A TECHNICAL REPORT ON THE SIX (6) MONTHS
STUDENTS INDUSTRIAL WORK EXPERIENCE SCHEME
(SIWES)
UNDERTAKEN AT
LAGOS WATER CORPORATION (LWC)
5th FLOOR, WATERHOUSE
IJORA CAUSEWAY
IJORA, LAGOS
BY
ODOGWU STEPHEN ONYINYE
MATRIC NO: QSV/12/0286
2015/2016
FROM
MAY 3RD 2016 TO OCTOBER 28TH 2016
SUBMITTED TO
THE DEPARTMENT OF QUANTITY SURVEYING,
SCHOOL OF ENVIRONMENTAL TECHNOLOGY.
FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE. ONDO.
JANUARY 2017
CERTIFICATION
I hereby certify that this technical report was written by me, ODOGWU STEPHEN ONYINYE (QSV/12/0286) of the Department of Quantity Surveying, Federal University of Technology, Akure, and that I covered all works that was executed during the 2015/2016 SIWES undertaken at LAGOS WATER CORPORATION situated at WATER HOUSE, LAGOS WATER CORPORATION HEADQUARTERS, IJORA CAUSEWAY, IJORA, LAGOS.
_______________________ ______________________
Student’s signature/Date Mrs. Adeojo C.O
SIWES Coordinator signature/date
ACKNOWLEDGMENT
My deepest gratitude and appreciation goes to LAGOS WATER CORPORATION for accepting me into their company to have my industrial training which lasted for six months. I had an insightful experience and was well received by the staff of the department where I worked.
My appreciation also goes to the Project Coordinator, Engr. S.O Ogunlana for his support throughout the scheme. Despite his tight schedule, he still found time to attend to me during my stay at the department.
I thank the workmen on the site much enough for willingly sharing their wealth of experience with me. I am especially grateful to the chief project engineer, Engr. Godspower and Engr. Seun amongst the many other workers on site. They really imparted their practical knowledge into me. I immensely appreciate the entire teaching and non-teaching members of staff of the Quantity Surveying department, Federal University of Technology, Akure who have nurtured me up to this level.
DEDICATION
This technical report is dedicated to Almighty God for his loving kindness in my life through the years and for guiding me through all my affairs in life.
To my family members, my gratitude could never be enough for the financial support provided during the course of the program ensuring that all my needs were met.
I also want to specially thank my wonderful supervisor and boss, Mr Adeyinka Olarinoye of Lagos Water Corporation for his ever readiness to assist in my academic pursuits and to the entire staff of IDMON Engineering and Construction Company Nigeria Limited for the knowledge imparted unto me during my stay with them, Engr. Godspower Iniyoviverhi, Engr. Emmanuel, Engr. Charles Uzonwanne just to mention a few.
ABSTRACT
I participated in The Students’ Industrial Work Experience Scheme (SIWES) Training Programme at Lagos Water Corporation, Ijora.
This report provides a complete detail of my daily activities which was done under the supervision of Mr. Adeyinka Olarinoye, Project Manager, Project Implementation Unit, Lagos Water Corporation.
The areas of learning included Pipe laying and Sanitary Engineering. I learnt how water is supplied and distributed from place of production (Waterworks) to the final consumer. Civil and Engineering construction works accompanied the projects all of which were aimed at my professional development in the practice of Quantity Surveying.
