JOB SHEET # 2-2
TITLE: PREPARE THE BILL OF MATERIALS AND SUMMARY COST
Purpose ESTIMATES
To prepare the Bill of Materials and Summary Cost
Estimates
Equipment, Tools and Writing pads, calculator, ball pen
Materials
Precautions Make sure that you have made your canvass of prices
from 2 or more suppliers in the market.
Procedures
STEP #1. Prepare the Bill of Materials.
After computing and determining the various materials needed for the construction of the
facilities, the data should be organized and presented in a Bill of Materials form which
includes a summary of cost estimates for materials, labor, and other construction
expenses.
The Bill of Materials may be prepared using several pages. Different pages may be used
for the different phases or aspects of construction: Foundation works, Floorings, Concrete
Columns and Beams, Walls and Partitions, etc. The Bill of Materials may also be
presented by area (e.g. Office, Stockroom, Laboratory, etc.) with subheadings on
masonry, woodworks, electrical, etc.
Description of Materials. The first column of the Bill of Materials provides
descriptions of the materials needed. To the extent possible, all specifications,
including brand names and the like, should be indicated. Where necessary,
pictures or illustrations should be included, and dimensions and specifications duly
stated.
Quantity. The second column if for the number of pieces, volume, etc. of the
materials needed.
Unit. The third column indicates the appropriate units of measure by which they
are sold are used and shown in this column.
Unit Cost. The fourth column refers to the current selling price per indicated unit
of measure of the materials. If prevailing costs is not yet available, this column
may be left blank, and may be filled after a canvass of material prices have been
made.
• Total Cost. The fifth and last column is the product of the quantity multiplied by
the unit cost.
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STEP #2.
The last page of the bill of materials contains a summary of the different Bills of Materials
for the different phases or aspects of construction. An estimate of the cost of labor is
likewise indicated. An acceptable allowance for contingencies and price adjustments is
also indicated.
When the construction is planned to be contracted out, provisions for Contractor’s Profit
and Contractor’s Tax is also included. The summation of this page is the total estimated
construction cost for the hatchery.
LEARNING EXERCISE #1: Please fill up the following table to present your data
for the Bill of Materials.
BILL OF MATERIALS
Project Title :
Owners :
Location :
Description of Materials Quantity Unit Unit Total
Cost Cost
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Learning Exercise #2: Accomplish the following form in order to summarize the
cost of labor, materials and other construction expenses. Refer back to the detailed
cost of materials in Learning Exercise #1 in preceding page,
SUMMARY COST ESTIMATES FOR MATERIALS, LABOR, AND OTHER
CONSTRUCTION EXPENSES
PARTICULARS Sub-Total 1 Sub-Total 2 Totals
A. Estimated Cost of Materials Xxxxx
1. Foundation, Columns, etc.
2. Floor Framing xxxxx
3. Roof framings xxxxx
4. Roofing Materials xxxxx
5. Plumbing Pipes and Fittings xxxxx
6. Plumbing fixtures, etc. xxxxx
7. Ceilings, partitions, etc. xxxxx
8. Electrical Materials xxxxx
9. Doors, windows, etc. xxxxx
xxxxx
10. Painting materials xxxxx
11. Miscellaneous materials xxxxx
B. Estimated Cost of Labor Xxxxx
C. Contingency Provision Xxxxx
Estimated Total Direct Cost xxxxx
D. Contractor’s Fees xxxxx
E. Contractor’s Tax xxxxx
Estimated Total Project Cost xxxxx
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INFORMATION SHEET # 2-2
BASIC CONSIDERATIONS IN SELECTING PUMPS
If you must lift water, reducing the lift will improve the overall efficiency of operation.
Surface sources of water usually require much less lift than pumping from wells. Two
common types of pumps designed primarily for low-lift operations are the propeller axial
flow pump and the horizontal PTO-driven centrifugal pump. Axial flow propeller pumps
have very high efficiencies and are capable of pumping large volumes. Horizontal
centrifugal PTO-driven pumps are less efficient but still maintain the capability of pumping
large volumes of water. They also are portable and often fit into a flexible management
plan for aquaculture production.
o Pump efficiency. Selecting a correct pumping plant not only will conserve valuable
energy supplies but also will reduce total annual pumping costs. Inefficient
pumping plants can increase costs dramatically. The efficiency of a pump is a
measure of the degree of its hydraulic and mechanical perfection. Pump efficiency
is the ratio of the output water horsepower to the input shaft horsepower
expressed as a percentage: A horsepower is defined as the power required to
raise a weight of 33,000 pounds a vertical distance of 1 foot in 1 minute. The rate
of work performed by a pump (in horsepower) is proportional to the weight of the
water it delivers per minute multiplied by the total equivalent vertical distance in
feet through which it is moved.
o Well size and capacity limits. There are definite capacity limitations for a given
diameter of well casing. To obtain this limit, the pump must have sufficient
capacity. The capacity of a centrifugal pump varies directly with its speed of
operation. It may be necessary to increase the pump speed to get maximum
capacity from a given well size. Maximum permissible speed depends upon a
number of factors, but for 4-inch, 6-inch and even 8-inch pumps, a speed of 3,600
rpm is not uncommon. For larger sizes, however, this speed is not advisable.
Since nominal electric motor speeds used in pumping are either 1,760 rpm or
3,450 rpm, intermediate speeds may be achieved with right-angle gears of suitable
ratio or with belt and pulley drives.
o Pumping from a well. Changes in pumping heads because of different operating
systems usually require a change in the pumps to maintain greatest efficiency.
Does your pump surge? If you observe a surge in the discharge, the pump may be
having difficulty getting enough water. Assuming that adequate water is available
to flow into the well and that encrusted wells are not the problem, then the surge is
normally caused by the pump not being submerged enough to provide water for
intake. Where the pump is located some distance from the bottom of the well, it is
often possible to lower the pump and reduce the amount of surging. This can
require more power since full water flow may be obtained along with higher head.
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This may overload the existing motor. In some instances you may have to add
another stage and change the motor to one of greater horsepower.
When the pump is set near the bottom of the well and it is impossible to lower the
pump to minimize surging, consider other alternatives. Long-term solutions
resulting in higher efficiency include pulling the pump and trimming the impeller or
replacing the pump with a different pump of a smaller capacity. It might also be
possible to decrease the pump speed and thus decrease the amount of water
which is pumped, but this could result in a sizable decrease in efficiency. These
short-term solutions for a single pumping season will result in a decrease in
efficiency; adjustment of the impellers upward, throttling of the discharge by
closing a valve on the discharge side, and, for belt-driven pumps, the exchange of
pulleys in such a way to decrease rpm.
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JOB SHEET # 2-3
TITLE: PROCEDURE FOR DETERMINING PUMP CAPACITIES
Purpose To determine pump capacities for selecting the required
equipment
Equipment, Tools and Writing pads, ball pen, calculator
Materials
Precautions Make sure that you have made a good list of all types of
pumps available in the market and their specifications
PROCEDURES
STEP # 1: Match the pipe to the piping system and required flow rate.
In order to obtain a pumping system that will meet your requirements, and meet them in
an efficient manner, you must match the pump to the piping system and required flow
rate.
STEP #2 Make an analysis of initial cost of capital investment, annual fixed cost
and operating cost.
All three costs are somewhat dependent on each other. The type of pumping equipment,
size of pipelines, size of pumps and type of water supply affect not only the initial cost but
also the fixed cost as well as the operating cost. For example, piping systems using large
pipes may cost more but could allow the use of smaller horsepower pumps which cost
less, require smaller power sources and cost less to operate than a piping system with
small diameter pipe. The lowest priced system is not always the best buy, especially if
the lower price means less efficient pumps. To get the most efficient pump, an analysis
should be made of all pumping requirements.
• Cetrifugal Pumps. Pumps used in aquaculture often are a form of the centrifugal
pump. Two basic types of centrifugal pumps are horizontal and vertical. As the
name implies, centrifugal pumps use centrifugal force to move water from one
point to another and to overcome resistance to its flow. In its simplest form, this
pump consists of an impeller fixed on a rotating shaft within a volute-type (spiral)
casing. Water enters at the center of the impeller and is forced to the outer edge at
a high velocity by the rotating impeller. The water is discharged by centrifugal force
into the casing where the high velocity head is converted to pressure head.
o Horizontal centrifugal pumps (for surface supply and shallow wells). Horizontal
centrifugal pumps are frequently used if the source of water is a surface supply,
such as a lake, stream, canal or pond, or a shallow well. A shallow well, as
opposed to a deep well, is one in which the water level in the well is high
enough to permit the vacuum at the pump to lift the water and keep it flowing at
an acceptable rate. As the name implies, horizontal centrifugal pumps normally
have a horizontal shaft.
