Const. Productivity Management

1. Question#1
Explain “Construction Productivity” and highlight its importance.
Answer
Productivity is a term that can be defined in many ways and it is often confused with the term
“Production” because many people think that the greater the production, the greater the
productivity but this is not necessarily true. Productivity is concerned with the efficient and
effective utilization of resources in producing goods and services. In business world, productivity
measures investment in capital against profit but particularly the term Construction Productivity
means efficiency in execution process by considering all aspects of competitiveness and
innovation. As we know that construction productivity largely depends upon human
performance, it can be simply calculated through the output of any aspect of production per unit
of input. In an ideal case, perfect productivity (1.0) would be accomplished if all the engineering
drawings would be 100 percent complete, there would be no delays of any kind, everyone would
work safely, everything would fit perfectly the first time, the weather would be 70 degrees
Fahrenheit, and there would be no litigation at the end of the project.
On this basis we can say that construction productivity decline due to so many factors e.g. design
complexity, dilution of supervision, high accident rate, jurisdictional disputes, adverse
temperature and impractical QA/QC tolerances etc. All these factors of productivity can be
summarize as follows,
 Project Uniqueness
 Technology
 Management
 Motivation factor
 Hygiene factor
Productivity usually measures in terms of 3M (Manpower, Material & Machinery). Two distinct
and independent methodologies are used to determine productivity changes. The first approach is
an output-based one, in which real costs per square foot for several buildings types, further
adjusted for enhancements in quality and content, are compared over the study period.
PT = [(1+PN) x (1+PL)] -1
Where PT = total productivity increase, PN = quantitative productivity increase, and PL = qualitative productivity
increase.
The second approach, termed the input-based approach, constructs a model based upon
observable changes in labor productivity at the task level, changes in real materials costs, and
changes in costs of tools and equipment utilized at the jobsite.
PL = (0.72 x PG) + (0.16 x PM) + (0.12 x PE)
Where PL = total labor productivity increase, and PG, PM, and PE = categorical labor productivity increases for
general, mechanical, and electrical construction respectively.

2. Importance of Productivity
Productivity in construction is very important for an individual or for the whole industry
especially from the economic point of view because construction industry accounts for 3-8% of
the GDP in most countries. Unfortunately we are living in the world of great uncertainty
therefore to improve or maintain the construction productivity is very challenging.
 Higher production output, lower inflation rate and further productivity growth could be
benefited from productivity improvement.
 With a higher productivity, the local contractors are able to reduce the construction cost
and therefore benefit from a higher profit. Also, the contractor can even offer a lower
bidding price to increase his competitiveness.
A productivity benefit model is presented by David J. Sumanth in 1980, according to which
total productivity improvement in organizations benefits everyone consumers, employees,
owners/stockholders, the society and the nation as a whole.
Therefore, productivity cycle concept show us that productivity improvement must be preceded
by measurement, evaluation, and planning. All four phases are important, not just productivity
measurement or just productivity improvement. Hence it shows that productivity program is not
a one-time project, but rather a continuous, on-going process.

3. Question#2
Explain the process of crane selection for the construction of a multi storey building. What effect
does it have on the overall productivity?
Answer
The selection process of tower crane, for any multistory building, is not an easy task because in
order to make construction convenient and highly economic we have to consider some important
factors. Factors affecting the selection of cranes, including: shape, number of floors, the height of
each floor; total volume; construction progress; ground conditions and construction areas, traffic
conditions the crane service provision of units and the requirements of economic efficiency.
Other basic considerations are as follows,
APPLICATION: You should know the weight of objects that will be lifting and moving, the
height of the lift, length and width of the move and the duty cycle of the crane including how
often and for how long it will be used.
ENVIRONMENT: Will the crane be used indoors or outdoors? Is your environment corrosive or
have extreme temperatures? Is it going into a sterile environment such a food manufacturing?
FACILITIES: When determining the type of crane and how it will be installed, you must take
into consideration the limitations of your facilities. The roof, wall or floor structure must be
assessed to ensure it will hold the crane and its load.
QUALITY: Your crane must meet the crane codes. Also consider the classification (C1 to C9) of
the crane which advises its lifespan and duty cycle.
COST: The price of the crane is only the first part of this equation. You also must add in the cost
of installation, maintenance, and the possibility for future expansion.
As a conclusion, to choose the most affordable tower cranes should follow these steps:
 Based on the characteristics of the work, technology and mass construction crane to
choose.
 Select the correct crane working mode.
 Select the specifications of the crane in accordance with the real working conditions.
 Compare the economic and technical indicators to select crane satisfaction.