TABLE OF CONTENT
TITLE PAGE
CERTIFICATION
ACKNOWLEDGEMENT
DEDICATION
ABSTRACT
TABLE OF CONTENT
LIST OF TABLES
LIST OF FIGURES
CHAPTER ONE
INTRODUCTION
RATIONALE FOR SIWES
AIMS AND OBJECTIVES OF SIWES
BENEFITS OF INDUSTRIAL TRAINING
QUANTITY SURVEYING PROFESSION
1.4.1 ECONOMIC IMPORTANCE OF QUANTITY SURVEYING
1.4.2 WHO IS A QUANTITY SURVEYOR?
1.4.3 SERVICES RENDERED BY A QUANTITY SURVEYOR
CHAPTER TWO
THE FIRM
2.1 COMPANY PROFILE
2.2 COMPANY BACKGROUND
2.3 COMPANY VISION
2.4 ORGANISATIONAL STRUCTURE
CHAPTER THREE
3.1 WORKING EXPERIENCE
3.2 INTRODUCTION TO PROJECT IMPLEMENTATION UNIT (PIU)
3.3 REHABILITATION AND EXPANSION OF DISTRIBUTION NETWORK
3.4 IDMON ENGINEERING AND CONSTRUCTION COMPANY
3.5 PIPELAYING
3.5.1 SETTING OUT AND SURVEYING WORKS
3.5.2 DETECTION OF EXISTING UTILITIES AND SERVICES
3.5.3 TRENCH EXCAVATION INCLUDING DEWATERING WORK
3.5.4 CUTTING OF ROADS AND PAVEMENT
3.5.5 TRENCHLESS BORING WORKS
3.5.6 INSTALLATION OF METALLIC WIRE TAPE PIPE TRACKER
3.6 CIVIL WORKS
3.7 HDPE PIPES
3.7.1 FEATURES OF HDPE PIPES
3.7.2 ADVANTAGES OF HDPE PIPES
3.7.3 HDPE PIPE JOINING TECHNIQUES
3.8 HYDROTESTING
3.8.1 PRESSURE TESTING
3.8.2 CHLORINATE AND FLUSH LINES
CHAPTER FOUR
4.0 CONCLUSION
4.1 RECOMMENDATION
CHAPTER ONE
INTRODUCTION
1.1 RATIONALE FOR STUDENTS` INDUSTRIAL WORK EXPERIENCE SCHEME
The Students’ Industrial Work Experience Scheme (SIWES) is an indispensable program that was initiated by the Federal Government of Nigeria through the Industrial Training Fund (ITF), in collaboration with the Nigerian University Commission (NUC). It forms part of the approved minimum academic standards for various degrees in all the disciplines in the Federal University of Technology, Akure.
The aim of SIWES is to create an opportunity for students of various disciplines in Nigerian Tertiary institutions to gain industrial work experience in their chosen fields of study, in relevant industries and establishments. It also provides students the opportunity to apply their theoretical knowledge in real work situations. This is a great advantage in technical fields such as Science and Engineering where practical experience goes a long way in enhancing and improving understanding. All these come together to equip and update the student with the current trend in the industrial world.
The bridge between theory and practice also helps to develop work ethics, communication, interpersonal skills and industrial safety practices, through interaction with members of staff.
1.2 THE OBJECTIVES OF STUDENTS INDUSTRIAL WORK EXPERIENCE SCHEME
Students Industrial Work Experience Scheme is a planned and structured programme based on stated and specific career objectives which are geared toward developing the occupational competencies of participants. The Industrial Training Fund’s Policy Document No. 1 of 1973 which established SIWES outlined the objectives of the scheme. The objectives are to:
Provide an avenue for students in institutions of higher learning to acquire industrial skills and experience during their courses of study;
Prepare students for industrial work situations that they are likely to meet after graduation
Expose students to work methods and techniques in handling equipment and machinery that may not be available in their institutions;
Makes the transition from school to the world of work easier and enhance students’ contacts for later job placements;
Provide students with the opportunities to apply their educational knowledge in real work situations, thereby bridging the gap between theory and practice;
Enlist and strengthen employers’ involvement in the entire educational process through SIWES.
1.3 BENEFITS OF INDUSTRIAL TRAINING TO THE STUDENT
The major benefits accruing to students who participate conscientiously in the industrial training are the skills and competitions they acquire. These relevant production skills remain a part of the recipients of industrial training as life-long assets which cannot be taken away from them. This is because the knowledge and skills acquired through training are internalized and become relevant when required to perform jobs or functions.
Several other benefits can accrue to students who participate in industrial training. These include the following:
Exposure of student to the environment in which they will eventually work, thereby enabling them to see how their future professions are organized in practice.
Enabling science, engineering and technology students appreciate work methods and gain experience in handling equipment and machinery which may not be available in their institutions.
Preparing students to contribute to the productivity of their employers and national development immediately after graduation.
Minimization of the bewilderment experienced by students, particularly those from a non-technological background, pursuing courses in science, engineering and technology with regard to different equipment, processes, tools etc. available in industry.
