1 UNESCO-NIGERIA TECHNICAL & VOCATIONAL EDUCATION REVITALISATION PROJECT-PHASE II YEAR 2 - SE MESTER I THEORY Version 1: December 2008 NATIONAL DIPLOMA IN BUILDING TECHNOLOGY BUILDING SERVICES COURSE CODE: BLD 207 Water Sources Water Sources Water Sources Water Sources
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UNESCO-NIGERIA TECHNICAL & VOCATIONAL
EDUCATION REVITALISATION PROJECT-PHASE II
YEAR 2 - SE MESTER I
THEORY
Version 1: December 2008
NATIONAL DIPLOMA IN
BUILDING TECHNOLOGY
BUILDING SERVICES
COURSE CODE: BLD 207
Water SourcesWater SourcesWater SourcesWater Sources
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TABLE OF CONTENTS
WEEK1: THE SOURCES, QUALITY AND CLASSIFICATION OF W ATER
1.1 Course Introduction to Students
WEEK2: THE SOURCES, QUALITY AND CLASSIFICATION OF W ATER
1.1 Sources of Water
WEEK3 : THE SOURCES, QUALITY AND CLASSIFICATION OF WATER
1.2 State the Quality of Water from the Sources in 1.1
1.3 State the Two Classes of Water
1.4 Describe the Methods of Purification of Water
WEEK 4: THE SYSTEM OF DISTRIBUTION OF PIPE-WORK FOR DOMESTIC COLD WATER SUPPLY.
2.1 Illustrate the Direct and Indirect Method of Water Supply
2.2 Identify the Sizes and Types of Pipes Used Along the Distribution System
2.3 Describe with Sketches Cold Water Supply System
2.4 Describe Means of Providing Drinking Water
2.5 Differentiate Between Service, Communication and Other Pipes
WEEK 5: WATER DISTRIBUTION SYSTEMS 2
1.4 Water Purification/Treatment Flow chart
2.5 Differences between Distribution Lines
2.0 Water Supply and the African Peculiar Experience
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WEEK 6 WATER DISTRIBUTION SYSTEMS 3
2.0 Water Connection/Distribution Details in Drawings
WEEK 7: HOT WATER SUPPLY
WEEK 8: HOT WATER SUPPLY2
3.3 Precaution Against Dead Leg
WEEK 9: SANITARY APPLIANCES AND FITTINGS
4.1 Sanitary Appliances Description
WEEK 10: SANITARY APPLIANCES AND FITTINGS 2
4.1 -2 Taps and Valves
4.3 Construction Requirements for Fittings
WEEK 11: DRAINAGE SYSTEM USED IN BUILDINGS
WEEK 12: DRAINAGE SYSTEM USED IN BUILDINGS 2.
WEEK 13: DAYLIGHT AND ARTIFICIAL LIGHTING
WEEK 14: ELECTRICAL FITTINGS AND CONTROL
WEEK 15: REVISION AND CLASS WORK
7.5 Design and Installation Practice for Simple Building
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WEEK1: COURSE INTRODUCTION/OVERVIEW (1.0)
INTRODUCTION
Building Services is a course that deals with the provision of facilities to buildings to make such
buildings comfortable for human use. A building as a basic structure only offers protection
against adverse weather conditions, such as rainfall, snowfall, sunshine, wind etc.
For the convenience of the users of buildings, more is required of this basic structure; these
requirements include among others toilet facilities, this brings up the need for collection,
transportation, disposal and treatment of waste.
The need for water to make this modern toilet functional also makes it imperative to provide
water.
The waste generated in addition to the collection and disposal of storm water also brings up the
issue of drainage systems in building.
The heat generated by the sun’s radiation causes a lot of inconvenience to building users in form
of raised body temperature; this situation requires adequate ventilation – a good air
circulation/movement. The natural form of circulation might not be adequate hence the need for
means of artificial air circulation that can only be made possible by the use of energy the most
common of which is electricity. Closely linked to this is the need to provide lighting to a
building. Building being basically a boxlike enclosure usually requires lighting to allow for
visibility of the interior, this is only made possible by either natural lighting – obtained by the
creation of openings in building, or artificial lighting obtained via the use of electricity or any
other sources of energy.
The foregoing basically is what services to a building are all about. Put in a different form
Building services or general services are those provisions in and around buildings that make the
use of the built environment convenient for users.
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Some of the facilities provided in around buildings to make them functionally acceptable are as
explained below:
Water Supply
Water is one of the basic human needs. That water is needed cannot be over emphasized, the
availability of water on earth is also not in question. What is usually the problem is the quality,
the sources, the supply of potable water after treatment and the form/convenience by which the
supply gets to the users.
Building services in this respect seek to create an understanding of the real meaning of water, the
sources, the quality, the purification/treatment/ storage and supply to ensure adequacy and
availability all time round.