4. Effect of Crane on Overall Productivity
The purpose behind the proper selection of crane is to improve the overall productivity of
construction but in contrast, operating a crane is a very precise work. The person at the controls
wields a lot of power, swinging heavy items into place while a crew on the ground assists.
Hazards at construction sites can change quickly, putting employees who operate cranes or work
around them at high risk for serious injuries, and even death. Electrocution, falls, moving
machinery, excavations, and overhead loads are examples of a few common hazards that can
plague rigging and other activities involving cranes. A Ensuring that equipment and personnel
meet certification and other safety requirements helps employers prevent accidents and ensure
that everyone goes home safely at the end of a long day.
The overall productivity dictated by the efficiency of tower cranes that largely depends on their
type, number and location. As the number of work tasks and the demand for tower cranes
increase, planners may experience difficulties in making an appropriate decision about the
optimum layout of tower cranes. A poor decision, however, is likely to have significant negative
effects, which will lead to additional costs and possible delays. As a thumb rule, crane usually
placed at a center location where it can cover the maximum construction area. Where there are
other cranes on the same site and there is a risk of collision, a crash radio system is to be
established and be used. This will be determined by the lifting assessment.
Any other plant (Other cranes, Concrete Booms, Piling Rigs etc) that may be working within the
radius of a crane, their operator must be made aware of such risks and a system must be put in
place to control their movements (this may be via the crash radio or a permit to work system).

5. Question#3
Explain the term “Work Breakdown”. Does it have any effect on the productivity of a project?
Explain in detail.
Answer
In simple words, work breakdown structure (WBS) is a logical grouping tool that is used for
better understanding by subdividing the total work scope of a project into small work packages.
According to Project Management Body of Knowledge “A Work Breakdown Structure is a
deliverable-oriented hierarchical decomposition of the work to be executed by the project team
to accomplish the project objectives and create the required deliverables.” In WBS, much larger
tasks are broken-down to manageable chunks of work. These chunks can be easily supervised
and estimated but considerable thought and planning should be given to its development and
implementation so that subsequent changes are minimized.
Work Breakdown Structure (WBS) generally consist of five level hierarchy describing the entire
effort to be accomplished by the primary organization, that number may not be appropriate for
all situations.
Following are a few reasons for creating a WBS in a project.
 Accurate assignment of responsibilities to the project team.
 Indicates the project milestones and control points.
 Helps to estimate the cost, time, and risk.
 Illustrate the project scope, so the stakeholders can have a better understanding of the
same.

6. Effects of WBS on Construction Productivity
Construction Productivity is heavily depends upon comprehensive planning and the quality of
planning is judged by the quality of work breakdown structure. In this sense, Work Breakdown
Structure (WBS) can affect the productivity up to great extent because more clearly the scope of
the project is articulated before the actual work begins, the more likely the success of the project.
Experienced project managers know there are many things that can go wrong in projects
regardless of how successfully they plan and execute their work. The positive and negative
effects of WBS over productivity can be explain separately as follow,
Positive Side:
The WBS provides the project manager and team with the necessary framework of tasks going
forward to create detailed cost estimates and also to provide major input to project task
scheduling at the most detailed and accurate level possible. By going through the WBS motions,
the project manager and team will have a pretty good idea whether or not they’ve captured all the
necessary tasks, based on the project requirements, that are going to need to happen to get the job
done with improve productivity.
The WBS forces the project manager and team members to delineate the steps required to build
and deliver the product or service. The exercise alone encourages a dialogue that will help clarify
ambiguities, bring out assumptions, narrow the scope of the project, and raise critical issues early
on.
Negative Side:
On the other hand, developing a WBS is not easy. It can be a painstaking process. And it can
take quite a bit of time. A large WBS (one that identifies several thousand activities) can take
many, many hours to develop. For another, it requires effort. There is a knowledge transfer and
exercise of brainpower. The larger the scope of the project, the larger the WBS will be. More
people must provide input and then approve the portion they are responsible to perform. There
must be some logical pattern to the way in which these pieces are broken off. We don’t want it to
be like smashing a piece of glass into lots of tiny pieces that can’t be put back together again. No
we are looking for something more like a jigsaw puzzle, where every piece can be slotted into its
right place to make the big picture without affecting the productivity.
Even after considering the downsides, the overall advantages still outweigh the known
challenges. A good WBS makes planning and executing a project easier and lays the groundwork
for the schedule, the tracking, the budgeting, and all the accountability throughout the rest of the
engagement that finally results productivity improvement.