Preparing students for employment and making the transition from school to the world of work easier after graduation.
Enabling students’ contacts with potential employers while on training.
Opportunity for student to blend theoretical knowledge acquired in the classroom with practical hands-on application of knowledge required to perform work in industry.
Provision of an enabling environment where students can develop and enhance personal attributes such as critical thinking, creativity, initiative, resourcefulness, leadership, time management, presentation skills and interpersonal skills, amongst others.
1.4 QUANTITY SURVEYING PROFESSION
Quantity Surveying is a practice that originated in Great Britain in the 17th century shortly after the Great fire of 1666. Buildings had to be reconstructed in the cities by architects/designers who employed professionals called “Master Craftsmen” who in turn engaged the services of a surveyor to prepare accounts.
Quantity Surveying as a professional field has evolved over the centuries, the profession was developed during the 19th century where construction and building works increased in volumes and the method of setting out cost of work became paramount among all stakeholders in the construction works (Building, Civil and Heavy Engineering), calculation of cost and management of the construction projects.
Professionals who practice the field of Quantity Surveying are known as Quantity Surveyors, Cost Engineers, Estimators or Measurers. A Quantity Surveyor must have a good knowledge in all areas of construction works, different systems of construction and its rudiments, as well as its management for effectiveness.
1.4.1 ECONOMIC IMPORTANCE OF QUANTITY SURVEYING
The present situation of global economy is no longer hearsay but what calls for critical attention from all and sundry. The rate at which global economy is going down the drain is alarming and this calls for joint-hands to proffer solutions to this chaotic condition. Professional’s knowledge in field of economics, commerce and related disciplines is of great essence and out of this versed professions; Quantity Surveying is such with effects and influence that cannot be undermined.
Quantity Surveying is a profession that is concerned with financial probity and achieving ‘value for money (VFM)’ in the conceptualizations, planning and execution of building projects, civil works, heavy engineering works and other related works. Seeley (1997) defined Quantity Surveyor as a construction professional, who is qualified and adequately trained to advice on all aspects of Construction costs, Financial and Contractual administration. The role of Quantity Surveyor is to ensure that the resources of the construction industry are utilized to the best advantage of the Society by providing the financial management for the project and a cost consultancy service to the client and designer during the whole construction process. Generally, the vast majority of Quantity Surveyors are employed in private or public practice or in a contractor’s organization. The change in the economy for the past two decades has made Quantity Surveyors to broaden their horizon beyond the scope of construction industry sector. It has embraced duty in banking industry, petroleum industry and so on (Hanid et al 2007)
Development is what every sector of the economy clamors for and this is gearing from all that goes on in the global economy; unstable market and economy condition. Quantity Surveying services have multifaceted disciplines to function in manner that would suite and gear the economy to a better platform. Osheidu, (2007) asserted that industrial development in any country provides the brightest hope for generating sustenance growth, employment, savings and investments. Obviously, no industrial structure will stand the test of time without involvement of Structural Engineers and Cost Engineers also known as Quantity Surveyor. All processes needed for the actualization of this industrial structure are such that need constant help of Quantity Surveyors in procurement, advice on tendering procedure and contractual arrangement, taxation, budgeting, forecasting, guarantee and bonds, indemnity and insurance, and other core services that cannot be done with Industrialization and Structural transformation are imperative to quest for development.
Diversity in an economy is also key to apt development moving from growth to development is of essence at this condition of global economy. Focusing on single sector and embracing it more than other sector could be detrimental. There is need to explore other sector to bring out the gold in them. In Nigeria, oil and gas is such that was of most importance to government neglecting other sector such as Agriculture. The boom of oil and gas sector should not cause Agriculture sector downfall. Quantity Surveying services is such that finds it wit into the Agricultural sector in the sense that it could help the sector in preparing documents that could be used in securing loan from banks and other financial institutions which could place the sector in a pinnacle for other sector-serving as advisor to help guide against actions that could mar the sector.
Feasibility report for businesses is critical to making decision for intended businessmen. This service can be rendered by Quantity Surveyor; these small-firms are such that has been recorded to employ the greater percentage of workforce in any country. If the viability and feasibility of their businesses is not known, it could cause sudden halt to many businesses, and this could send hundreds of people back to labor market. Quantity Surveying is a profession that encourages small firm and business in establishing their aim which in turn become labor employee. An economy that does not encourage small businesses and firms is ready to crumble and fizzle out.