This type of pump is usually subdivided into two groups, single suction (end
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suction) and double suction (often called split case). Either of these may be
single or multistage; that is, they may have only one impeller or they may have
two or more impellers. These impellers are so constructed that the water, in
passing through the pump, is conducted from the discharge of one impeller to
the suction of the second; thus, the total head is that developed by a single
impeller multiplied by the number of impellers in the pump. The most common
pump and the lowest in cost is the end suction, single stage.
Jet pumps. A jet pump is often used for very low capacity requirements (5
to 20 gpm), such as a home water system. This pump consists of a small
centrifugal pump located at ground level connected to a jet installed below
the water level in the well (Figure 4). By circulating part of the water from
the pump back through the jet, water is forced up to the impeller in the
pump, and a continuous flow at reasonable pressure is provided. Shallow-
well jet pumps operate on the recirculation principle, but the jet is installed
above ground and the allowable lift is limited to about 22 feet. Deep-well jet
pumps, however, have a maximum lift of about 65 feet. Jet pumps are
designed for home water systems, and their capacities are seldom
adequate for aquacultural purposes. Also, the jet pump requires about twice
the horsepower that a submersible requires to deliver the same amount of
water from the same depth.
Axial flow propeller pumps. Axial flow propeller pumps are designed to
operate efficiently for aquacultural, irrigation or drainage pumping at low
head and high volume (more than 500 gpm). Their efficiency is high,
especially when the total head is in the range of 8 to 20 feet. The pumping
element of an axial flow propeller pump consists mainly of a revolving
propeller in a stationary bowl which contains vanes above and below the
propeller. Water enters the pump through the intake bell. It is discharged
into the distributor section and then out the discharge elbow. Flowing in
essentially a straight line along the pump axis keeps friction and turbulence
to a minimum. The propeller of an axial flow pump must be submerged in
the source of water. One of the advantages of this pump is that it will
handle some debris.
o Deep well vertical turbine pumps. For a deep well, the most widely used pump
is a vertical centrifugal, commonly referred to as a “deep well turbine.”
Basically, this is a centrifugal pump designed to be installed in a well. It will not
handle debris.
Because of the limited diameter of its impellers, each impeller develops a rather
low head, and it is necessary in the average application to stack several
impellers in series one above the other with each in its own bowl or diffuser
housing. This is called staging. Thus, a four-stage bowl assembly contains
four impellers, all attached to a common shaft through the separate housing or
bowls. The bowl shaft is attached to the line shaft through the center of the
pump column pipe and must be long enough to locate the bowl assembly below
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the level of the water in the well when pumping at required capacity.
Water/Oil Lubricated turbine pumps. Water-lubricated turbine pumps are
simpler, cheaper and more commonly used. If more than four or five of the
rubber shaft bearings are above the water level and become dry when the
pump is not operating, some means of pre-lubrication, such as a small pre-
lub tank from which water can be spilled over the bearings before starting
the pump (Figure 6), is required. With smaller pumps, a foot valve can be
installed below the bowl assembly to keep the column pipe full of water.
Because of friction loss, it is impractical to use a foot valve for applications
requiring large flows.
When the water level is very deep, oil lubrication is normally used. Although
there is no definite point at which it becomes necessary, it is usually
recommended for depths of more than 150 to 200 feet.
Submersible pumps. The submersible pump consists of a multistage
vertical turbine pump connected directly to an electric motor designed to
operate under water. Both the pump and motor are suspended in the well
below the water level by a pipe that conducts the water to the surface. This
type is available in a wide range of capacities for 4-inch wells and larger.
Most submersible pumps used for aquaculture require three-phase
electrical service.
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Learning Exercise: Please fill up the following table to analyze your options before
making a recommendation.
Type of Size of Size of pumps Type of water recommendation
pumping pipelines supply
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INFORMATION SHEET #2-3
AERATION DEVICES
Several types of aeration devices have been evaluated for use in commercial fish
ponds. Most aerators are in one of the following categories:
o Surface spray or vertical pump. Surface spray aerators have a submersible
motor which rotates an impeller to pump surface water into the air as a spray.
They float, are lightweight, portable and electrically powered. Units of 1 to 5 hp
with pumping rates of 500 to 2,000 gpm are available.
They are designed to be operated continuously during nighttime, cloudy
weather, or when low dissolved oxygen concentrations are expected. Surface
spray aerators have prevented fish kills when used at 1.5 to 2 hp/acre. They
are usually of little use in large ponds, because of relatively low oxygen transfer
rates and their inability to create an adequately large area of oxygenated water.
o Pump sprayer. Pump sprayer aerators are found on many fish farms. Most are
powered by a tractor power takeoff or electricity. Some units are engine driven
and require mounting on a trailer frame for transport. Pump sprayer aerators
are equipped with either an impeller suction pump, an impeller lift pump, or a
turbine pump. Some have a capped sprayer pipe or “bonnet” with outlet slits
attached to the pump discharge. Others discharge directly through a manifold
which has discharge slits on top and outlets at each end. Water is sprayed
vertically through the discharge slits and from each end of the manifold. This
type is commonly referred to as a T-pump or bankwasher and directs
oxygenated water along a pond bank where distressed fish often go. Pump
sprayers typically have no gear reduction which reduces mechanical failure and
maintenance. These units do not erode the pond bottom, and minimum
operating depth is reached when the intake is covered with water.
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o Paddlewheel aerators.
Paddlewheel aerators have been
used on catfish farms for many
years. Farm-made paddlewheels
are usually made from 3/4 ton truck
differentials and vary with drum size
and configuration, shape, number
and length of paddles. Units are
powered by power takeoffs or
driven by self-contained diesel
engines. The self-contained units
are usually on floats and attached
to the pond bank or held in place by
steel bars secured in the bank or
pond bottom.
Paddlewheel through
Speed and Depth. Studies have demonstrated that increasing either the
speed of the drum rotation (rpm) or paddle depth generally increases
aeration capacity. Paddle depth affects oxygen transfer rates more than
does the speed of rotation. This increase in capacity is not cost free,
because horsepower requirements increase and oxygen transfer efficiency
may decrease. The maximum rotational speed of a tractor-powered
paddlewheel aerator for extended operation is limited by the tractor, its
recommended power takeoff speed under load, and the gear reduction of
the paddlewheel.
Shape of Paddles. The shape of the paddles is also important; for example,
U, V, or cup shapes are more efficient designs than flat paddles.
Paddlewheels create vibrations that can be reduced when paddles are
arranged in a spiral pattern. The oxygen transfer rate and power
requirement increase with paddle immersion depth and the diameter of the
paddlewheel drum. The size of the spray pattern likewise increases. The
power required to operate a paddlewheel aerator at any given speed and
paddle depth is constant. Fuel consumption and operating costs depend on
the power source.
o Electric paddlewheel. Electric paddlewheel units are 4 to 12 feet long with
paddles of triangular cross section and a total drum diameter of about 28 to 36
inches. Paddlewheel speed is usually 80 to 90 rpm with a paddle depth of
about 4 inches, enough to load the motor. The correct paddle depth can be
determined in the field as the depth needed to draw the rated amperes of the
motor. To extend the service life of the motor, the motor should draw only 90
percent of full load amperes rating, unless the manufacturer recommends
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differently. Motor sizes range from 1/2 hp to 19 hp and larger. Motors operating
on single or three-phase current are available.
Methods used to reduce the motor speed to the desired aerator shaft speed
include v-belts and pulleys, chain drive and gears and gearboxes. Shafts of
most electric motors run at 1,750 rpm and most units are mounted on floats.
o Diffused air systems. Diffuser aerators operated by low pressure air blowers or
compressors forcing air through weighted aeration lines or diffuser stones
release air bubbles at the pond bottom or several feet below the water surface.
Efficiency of oxygen transfer is related to the size of air bubbles released and
water depth. The smaller the bubble and the deeper it is released, the more
efficient this type aerator becomes. When tested at normal catfish pond depths,
these aerators were found to be inefficient compared to other devices.
Limited studies in commercial catfish ponds showed no improvement in fish
production when a diffused aeration system was used. One of the biggest
problems with diffused-air systems is clogging of the air lines and diffusers so
that periodic cleaning is required. Also, the air lines interfere with harvesting.
o Propeller-aspirator pump. These aerators consist of a rotating, hollow shaft
attached to a motor shaft. The submerged end of the rotating, hollow shaft is
fitted with an impeller which accelerates the water to a velocity high enough to
cause a drop in pressure over the diffusing surface which pulls air down the
hollow shaft. Air passes through a diffuser and enters the water as fine bubbles
that are mixed into the pond water by the turbulence created by the propeller.
They are electrically powered, and models range from 0.125 to 25 hp.
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JOB SHEET # 2-4
TITLE: PROCEDURE FOR DETERMINING THE TYPE OF AERATORS
Purpose To determine the type of aerators needed in the
hatchery.