7. Question#4
Explain the process of planning, controlling and managing skilled and unskilled labor for a
construction site.
Answer
A successful project requires careful planning, proper controlling and managing efforts
throughout for human resource because it is beneficial for both client and contractor in order to
achieve a timely and satisfactorily outcome. Construction uses more manpower in its activities as
compared to the other field and the main challenge is to obtain proper mix ratio of work force
both skilled and unskilled labor. The actual problems that we always face are shortage of skilled
labor and dynamic work force, lack of effective training and performance in the Construction
Projects. Productivity can also be defined in terms of labor as a “relative measure of labor
efficiency, either good or bad, when compared to an established base or norm.”
Skilled labor is the portion of workers that have specific technical industry skills while unskilled
labor is the cheaper and less technical portion of the workforce but both are required for any
construction site. Although skilled workers are more expensive than other workers in the market,
they provide tremendous value by improving the productivity on the basis of their expertise.
Similarly, unskilled labor also plays the important part of performing repetitive tasks that do not
require technical abilities.
Human resource planning is the process by which an organization attempts to ensure that it has
the right number and right kind of people in the right jobs at the right time.
Best practice of Project HR Planning:
 Fast growth in exchange of Technology and Machinery operations.
 Organizational structure with right people at right-time.
 Proper Organization Structure and clear responsible Org. Chart.
 Proper rewarding-scheme and good incentive wages.
Positive Impact in performance of the Construction project on:
 Efficiency of the project execution.
 Managerial and Organizational Competencies.
 Personal Capability growth.
 Technical performance and innovation creativity.
 Team Performance and interfaces.

8. Question#5
Write short notes on the following
I. Management of Sub Contractors
II. Site Assembly
III. Cladding
IV. Precast Construction Technology
V. Role of Construction Managers in productivity improvement and management
VI. Steel Construction
Answer
Management of Sub Contractors: Sometimes a major construction project is channeled from
the prime contractor to other contractors who act as "subcontractors". They are usually required
when the prime contractor may not have expertise in an area or may not have the physical
resources to deliver it.
Managing subcontractors is an important aspect of any project because each component of a
project can affect the final outcome. Since subcontractors are not directly responsible to client,
another challenge in managing them is to coordinate schedules to ensure that a project is
completed in a given time period. Therefore the prime contractor required to follow some
important instruction which are as follows,
1. Selecting subcontractors because of their reputation in providing good service in a
particular area.
2. Identifying the things that you might do better than a subcontractor.
3. Arrange a meeting with the subcontractor before the project is set to begin. Discuss
expectations and costs. This is especially important if you have not worked with this
subcontractor before.
4. Have the subcontractor sign a contract. Having everything in writing will ensure that the
project is done to your satisfaction before the subcontractor can be paid, and will avoid
any attempt by the subcontractor to break the terms of your agreement.
5. Working in partnership with subcontractors, building a relationship of trust and co-operation.
6. Set clear deadlines. One of the most important parts of managing a subcontractor is time
management, so agree to a start and finish date before beginning any project.
7. Encourage subcontractors to communicate with each other to help the project go
smoothly. For example, in a project that has a copywriter and a graphic designer; the two
subcontractors should have one another's contact information so that questions can be
answered quickly and efficiently.
8. Be available if any problems arise. Subcontractors should be able to reach you
immediately for any questions or problems.
9. Taking action if a subcontractor's performance falls short.