One of the inputs of Quantity Surveying is helping intending organizations, established organizations and others to be cost conscious. Knowledge of cost is key to help one avoid unwanted crisis and to be aware of financial risks to be taken. Knowing the probable cost of executing a project will help to know what to do in terms of obtaining loan and setting priorities. Government that wishes to put up a public infrastructure is helped to know the Cost Benefit Analysis (CBA) of such project to embark on.
Knowledge of risk management is also imperative of global economy resuscitation and its effects cannot be undermined. Quantity Surveying helps in diverse means in managing risk for any project at hand and proposed one. The advent of knowledge management in this millennium can also help combat the menace of global economy. It poses a platform for all professionals to put head together and bring in diverse knowledge that could help the economy.
Quantity Surveying is such with practices and services that could be employed to put a drastic solution to the menace of global economy as it renders services beyond construction industry.
1.4.2 WHO IS A QUANTITY SURVEYOR?
A Quantity Surveyor (QS) is a professional working within the construction industry concerned with construction costs and contracts. The Nigeria Institute of Quantity Surveyors (NIQS) refers to Quantity Surveyors as the expert professional trained and experienced in dealing with construction cost, construction management and construction communication; which is exhibited in various types of projects including building construction, civil and structural engineering, mechanical building and engineering services, petrochemicals, mineral extraction, cost and production engineering, environmental economics, planning and urban development, landscaping, interior design and other relevant areas.
The Quantity Surveyor is often referred to as the Cost Accountant of the construction industry. He assists the Client in controlling the cost of the project from the inception to the completion stage.
1.4.3 SERVICES RENDERED BY A QUANTITY SURVEYOR
The services provided by a Quantity Surveyor may include:
Cost planning and commercial management throughout the entire life cycle of the project from inception to post-completion.
Value Engineering.
Risk management and calculation.
Procurement advice and assistance during the tendering procedures.
Tender analysis (evaluation and report), and agreement of the contract sum.
Commercial management and contract administration.
Assistance in dispute resolution.
Feasibility and Viability studies.
Interim valuations and payment assessment.
Cost control and post contract management.
Assessing the additional costs of design variations.
Estimation.
Preliminary cost advice.
The services rendered by Quantity Surveyors can be divided into two stages, which are:
Pre-contract stage: this is a stage where services are carried out before a contract is awarded to a contractor to undertake a project for a Client.
These services are: Feasibility and Viability studies, preparation of Bill of Quantities, advice on Tendering procedures and Contractual arrangement and so on.
Post-contract stage: this is a stage where services are rendered by the Quantity Surveyor after a contract has been awarded to a contractor which the Client decided to execute the project. e.g. Supervision, Project management, Contract administration etc.
CHAPTER TWO
THE FIRM
COMPANY’S PROFILE
LAGOS WATER CORPORATION
PRODUCTION, DISTRIBUTION, COMMERCIAL, QUALITY ASSURANCE
HEADQUARTERS: 5th floor, Waterhouse, Ijora Causeway, Ijora Olopa, Lagos.
WEBSITE: www.lagoswater.org
TEL: (01) 774 3013, 474 6040-1
LWC HEADQUARTERS WATERHOUSE IJORA
COMPANY’S BACKGROUND
The Lagos Water Corporation (LWC) has gone through various developmental stages since its inception. It was formerly known as the Federal Water Supply (under Federal Government), established in 1910, with the construction of Iju Waterworks. The Waterworks was commissioned by Sir Lord Lugard, the then Governor General of Lagos, in 1915 at Obun Eko area of Lagos.
The Iju treatment plant has a design capacity of 2.4 million gallons per day and was constructed primarily to supply water to the colonial residents of Ikoyi in those days. In order to meet the water demand of the ever increasing population of the state, water facilities such as treatment plants and equipment were installed under the Corporation’s continuous expansion schemes. This led to the construction of Ishasi (1976) and Adiyan waterworks (1991) respectively.
