during compounding and

mixing, Moulding operations, forming processes and finishing operations. Mentioned chemicals

released with air are;

1,1-Dichloro-1-Fluoroethane

1-Chloro-1,1-Difluoroethane

Carbon Disulfide;

Dichloromethane;

Methanol;

Methyl Ethyl Ketone (MEK);

Styrene;

Toluene;

Xylene (Mixed Isomers); and

Zinc Compounds

2.2.2 Solid waste (Container residue)

Plastics make up a significant portion of the nation's waste stream. The most common are both

single plastic resins and mixtures of plastic resins; this comes from moulding step, compounding

and mixing, trimming operations, chemical storage as well as finishing process.

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2.2.3 Waste water/slurries

Waste water can be divided into three categories: contact cooling and heating water; cleaning

water; and finishing water. In finishing water, the data indicate that the only pollutants present in

treatable concentrations are TSS and three phthalates.

2.2.4 Plastic pellets spills

The issue of plastic resin pellet loss to the environment during the manufacturing process is

being addressed by manufacturers through participation in "Operation Clean Sweep" (OCS). All

participating facilities take measures to minimize spills, promptly and thoroughly clean up spills,

and properly dispose of pellets. This comes from compounding and mixing.

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CHAPTER THREE

3.0 INDUSTRIAL UTILITIES INFRASTRUCTURES AND SAFETY SERVICES

Industrial utilities and safety services must be provided in order to reduce waste and hence

operating costs; gain a competitive advantage; establish and show a system for continual

environmental improvement; demonstrate compliance with its legal obligations; improve its

public image.

3.1 INDUSTRIAL UTILITIES INFRSTRUCTURES

The following are utilities to be designed and monitored in plastic industry: these utilities are

based on the elimination of all kind of wastes to the industry as well as other provisions which

provides for comfort;

3.1.1 Waste water Treatment system

Various physical, biological or chemical processes are used to change the properties of the

wastewater in order to turn it into a type of water known as effluents that can be safely

discharged into the environment or that is usable for a certain reuse purpose in plastic industry.

The following are the units necessary for treating waste water;

3.1.1.1 Settling Unit

The only pollution prevention technology EPA has identified to remove TSS is a settling unit. A

physical/chemical treatment train, that included 24-hour preliminary settling followed by

coagulation/flocculation and sedimentation, was tested at a laboratory bench scale to treat liquid

swine manure for the removal of total suspended solids (TSS) and total phosphorus (TP).

Preliminary (i.e., natural) settling time had an effect on TSS removal within only the first 24

hours. TSS removal efficiency reached 75% (TSS concentration was reduced from 5,800 to

1,450 mg 1(-1)) after 24 hours of preliminary settling. Also, as a result of the 24-hour

preliminary settling, TP concentration was reduced from 533 to 318 mg 1(-1), thus leading to a

TP removal efficiency of 40%.

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3.1.1.2 Activated Carbon process

Physical adsorption is the primary means by which activated carbon works to remove to remove

phthalates present in finishing water. Carbon's highly porous nature provides a large surface area

for contaminants (adsorbents) to collect. In simple terms, physical adsorption occurs because all

molecules exert attractive forces, especially molecules at the surface of a solid (pore walls of

carbon), and these surface molecules seek other molecules to adhere to.

The large internal surface area of carbon has many attractive forces that work to attract other

molecules. Thus, contaminants in water are adsorbed (or held) to the surface of carbon by

surface attractive forces similar to gravitational forces. Adsorption from solution occurs as a

result of differences in adsorbent concentration in the solution and in the carbon pores.