The understanding of this issue of water revolves round the hydrological cycle of water. See figs.
1.1 and 1.2
Fig. 1.1 - Hydrological Cycle of water
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Fig. 1.2 - Surface/Underground water
Water Cycle Description
The water cycle has no starting or ending point. The sun, which drives the water cycle, heats
water in the oceans. Some of it evaporates as vapor into the air. Ice and snow can sublimate
directly into water vapor. Rising air currents take the vapor up into the atmosphere, along with
water from evapo-transpiration, which is water transpired from plants and evaporated from the
soil. The vapor rises into the air where cooler temperatures cause it to condense into clouds. Air
currents move clouds around the globe; cloud particles collide, grow, and fall out of the sky as
precipitation. Some precipitation falls as snow and can accumulate as ice caps and glaciers,
which can store frozen water for thousands of years. Snow packs in warmer climates often thaw
and melt when spring arrives, and the melted water flows overland as snowmelt. Most
precipitation falls back into the oceans or onto land, where, due to gravity, the precipitation flows
over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape,
with stream flow moving water towards the oceans. Runoff, and ground-water seepage,
accumulate and are stored as freshwater in lakes. Not all runoff flows into rivers. Much of it
soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes
aquifers (saturated subsurface rock), which store huge amounts of freshwater for long periods of
time. Some infiltration stays close to the land surface and can seep back into surface-water
bodies (and the ocean) as ground-water discharge, and some ground water finds openings in the
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land surface and emerges as freshwater springs. Over time, the water continues flowing, some to
re-enter the ocean, where the water cycle renews itself.
The different processes are as follows:
• Precipitation is condensed water vapor that falls to the Earth's surface. Most precipitation
occurs as rain, but also includes snow, hail, fog drip, graupel, and sleet. Approximately
505,000 km³ of water fall as precipitation each year, 398,000 km³ of it over the oceans.[2]
• Canopy interception is the precipitation that is intercepted by plant foliage and eventually
evaporates back to the atmosphere rather than falling to the ground.
• Snowmelt refers to the runoff produced by melting snow.
• Runoff includes the variety of ways by which water moves across the land. This includes
both surface runoff and channel runoff. As it flows, the water may infiltrate into the ground,
evaporate into the air, become stored in lakes or reservoirs, or be extracted for agricultural or
other human uses.
• Infiltration is the flow of water from the ground surface into the ground. Once infiltrated, the
water becomes soil moisture or groundwater.
• Subsurface Flow is the flow of water underground, in the vadose zone and aquifers.
Subsurface water may return to the surface (eg. as a spring or by being pumped) or
eventually seep into the oceans. Water returns to the land surface at lower elevation than
where it infiltrated, under the force of gravity or gravity induced pressures. Groundwater
tends to move slowly, and is replenished slowly, so it can remain in aquifers for thousands of
years.
• Evaporation is the transformation of water from liquid to gas phases as it moves from the
ground or bodies of water into the overlying atmosphere.[4] The source of energy for
evaporation is primarily solar radiation. Evaporation often implicitly includes transpiration
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from plants, though together they are specifically referred to as evapo-transpiration. Total
annual evapo-transpiration amounts to approximately 505,000 km³ of water, 434,000 km³ of
which evaporates from the oceans. Sublimation is the state change directly from solid water (snow
or ice) to water vapor. Advection is the movement of water — in solid, liquid, or vapour states —
through the atmosphere. Without advection, water that evaporated over the oceans could not
precipitate over land.[7]
• Condensation is the transformation of water vapour to liquid water droplets in the air, producing
clouds and fog.[8]
Reservoirs
In the context of the water cycle, a reservoir represents the water contained in different steps
within the cycle. The largest reservoir is the collection of oceans, accounting for 97% of the
Earth's water. The next largest quantity (2%) is stored in solid form in the ice caps and glaciers.
This small amount accounts for approximately 75% of all fresh water reserves on the planet. The
water contained within all living organisms represents the smallest reservoir.
The volumes of water in the fresh water reservoirs, particularly those that are available for
human use, are important water resources.
In hydrology, residence times can be estimated in two ways. The more common method relies on
the principle of conservation of mass and assumes the amount of water in a given reservoir is
roughly constant. With this method, residence times are estimated by dividing the volume of the
reservoir by the rate by which water either enters or exits the reservoir. Conceptually, this is
equivalent to timing how long it would take the reservoir to become filled from empty if no
water were to leave (or how long it would take the reservoir to empty from full if no water were
to enter).
An alternative method to estimate residence times, gaining in popularity particularly for dating
groundwater, is the use of isotopic techniques. This is done in the subfield of isotope hydrology.