9. 10. Be flexible, but don't allow subcontractors to take advantage of you. Sometimes other
projects need to take precedence, so allow subcontractors the ability to do emergency
work if they need to. At the same time, make sure they know when you expect your
project to be completed.
All the above mention instructions can be summarize in two bullets as given below,
 Good selection of subcontractors
 Quality monitoring of subcontractors
Site Assembly: “Prefabrication and modular construction processes have been used for years,
but today, with the emergence of new technologies and construction practices, we have the
ability to utilize these strategies to create innovative and quality buildings, while also improving
construction productivity,”
The theory behind the method is that time and cost is saved if similar construction tasks can be
grouped, and assembly line techniques can be employed in prefabrication at a location where
skilled labor is available, while congestion at the assembly site, which wastes time, can be
reduced. The method finds application particularly where the structure is composed of repeating
units or forms, or where multiple copies of the same basic structure are being constructed.
Prefabrication avoids the need to transport so many skilled workers to the construction site, and
other restricting conditions such as a lack of power, lack of water, exposure to harsh weather or a
hazardous environment are avoided. Against these advantages must be weighed the cost of
transporting prefabricated sections and lifting them into position as they will usually be larger,
more fragile and more difficult to handle than the materials and components of which they are
made.
Some major advantages are as follows,
1. Self-supporting ready-made components are used, so the need for formwork, shuttering
and scaffolding is greatly reduced.
2. Construction time is reduced and buildings are completed sooner, allowing an earlier
return of the capital invested.
3. On-site construction and congestion is minimized.
4. Quality control can be easier in a factory assembly line setting than a construction site
setting.
5. Prefabrication can be located where skilled labor is more readily available and costs of
labor, power, materials, space and overheads are lower.
6. Time spent in bad weather or hazardous environments at the construction site is
minimized.
7. Less waste may occur
8. Advanced materials such as sandwich-structured composite can be easily used,
improving thermal and sound insulation and air tightness.

10. Increased adoption of Building Information Modeling, or “BIM,” is also fueling the reemergence
of prefabrication and modularization as a critical new trend. Together, BIM and
prefabrication/modular construction improve worksite productivity.
Productivity improvements include decreased project schedules (66% report a positive impact—
35% say it’s by four weeks or more), decreased costs (65% report positive impact— 41% say
budgets decreased by 6% or more), and decreased construction site waste (77% report a positive
impact— 44% say waste was decreased by 5% or more).
Cladding: Cladding can be defined as an exterior finishing system that’s purpose is to protect
the underlying structure as well as to provide a decorative finish. Cladding is surprisingly
durable product that will last for up to fifty years, depending on the type of cladding that you
choose and how it is looked after. It is getting more attention nowadays because it is very quick
to install and also easy to work with. It is used to complement the architectural style of the
building while also offering protection from rain, wind, snow, and other outside elements.
Building cladding can also add insulation to the structure while minimizing sound transmission
through the walls.
Before exterior cladding can be installed, the structural framing of the building must be
complete. This typically involves using wood or steel studs to frame out the exterior walls. These
walls are then covered with plywood or oriented-strand board (OSB) to help brace against wind
and other forces.
Different types of cladding are as follows,
 Weatherboard cladding: It is made from timber, reconstituted hardwood, fiber cement
or vinyl. Weatherboards can be fixed to all kinds of substrates. Timber and fiber cement
weatherboards need periodic maintenance to keep them looking their best while vinyl
weatherboards are practically zero maintenance.
 Vinyl cladding: If you’re after a cladding material that requires practically no
maintenance, then vinyl cladding is for you! Vinyl cladding suits all kinds of homes and
comes in a range of colors. It is also economical. Vinyl cladding is recyclable and uses
fewer resources in its manufacturing than other types of cladding. It is easy to add
insulation to vinyl cladding as well.
 Fiber cement cladding: this type of cladding is made by compressing sand, cement, and
cellular fiber into sheets. Fiber cement cladding gives the appearance of wood but it is
lighter, easier to install, and requires less maintenance.
 External foam cladding: this is also known as an External Insulated Finish System (EIFS)
and it is made from expanded polystyrene that has been reinforced with fiberglass mesh