Equipment, Tools and Materials Writing pads, ball pen
Precautions Make sure that you have exhausted a good list of all
types of aerators and their specifications.
PROCEDURES
STEP #1. In order to decide which aeration device should be purchased or built, identify
and determine the specific application and associated costs of energy and equipment for
each type of available aerator in the market.
STEP #2. Make a comparative analysis and evaluation of advantages and
disadvantages of choosing between emergency aerators powered by tractor power
takeoffs (PTOS) or electric aerators.
STEP #3. Decide if large tractor-powered aerators will still used as back-ups during
severe oxygen depletions, equipment failure, or power outages.
pond aerator
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LEARNING EXERCISE: Fill up the following table to provide information you
gathered about available aerators before making your decision on what type of
aerators to use.
Evaluation Sheet Form
Type of Aerator Features Advantages Disadvantages
Recommendation ________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
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SELF CHECK #2-1
1. What are the materials to be used in hatchery construction?
2. Do you know how to prepare the Bill of Materials?
3. Prepare a sample Summary Cost Estimates.
4. How do you determine the appropriate aerator system for the hatchery?
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ANSWER KEY #2-1
1. What are the materials to be used in hatchery construction?
Answer: Cement, sand, grave, steel reinforcing bars, lumber boards.
2. Do you know how to prepare the Bill of Materials?
Answer: The Bill of Materials may also be presented by area (e.g. Office, Stockroom,
Laboratory, etc.) with subheadings on masonry, woodworks, electrical, etc. T
Description of Materials. The first column of the Bill of Materials provides
descriptions of the materials needed. To the extent possible, all specifications,
including brand names and the like, should be indicated. Where necessary,
pictures or illustrations should be included, and dimensions and specifications duly
stated.
Quantity. The second column if for the number of pieces, volume, etc. of the
materials needed.
Unit. The third column indicates the appropriate units of measure by which they
are sold are used and shown in this column.
Unit Cost. The fourth column refers to the current selling price per indicated unit
of measure of the materials. If prevailing costs is not yet available, this column
may be left blank, and may be filled after a canvass of material prices have been
made.
Total Cost. The fifth and last column is the product of the quantity multiplied by
the unit cost.
Project Title :
Owners :
Location :
Description of Materials Quantity Unit Unit Total
Cost Cost
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3. Prepare a sample Summary Cost Estimates.
Answer:
SUMMARY COST ESTIMATES FOR MATERIALS, LABOR, AND OTHER
CONSTRUCTION EXPENSES
PARTICULARS Sub-Total 1 Sub-Total 2 Totals
A. Estimated Cost of Materials xxxxx
1. Foundation, Columns, etc.
2. Floor Framing xxxxx
3. Roof framings xxxxx
4. Roofing Materials xxxxx
5. Plumbing Pipes and Fittings xxxxx
6. Plumbing fixtures, etc. xxxxx
7. Ceilings, partitions, etc. xxxxx
8. Electrical Materials xxxxx
9. Doors, windows, etc. xxxxx
xxxxx
10. Painting materials xxxxx
11. Miscellaneous materials xxxxx
B. Estimated Cost of Labor xxxxx
C. Contingency Provision xxxxx
Estimated Total Direct Cost xxxxx
D. Contractor’s Fees xxxxx
E. Contractor’s Tax xxxxx
Estimated Total Project Cost xxxxx
When the construction is planned to be contracted out, provisions for Contractor’s Profit
and Contractor’s Tax is also included. The summation of this page is the total estimated
construction cost for the hatchery.
4. How do you determine the appropriate aerator system for the hatchery?
Answer:
Aerators are tested to determine the rate at which they transfer oxygen into water. These
tests are conducted in large tanks under standard conditions with clean tap water at 68° F
and no initial dissolved oxygen. Two terms are commonly used to compare the aerator
performance:
The standard oxygen transfer rate (SOTR) is the amount of oxygen that the
aerator adds to the water per hour under standard conditions and is reported as lb
O2/hr. Ratings for tractor-powered aerators are generally given as standard
oxygen transfer ratings (SOTR).
The standard aeration efficiency (SAE) is the standard oxygen transfer rate divided
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by the amount of power required and is expressed as lbs O2/hr per horsepower (hp)
or lbs O2/hp-hr. Smaller aerators are normally given standard aeration efficiency
ratings (SAE).
Efficiency ratings are based on the horsepower applied to the aerator shaft and not the
horsepower of the power source. Most commercial aerators have ratings between 1 and
5 lbs O2/hp-hr. Test results of different aerators can be compared in selecting an
effective and energy-efficient unit. Some manufacturers test their own equipment. When
comparing test results, it is important to know if test conditions were standardized. Also,
an aerator may have a high oxygen transfer rate with low efficiency rating. Cost of
operation should be less for a more efficient aerator.
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QUALIFICATION : AQUACULTURE NC III
UNIT OF COMPETENCY : Operate Catfish Hatchery
MODULE : Layout, Designing and Constructing a
Catfish Hatchery
LEARNING OUTCOME #3:
Construct catfish hatchery facilities.
ASSESSMENT CRITERIA
1. Required materials are selected and prepared.
2. Hatchery facilities are identified and constructed according to plan.
CONTENTS
1. Preparation of materials
2. Construction of Hatchery Facilities
RESOURCES
Equipment and Facilities Tools and Instruments Supplies and Materials
1. Power tractor 1. Aerator devices
1. Cement,
2. Sand & gravel
3. Steel bars
METHODOLOGY
1. Lecture type
2. Discussion
3. Demonstration
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Learning Outcome # 3: Construct hatchery facilities
LEARNING ACTIVITIES SPECIAL INSTRUCTIONS
1. In the workshop with appropriate Prepare canvass sheet and conduct
guidance and materials, the trainees will canvassing of prices.
perform the correct steps and prepare
the requirements in determining pond Prepare and fill up index cards for
materials and equipment for a catfish recording of materials to be stocked
hatchery. and stored.
1.1Read Information Sheets # 3-1, Make a checklist of the documents
“Ordering and stocking construction needed to gathered and analyzed
materials ”. during the pre-construction activities.
1.2 Perform Job Sheet # 3-1, Select the best protective equipment
“Procedure for ordering and stocking from your list of available equipment in
construction materials and Job the market by using procedure on
Sheet # 3-2, “Procedure for ensuring safety at the workplace.
convening pre-construction forum to .
gather and analyze all relevant
documents”. Read Self-Check # 3-1 questions and
write down your answers.
1.3 Read Information Sheet #3.2,
Personal Protective Equipment and Refer to Answer Key # 3-1 and check if
Information Sheet #3.3, General you got the right answers.
Safety Practices at Jobsite”
1.4 Perform Job Sheet # 3-3,
“Procedure for Implementing and
Managing the Construction”.
2. Answer Self-Check # 3-1.
3. Check your answers.
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INFORMATION SHEET #3-1
ORDERING AND STOCKING CONSTRUCTION MATERIALS
In construction projects, the importance of getting the right materials delivered by
suppliers to the site on time cannot be taken for granted. The absence of a minor item or
low-value material can stop the whole construction process. So, in general, the following
major factors affecting logistics are carefully managed:
Quality of the materials;
Quantity of the materials;
Time of Delivery; and
Price of the materials.
• Inventory Control. Part of the function of the logistics person is to ensure the
installation and maintenance of an effective Inventory Control. Operated normally
on a First-In First-out basis (FIFO), an efficient Inventory Control must be able to
provide all the materials on time, at the right quantity, and in the right quality.
Aside from current requirements, adequate buffer stocks are maintained as safety
insurance against shortages in the market. Be that as it may, inventory levels are,
however, kept in a safe level that balances the value of having buffer stocks on
one hand, and, on the other hand, the opportunity costs that a high level of
inventory normally incurred in over-stocking.
• Warehouse Management. An important aspect in Materials Management is
warehouse management. This concerns the safekeeping of all materials and
equipment. For ease in operations, different materials are stored/stacked in an
orderly and organized manner. They are also properly protected from loss,
deterioration, or damage.
2. Construction of Hatchery Facilities
This section will introduce you in managing the construction activities. Topics in this
section dwell on:
Æ Managing the construction; and
Æ Observing safety practices in construction.
OBSERVING SAFETY PRACTICES IN CONSTRUCTION
Organizations need to institute and maintain a program of policies, procedures, and
practices to protect employees and laborers from, and help them recognize, job-related
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safety and health hazards. The safety program should include procedures for the
identification, evaluation, and prevention or control of workplace hazards, specific job
hazards, and potential hazards that may arise. An effective safety program will include
the following four main elements:
¾ Management Commitment - The most successful company safety program
includes a clear statement of policy by the owner, management support of safety
policies and procedures, and employee involvement in the structure and operation
of the program.