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Common Water Treatment Techniques and Devices:
Once contamination is detected in a drinking water supply it is important to use the proper treatment device to remove the contaminant. The following section is intended as a guide to help in the selection of a treatment device. Before buying a treatment device have the water supply tested for contamination and consult a specialist when selecting the best treatment device. If the specific contaminant is known the following methods and devices are used for treatment:
(a) Activated Alumina (b) Activated Carbon ( c) Aeration
soak-away and waste treatment plants. The sewer lines can either be single or combined to
collect separately the different types/forms of waste.
The drawing in fig. 1.3 shows a typical layout of sanitary fittings showing their connection to
sewer pipes.
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Fig. 1.3 – Typical layout of sanitary drainage system
DAYLIGHT AND ARTIFICIAL LIGHT
Building as an enclosure requires the provision of light in the interior to offer adequate
illumination at various time and level of desired brightness. This is usually taken care of by a
careful provision of openings in building to admit daylight and the provision of artificial (man
made) light in the form various energy driven forms of illuminants. The careful and intelligent
integration of these two forms of illumination is a subject matter needing adequate
understanding. This is to be discussed under the following subheads:
• Artificial and natural lighting methods
• How artificial lighting is provided in a house
• The integration of natural and artificial lighting in a house.
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• Electrical source of energy to power artificial lighting
• Cables used in power distribution and general connections
• Electrical fittings
• Construction provisions made for electrical fittings
• Simple electrical circuit system used in residential houses.
• Typical electrical wiring in low rise building.
• Regulations - I.E.E. (Institution of Electrical Engineering)
- N.E.P.A. (National Electricity Power Authority)
Electrical Installation Drawings samples:
Electricity Supply involves the design and installation of electricity need based on power consumption
needs. The design results are usually presented in drawings for interpretation during installation. Shown
in fig. 3.4 next page is an example of sketch drawing showing electrical provisions and conduit/cable
connections.
Fig. 3.4 - Electrical Design Drawing
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WEEK2: SOURCES,QUALITY AND CLASSIFICATION OF WATER 2
Sources of Water
Water is obtained generally within the hydrological cycle of water – a term used to refer to the
journey of water in the earth system. Because this journey is cyclic in nature, meaning that it
starts from one point and end at another point only to continue on its journey again from the
same starting point. It starts with rainfall from the cloud in the form of precipitation, turn into
run-offs to form stream, river and ground water from where we obtain both deep and shallow
wells. In addition to these we have spring water, borehole water that that are obtained from water
at the water table point.
The foregoing lead to having a list of sources of water as follows:
1. Stream
2. River
3. Ocean
4. Shallow Well
5. Driven wells
6. Deep Well
7. Bore Hole
8. Spring
Stream is simply described as a small river: a narrow and shallow river
River is a large natural channel of water: a natural stream of water that flows through land and
empties into a body of water such as an ocean or lake
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Ocean is a large sea: a large expanse of salt water, especially any of the Earth's five main such
areas, the Atlantic, Pacific, Indian, Arctic, and Antarctic oceans.
The oceans occupy huge regions of the Earth's surface, and their boundaries are usually
established by continental land masses and ridges in the ocean floor.
Types of water wells
Water wells are means by which assess to ground water is achieved. It involves digging by
different means into the ground, the pressure difference created by the space within the ground
lead to the movement of water from the surrounding into the well. The depth of well depends on
the water level, the degree of saturation of the ground and the water table position. As shown in
figures 2.1 to 2.5
Dug wells
Fig. 2.1 – Interior of Dug well - brick lined water well
Until recent centuries, all artificial wells were pump-less dug wells of varying degrees of
formality. Their indispensability has produced numerous literary references, literal and
figurative, to them, including the Christian Bible story of Jesus meeting a woman at Jacob's well
(John 4:6) and the "Ding Dong Bell" nursery rhyme about a cat in a well.
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Such primitive dug wells were excavations with diameters large enough to accommodate men
with shovels digging down to below the water table. Relatively formal versions tended to be
lined with laid stones or brick; extending this lining into a wall around the well presumably
served to reduce both contamination and injuries by falling into the well. The iconic American
farm well features a peaked roof above the wall, reducing airborne contamination, and a cranked
windlass, mounted between the two roof-supporting members, for raising and lowering a bucket
to obtain water.
More modern dug wells may be hand pumped, especially in developing countries.
Note that the term "shallow well" is not a synonym for dug well, and may actually be quite deep
- see Aquifer type, below.
Driven wells
Driven wells may be very simply created in unconsolidated material with a "well point", which
consists of a hardened drive point and a screen (perforated pipe). The point is simply hammered
into the ground, usually with a tripod and "driver", with pipe sections added as needed. A driver
is a weighted pipe that slides over the pipe being driven and is repeatedly dropped on it. When
groundwater is encountered, the well is washed of sediment and a pump installed.