11. and finished with a render. It comes in panel form, is easy to install, is extremely tough
and weather resistant, and is extremely energy efficient.
 Metal cladding: metal cladding is either steel or aluminum cladding. The metal is
protected through anodizing, galvanizing or powder coating and a range of different
colors are available to suit any color scheme. A range of looks can be created using
metal cladding such as sleek flat panels or corrugated looks. Metal cladding is also very
low maintenance.
Precast Construction Technology: The building system is the basis of an economy of every
country. The industrialization demands apply to the need to increase paces of construction
significantly, to reduce construction costs and improve quality standards. The Precast
construction technology ensures both, well pace of construction and reduction in costs with
improve quality, if handle properly.
Compared with traditional construction methods and other building materials, prefabrication as a
construction method, and concrete as a material, have a number of positive features. Therefore
the use of precast concrete in construction is widely regarded as an economic, durable,
structurally sound and architecturally versatile form of construction. The main features of this
construction process are given below,
 The division and specialization of the human workforce
 The use of tools, machinery, and other equipment, usually automated, in the
production of standard, interchangeable parts and products.
Demand for precast concrete buildings continues to increase throughout. The profit potential of
pre-casting, both in a production facility and on the jobsite, is indeed appealing. In general, labor
costs are below conventional casting methods. Pre-casting techniques, however, differ
considerably from conventional site-casting methods. A thorough understanding of this highly
specialized system of concrete construction is prerequisite to a successful as well as profitable
pre-casting operation. The growing popularity of the precast concrete frame technology is
explained by the fact that it has significant advantages over traditional construction techniques:
 Rapid construction on site
 High quality because of the controlled conditions in the factory
 Entire building can be precast-walls, floors, beams, etc.
Precast construction technology also has some drawbacks which are as follows,
 Very heavy members
 Somewhat limited building design flexibility
 Joints between panels are often expensive and complicated.
 Skilled workmanship is required in the application of the panel on site.
 Cranes are required to lift panels.

12. Role of Construction Managers in productivity improvement and management: In general
people think that the two terms, Project manager and Construction manager, are the same but
there is a difference between these two. On a same project considering both equivalents in terms
of frame works but differs in terms of its scope. So it is very important to first differentiate
between Project Manager and Construction Manager.
The title Project manager implies managerial responsibility for all aspects of a project from start
to finish while the Construction manager have managerial responsibility for a portion of a
project that require civil work and handles a construction job. The primary role of the
construction manager is to ensure that the project is completed on time, within budget, and in
keeping with the original specifications. Hence we can say Construction manager is a sub set of
Project manager where Project manager is a planner and construction manager is more the doer.
In the current environment, construction managers are hard pressed to find ways to gain a
competitive advantage and improve profit. In any given geographic area, construction labor,
material and equipment cost are essentially the same. One of the few opportunities to improve
the bottom line is to increase productivity.
Studies show that workers on a construction project are unproductive for 50 percent of their time
on site. Waiting eats up more than half of an employees’s unproductive time and about one-third
of total project time. It can wreck a schedule and reduce the profit.
There are many other drains of productivity at the construction site that must be consider by the
construction manager, including:
 Poorly planned materials management
 Cleaning up the job site
 Material waste and theft
 Accidents
 Substance abuse
 Redoing substandard work and completing client punch list.
Steel Construction: Nowadays more and more construction is being carried with the help of
steel components all over the world. The reason of metal and steel components' wide distribution
is simple: they are firm, more or less cheap, aesthetic, do not require further treatment and are
environmentally friendly. This is not the whole list of their advantages but even these qualities
are enough to draw attention to metal and steel component. On the other hand, corrosion is one
of the biggest disadvantages of metal parts used for construction though nowadays most of the
manufacturers heat-treat metal parts in order they become stainless and stone-like.
Structural steel enhances construction productivity because of its shop fabrication while
maintaining tight construction tolerances. Field placed material will always lag behind the
productivity curve. Productivity enhancements for construction will occur not in labor based
field activities, but in shop based technology enhancements. Technology exists today in the form