The first executive governor of Lagos state, Alhaji Lateef Jakande changed the name of the agency to Lagos State Water Management Board (LSWMB) in 1979. The Lagos State Water Corporation (LSWC) was formally launched in 1986 by the then Military Administrator of Lagos state, Group Captain Gbolahan Mudashiru. Later, His Excellency, Asiwaju Bola Ahmed Tinubu, the third executive governor, Lagos state, rechristened it Lagos Water Corporation (LWC) in the year 2004, by virtue of Lagos State Water Sector Law (No. 14).
The Corporation operates as an effective and efficient state government parastatal, charged with the responsibility of providing potable and safe water to over 18 million people in Lagos state. Currently, the total installed water production capacity is 210 million gallons per day (MGD); which is lower than the current demand. In the Corporation’s renewed effort to solve the problem of water shortage and ensure steady supply of the growing population of Lagos, the Lagos Water Corporation has developed a Lagos Water Supply Master plan as a “Road Map” to take the water production capacity of the state to 745 million gallons per day (MGD) by year 2020.
COMPANY’S VISION
To provide safe drinking water in sufficient and regular quantity, maintain good quality service through revenue generation to sustain operations, meet customer expectation by planning sustainable growth and promote community health by good potable water.
ORGANISATIONAL STRUCTURE
CHAPTER 3
3.1 WORKING EXPERIENCE
On my first day of resumption at Lagos Water Corporation, I was posted by Human Resources to Project Implementation Unit (PIU) department headed by a Project Coordinator; Engr. S.O Ogunlana. I was introduced to his secretary; Mrs. Olaide Agbaje, personal assistant; Mr. Babatunde Akanni and the contract manager who was also my supervisor Mr. Adeyinka Olarinoye.
Working hours are from 8am to 4pm, Mondays to Fridays and occasionally when workload is much and schedule is tight Saturdays.
3.2 INTRODUCTION TO PROJECT IMPLEMENTATION UNIT (PIU)
Project Implementation Unit (PIU) is a department situated on the 5th floor of Waterhouse of Lagos Water Corporation Headquarters in Ijora.
Staffs in this department are 15 in number consisting of Engineers, Project Managers, Contract Managers, Legal Adviser and Consultant.
World Bank finances the expansion and rehabilitation project of the Corporation and the Project Implementation Unit is charged with the implementation of those projects
The project I met upon my commencement of training is the Second National Urban Water Sector Reform Project (2NUWSRP). The scope of the project is the Rehabilitation and Expansion of the water distribution network in Lagos.
The contract for the project was awarded to Idmon Engineering and Construction Company. (contractors)
3.3 REHABILITATION AND EXPANSION OF DISTRIBUTION NETWORK
The first treatment plant, with a capacity of 11,000m3 per day (2.42 mgd) was installed at Iju village, a part of Ogun state, abstracting water from the spring water trenches within the Iju hills. The scheme was designed and executed to serve the residential reservation of the colonial administration living in Ikoyi in Lagos state when the first cast iron trunk main “A” of nominal diameter 700mm was laid
Subsequent expansion was made to the plant by increasing it’s capacity to 27,000m3 per day (6mgd), accompanied by the laying of another cast iron trunk main “B” of nominal diameter 600mm. The plant drew it’s raw water resource from Iju River.
The plant capacity was again increased to 50,000m3 per day (11mgd) with the increasing demand of the residents and the growth of the industrial sector, the production and distribution potential became overstretched.
The main concern of the authorities managing water supply to Lagos has always been how to increase the supply of water due to the ever increasing population of Lagos
Over the years , the supply from Iju was no longer enough to meet the demands of Lagosians and a second waterworks had to be constructed at Ishasi.
In view of the fact that rapid population growth in Lagos has posed a heavy burden on the public water system, there has been a continuous demand and need for expansion of the Lagos water supply and distribution capacities.
With the contract already awarded, the new rehabilitated pipe network would consist of pipes made of High Density Polyethylene (HDPE)
These new HDPE pipes would be of varying diameters ranging from 110mm to 400mm and would hook up to the existing steel pipes and mains thereby expanding the distribution network in the state.