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Borehole/Drilled wells
Fig. 2.2 - Cable tool water well drilling rig.
Drilled wells can get water from a much deeper level by mechanical drilling.
Drilled wells with electric pumps are currently used throughout the world, typically in rural or
sparsely populated areas, though many urban areas are supplied partly by municipal wells.
Drilled wells are typically created using either top-head rotary style, table rotary, or cable tool
drilling machines, all of which use drilling stems that are turned to create a cutting action in the
formation, hence the term 'drilling'. Most shallow well drilling machines are mounted on large
trucks, trailers, or tracked vehicle carriages. Water wells typically range from 20 to 600 feet
(180 m), but in some areas can go deeper than 3,000 feet (910 m).
Rotary drilling machines use a segmented steel drilling string, typically made up of 20-foot
(6.1 m) sections of steel tubing that is threaded together, with a bit or other drilling device at the
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bottom end. Some rotary drilling machines are designed to install (by driving or drilling) a steel
casing into the well in conjunction with the drilling of the actual bore hole. Air and/or water is
used as a circulation fluid to displace cuttings and cool bits during the drilling. Another form of
rotary style drilling, termed 'mud rotary', makes use of a specially made mud, or drilling fluid,
which is constantly being altered during the drill so that it can consistently create enough
hydraulic pressure to hold the side walls of the bore hole open, regardless of the presence of a
casing in the well. Typically, boreholes drilled into solid rock are not cased until after the drilling
process is completed, regardless of the machinery used.
The oldest form of drilling machinery is the Cable Tool, still used today. Specifically designed to
raise and lower a bit into the bore hole, the 'spudding' of the drill causes the bit to be raised and
dropped onto the bottom of the hole, and the design of the cable causes the bit to twist at
approximately 1/4 revolution per drop, thereby creating a drilling action. Unlike rotary drilling,
cable tool drilling requires the drilling action to be stopped so that the bore hole can be bailed or
emptied of drilled cuttings.
Drilled wells are typically cased with a factory-made pipe, typically steel (in air rotary or cable
tool drilling) or plastic/PVC (in mud rotary wells, also present in wells drilled into solid rock).
The casing is constructed by welding, either chemically or thermodynamically, segments of
casing together. If the casing is installed during the drilling, most drills will drive the casing into
the ground as the bore hole advances, while some newer machines will actually allow for the
casing to be rotated and drilled into the formation in a similar manner as the bit advancing just
below. PVC or plastic is typically welded and then lowered into the drilled well, vertically
stacked with their ends nested and either glued or splined together. The sections of casing are
usually 20' (6 m) or more in length, and 6" - 12" (15 to 30 cm) in diameter, depending on the
intended use of the well and local groundwater conditions.
Surface contamination of wells in the United States is typically controlled by the use of a 'surface
seal'. A large hole is drilled to a predetermined depth or to a confining formation (clay or
bedrock, for example), and then a smaller hole for the well is completed from that point forward.
The well is typically cased from the surface down into the smaller hole with a casing that is the
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same diameter as that hole. The annular space between the large bore hole and the smaller casing
is filled with bentonite clay, concrete, or other sealant material. This creates an impermeable seal
from the surface to the next confining layer that keeps contaminants from traveling down the
outer sidewalls of the casing or borehole and into the aquifer. In addition, wells are typically
capped with either an engineered well cap or seal that vents air through a screen into the well,
but keeps insects, small animals, and unauthorized persons from accessing the well.
At the bottom of wells, based on formation, a screening device, filter pack, slotted casing, or
open bore hole is left to allow the flow of water into the well. Constructed screens are typically
used in unconsolidated formations (sands, gravels, etc.), allowing water and a percentage of the
formation to pass through the screen. Allowing some material to pass through creates a large area
filter out of the rest of the formation, as the amount of material present to pass into the well
slowly decreases and is removed from the well. Rock wells are typically cased with a PVC
liner/casing and screen or slotted casing at the bottom, this is mostly present just to keep rocks
from entering the pump assembly. Some wells utilize a 'filter pack' method, where an undersized
screen or slotted casing is placed inside the well and a filter medium is packed around the screen,
between the screen and the borehole or casing. This allows the water to be filtered of unwanted
materials before entering the well and pumping zone.
Two additional broad classes of well types may be distinguished, based on the use of the well:
• production or pumping wells, are large diameter (> 15 cm in diameter) cased (metal,
plastic, or concrete) water wells, constructed for extracting water from the aquifer by a
pump (if the well is not artesian).
• monitoring wells or piezometers, are often smaller diameter wells used to monitor the
hydraulic head or sample the groundwater for chemical constituents. Piezometers are
monitoring wells completed over a very short section of aquifer. Monitoring wells can
also be completed at multiple levels, allowing discrete samples or measurements to be
made at different vertical elevations at the same map location.