¾ Worksite Analysis - An effective company safety program sets forth procedures to
analyze the jobsite and identify existing hazards and conditions and operations in
which changes might occur to create new hazards.
¾ Hazard Prevention and Control - An effective safety program establishes
procedures to correct or control present or potential hazards on the jobsite.
¾ Safety and Health Training - Training is an essential component of an effective
company safety program. The complexity of training depends on the size and
complexity of the worksite as well as the characteristics of the hazards and
potential hazards at the site.
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JOB SHEET # 3-1
TITLE: PROCEDURE FOR ORDERING AND STOCKING CONSTRUCTION
MATERIALS
Purpose To make the stocking and recording of construction
materials orderly
Equipment, tools and materials Writing instruments, pads, index cards, index box
Precautions None
Procedures
STEP # 1
Know and maintain records showing the materials (and their possible substitutes),
sources of supply, prices, procurement and delivery lead-times, and normal quantities
that are readily available;
STEP #2
Maintain record of all purchases, withdrawals, defects, rejected items, etc.
STEP#3
Assess the feasibility of simplifying the specification, or standardizing them to facilitate
construction, application, and also procurement; and,
STEP #4
Place orders with suppliers and negotiate for on-time deliveries and possible extension of
credit.
STEP #5
Gather and analyze price quotations and fluctuations;
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JOB SHEET # 3-2
TITLE: PROCEDURE FOR CONVENING A PRE-CONSTRUCTION FORUM
Purpose To gather and analyze all relevant documents and
information during a pre-construction forum for the
Equipment, tools, purpose of determining owner’s preferences and
materials resources availability.
Precautions Writing pads, writing instruments, tables & chairs, site
plan, construction plans, bill of materials, cost estimates
None
Procedures
STEP #1 Construction Timetable
Undertake a review of the Construction Timetable to determine the logical construction
sequence.
The optimum time for each construction phase is estimated by carefully analyzing all the
activities needed to be performed. Since construction time is also highly influenced by
the number of workers assigned to the task, an iterative procedure with manpower
planning is essential. The end product of this exercise is a time-series chart where the
different phases of construction is laid out in time-based logical and sequential order.
Time “floats” are normally built into the estimates to reckon with possible delays due to
uncertainties. The construction timetable will provide:
The earliest and latest project completion dates;
The earliest and latest start and finish of each construction phase; and,
The logical sequence or inter-dependence of the various construction phases.
STEP #2 Manpower Requirement
Plot in the construction timetable for each of the different construction phases the
different skills and trades and actual number of craftsmen needed.
A Manpower Plan showing the following information is developed:
The numbers and skills of workers needed for specified durations of time, and for
specific construction phases;
A contingency factor is often reflected to indicate the additional number of workers
that will be needed if work duration is needed to be hastened or compressed.
Manpower costs are determined based on prevailing industry and market rates.
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STEP #3. Materials and Equipment Requirements and Deadlines.
Determine all the materials and equipment rentals or acquisitions based likewise on the
Construction Timetable.
Ordering and shipping time should never be underestimated. In essence, the Materials
and Equipment Plan that must be developed must provide for many contingencies:
orders must be initiated early, and back-up suppliers identified, etc., to ensure that
materials and equipment are there when needed! While there is temptation to procure all
materials at the same time to avoid problems in delivery delays, problems attendant to
materials storage, safety from destruction or pilferage, and financial cash flow burdens,
dictates a safe and economical balance between periodic big-bulk purchases and small-
quantity just-in-time purchases.
STEP #4 Financial Requirements.
Summarize the financial implications of the Manpower Plan and the Materials and
Equipment Plan in a Financial Plan which is comprised of:
The total cost of the construction project: divided by phase, type of activity, and
nature of expenditure; and,
Cash Flows that signals the amounts of financial resources at specific time
intervals needed to support the on-going construction.
STEP #5 Management Team.
Form a construction management team to oversee all these plans.
The Project Manager is identified, as well as the Project Engineer, and all other key
construction staff: Logistics Officer, Safety Officer, Field Supervisor, Foreman, etc. Their
specific roles, duties and responsibilities are determined. The chain of command is
clearly established.
STEP #6 Use of Contractors.
Unless the construction is very small or limited, construction jobs are usually contracted
out to qualified contractors for two (2) major reasons:
They have access to a ready pool of skills and crafts which otherwise will normally create
big problems if the construction is managed in-house; and,
They are more technically qualified and competent to assure availability of technical
know-how to ensure quality control in construction.
One of the principal duties, therefore, of the management team is to conduct a selection
process for the most qualified and most cost-effective contractor.
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INFORMATION SHEET #3-2
PERSONAL PROTECTIVE EQUIPMENT
Workers must use personal protective equipment, but it is not a substitute for taking
safety measures. Workers still need to avoid hazards.
• Head Protection
o Workers must wear hard hats when overhead, falling, or flying hazards exist
or when danger of electrical shock is present.
o Inspect hard hats routinely for dents, cracks, or deterioration.
o If a hard hat has taken a heavy blow or electrical shock, you must replace it
even when you detect no visible damage.
o Maintain hard hats in good condition; do not drill; clean with strong
detergents or solvents; paint; or store them in extreme temperatures.
• Eye and Face Protection
o Workers must wear safety glasses or face shields for welding, cutting,
nailing (including pneumatic), or when working with concrete and/or harmful
chemicals.
o Eye and face protectors are designed for particular hazards so be sure to
select the type to match the hazard.
o Replace poorly fitting or damaged safety glasses.
• Foot Protection
o Residential construction workers must wear shoes or boots with slip-
resistant and puncture-resistant soles (to prevent slipping and puncture
wounds).
o Safety-toed shoes are recommended to prevent crushed toes when working
with heavy rolling equipment or falling objects.
• Hand Protection
o High-quality gloves can prevent injury.
o Gloves should fit snugly.
o Glove gauntlets should be taped for working with fiberglass materials.
o Workers should always wear the right gloves for the job (for example,
heavy-duty rubber for concrete work, welding gloves for welding).
• Fall Protection
o Use a safety harness system for fall protection.
o Use body belts only as positioning devices—not for fall protection.
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INFORMATION SHEET #3-3
GENERAL SAFETY PRACTICES AT JOBSITE
• Housekeeping and Access at Site
o Keep all walkways and stairways clear of trash/debris and other materials such
as tools and supplies to prevent tripping.
o Keep boxes, scrap lumber and other materials picked up. Put them in a
dumpster or trash/debris area to prevent fire and tripping hazards.
o Provide enough light for workers to see and to prevent accidents.
• Stairways and Ladders
o install permanent or temporary guardrails on stairs before stairs are used for
general access between levels to prevent someone from falling or stepping off
edges.
o Do not store materials on stairways that are used for general access between
levels.
o Keep hazardous projections such as protruding nails, large splinters, etc. out of
the stairs, treads or handrails.
o Correct any slippery conditions on stairways before they are used.
o Keep manufactured and job-made ladders in good condition and free of
defects.
o Inspect ladders before use for broken rungs or other defects so falls don't
happen. Discard or repair defective ladders.
o Secure ladders near the top or at the bottom to prevent them from slipping and
causing falls.
o When you can't tie the ladder off, be sure the ladder is on a stable and level
surface so it cannot be knocked over or the bottom of it kicked out.
o Place ladders at the proper angle (1 foot out from the base for every 4 feet of
vertical rise).
o Extend ladders at least 3 feet above the landing to provide a handhold or for
balance when getting on and off the ladder from other surfaces.
o Do not set up a ladder near passageways or high traffic areas where it could be
knocked over.
o Use ladders only for what they were made and not as a platform, runway, or as
scaffold planks.
o Always face the ladder and maintain 3 points of contact when climbing a
ladder.
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• Scaffolds and Other Work Platforms
General :
o Provide safe access to get on and off scaffolds and work platforms safely. Use
ladders safely (see Stairways and Ladders).
o Keep scaffolds and work platforms free of debris. Keep tools and materials as
neat as possible on scaffolds and platforms. These practices will help prevent
materials from falling and workers from tripping.
o Erect scaffolds on firm and level foundations.
o Finished floors will normally support the load for a scaffold or work platform and
provide a stable base.
o Place scaffold legs on firm footing and secure from movement or tipping,
especially surfaces on dirt or similar surfaces.
o Erect and dismantle scaffolds only under the supervision of a competent
person.
o Each scaffold must be capable of supporting its own weight and 4 times the
maximum intended load.
o The competent person must inspect scaffolds before each use.
o Use manufactured base plates or mud sills made of hardwood or equivalent to
level or stabilize the footings. Don't use blocks, bricks, or pieces of lumber.
o Strictly observe the following “DO NOTS” :
DO NOT use damaged parts that affect the strength of the scaffold.