3.4 IDMON ENGINEERING AND CONSTRUCTION COMPANY
Upon commencement of the aforementioned project, I was assigned to Idmon Engr. & Construction Company to witness the daily activities of the contractors on site. I was attached to the Project Engineer; Engr. Godspower Iniyoviverhi and occasionally went for site inspection visits with the Project Manager; Engr. Segun Ogundele
I reported daily to Idmon site office on Saka Tinubu Street, Victoria Island from where the engineers and I would drive to LWC Lekki Waterworks, Lekki Phase 1 where the laydown and storage area are located.
The laydown and storage area are places where equipment, building materials and other relevant resources were kept during the project duration. Site facilities i.e. generator, pumping machine, cutting tools are mobilized from the laydown .
Preceding the site mobilization was the certification of all equipment, slings, lifting belts and tools by a third party who certified the serviceability of all equipment and tools.
3.5 PIPELAYING
The following are activities that occur before, during and after the pipe laying process:
3.5.1 SETTING OUT AND SURVEYING WORKS
This involves the staking out of reference points and markers that will guide the construction of new structures such as road, buildings and in this scenario, pipes. It is a pre-construction activity; hence, it is carried out long before pipelaying is set to take place. Setting out entails marking out of any physical feature that appears on an engineering plan. A layout of the entire existing pipe network was provided before the project commenced aiding the setting out and surveying process.
Work proceeds by marking out points on the ground surface connoting the location of the existing pipes underground where the new pipes would hook-up to. Topography, soil type and other relevant information were taken note of.
3.5.2 DETECTION OF EXISTING UTILITIES AND SERVICES
The scope of this project is expansion and rehabilitation, implying the presence of existing utilities and services. These utilities are identified via the layout/plan provided by Lagos Water Corporation indicating the location of existing pipes with further information like pipe diameter, depth below ground level, street where it is located etc. This information is the skeletal framework upon which the new distribution network would build on for expansion.
3.5.3 TRENCH EXCAVATION INCLUDING DEWATERING WORKS
After the first two steps listed above must have been carried out, excavation of trenches is next on the list. Having set out the area to be excavated, laborers excavate trenches under the supervision of the engineer in charge of that site. Excavation is done to depths stated in the plan/specification for that particular site. In some cases, owing to the fact that the Victoria Island and Lekki are regions close to waterbodies or dredged land, trenches are waterlogged upon excavation necessitating the use of dewatering pumps to pump out the water.
3.5.4 CUTTING OF ROADS AND PAVEMENT
Road surface at many instances in this project had to be broken and or cut through because pipes were to pass through the section beneath them. In such cases, the traffic management agency, Lagos State Traffic Management Agency (LASTMA) would have been informed prior to the time of cutting of road so as for them to manage the traffic situation created by the road breaking. In some cases, such works are carried out overnight when traffic congestion is low but the work would have to be completed and the road completely restored before morning to prevent hassle.
3.5.5 TRENCHLESS BORING WORKS
Trenchless boring methods are used for installing utility pipes, especially those running under busy roads or rivers. In this case the road surface is not broken unlike in trench excavation. It involves the placing of a new pipe in the ground between two sides of a road without open cut excavation between them.
The advantages of using trenchless boring as opposed to open cut excavation methods include:
Minimizing the environmental effects which the open cut excavation methods cause due to disturbing the soil, organisms and water bodies.
Encountering fewer unknowns in the ground
Saving time and cost related to surveying and design calculations
Minimizing installation time in comparison to open cut excavation methods
Improving safety compared to steep excavations
There are various methods of trenchless boring that may be used and the type of method chosen is dependent upon the pipe size that needs to be installed, the depth it needs to be installed at, the soil conditions of the ground and the overall cost of the method.
Method
Type of Soil
Comments
Pipe Jacking
All soil types
Exception of non-displaceable hard soil and rock
Microtunnelling
All soil types
Very fast and reliable system
Impact moling
Soft clay and silts
Suitable for shallower depths
Auger boring
Soils with sufficient stand-up time
Suitable for shallower depths
Thrust boring
All soil types
No limitation
Thrust Boring is the method of boring used for all the trenchless boring works carried out. It is a solution for installing new pipes in virgin ground where accuracy is critical. Working from a compact launch pit, a rod is thrust into the ground which pulls through a pipe into its proposed position.