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Obviously, a well constructed for pumping groundwater can be used passively as a monitoring
well and a small diameter well can be pumped, but this distinction by use is common.
Well Water Quality and Hygiene
Fig. 2.3 – Concrete lined well in Africa
Shallow pumping wells can often supply drinking water at a very low cost, but because
impurities from the surface easily reach shallow sources, a greater risk of contamination occurs
for these wells when they are compared to deeper wells. In shallow and deep wells, the water
requires pumping to the surface; in artesian wells, conversely, water usually rises to a greater
level than the land surface when extracted from a deep source.
Well water for personal use is often filtered with reverse osmosis water processors; this process
can remove very small particles. A simple, effective way of killing micro organisms is to boil the
water (although, unless in contact with surface water or near areas where treated wastewater is
being recharged, groundwater tends to be free of micro organisms). Alternately the addition of
1/8 teaspoon (0.625 mL) of bleach to a gallon (3.8 L) of water will disinfect it after a half hour.
Contamination of groundwater from surface and subsurface sources can usually be dramatically
reduced by correctly centering the casing during construction and filling the casing annulus with
an appropriate sealing material. The sealing material (grout) should be placed from immediately
above the production zone back to surface, because, in the absence of a correctly constructed
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casing seal, contaminated fluid can travel into the well through the casing annulus. Centering
devices are important (usually 1 per length of casing or at maximum intervals of 30 feet/9 m) to
ensure that the grouted annular space is of even thickness.
Anthropogenic contamination
Contamination related to human activity is a common problem with groundwater. For example,
benzene, toluene, ethylbenzene, and total xylenes (BTEX), which come from gasoline refining,
and methyl-tert-butyl-ether (MTBE), which is a fuel additive, are common contaminants in
urbanized areas, often as the result of leaking underground storage tanks. Many industrial
solvents also are common groundwater contaminants, which may enter groundwater through
leaks, accidental spills or intentional dumping. Military facilities also produce considerable
amounts of groundwater contamination, often in the form of solvents like trichloroethylene
(TCE).[3] Cleanup of contaminated groundwater tends to be very costly. Effective remediation of
groundwater is generally very difficult.
Natural contaminants
Some very common constituents of well water are natural contaminants created by subsurface
mineral concentrations. Common examples include iron, magnesium and calcium. Large
quantities of magnesium and calcium ions cause what is known as "hard water". Certain
contaminants such as arsenic and radon are considered carcinogenic. [2] and therefore chronic
contaminants. Other natural constituents of concern are nitrates and Coliform bacteria, both of
which are considered acute contaminants and may seriously sicken persons considered to be "at
risk", mainly the elderly, infirm and infants. Also of consequence can be radionuclides such as
radium, uranium and other elements. Upon the construction of a new test well, it is considered
best practice to invest in a complete battery of chemical tests on the well water in question.
Point-of-use treatment is available for individual properties and treatment plants are often
constructed for municipal water supplies that suffer from contamination. Most of these treatment
methods involve the filtration of the contaminants of concern, and additional protection may be
garnered by installing well-casing screens only at depths where contamination is not present.
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Ancient well
fig. 2.4 – Old dug well
Fig. 2.5 - Water being lifted from a traditional well
Spring Water
Spring (hydrosphere)
A spring is a point where groundwater flows out of the ground, and is thus where the aquifer
surface meets the ground surface.
Dependent upon the constancy of the water source (rainfall or snowmelt that infiltrates the
earth), a spring may be ephemeral (intermittent) or perennial (continuous).
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Fig. 2.6 - Big Spring
Formation
Fig. 2.6 - A natural spring.
Water issuing from an artesian spring rises to a higher elevation than the top of the confined
aquifer from which it issues. When water issues from the ground it may form into a pool or flow
downhill, in surface streams. Sometimes a spring is termed a seep.
Minerals become dissolved in the water as it moves through the underground rocks. This may
give the water flavor and even carbon dioxide bubbles, depending upon the nature of the geology
through which it passes. This is why spring water is often bottled and sold as mineral water,
although the term is often the subject of deceptive advertising. Springs that contain significant
amounts of minerals are sometimes called 'mineral springs'. Springs that contain large amounts
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of dissolved sodium salts, mostly sodium carbonate, are called 'soda springs'. Many resorts have
developed around mineral springs known as spa towns.
Fig. 2.7 – Water Pool from spring.
A stream carrying the outflow of a spring to a nearby primary stream is called a spring branch or
run. The cool water of a spring and its branch may harbor species such as certain trout that are
otherwise ill-suited for a warmer local climate.