DO NOT allow employees to work on scaffolds when they are feeling weak,
sick, or dizzy.
DO NOT work from any part of the scaffold other than the platform.
DO NOT alter the scaffold.
DO NOT move a scaffold horizontally while workers are on it, unless it is a
mobile scaffold and the proper procedures are followed.
DO NOT allow employees to work on scaffolds covered with snow, ice, or
other slippery materials.
DO NOT erect, use, alter, or move scaffolds within 10 feet of overhead
power lines.
DO NOT use shore or lean-to scaffolds.
DO NOT swing loads near or on scaffolds unless you use a tag line.
DO NOT work on scaffolds in bad weather or high winds unless the
competent person decides that doing so is safe.
DO NOT use ladders, boxes, barrels, or other makeshift contraptions to
raise your work height.
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DO NOT let extra material build up on the platforms.
DO NOT put more weight on a scaffold than it is designed to hold.
• Fall Protection
Floor and Wall Openings
o Install guardrails around openings in floors and across openings in walls when
the fall distance is 6 feet or more. Be sure the top rails can withstand a 200-lb
load.
o Construct guardrails with a top rail approximately 42 inches high with a mid-rail
about half that high at 21 inches.
o Install toe boards when other workers are to be below the work area.
o Cover floor openings larger than 2x2 inches with material to safely support the
working load.
Alternatives
o Use other fall protection systems such as slide guards, roof anchors or
alternative safe work practices when a guardrail system cannot be used.
o Wear proper slip-resistant shoes or footwear to lessen slipping hazards.
o Train workers in safe work practices before performing work on foundation
walls, roofs, trusses, or before they perform exterior wall erections and floor
installations.
Work on Roofs
o Inspect for and remove frost and other slipping hazards before getting onto roof
surfaces.
o Cover and secure all skylights and openings, or install guardrails to keep
workers from falling through the openings.
o When the roof pitch is over 4:12 and up to 6:12, install slide guards along the
roof eave after the first 3 rows of roofing material.
o When the pitch exceeds a 6:12 pitch, install slide guards along the roof eave
after the first 3 rows of roofing material are installed and again every 8 feet up
the roof.
o Use a safety harness system with a solid anchor point on steep roofs with a
pitch greater than 8:12 or if the ground-to-eave height exceeds 25 feet.
o Stop roofing operations when storms, high winds or other adverse weather
conditions create unsafe conditions.
o Remove or properly guard any impalement hazards.
o Wear shoes with slip-resistant soles.
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• Excavations and Trenching
General
o Find the location of all underground utilities by contacting the local utility
locating service before digging.
o Keep workers away from digging equipment and never allow workers in an
excavation when equipment is in use.
o Keep workers from getting between equipment in use and other obstacles and
machinery that can cause crushing hazards.
o Keep equipment and the excavated dirt (spoils pile) back 2 feet from the edge
of the excavation.
o Have a competent person conduct daily inspections and correct any hazards
before workers enter a trench or excavation.
o Provide workers a way to get into and out of a trench or excavation such as
ladders and ramps. They must be within 25 feet of the worker.
o For excavations and utility trenches over 5 feet deep, use shoring, shields
(trench boxes), benching, or slope back the sides. Unless soil analysis has
been completed, the earth's slope must be at least 1½ feet horizontal to 1
vertical.
o Keep water out of trenches with a pump or drainage system, and inspect the
area for soil movement and potential cave-ins.
o Keep drivers in the cab and workers away from dump trucks when dirt and
other debris are being loaded into them. Don't allow workers under any load
and train them to stay clear of the backs of vehicles.
Foundations
o After the foundation walls are constructed, take special precautions to prevent
injury from cave-ins in the area between the excavation wall and the foundation
wall.
o The depth of the foundation/basement trench cannot exceed 7½ feet deep
unless you provide other cave-in protection.
o Keep the horizontal width of the foundation trench at least 2 feet wide. Make
sure no work activity vibrates the soil while workers are in the trench.
o Plan the foundation trench work to minimize the number of workers in the
trench and the length of time they spend there.
o Inspect the trench regularly for changes in the stability of the earth (water,
cracks, vibrations, spoils pile). Stop work if any potential for cave-in develops
and fix the problem before work starts again.
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• Tools and Equipment
o Maintain all hand tools and equipment in a safe condition and check them
regularly for defects. Remove broken or damaged tools and equipment from
the jobsite.
o Follow the manufacturer's requirements for safe use of all tools.
o Use double insulated tools, or ensure that the tools are grounded.
o Equip all power saws (circular, table, etc.) with blade guards.
o Make sure guards are in place before using power saws. Don't use power saws
with the guard tied or wedged open.
o Turn off saws before leaving them unattended.
o Raise or lower tools by their handles, not by their cords.
o Don't use wrenches when the jaws are sprung to the point of slippage.
Replace them.
o Don't use impact tools with mushroomed heads. Replace them.
o Keep wooden handles free of splinters or cracks and be sure the handles stay
tight in the tool.
o Workers using powder-activated tools must receive proper training prior to
using the tools.
o Always be sure that hose connections are secure when using pneumatic tools.
o Never leave cartridges for pneumatic or powder-actuated tools unattended.
Keep equipment in a safe place, according to the manufacturer's instructions.
o Require proper eye protection for workers.
• Vehicles and Mobile Equipment
o Train workers to stay clear of backing and turning vehicles and equipment with
rotating cabs.
o Be sure that all off-road equipment used on site is equipped with rollover
protection (ROPS).
o Maintain back-up alarms for equipment with limited rear view or use someone
to help guide them back.
o Be sure that all vehicles have fully operational braking systems and brake
lights.
o Use seat belts when transporting workers in motor and construction vehicles.
o Maintain at least a 10-foot clearance from overhead power lines when
operating equipment.
o Block up the raised bed when inspecting or repairing dump trucks.
o Know the rated capacity of the crane and use accordingly.
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o Ensure the stability of the crane.
o Use a tag line to control materials moved by a crane.
o Verify experience or provide training to crane and heavy equipment operators.
• Electrical
o Prohibit work on new and existing energized (hot) electrical circuits until all
power is shut off and a positive Lockout/Tagout System is in place.
o Don't use frayed or worn electrical cords or cables.
o Use only 3-wire type extension cords designed for hard or junior hard service.
(Look for any of the following letters imprinted on the casing: S, ST, SO, STO,
SJ, SJT, SJO, SJTO.)
o Maintain all electrical tools and equipment in safe condition and check regularly
for defects.
o Remove broken or damaged tools and equipment from the jobsite.
o Protect all temporary power (including extension cords) with ground fault circuit
interrupters (GFCIs). Plug into a GFCI-protected temporary power pole, a GFCI
protected generator, or use a GFCI extension cord to protect against shocks.
o Don't bypass any protective system or device designed to protect employees
from contact with electrical current.
o Locate and identify overhead electrical power lines. Make sure that ladders,
scaffolds, equipment or materials never come within 10 feet of electrical power
lines.
• Fire Prevention
Provide fire extinguishers near all welding, soldering, or other sources of ignition.
o Keep fire extinguishers easy to see and reach in case of an emergency.
o Provide one fire extinguisher within 100 feet of employees for each 3,000
square feet of building.
o Don't store flammable or combustible materials in areas used for stairways or
exists.
o Avoid spraying of paint, solvents, or other types of flammable materials in
rooms with poor ventilation. Build-up of fumes and vapors can cause
explosions or fires.
o Store gasoline and other flammable liquids in a safety can outdoors or in an
approved storage facility.
o Don't store LP gas tanks inside buildings.
o Keep temporary heaters at least 6 feet away from any LP gas container.
o Ensure that leaks or spills of flammable or combustible materials are cleaned
up promptly.
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JOB SHEET # 3-3
TITLE: PROCEDURE FOR IMPLEMENTING AND MANAGING THE
CONSTRUCTION
Purpose To implement construction activities according to plans
and manage the implementation stage.
Equipment, tools, Writing pads, writing instruments, tables & chairs, site
materials plan, construction plans, bill of materials, cost estimates
Precautions
• Keep the workplace free from hazards;
• Inform employees of how to protect themselves
against hazards that cannot be controlled; and to
• Conduct regular jobsite safety inspections;
• Have someone trained in first aid on side if there
are no emergency response facilities nearby.
Procedures:
Even with a contractor, management has to effectively intervene in the following
manner:
o Work Monitoring. Monitor the progress of the work regularly. Plot actual
accomplishments against the Construction Timetable. Analyze delays and
determine whether:
They can be accommodated by the “slacks” or buffer time estimates;
or
They will cause delays in the completion of the whole project.
