MAJOR BUILDING SYSTEMS

                                                 MAJOR BUILDING SYSTEMS
The simplest building system consists of only two components. One component is
a floor, a flat, horizontal surface on which human activities can take place. The
other component is an enclosure that extends over the floor and generally also
around it to provide shelter from the weather for human activities.
The ground may serve as the floor in primitive buildings. In better buildings,
however, the floor may be a structural deck laid on the ground or supported above
ground on structural members, such as the joist and walls in Fig. 1.1. Use of a
deck and structural members adds at least two different types of components, or
two subsystems, to the simplest building system. Also, often, the enclosure over
the floor requires supports, such as the rafter and walls in Fig. 1.1, and the walls,
in turn, are seated on foundations in the ground. Additionally, footings are required
at the base of the foundations to spread the load over a large area of the ground,
to prevent the building from sinking (Fig. 1.2a). Consequently, even slight improvements
in a primitive building introduce numerous additional components, or subsystems, into a building.
      More advanced buildings consist of numerous subsystems, which are referred to
as systems in this book when they are major components. Major subsystems generally
include structural framing and foundations, enclosure systems, plumbing,
lighting, acoustics, safety systems, vertical-circulation elements, electric power and
signal systems, and heating, ventilation, and air conditioning (HVAC).
Structural System. The portion of a building that extends above the ground level
outside it is called the superstructure. The portion below the outside ground level
is called the substructure. The parts of the substructure that distribute building
loads to the ground are known as foundations.
Foundations may take the form of walls. When the ground under the building
is excavated for a cellar, or basement, the foundation walls have the additional task
of retaining the earth along the outside of the building (Fig. 1.1). The superstructure in such cases is erected atop the foundation walls.

FIGURE 1.1 Vertical section through a one-story building with basement shows location
of some major components. (Reprinted with permission from F. S. Merritt and J. Ambrose,
‘‘Building Engineering and Systems Design,’’ 2d ed., Van Nostrand Reinhold, New York.)

BUILDING COSTS

                                                      BUILDING COSTS
Construction cost of a building usually is a dominant design concern. One reason
is that if construction cost exceeds the owner’s budget, the owner may cancel the
project. Another reason is that costs, such as property taxes and insurance, that
occur after completion of the building often are proportional to the initial cost.
Hence, owners usually try to keep that cost low. Designing a building to minimize
construction cost, however, may not be in the owner’s best interests. There are
many other costs that the owner incurs during the anticipated life of the building
that should be taken into account.
Before construction of a building starts, the owner generally has to make a sizable investment in the project. The major portion of this expenditure usually
goes for purchase of the site and building design. Remaining preconstruction costs
include those for feasibility studies, site selection and evaluation, surveys, and program
definition.
The major portion of the construction cost is the sum of the payments to the
general contractor and prime contractors. Remaining construction costs usually consist
of interest on the construction loan, permit fees, and costs of materials, equipment,
and labor not covered by the construction contracts.
The initial cost to the owner is the sum of preconstruction, construction, and
occupancy costs. The latter covers costs of moving possessions into the building
and start-up of utility services, such as water, gas, electricity, and telephone.
After the building is occupied, the owner incurs costs for operation and maintenance
of the buildings. Such costs are a consequence of decisions made during building design.
Often, preconstruction costs are permitted to be high so that initial costs can be
kept low. For example, operating the building may be expensive because the design
makes artificial lighting necessary when daylight could have been made available
or because extra heating and air conditioning are necessary because of inadequate
insulation of walls and roof. As another example, maintenance may be expensive
because of the difficulty of changing electric lamps or because cleaning the building
is time-consuming and laborious. In addition, frequent repairs may be needed because
of poor choice of materials during design. Hence, operation and maintenance
costs over a specific period of time, say 10 or 20 years, should be taken into account
in optimizing the design of a building.
Life-cycle cost is the sum of initial, operating, and maintenance costs. Generally,
it is life-cycle cost that should be minimized in building design rather than construction
cost. This would enable the owner to receive the greatest return on the
investment in the building. ASTM has promulgated a standard method for calculating
life-cycle costs of buildings, E917, Practice for Measuring Life-Cycle Costs
of Buildings and Building Systems, as well as a computer program and user’s guide
to improve accuracy and speed of calculation.
Nevertheless, a client usually establishes a construction budget independent of
life-cycle cost. This often is necessary because the client does not have adequate
capital for an optimum building and places too low a limit on construction cost.
The client hopes to have sufficient capital later to pay for the higher operating and
maintenance costs or for replacement of undesirable building materials and installed
equipment. Sometimes, the client establishes a low construction budget because the
client’s goal is a quick profit on early sale of the building, in which case the client
has little or no concern with future high operating and maintenance costs for the
building. For these reasons, construction cost frequently is a dominant concern in design.