Water emanating from karst topography is another type of spring, often called a resurgence as
much of the water may come from one or more sinkholes at a higher altitude. Karst springs
generally are not subjected to as great a degree of ground filtering as spring water which may
have continuously passed through soils or a porous aquifer.
Classification
Springs are often classified by the volume of the water they discharge. The largest springs are called "first-magnitude," defined as springs that discharge water at a rate of at least 2800 L/s. The scale for spring flow is as follows:
Contours of equal amounts of daylight can be produced for rooms to give an indication of where the illumination from outside falls and the effects of differing window shapes, as shown below.
2%
5%
10% 15% 15%
20% 20%
Plan
Daylight factor contours
148
WINDOWS
Windows facing the direction of the sun (south in the northern hemisphere) will receive more daylight than those facing in the opposite direction.
Tall windows will push the daylight factor contours back into a room while wide windows give a better distribution across the width of a room but do not let the light penetrate to the back.
To obtain an internal illuminance of 500 lux the daylight factor would need to be about 10% in the U.K., this is higher than is normally expected, therefore artificial light is added to daylight in most buildings. Artificial sources of light are needed at night time anyway, but this does not mean that we should neglect window design.
One design process is used to ensure that the back of a room is not dull. It uses the formula as follows:
( L / W + L / W ) shall not exceed 2 / ( 1 – RB)
Where;
L = depth of room from window to back wall (m)
W = room width (m)
H = height from window lintel to floor level (m)
RB = average reflectance of the half of the interior at the back of the room.
Lumen Method The quantity of light reaching a certain surface is usually the main consideration in designing a lighting system.
This quantity of light is specified by illuminance measured in lux, and as this level varies across the working plane, an average figure is used.
CIBSE Lighting Guides give values of illuminance that are suitable for various areas.
The section - Lighting Levels in these notes also gives illuminance values.
The lumen method is used to determine the number of lamps that should be installed for a given area or room.
149
Calculating for the Lumen Method
The method is a commonly used technique of lighting design, which is valid, if the light fittings (luminaires) are to be mounted overhead in a regular pattern.
The luminous flux output (lumens) of each lamp needs to be known as well as details of the luminaires and the room surfaces.
Usually the illuminance is already specified e.g. office 500 lux, kitchen 300 lux, the designer chooses suitable luminaires and then wishes to know how many are required.
The number of lamps is given by the formula:
where,
N = number of lamps required.
E = illuminance level required (lux)
A = area at working plane height (m2)
F = average luminous flux from each lamp (lm)
UF= utilisation factor, an allowance for the light distribution of the luminaire
and the room surfaces.
MF= maintenance factor, an allowance for reduced light output because of deterioration and dirt.
Example 1
A production area in a factory measures 60 metres x 24 metres.
E x A N =
F x UF x MF
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Find the number of lamps required if each lamp has a Lighting Design Lumen (LDL) output of 18,000 lumens.
The illumination required for the factory area is 200 lux.
Utilisation factor = 0.4
Lamp Maintenance Factor = 0.75
N = ( 200 lux x 60m x 24m ) / ( 18,000 lumens x 0.4 x 0.75 )
N = 53.33
N = 54 lamps.
Spacing
The aim of a good lighting design is to approach uniformity in illumination over the working plane.
Complete uniformity is impossible in practice, but an acceptable standard is for the minimum to be at least 70% of the maximum illumination level.
This means, for example, that for a room with an illumination level of 500 lux, if this is taken as the minimum level, then the maximum level in another part of the room will be no higher than 714 lux as shown below.
500 / 0.7 = 714 lux
Data in manufacturer's catalogues gives the maximum ratio between the spacing (centre to centre) of the fittings and their height ( to lamp centre) above the working plane (0.85 metres above f.f.l.)
0.85 metres
Spacing distance Mounting
Height
f.f.l.
This percentage value is known as a Daylight Factor.
Daylight Factor Definition
The Daylight Factor is defined as the ratio of the illuminance at a particular point within an
enclosure to the simultaneous unobstructed outdoor illuminance under the same sky conditions,
expressed as a percentage. Once both the Daylight Factor and Design Sky are known
multiplying the two together gives the illuminance level (in either lux or foot candles) due to
daylight at the point.
Daylight Factor Calculations
Working out the Daylight Factor in different areas of a building can be a time consuming and
laborious process. In most cases it is done using a computer program, of which there are quite a
few to choose from. However, a good knowledge of manual calculation methods is very
important if you are to fully understand the processes involved and therefore
computer programs in the most appropriate ways. There are a number of ways to calculate the
Daylight Factor for a space:
• Average Daylight Factor
This is quite a simple equation that requires only a few parameters and makes quite a
few assumptions about the nature of your space. The result is a single value room
average daylight factor.
• Daylight Factor Protractors
Also known as the Split Flux Method, this involves overlaying protractors onto the
plans and sections of your building. This can be done directly on print
the new Square One DF Protractor tool
your favourite CAD tool.