3.1.2 Solid waste management

Thermoplastic resins may be handled in a variety of forms, from solvent suspended solutions to

pellets, beads, flake, or granular form. In general, materials handled in finely divided solid form

(resins or flakes) are more likely emitted from handling operations than materials handled in

larger solid form (chips) or in aqueous solution. The most common pollution prevention method

currently used is recycling. Both single plastic resins and mixtures of plastic resins can be

recycled, but the end products from mixtures are often lower in quality than those from just one

type of resin. Therefore, the success of plastic recycling will depend on the development of

technologies to separate mixed plastic into single resins, and on increasing the markets for

products made of mixed plastic resins. Although recycling is the most common method of plastic

waste pollution prevention, at present, less than one percent of all plastics products are recycled.

3.1.3 Turbine roof Ventilation system

The positive extraction of the Tornado Turbine Ventilation System eliminates dust penetration

and a down-draught into the building. The design of the Tornado enables the ventilator to be

activated by natural convection from the inside of the building and also allows it to be assisted

by the wind outside. Wind creates a flow of air through the throat of the Tornado to enhance

extraction.

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3.1.3.1 Components of Turbine roof Ventilator:

The following are typical components of industrial ventilation system present;

Dome - vertical mounted blades specially formed to prevent water and dust penetration.

Shaft - yellow cadmium plated bright mild steel.

Bearing System - unique and patented type ZZ lubricated bearings in a

reinforced housing to prevent from corrosion.

Cylindrical throat - two piece elbow type that will fit most inclined roof tops.

Base plate – ensures water and dust proof attachment to the roof.

3.1.3.2 Installation procedures;

Installing a Turbine roof ventilator needs the following procedures for its efficiency operations:

Place the baseplate onto the roof and mark the hole to be cut. Ensure that the baseplate is

pushed under the ridge cap and Cut the marked hole square with an angle grinder.

Bend the sheeting back at the bottom end of the cut out and remove closure from under

ridging

Insert closure at the bottom end of baseplate and pop rivet the baseplate onto the roof and

Waterproof baseplate using silicon or membrane and sealer

Place the throat and dome section onto the baseplate and Make sure that the locking

brackets are loose.

Adjust throat in order to get the top section of the throat and the dome in a level position

and Fasten the locking brackets

Fix the throat onto the baseplate by drilling and using pop rivets.

If more than one unit is required stagger the units across the roof.

Refer appendixes for engineering drawing attached to this report at the end

3.1.4Air pollution Control

In order to minimize emissions from industries there are number of technology but here the

scrubbing system will be provided to the industry for the purpose of collecting, capture and

retain pollutants before entering the environment, (refer appendixes for engineering drawings for

a scrubber system)

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3.1 PUBLIC AND OCCUPATIONAL HEALTH AND SEFETY

As Safety Engineers we have to make sure workplaces are safe. Monitoring the general work

environment, inspect buildings and machines for hazards and safety violations, and recommend

safety features in new processes and products should be done in respective manner. Also

evaluation plans for new equipment to assure that it is safe to operate and investigate accidents to

determine the cause and how to keep them from happening again. Lastly a design for special

safety clothing and safety devices to protect workers from injury when operating machines

should be included. All the above can be accomplished if and only if the workers should be

educated and trained. Due to my case study the following should be provided in an industry.

3.2.1 Fire escaping routes

Fire escaping route is categorized into two groups, in building escaping route and external

environment (plant) escaping route. Talking of in building fire emergencies, there are designed

escaping routes for evacuation from the building and fire extinguisher to control fire outbreak if

possible, fire extinguisher are used depending on the class of fire. Common classes of fire at the

industry are;

Fire class B: due to flammable liquid such as petrol, oil and diesel

Best fire extinguishers are water spray, foam, light water, carbon dioxide and dry

chemical powder.

Fire class C: due to burning of flammable gases, such as Methane.

Best fire extinguishers are CO2, Dry Chemical Powder and water in the form of spray.

3.2.1 Personal Protective Equipment

These are device used to reduce employee exposure to hazards when engineering and

administrative controls are not feasible or effective in reducing these exposure to acceptable

levels, PPE should not be used as a substitute for engineering, work practices, and/or

administrative controls to protect employees from workplace hazards, PPE should be used in

conjunction with permanent protective measures, such as engineered guards, substitution of less

hazardous chemicals, and prudent work practices.