3.5.6 INSTALLATION OF METALLIC WIRE TAPE PIPE TRACKER
This is an underground detectable warning tape which helps to ensure that buried pipelines are not accidentally cut. They are used for covering the location of underground utility lines and is easily identified because of its sharply printed legend on color-coded background. Approximately 10,000 meters of this tracker was installed at every site where pipes were laid.
3.6 CIVIL WORKS
Some of the civil works carried out includes the construction of the following:
Manhole/ Chamber: A manhole (alternatively utility hole, cable chamber, maintenance hole, inspection chamber, access chamber, sewer hole, or confined space) is the top opening to an underground utility vault used to house an access point for making connections, inspection, valve adjustments or performing maintenance on underground and buried public utility and other services including water, sewers, telephone, electricity, storm drains, heating and gas.
Manhole closings are protected by a manhole cover, a flat plug designed to prevent accidental or unauthorized access to the manhole. Those plugs are traditionally made of metal, but may be constructed from precast concrete, glass reinforced plastic or other composite material. Manholes were constructed during the project to house water utility services.
Thrust Blocks: this a concrete mix of 1:2:4 which is cast on the joints of pipework to absorb the vibrations from water pressure. It is cast based on the specifications given before the trench is backfilled. These thrust blocks are cast in situ, allowed to harden before the trench is backfilled.
Concrete markers & Surface boxes: : Concrete markers are installed extensively throughout the utility industries providing a warning to site personnel working or excavating in close proximity to underground pipes. Above ground marker posts clearly identify the exact location of underground utility services - concrete marker posts indicate the local presence of fire hydrants, water and gas valves and field markers. Various types of concrete cable markers are available impressed with a text for boundary marking or inclusive of snap-fit marker plates.
Concrete cable marker posts are reinforced to minimize risk of damage.
Cable posts manufactured from concrete, reinforced with steel rod.
Concrete marker posts are supplied with a recess to suit a fire hydrant or water valve plate manufactured to BS3251.
Reinstatement of road and asphalt: Road surfaces affected during pipe laying are reinstated immediately after work beneath road surface is complete. The contract makes room for this and Lagos State Public Works Corporation (LSPWC) is contacted beforehand to undertake the project of reinstating the roads.
3.7 HIGH DENSITY POLYETHYLENE (HDPE) PIPES
Definition: HDPE is a hydrocarbon polymer prepared from ethylene/petroleum by a catalytic process. It is a kind of thermoplastic which is famous for its tensile strength. Its unique properties can stand high temperatures.
Piping made from polyethylene is a cost effective solution for a broad range of piping problems in municipal, industrial, marine, mining, landfill, duct and agricultural applications. It has been tested and proven effective for above ground, surface, buried, slip lined, floating, and sub-surface marine applications.
High-density polyethylene pipe (HDPE) can carry potable water, wastewater, slurries, chemicals, hazardous wastes, and compressed gases. In fact, polyethylene pipe has a long and distinguished history of service to the gas, oil, mining and other industries. It has the lowest repair frequency per mile of pipe per year compared with all other pressure pipe materials used for urban gas distribution.
Polyethylene is strong, extremely tough and very durable, trouble-free installation, flexibility, resistance to chemicals or a myriad of other features, high-density polyethylene pipe meets all requirements.
3.7.1 FEATURES OF HDPE PIPES
Leak Free: Polyethylene pipe is normally joined by heat fusion. Butt, socket, sidewall fusion and electrofusion create a joint that is as strong as the pipe itself, and is virtually leak free. This unique joining method produces significant cost reductions compared to other materials.
Corrosion. Abrasion and Chemical resistance: Polyethylene piping’s performance in mining, dredging and similar applications proves it will outwear many more costly piping materials when conveying a variety of abrasive slurries. HDPE has excellent corrosion resistance and is virtually inert. It does not need expensive maintenance or cathodic protection. It offers better overall resistance to corrosive acids, bases and salts than most piping materials. In addition, polyethylene is unaffected by bacteria, fungi and the most “aggressive” naturally occurring soils. It has good resistance to many organic substances, such as solvents and fuels.