151
This percentage value is known as a Daylight Factor.
Daylight Factor Definition
is defined as the ratio of the illuminance at a particular point within an
enclosure to the simultaneous unobstructed outdoor illuminance under the same sky conditions,
expressed as a percentage. Once both the Daylight Factor and Design Sky are known
multiplying the two together gives the illuminance level (in either lux or foot candles) due to
Daylight Factor Calculations
Working out the Daylight Factor in different areas of a building can be a time consuming and
borious process. In most cases it is done using a computer program, of which there are quite a
few to choose from. However, a good knowledge of manual calculation methods is very
important if you are to fully understand the processes involved and therefore
computer programs in the most appropriate ways. There are a number of ways to calculate the
Average Daylight Factor
s is quite a simple equation that requires only a few parameters and makes quite a
few assumptions about the nature of your space. The result is a single value room
average daylight factor.
Daylight Factor Protractors
Also known as the Split Flux Method, this involves overlaying protractors onto the
plans and sections of your building. This can be done directly on print
DF Protractor tool , directly over a scanned image or within
your favourite CAD tool.
is defined as the ratio of the illuminance at a particular point within an
enclosure to the simultaneous unobstructed outdoor illuminance under the same sky conditions,
expressed as a percentage. Once both the Daylight Factor and Design Sky are known, simply
multiplying the two together gives the illuminance level (in either lux or foot candles) due to
Working out the Daylight Factor in different areas of a building can be a time consuming and
borious process. In most cases it is done using a computer program, of which there are quite a
few to choose from. However, a good knowledge of manual calculation methods is very
important if you are to fully understand the processes involved and therefore apply these
computer programs in the most appropriate ways. There are a number of ways to calculate the
s is quite a simple equation that requires only a few parameters and makes quite a
few assumptions about the nature of your space. The result is a single value room-
Also known as the Split Flux Method, this involves overlaying protractors onto the
plans and sections of your building. This can be done directly on print-outs or, using
rectly over a scanned image or within
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• Projecting Points of Equal Sky Illuminance
This is a simplified method involving the projection of points over the sky dome
within a 3D view of your model or in a Sun-Path diagram. You can then simply count
the points you can 'see' through windows and skylights.
Example 2
Using data in the previous example show the lighting design layout below.
The spacing to mounting height ratio is 3 : 2.
The mounting height (Hm) = 4 metres.
The spacing between lamps is calculated from from Spacing/Hm ratio of 3 : 2.
If the mounting height is 4 m then the maximum spacing is:
3 / 2 = Spacing / 4
Spacing = 1.5 x 4 = 6 metres
The number of rows of lamps is calculated by dividing the width of the building (24 m) by the spacing:
24 / 6 = 4 rows of lamps
This can be shown below. Half the spacing is used for the ends of rows.
Factory Plan
24 metres
60 metres
Scale 1 cm = 4 metres
Half spacing = 3 m
Spacing between rows = 6 m
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The number of lamps in each row can be calculated by dividing the total number of lamps found in example 1 by the number of rows.
Total lamps 54 / 4 = 13.5 goes up to nearest whole number = 14 lamps in each row.
The longitudinal spacing between lamps can be calculated by dividing the length of the building by the number of lamps per row.
Length of building 60 m / 14 = 4.28 metres.
There will be half the spacing at both ends = 4.28 / 2
= 2.14 metres
This can be shown below.
Factory Plan
24 metres
60 metres
Scale 1 cm = 4
metres
6 m
4.28
metres
Half Spacing 2.14
metres
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The total array of fittings can be shown below.
For more even spacing the layout should be re-considered.
The spacing previously was 6 m between rows and 4.28 m between lamps.
If 5 rows of 11 lamps were used then the spacing would be:
Spacing between rows = 24 / 5 = 4.8 metres
Spacing between lamps = 60 / 11 = 5.45 metres
Installed Flux
Sometimes it is useful to know the total amount of light or flux, which has to be put into a space.
Installed flux (lm) = Number of fittings (N) x Number of lamps per fitting x L.D.L. output of each lamp (F)
Lighting is the illumination of buildings. There are two methods of lighting in building – Natural
and Artificial lighting.
Factory Plan
24 metres
60 metres
Scale 1 cm = 4 metres
6 m
4.28 m Light Fittings
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Natural lighting, also referred to as Day light, derives its illumination ability from the sun. The
sunshine illuminates the environment within which the building is and the openings under
fenestration in building allowed controllable amount of natural lighting into buildings.
Artificial lighting derives its source from electrical illuminants – incandescent lamps or
fluorescent lights. They are provided under electrical provision in buildings.