Risks of project delays must be given serious attention. How will it impact
on costs? How will it adversely affect operations and the overall financial
targets of the project?
o Site Management. While the contractor is responsible for getting the
construction jobs done, it is the responsibility of management to ensure that
safety, discipline, and order is maintained at the job site.
o Financial Management. Definitely, financial management is a principal
concern of management. Accomplish the project within budget. Minimize
wastages. Cost-effectiveness must be promoted by improving processes
and procedures in construction.
o Procurement and Materials Management. Contractor services are normally
limited to the provision of services. The procurement, stocking, and
issuance of materials and equipment are usually retained by management.
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SELF CHECK #3-1
1. What are the steps to be done in ordering and stocking of materials?
2. What is the procedure for gathering and analyzing all documents in a pre-
construction forum?
3. What are the elements of an effective safety program?
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ANSWER KEY #3-1
1. What are the steps to be done in ordering and stocking of materials?
STEP # 1 Know and maintain records showing the materials (and their possible
substitutes), sources of supply, prices, procurement and delivery lead-times,
STEP #2 and normal quantities that are readily available;
STEP#3
STEP #4 Maintain record of all purchases, withdrawals, defects, rejected items, etc.
STEP #5
Assess the feasibility of simplifying the specification, or standardizing them
to facilitate construction, application, and also procurement; and,
Place orders with suppliers and negotiate for on-time deliveries and
possible extension of credit.
Gather and analyze price quotations and fluctuations
2. What is the procedure for gathering and analyzing all documents in a pre-
construction forum?
Step #1 Undertake a review of the Construction Timetable to determine the logical
STEP #2 construction sequence.
Plot in the construction timetable for each of the different construction
STEP #3. phases the different skills and trades and actual number of craftsmen
STEP #4 needed.
STEP #5 Determine all the materials and equipment rentals or acquisitions based
STEP #6 likewise on the Construction Timetable.
Summarize the financial implications of the Manpower Plan and the
Materials and Equipment Plan in a Financial Plan which is comprised of:
Form a construction management team to oversee all these plans.
Unless the construction is very small or limited, construction jobs are usually
contracted out to qualified contractors for two (2) major reasons:
3 What are the elements of an effective safety program?
An effective safety program will include the following four main elements:
¾ Management Commitment - The most successful company safety program
includes a clear statement of policy by the owner, management support of safety
policies and procedures, and employee involvement in the structure and operation
of the program.
¾ Worksite Analysis - An effective company safety program sets forth procedures to
analyze the jobsite and identify existing hazards and conditions and operations in
which changes might occur to create new hazards.
¾ Hazard Prevention and Control - An effective safety program establishes
procedures to correct or control present or potential hazards on the jobsite.
¾ Safety and Health Training - Training is an essential component of an effective
company safety program. The complexity of training depends on the size and
complexity of the worksite as well as the characteristics of the hazards and
potential hazards at the site.
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QUALIFICATION : AQUACULTURE NC III
UNIT OF COMPETENCY : Operate Catfish Hatchery
MODULE : Layout, Designing and Constructing a
Catfish Hatchery
LEARNING OUTCOME #4:
Install life support system.
ASSESSMENT CRITERIA
1. Life support systems are identified and prepared.
2. Different parts of the system are identified and prepared.
3. Life support systems are installed.
CONTENTS
1. Components of life support
2. Parts of the catfish hatchery system
3. Installation of life support system
RESOURCES Tools and Instruments Supplies and Materials
Equipment and Facilities 1. Index cards
1. Electrical tools
1. Aerator 2. Plumbing tools
3. Hoses
4. Air stones
REFERENCES
Anderson, M.J. and A.W. Fast. 1991. Temperature and feed rate effects on Chinese
catfish Clarias-fuscus Lacepede growth. Aquaculture and Fisheries Management,
v. 22 (4), pp.435-442.
Fermin AC, Bolivar MEC, 1991. Larval rearing of the Philippine freshwater catfish, Clarias
acrocephalus (Gunther), fed live zooplankton and artificial diet: a preliminary study.
The Israeli Journal of Aquaculture– Bamidgeh 43 (3): 87-94
Santiago CB, Gonzal AC, 1997. Growth and reproductive performance of the Asian
catfish Clarias macrocephalus (Gunther) fed artificial diets. Journal of Applied
Ichthyology 13: 37-40
Code No. Lay-Out, Designing and Constructing a Date: Date Page #
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Young, M.J.A., Fast, A.W., Olin, P., 1989. Induced maturation and spawning of the
Chinese catfish Clarias fuscus. World Aquaculture Society, 20(1):-11.
METHODOLOGY
1. Lecture type
2. Discussion
3. Demonstration
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Learning Outcome # 4: Install life support system
LEARNING ACTIVITIES SPECIAL INSTRUCTIONS
1. In the workshop with appropriate Prepare canvass sheet for checking the
guidance and materials, the trainees will types of piping system available in the
perform the correct steps and prepare market;
the requirements in determining pond
materials and equipment for a catfish Prepare and fill up index cards for
hatchery. recording the features of each piping
system to be used in the hatchery.
1.1 Read Information Sheets # 4-1,
“Components of a life support Make a checklist of the different
system” and 4.2.”Determining a features and essential points of
suitable piping system”; different aerators.
1.2 Perform Job Sheet # 4-1, “Procedure Make a list of your options and select
for analyzing your piping system or a your best choice for powering life
piping system that you are support systems for a catfish hatchery..
considering.”
.
1.3 Read Information Sheet # 4-3,
“Determining the types of aerators.” Read Self-Check # 4-1 questions and
write down your answers.
1.4 Perform Job Sheet # 4-2, “Procedure Refer to Answer Key # 4-1 and check if
for evaluating an aerator”. you got the right answers.
1.5 Read Information Sheet # 4-4,
“Filtration and Biofiltration Systems”
and #4-5, Important Considerations
in Choosing a Power Plant.”
1.6 Perform Job Sheet # 4-3, Powering
Life Support Systems.”
2. Answer Self-Check # 4-1.
3. Check your answers.
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INFORMATION SHEET#4-1
COMPONENTS OF LIFE SUPPORT
1. THE PIPING SYSTEM
Whether you are pumping water to fill a pond or to aerate, it pays to do it as
economically as possible. A key to economical operation is to minimize the work
you have to do and to match your pump to the requirements. Both depend upon
the piping system you move your water through.
2. AERATOR SYSTEMS
No one should attempt to be a commercial fish farmer without having aeration
devices and the knowledge of when and how to use them. Aerators can be used
exclusively for emergencies, continuously at night, or all day and night. Aerators
work by increasing the area of contact between air and water. Aerators also
circulate water so fish can find areas with higher oxygen concentrations.
Circulation reduces water layering from stratification and increases oxygen
Transfer efficiency by moving oxygenated water away from the aerator. Many units
are electrical, so wiring should be properly protected and installed to avoid any
hazards from an electrical shock.
3. FILTRATION AND BIO- BIOFILTER MATS
FILTRATION SYSTEMS
While aeration can compensate for
the water exchange in providing
adequate DO, it does very little in
eliminating harmful elements and
particles in the water that is caused
by excretions and natural growth and
decay processes in the water.
Because of this, the use of filtrations
and biofiltrations in a recirculating
system is becoming very popular in
aquaculture.
In aquaculture, filtration and
biofiltration are very distinct and
separate entities and they must be
treated as such.
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INFORMATION SHEET # 4-2
DETERMINING A SUITABLE PIPING SYSTEM
A suitable piping system for your operation can be determined by considering the three
components that make up the total resistance to water movement in the pipe. This
resistance, called the total dynamic head (TDH), determines the amount of work
required to move each gallon of water. The total dynamic head is the sum of the lift, the
velocity head and the friction head.
TDH = Lift + Velocity Head + Friction Head
• Lift. Lift is the vertical distance between the level of supply water’s surface and
point of discharge at the end of the pipe while the pump is running. It is the only
component of the total dynamic head which is not directly affected by the piping
system.
• Velocity Head. The energy contained in a stream of water due to its velocity. This
energy is lost when the water is discharged. The amount of work required to
produce this velocity is equivalent to picking up the water high enough so that it
would obtain the required velocity in falling. This height is called a “head” and is
commonly measured in feet of water (the height the water has to be picked up).
Numerically, it is equal to the square of the velocity (in feet per second) divided by
64.
Most losses, and the work required to move the water in the pipe, vary with the
velocity head. For a given flow rate, the velocity head is very sensitive to the size
of the pipe. The velocity head depends upon the fourth power of the pipe diameter.
• Friction Head. The friction head is the pressure loss (in feet of water) caused by
friction resistance when water flows through pipe, fittings, valves, etc. This loss is
directly dependent on the length of the pipe and the number of fittings. A pipe twice
as long as another pipe of the same diameter with the same water flow would have
twice the friction loss and require twice the power to overcome the loss. The
friction losses vary approximately as the velocity squared. Thus, like the velocity
head they are very dependent on pipe diameter – the smaller the pipe the more
losses (pressure drop) and the more pumping power required to move the same
amount of water. Friction losses for pipe are quite often given as the loss in feet of
water at a given flow rate for a 100 foot length of pipe. The following tables list
head loss at various flow rates of water for 100 feet of several diameters of pipes.