Excellent flow characteristics: Because polyethylene is smoother than steel, cast iron, ductile iron, or concrete, a smaller PE pipe can carry an equivalent volumetric flow rate at the same pressure. It has less drag and a lower tendency for turbulence at high flow. Its superior chemical resistance and “non-stick” surface combine to almost eliminate scaling and pitting and preserve the excellent hydraulic characteristics throughout the pipe service life.
Lightweight and Flexible: Polyethylene pipe is produced in straight lengths or in coils. Made from materials about one-eighth the density of steel, it is lightweight and does not require the use of heavy lifting equipment for installation. It reduces the need for fittings, is excellent in shifting soils and performs well in earthquake-prone areas. HDPE resists the effects of freezing and allows bending without the need for an excessive number of fittings. Since HDPE is not a brittle material, it can be installed with bends over uneven terrain easily in continuous lengths without additional welds or couplings.
Ductility and toughness: Polyethylene pipe and fittings are inherently tough, resilient and resistant to damage caused by external loads, vibrations, and from pressure surges such as water hammer. Even in cold weather polyethylene pipe is tolerant to handling and bending.
Available in wide range of diameters: Polyethylene pipe is available in a wide range of diameters and wall thickness, with flanges, elbows, tees, wyes, and valves, providing a total system solution. Diameters include 110mm, 160mm, 200mm, 225mm, 315mm, 375mm, 400mm. These are the sizes used in the pipe distribution network
3.7.2 ADVANTAGES OF HDPE PIPES
It maintains the general properties of the fluid inside. • Due to the inner surface can be used in drinking water systems. • Due to its chemical nature, it has a high resistance to chemicals. • It has ability to take shape and slope of the sloping terrain due to it’s flexibility • Due to its high elasticity properties, it is good for use in areas where a lot of
seismic activity. It can orient itself according to ground motion and not break. • Welding and assembly methods for HDPE are very simple. • Easy to carry because of the weight and thus shipping is cheap. • It is highly resistant to acids and alkalis. It is only damaged by nitric acid. • Environmentally friendly. • They are not affected underground, there are no refractive properties. • It does not conduct electricity. • A good level of friction, wear and has a rustproof. • It is strong against microorganisms.
3.7.3 HDPE PIPE JOINING TECHNIQUES
Pipes are melted with each other to combine the polyethylene pipe or they are connected with mechanical fittings. Various fittings for remaining outside of polyethylene pipes, flanges or developed in accordance with the objectives of the transition adapter provided with connection. Known Combining methods for joining HDPE pipes;
Electro Fusion 2) Butt-fusion (Butt Welding) 3) Socket Supply 4) Flange Connection
All our pipe joining was done with butt fusion welding which will be explained in detail below. Butt fusion welding is done in four stages:
* Cutting Unit: this component is used to make pipes surface smooth and flat, this part of the welding process as a result of the transaction would adversely affect the cleared dirt and oxide layer. * Clamps: Adjust the component of the welding equipment that keeps the pipe is fixed. Get set for each source alone, it should be done differently in the pipe. * Heating Unit: it faces the pipe and is used in heating equipment consisting of those resistances. * Hydraulic Unit: Shaving, heating, allowing the pressure required in the assembly process.
3.8 HYDROTESTING
Hydrostatic Testing is the most common method employed for testing pipes and pressure vessels. Using this test helps maintain safety standards and durability of a vessel over time.
3.8.1 PRESSURE TESTING
This is a way in which pressure vessels such as pipelines, plumbing, gas cylinders, boilers and fuel tanks can be tested for strength and leaks. The test involves filling the vessel or pipe system with a liquid, usually water, which may be dyed to aid in visual leak detection, and pressurization of the vessel to the specified test pressure. Pressure tightness can be tested by shutting off the supply valve and observing whether there is a pressure loss. The location of a leak can be visually identified more easily if the water contains a colorant. Strength is usually tested by measuring permanent deformation of the container. Hydrostatic testing is the most common method employed for testing pipes and pressure vessels. Using this test helps maintain safety standards and durability of a vessel over time. Newly manufactured pieces are initially qualified using the hydrostatic test. They are then re-qualified at regular intervals using the proof pressure test which is also called the modified hydrostatic
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3.8.2 CHLORINATE AND FLUSH LINES
Pipelines are treated for germs by flushing the lines with chlorine which acts as a germicide a