Provision of Natural lighting in Buildings
Natural lighting in building is provided by making provision in building to admit adequate
daylight into it. This provision is referred to as FENESTRATION or commonly known as
Openings in Building. The openings include among others windows, doors, screen walling, roof
light, lighting glass blocks etc.
Provision of Artificial Lighting in Buildings
Artificial lighting as previously mentioned is provided by the use of incandescent lamps or
fluorescent lights. The lights are powered by various sources of energy but most commonly by
electrical energy. This is part of the electrical engineering design of buildings. They form part of
electrical installation in buildings.
The integration of Lighting: Natural and Artificial in building.
The two lighting method are usually combined effectively to minimize the use of artificial
lighting that is usually costly to use. This is achieved by architectural design provisions in
conjunction with electrical engineering design provisions.
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WEEK 14: ELECTRICAL FITTINGS AND CONTROL
Cables
Cables are used for electrical wiring in building. The conduct current to various fittings. Various
fittings require different level or amount of current to run or drive them. The flow of current is
dependent on the size, type and quality of cable use. An improper use of cables result in heat
generation and possibly fire hazard hence the importance proper cable type and size selection
and use for the different types of fittings in buildings.
The following are the different types of cables based on form, material and sizes (some of the
cables are as shown in figure 14.1:
1. Single core cables
2. Double core cables
3. Multiple core cables
4. Armoured cables
5. Copper cables
6. Aluminum cables
7. 1.0 mm2
8. 1.5 mm2
9. 2.5 mm2
10. 4.0 mm2
11. 6.0 mm2
12. PVC insulated cables etc.
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Fig. 14.1 – Samples of Electrical Cables
Electrical design and installation involve the use of symbols and conduit fittings the detail
description of which is beyond this syllabus, but for the purpose of a general understanding the
following figures 14.2 14.6 shows the various items that fall under the aforementioned.
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Fig 14.2 – Electrical Bulbs
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Fig. 14.3 – Armoured Cables
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Fig.14.4 – Conduit Materials
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Fig. 14.5 – Ceiling Fittings
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Fig. 14. 6 – Lighting Point Details 1
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Fig. 14. 6 – Lighting Point Details 2
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Lighting symbols for Installations
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Table 1 = Method 4 Encased in insulated wall
Cable size Rating in Amps
1mm 11
1.5mm 14
2.5mm 18.5
4.00mm 25
6.00mm 32
10.00mm 43
Table 2 = Method 1 Clipped Direct
Cable size Rating in Amps
1mm 15
1.5mm 19.5
2.5mm 27
4mm 36
6mm 46
10mm 63
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List of Electrical Fittings and Controls
The following are the list of electrical fittings and controls showing their uses:
1. Socket outlet - use for 13A and 15A power sockets
2. Switches - use for putting on/off light
3. Wall Bracket - use for lighting fitting
4. Bulk head fitting - use for external lighting
5. Ceiling Rose - use as power point terminal
6. Cooker Control Unit - use for socket and power supply to
cooker in kitchen
7. Distribution Board - use for current distribution to various
points in buildings
8. ELCB - use for power supply protection, it
serves as circuit-breaker in the event of
short circuiting.
9. Change over switch - use for controls in double source power
supply
10. Others
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Construction Provisions made for electrical fittings.
Construction provisions are for electrical fittings in buildings to allow for a seamless and highly
integrated installation at various points of the building.
The essential provisions made arising from the design detail are as follows:
1. Conduit pipe installation within walls, floors
2. Fixing base to receive fittings
3. Bored holes for passage of pipes/cables
4. Others
QUIZ 14
Sketch a three bedroom flat and show the electrical and power supply design, use keys
appropriately.
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WEEK 15: ELECTRICAL FITTINGS AND CONTROL2
Design and Installation of electric wiring:
Class work involving the design and installation of electrical for a three bedroom apartment.
THE REVIEW ALL THAT HAS BEEN DONE SO FAR AND ANSWERING OF THE
FOLLOWING QUIZ IN CLASS TO MARK THE END OF COURSE:
ASSIGNMENTS
1. Choose appropriate lamp and fitting types for the buildings listed below;
(a) Hospital ward
(b) Factory
(c) Bank hall
(d) School classroom
(e) Large Public Library
(f) Football Stadium
(g) Retail Outlet window
(h) Temporary lighting for construction site.
(i) Scientific experimentation Laboratory.
(j) Cinema
2. Describe a typical emergency lighting scheme for a large building.
Discuss the systems and categories that may be used.
Describe various luminaries and wiring systems that can be used in emergency
lighting.
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Discuss the location of fittings.
3. Describe, with the aid sketches, typical control gear for gas discharge and low
voltage light fittings.
4. Produce an appropriate lighting scheme for the Leisure Centre building.
Choose fittings and produce a design that is efficient, energy saving and cost