13. of 3-D interoperability and Building Information Modeling to allow the close cooperation
between designers and steel specialty contractors in the design, fabrication and erection of
building structures. This technology allows designs to save both time and cost in the construction
process by integrating fabricating and erection efficiencies in the design and passing design
models between analysis, detailing and fabricating operations.
Today, when competing framing systems are evaluated for projects using comparable, current
cost data, structural steel remains the cost leader for the majority of construction projects.
Comparative studies indicate that a structural steel framing system including decking and fire
protection will typically cost 5% to 7% less than a concrete framing system on a national basis.
And that is not surprising; structural steel has remained the cost leader for construction materials
over the past 30+ years. According to the Bureau of Labor Statistics the price for fabricated
structural steel prices for commercial buildings increased 62% from their base date of 1980. In
contrast, ready-mix concrete prices have escalated 114% during that same period. Why the
difference? In 1980, 10 man-hours were required to produce a single ton of steel. Today that
same ton of structural steel requires substantially less than a single man-hour. While not as
dramatic, similar productivity enhancements have impacted the cost of detailing and fabrication.
The end result is that the structural steel component of the construction industry is one of the few
segments where significant productivity increases have occurred.
Steel in construction allows the project architect a greater degree of expression and creativity in
their design than any other construction material as they address both the functional demands of
the building and unique identity of their client. Architects praise the natural beauty of steel and
are excited about exposing it in the design of their structures to emphasize grace, slenderness,
strength and transparency of frame. Column-free clear spans, the use of colored coatings and the
opportunity for natural lighting highlight the elegant simplicity of using structural steel.
Structural steel sections can be bent and rolled to create non-linear members to further enhance
the aesthetic appeal of the structure.
The following advantages in general may be credited to steel as a structural design material:
 High strength/weight ratio
 Good in ductility
 Fast speed of erection
 Adaptation of prefabrication
The following may be considered as disadvantages of steel in certain cases:
 High General cost
 Week in Fireproofing.
 More maintenance required.
 Susceptibility to buckling.

14. Question#6
Explain the role of “Computer Applications” in improving productivity of construction projects
in terms of:
I. Architectural Design
II. Structural Design
III. Project Planning and Scheduling
IV. Progress Monitoring and Control
V. Accounting
VI. Site Management
Answer
The construction industry involves many specialized fields e.g. architectural, structural,
planning, accounting and management etc. These fields form part of construction engineering. In
almost all of these fields there is an inter-relationship between the kinds of skills required. In
order to make work easier and more accurate many computing software and computer generated
programs and equipments have been developed.
In today’s environment, computers and the art of computing have revolutionalized the
construction industry. In order to construct more energy saving buildings it has been imperative
that computer programs that analyze all the possible outcomes have had to be used. This has led
to the productivity improvement through reduction of the manual labor required as well as
reducing the monetary burden. In addition through the use of computerized programs more job
opportunities have been created in the information technology sector as more people with IT
skills are entering the market to produce more user friendly and efficient construction
engineering tools.
Architectural Design: Architectural design may be aided by using the computer applications
e.g. Computer Aided Program (CAD), that has both the features drafting as well as modeling. By
using these software programs, an optimum solution in the architectural design may be reached
since the architect can use the computer to examine a lot of designs before making a final
decision. Therefore modern practice of architecture requires much use of the computer in
applications such as design, creating computerized models, creating 3D models, structural
integrity testing and layout testing. Architectural models are the ones most benefited by the aid
of computers because these are jobs much harder when done by hand.

15. Structural Design: After the architectural design the second phase or the most important phase
is the structural design which involves complicated calculations on large scale. Structural
engineers are continually being asked to do more, in less time, and using a disconnected
workflow eats into profits quickly. Integrating analysis, design, documentation and detailing
increases productivity and is critical for business growth. Computer applications can be used in
solving these complicated calculations and in making the design, by an integration of computer
aided analysis through different software available in market e.g. SAP, E-tab and SAFE etc.
Project planning, scheduling, monitoring and control: In the area of construction
management, computers are useful as aids in planning, scheduling, monitoring and controlling
projects of all sizes. The merits of applying computers in the area of construction management
are numerous. Firstly it can quickly provide vast amount of information to the planner and
secondly, it provides the construction manager with the opportunity to simulate a project and
compare alternative proposal to arrive at a satisfactory solution. The most common software,
used for planning, scheduling, monitoring and controlling, are Primavera and MS-Project.
Accounting: The computer applications are beneficial for both office and side administration.
For instance, with the aid of a computer, a database and financial accounting software system,
the contractors may execute with ease the cash flow forecasting. The database can conveniently
store cash and other records of past projects with which the contractor can plan for new projects
and enables him make better informed decisions.
Site Management: Computers are also currently being used by quantity surveyors in the
preparation of bills of quantity and project estimate. Some of the available software systems also
incorporate the standard methods of measurements (SMM). There are various methods of data
input available. The input method can incorporate traditionally prepared dimensions, suitably
coded or the organization can use direct keyboard entry with automated squaring or a fully
integrated digitizer. Most computer aided estimating systems are either based on spread sheets,
or estimating packages. The building contractors may also use the computers to keep inventory
of all equipment, especially where it is necessary to maintain large volumes of equipment.