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The velocity head (in feet) and friction loss (in feet, for 100 ft PVC pipe) for various
diameter pipes and flow rates are given below as reference for computational work:
GPM VELOCITY HEAD (in feet) 12” FRICTION LOSS (in ft; for 100 ft PVC)
flow 4” 6” 8” 10” 0.00 4” 6” 8” 10” 12”
100 0.10 0.02 0.01 0.00 0.66 0.09 0.02 0.01 0.00
200
400 0.41 0.08 0.03 0.01 0.01 2.39 0.33 0.08 0.03 0.01
600
800 1.62 0.32 0.10 0.04 0.02 8.63 1.20 0.30 0.10 0.04
1,000
1,500 3.65 0.72 0.23 0.09 0.05 18.28 2.55 0.63 0.21 0.09
2,000
2,500 6.48 1.28 0.41 0.17 0.08 31.12 4.34 1.07 0.36 0.15
3,000
4,000 10.13 2.00 0.63 0.26 0.13 47.03 6.55 1.62 0.55 0.23
5,000
7,500 22.80 4.50 1.42 0.58 0.28 99.57 13.88 3.43 1.16 0.48
10,000
40.53 8.01 2.53 1.04 0.50 169.53 23.63 5.84 1.97 0.81
63.32 12.51 3.96 1.62 0.78 256.18 35.71 8.82 2.98 1.23
91.19 18.01 5.70 2.33 1.13 358.94 50.03 12.36 4.18 1.72
162.11 32.02 10.13 4.15 2.00 611.17 85.18 21.05 7.11 2.93
253.29 50.03 15.83 6.48 3.13 932.52 128.72 31.80 10.75 4.43
569.91 112.57 35.62 14.59 7.04 1955.31 272.53 67.33 22.76 9.38
1013.17 200.13 63.32 25.94 12.51 3329.29 464.03 114.64 38.76 15.98
A piping system or segments of a piping system may be arranged in series or parallel:
Æ Series pipe means that all the water will have to flow through each section of pipe,
one after the other. The total pressure drop in a series is found by adding the
pressure drop in each section.
Æ A parallel arrangement means that the water may flow in two or more paths. In a
parallel arrangement, the water will divide the total flow so that the total pressure
drop in each path will be the same. The total pressure drop in a parallel
arrangement is found by following one path and adding up all the pressure drops in
that path.
Finding the pressure drop in a parallel path may require a trial and error approach. A flow
rate in each path is assumed so that the total flow in all paths equals the total flow rate.
The pressure drop in each path is then determined. If the pressure drop in each path is
not the same, a new guess for the flow in each path is made and the pressure drops
determined. This procedure is continued until agreement is reached.
Code No. Lay-Out, Designing and Constructing a Date: Date Page #
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Usually, in aquaculture systems, series analysis can be used since all the water is likely
to be directed to one exit at some time during the operation and this will result in pipe
sizing that is satisfactory under other flow conditions.
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JOB SHEET # 4- 1
TITLE: PROCEDURE FOR ANALYZING YOUR PIPING SYSTEM OR A PIPING
SYSTEM YOU ARE CONSIDERING
Purpose To provide the procedure to be used to analyze your
piping system or a piping system you are considering
Equipment, Tools & Pressure pump, pipes, calculator, velocity and friction
Materials loss table (Information Sheet #4-2, writing pad, pen
Precautions None
Procedures:
The following procedure should be used to analyze your piping system or a piping system
you are considering:
1. Determine the required flow rate in gallons per minute (gpm). You may want to
add a safety factor, say 10 percent, to take care of pump wear and pipe aging.
2. Determine the lift in feet.
3. Choose the diameter of the pipe.
4. Determine the total equivalent length of the pipe. This is equal to the length of the
pipe plus the equivalent length of all fittings.
5. Use the velocity head table and diameter of the pipe at the discharge to
determine the velocity head. (It will not help much to suddenly enlarge the pipe
here because of the losses the enlargement will cause.)
6. Use the friction loss tables to determine the friction loss.
7. If the diameter of the pipe changes, treat each section of pipe of different
diameters separately and then add the total friction losses.
8. Add up the lift, the friction losses and the velocity head. The result is the total
head in feet that the pump will have to supply. The pressure (in psi) the pump
must supply is equal to the total head divided by 2.3.
9. The power a perfect pump (100 percent efficient) would require is called the
water horsepower and is computed as the sum of GPM multiplied by the Total
Head (in feet) divided by 3,960:
Water Horsepower = GPM x Total Head (in feet)
3,960
10. Examine the pressure and power requirements of the piping system. If the
performance is not suitable, try a different design and repeat the steps.
11. Determine the suction required of the pump. The suction required is the sum of
the lift to the pump, the friction head loss from the water source to the pump and
the velocity head. Choose a suitable pump. If no suitable pump can be found,
redesign the piping system.
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To illustrate how the analysis of a piping system is done, let’s take the following sample
situation:
It is required to pump 2,000 gpm of water from a source 5 feet
below and 400 feet from the discharge. Three ells and 20
couplings are required in the pipe run. Choose the size of pipe
to use. There is a quantity of 6-inch plastic pipe available.
Computational Steps 1st Iteration (6” pipes) 2nd Iteration (12”
pipes)
Determine the required GPM; 2,000 GPM (No Safety
may add 10% safety factor Factor) 2,000 GPM (No Safety
Factor)
Determine Lift in feet 5 ft 5 ft
Choose Pipe Diameter 6” since it is available 12”
Determine total equiv length Vertical run = 5 Vertical run =5
of the pipe: Length of Pipe +
Equiv Length of all Fittings ft ft
Horizontal run = Horizontal run =
400 ft 400 ft
3 ells Equiv Length = 3 ells Equiv Length =
45 ft 90 ft
(3X30X6/12 = 45) (3X30X12/12 = 90)
20 couplings = 20 couplings =
15 ft 30 ft
(20x1.5x6/12 = 15) (20x1.5x12/12 = 30)
Total Pipe Length = Total Pipe Length =
465 ft 525 ft
Determine Velocity Head From table, Velocity From table, Velocity
(refer to Table)
Head for 2000GPM for 6” Head for 2000GPM for
= 8.01 ft 12” = 0.50 ft
Determine Friction Loss From table, Friction Loss From table, Friction Loss
(refer to Table) for every 100 ft at 2000 for every 100 ft at 2000
GPM for 6” is GPM for 12” is
= 23.63 ft Therefore, for = 0.81 ft Therefore, for
465 ft= 109.9 ft [23.63 x 525 ft= 4.25 ft [0.81 x
(465/100)] (525/100)]
Provision for diameter No change No change
change
Add up the lift, velocity head, Total Lift = 5.00 Total Lift = 5.00
and friction loss to get TDH ft Velocity Head = ft Velocity Head =
8.01 ft Friction Loss 0.50 ft Friction Loss
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= 109.90 ft Tot Dynamic = 4.25 ft Tot Dynamic
Head = 122.91 ft Head = 9.75 ft
Determine Water HP GPMxTDH = 2000 x GPMxTDH = 2000 x
122.91 Product is divide
Determine PSI by: 3,960 Water HP 9.75 Product is divide
(PSI=TDH/2.3) and evaluate = 62.1 HP
in conjunction with HP PSI = (122.91/2.3) = 53.4 by: 3,960 Water HP
requirement. If not psi HP Requirement =
acceptable, try other options. 62.1 HP = 4.9 HP
Determine Pump Suction
requirement= Lift to pump + TOO LARGE!!! PSI = (9.75/2.3) = 4.2
Friction Loss(water to pump)+
Velocity Head Not Applicable psi HP Requirement =
4.9 HP
REASONABLE
VALUES
Lift to Pump =
100 ft (Assumed well
depth)
FrictionLoss(12”;100’)=
0.81 Velocity Head
= 0.50 Pump Suction
Rqmt= 101.31ft
This seems to be a reasonable value, although you may want to try a few more sizes of
pipe and compare the results. Step 11 depends upon the location of the pump, and will
not be considered until a candidate pump is chosen.
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INFORMATION SHEET # 4-3
DETERMINING THE TYPE OF AERATORS
• Types of aerators. Fish farmers have used emergency aerators powered by
tractor power takeoffs (PTOS) for many years. With production intensification and
the increasing need for aeration, these PTO aerators can be quite expensive
because each aerator requires a tractor. Therefore, more electric aerators are
being used than ever before. Large tractor-powered aerators are still used as
back-ups during severe oxygen depletions, equipment failure, or power outages.