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3.2.2 Assembly Point Design

Assembly points are to be provided so as to serve in case of emergency. At the industry, one

assembly point is designed, once an emergency occurs, personnel in charge of managing the

evacuation to the muster point and even past to an assembly point have multiple factors to

consider:

Determine the emergency and possible victims

Who must be alerted

How you plan to contact law enforcements

How many people are involved in the evacuation

Providing assistance to those physically, hearing, and visually impaired to the muster

point

Doing a head count at the muster point, including knowing which individuals should

have made it to the emergency location

Observing all individuals to ensure they do not wander from the muster point

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CHAPTER FOUR

4.0 CONLUSION AND RECCOMMENDATION

4.1 CONCLUSION

Much consideration is to be given in the actual forming site, Maintenance and servicing of

the production facilities and peripheral equipment, improvement activities for plastic forming

methods and conditions, Increase in plastic forming speed; pay attention to the cooling

conditions of metal mold and the product unloading speed, Yield improving activities.

Much difficulty follows trimming (similar to overall pinch off) of a large-sized product. If

the cutting-off portion of the molding die is sharpened, the jointing portion will be torn and if

the cutting-off portion of the molding die is made dull, the finishing process takes much

labor.

4.2 RECOMMENDATION

The first is the technology for reducing the electric power used for heaters of the plastic

heating process and the second is

There should be a technology to improve the quality and yield of products thereby

increasing the production quantity of the first class goods.

The know-how on modern energy saving and conservation technologies should, therefore, be

circulated to government and industrial managers, as well as to industrial engineers and

operators at the industry level in Tanzania

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LIST OF REFERENCES

1. Barlow, A., K. Adams, M. Holdren, P. Moss, E. Parker, and T. Schroer. 1997.

Development of Emission Factors for Ethylene-Vinyl Acetate and Ethylene-Methyl

Acrylate Copolymer Processing. Journal of the Air & Waste Management Association.

47:1111-1118.

2. Barlow, A., D. Contos, M. Holdren, P. Garrison, L. Harris, and B. Janke. 1996.

Development of Emission Factors for Polyethylene Processing. Journal of the Air Waste

Management Association. 46:569-580.

3. Contos, D., M. Holdren, D. Smith, R. Brooke, V. Rhodes, and M. Rainey. 1995.

Sampling and Analysis of Volatile Organic Compounds Evolved During Thermal

Processing of Acrylonitrile Butadiene Styrene Composite Resins. Journal of the Air &

Waste Management Association. 45:686-694.

4. EPA. 1996. Hazardous Air Pollutant Emissions from the Production of Flexible

Polyurethane Foam--Basis and Purpose Document for Proposed Standards. U.S.

Environmental Protection Agency, Office of Air Quality Planning and Standards, EPA-

453/R-96-008a. Research Triangle Park, North Carolina.

5. EPA. 1995. EPA Office of Compliance Sector Notebook Project: Profile of the Rubber

and Plastics Industry. U.S. Environmental Protection Agency, Office of Enforcement and

Compliance Assurance, EPA-310/R-95-016. Washington, D.C.

6. EPA. 1990. Control of VOC Emissions from Polystyrene Foam Manufacturing. U.S.

Environmental Protection Agency, Office of Air Quality Planning and Standards, EPA-

450/3-90-020. Research Triangle Park, North Carolina.

7. EPA. 1978. Source Assessment: Plastics Processing, State of the Art. U.S. Environmental

Protection Agency, Office of Research and Development, EPA 600/2-78-004c.

Cincinnati, Ohio

8. Krutchen, C., and W. Wu. 1988a. Gas Chromatographic Determination of Residual

Blowing Agents in Polystyrene Foams. SPE 46th ANTEC, Atlanta. April 18-21, 1988.