Each producer decides which aeration device should be purchased or built. This
decision is important and should be made with the specific application and
associated costs of energy and equipment in mind. Several types of aeration
devices have been evaluated for use in commercial fish ponds. Most aerators are
in one of the following categories:
o Surface spray or vertical pump. Surface spray aerators have a submersible
motor which rotates an impeller to pump surface water into the air as a spray.
They float, are lightweight, portable and electrically powered. Units of 1 to 5 hp
with pumping rates of 500 to 2,000 gpm are available.
They are designed to be operated continuously during nighttime, cloudy
weather, or when low dissolved oxygen concentrations are expected. Surface
spray aerators have prevented fish kills when used at 1.5 to 2 hp/acre. They
are usually of little use in large ponds, because of relatively low oxygen transfer
rates and their inability to create an adequately large area of oxygenated water.
o Pump sprayer. Pump sprayer aerators are found on many fish farms. Most are
powered by a tractor power takeoff or electricity. Some units are engine driven
and require mounting on a trailer frame for transport. Pump sprayer aerators
are equipped with either an impeller suction pump, an impeller lift pump, or a
turbine pump. Some have a capped sprayer pipe or “bonnet” with outlet slits
attached to the pump discharge. Others discharge directly through a manifold
which has discharge slits on top and outlets at each end. Water is sprayed
vertically through the discharge slits and from each end of the manifold. This
type is commonly referred to as a T-pump or bankwasher and directs
oxygenated water along a pond bank where distressed fish often go. Pump
sprayers typically have no gear reduction which reduces mechanical failure and
maintenance. These units do not erode the pond bottom, and minimum
operating depth is reached when the intake is covered with water.
o Paddlewheel aerators. Paddlewheel aerators have been used on catfish farms
for many years. Farm-made paddlewheels are usually made from 3/4 ton truck
differentials and vary with drum size and configuration, shape, number and
length of paddles. Units are powered by power takeoffs or driven by self-
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contained diesel engines. The self-contained units are usually on floats and
attached to the pond bank or held in place by steel bars secured in the bank or
pond bottom.
Speed and Depth. Studies have demonstrated that increasing either the
speed of the drum rotation (rpm) or paddle depth generally increases
aeration capacity. Paddle depth affects oxygen transfer rates more than
does the speed of rotation. This increase in capacity is not cost free,
because horsepower requirements increase and oxygen transfer efficiency
may decrease. The maximum rotational speed of a tractor-powered
paddlewheel aerator for extended operation is limited by the tractor, its
recommended power takeoff speed under load, and the gear reduction of
the paddlewheel.
Shape of Paddles. The shape of the paddles is also important; for example,
U, V, or cup shapes are more efficient designs than flat paddles.
Paddlewheels create vibrations that can be reduced when paddles are
arranged in a spiral pattern. The oxygen transfer rate and power
requirement increase with paddle immersion depth and the diameter of the
paddlewheel drum. The size of the spray pattern likewise increases. The
power required to operate a paddlewheel aerator at any given speed and
paddle depth is constant. Fuel consumption and operating costs depend on
the power source.
o Electric paddlewheel. Electric paddlewheel units are 4 to 12 feet long with
paddles of triangular cross section and a total drum diameter of about 28 to 36
inches. Paddlewheel speed is usually 80 to 90 rpm with a paddle depth of
about 4 inches, enough to load the motor. The correct paddle depth can be
determined in the field as the depth needed to draw the rated amperes of the
motor. To extend the service life of the motor, the motor should draw only 90
percent of full load amperes rating, unless the manufacturer recommends
differently. Motor sizes range from 1/2 hp to 19 hp and larger. Motors operating
on single or three-phase current are available.
Methods used to reduce the motor speed to the desired aerator shaft speed
include v-belts and pulleys, chain drive and gears and gearboxes. Shafts of
most electric motors run at 1,750 rpm and most units are mounted on floats.
o Diffused air systems. Diffuser aerators operated by low pressure air blowers or
compressors forcing air through weighted aeration lines or diffuser stones
release air bubbles at the pond bottom or several feet below the water surface.
Efficiency of oxygen transfer is related to the size of air bubbles released and
water depth. The smaller the bubble and the deeper it is released, the more
efficient this type aerator becomes. When tested at normal catfish pond depths,
these aerators were found to be inefficient compared to other devices.
Limited studies in commercial catfish ponds showed no improvement in fish
production when a diffused aeration system was used. One of the biggest
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problems with diffused-air systems is clogging of the air lines and diffusers so
that periodic cleaning is required. Also, the air lines interfere with harvesting.
o Propeller-aspirator pump. These AERATION & WATER XCHANGE
aerators consist of a rotating,
hollow shaft attached to a motor
shaft. The submerged end of the
rotating, hollow shaft is fitted with
an impeller which accelerates the
water to a velocity high enough to
cause a drop in pressure over the
diffusing surface which pulls air
down the hollow shaft. Air passes
through a diffuser and enters the
water as fine bubbles that are
mixed into the pond water by the
turbulence created by the propeller.
They are electrically powered, and
models range from 0.125 to 25 hp.
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JOB SHEET # 4-2
TITLE: PROCEDURE FOR EVALUATING AN AERATOR
Purpose To lay down the process to evaluate an aerator to select
an effective and energy efficient unit.
Equipment, tools and Writing pads, writing instruments
materials
Precautions None
Procedures
STEP #1 Test the aerators to determine the rate at which they transfer oxygen into
water. Conduct the tests in large tanks under standard conditions with clean
tap water at 68° F and no initial dissolved oxygen. Two terms are commonly
used to compare the aerator performance:
o The standard oxygen transfer rate (SOTR) is the amount of oxygen that the
aerator adds to the water per hour under standard conditions and is reported as
lb O2/hr. Ratings for tractor-powered aerators are generally given as standard
oxygen transfer ratings (SOTR).
o The standard aeration efficiency (SAE) is the standard oxygen transfer rate
divided by the amount of power required and is expressed as lbs O2/hr per
horsepower (hp) or lbs O2/hp-hr. Smaller aerators are normally given standard
aeration efficiency ratings (SAE).
Efficiency ratings are based on the horsepower applied to the aerator shaft and not the
horsepower of the power source. Most commercial aerators have ratings between 1 and
5 lbs O2/hp-hr.
STEP #2 Compare test results of different aerators to select an effective and energy-
efficient unit.
Some manufacturers test their own equipment. When comparing test results, it is
important to know if test conditions were standardized. Also, an aerator may have a high
oxygen transfer rate with low efficiency rating. Cost of operation should be less for a more
efficient aerator.
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INFORMATION SHEET #4-4
FILTRATION AND BIOFILTRATION SYSTEMS
There are three (3) forms of aquaculture wastes:
Æ Solid waste is typically categorized by its size and specific gravity. Settleable
solids are those solids which have a relatively high specific gravity compared to
the water in which they exist. They will settle to the bottom.
Æ Suspended solids are those in a category which have a specific gravity the
same as or slightly higher than the water. They tend to stay in suspension and
will only "drop-out" over a long period of time. Dissolved solids are those which
actually become a part of the water.
Æ The dissolved solids are eliminated by reverse osmosis, anion and cation
resins, activated carbon, etc.
• Filtration. Filtration is the removal of solid and suspended wastes. The methods
of filtration ranges from sedimentation tanks, screen mesh to sieve particles, to the
use of materials that “statically” attracts suspended particles.
o One method of removing solid waste from a round fish tank is to use a double
drain. It will direct the settled solids to a separate area from the suspended
solids. The settled solids can be directed into a small clarifier, much smaller
than one which had to be sized to handle the entire flow of recirculating water.
The other drain takes the suspended solids along with the nitrogenous waste.
o Suspended solids can be removed by several methods. One is the affinity bead
filter which incorporates the use of small polyethylene beads that have an
electrostatic charge. These beads have an affinity for the negatively charged
suspended solids. As the particles pass these beads, they are "statically"
drawn to them. When the beads are loaded with solids, it is time to backwash
them. (Too often, backwashing is not done frequently enough.) Suspended
solids can also be removed by mechanical means such as bag filters, drum
filters and vegetable filters.
• Biofiltration. Biofiltration is the aerobic (with oxygen) breakdown of dissolved
nitrogenous fish waste (ammonia). Fish will excrete about 14 grams of ammonia
for each pound of food eaten (at 35% protein). The nitrification of ammonia is
accomplished by two strains of autotrophic bacteria. These bacteria are naturally
occurring and will ultimately colonize the bio-media in your biofilter as well as the
tank walls etc. The speed of this process is dependent on temperature, pH,
salinity surface area, flow rate, etc.
Code No. Lay-Out, Designing and Constructing a Date: Date Page #
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