ROLE OF THE CLIENT IN DESIGN AND CONSTRUCTION

                   ROLE OF THE CLIENT IN DESIGN AND CONSTRUCTION
Administration of building construction is difficult, as a
result of which some clients, or owners, engage a construction manager or construction
program manager to act as the owner’s authorizing agent and project
overseer. The reasons for the complexity of construction administration can be seen
from an examination of the owner’s role before and during construction.
After the owner recognizes the need for a new building, the owner establishes
project goals and determines the economic feasibility of the project. If it appears
to be feasible, the owner develops a building program (list of requirements), budget,
and time schedule for construction. Next, preliminary arrangements are made to
finance construction. Then, the owner selects a construction program manager or
an architect for design of the building. Later, a construction manager may be chosen,
if desired.
The architect may seek from the owner approval of the various consultants that will be needed for design. If a site for the building has not been obtained at this
stage, the architect can assist in site selection. When a suitable site has been found,
the owner purchases it and arranges for surveys and subsurface explorations to
provide information for locating the building, access, foundation design and construction,
and landscaping. It is advisable at this stage for the owner to start developing harmonious relations with the community in which the building will be
erected.
During design, the owner assists with critical design decisions; approves schematic
drawings, rough cost estimates, preliminary drawings, outline specifications,
preliminary cost estimates, contract documents, and final cost estimate; pays designers’
fees in installments as design progresses; and obtains a construction loan.
Then, the owner awards the general contract for construction and orders construction
to start. Also, the owner takes out liability, property, and other desirable insurance.
At the start of construction, the owner arranges for construction permits. As
construction proceeds, the owner’s representatives inspect the work to ensure compliance
with the contract documents. Also, the owner pays contractors in accordance
with the terms of the contract. Finally, the owner approves and accepts the completed
project.
One variation of the preceding procedure is useful when time available for construction
is short. It is called phase, or fast-track, construction. In this variation,
the owner engages a construction manager and a general contractor before design
has been completed, to get an early start on construction. Work then proceeds on
some parts of the building while other parts are still being designed. For example,
excavation and foundation construction are carried out while design of the structural
framing is being finished. The structural framing is erected, while heating, ventilation,
and air-conditioning, electrical, plumbing, wall, and finishing details are
being developed. For tall buildings, the lower portion can be constructed while the
upper part is still being designed. For large, low-rise buildings, one section can be
built while another is under design.

TRADITIONAL CONSTRUCTION PROCEDURES

                             TRADITIONAL CONSTRUCTION PROCEDURES

Construction under the traditional construction procedure
is performed by contractors. While they would like to satisfy the owner and the building designers, contractors have the main objective of making a profit. Hence,
their initial task is to prepare a bid price based on an accurate estimate of construction
costs. This requires development of a concept for performance of the work
and a construction time schedule. After a contract has been awarded, contractors
must furnish and pay for all materials, equipment, power, labor, and supervision
required for construction. The owner compensates the contractors for construction costs and services.
     A general contractor assumes overall responsibility for construction of a building.
The contractor engages subcontractors who take responsibility for the work
of the various trades required for construction. For example, a plumbing contractor
installs the plumbing, an electrical contractor installs the electrical system, a steel
erector structural steel, and an elevator contractor installs elevators. Their contracts
are with the general contractor, and they are paid by the general contractor.
      Sometimes, in addition to a general contractor, the owners contracts separately
with specialty contractors, such as electrical and mechanical contractors, who perform
a substantial amount of the work required for a building. Such contractors are
called prime contractors. Their work is scheduled and coordinated by the general
contractor, but they are paid directly by the owner.
Sometimes also, the owner may use the design-build method and award a contract
to an organization for both the design and construction of a building. Such organizations are called design-build contractors. One variation of this type of
contract is employed by developers of groups of one-family homes or low-rise
apartment buildings. The home builder designs and constructs the dwellings, but
the design is substantially completed before owners purchase the homes.
      Administration of the construction procedure often is difficult. Consequently,
some owners seek assistance from an expert, called a professional construction
manager, with extensive construction experience, who receives a fee. The construction
manager negotiates with general contractors and helps select one to construct
the building. Managers usually also supervise selection of subcontractors. During
construction, they help control costs, expedite equipment and material deliveries,
and keep the work on schedule . In some cases, instead, the owner
may prefer to engage a construction program manager, to assist in administrating both design and construction.
Construction contractors employ labor that may or may not be unionized. Unionized
craftspeople are members of unions that are organized by construction
trades, such as carpenter, plumber, and electrician unions. Union members will
perform only the work assigned to their trade. On the job, groups of workers are
supervised by crew supervisors, all of whom report to a superintendent.
During construction, all work should be inspected. For this purpose, the owner,
often through the architect and consultants, engages inspectors. The field inspectors
may be placed under the control of an owner’s representative, who may be titled
clerk of the works, architect’s superintendent, engineer’s superintendent, or resident
engineer. The inspectors have the responsibility of ensuring that construction meets
the requirements of the contract documents and is performed under safe conditions.
Such inspections may be made at frequent intervals.
In addition, inspections also are made by representatives of one or more governmental
agencies. They have the responsibility of ensuring that construction meets
legal requirements and have little or no concern with detailed conformance with
the contract documents. Such legal inspections are made periodically or at the end
of certain stages of construction. One agency that will make frequent inspections
is the local or state building department, whichever has jurisdiction. The purpose
of these inspections is to ensure conformance with the local or state building code.
During construction, standards, regulations, and procedures of the Occupational
Safety and Health Administration should be observed. These are given in detail in
‘‘Construction Industry. OSHA Safety and Health Standards (29CFR1926/1910),’’
Government Printing Office, Washington, DC 20402.
Following is a description of the basic traditional construction procedure for a
multistory building:
After the award of a construction contract to a general contractor, the owner
may ask the contractor to start a portion of the work before signing of the contract
by giving the contractor a letter of intent or after signing of the contract by issuing
a written notice to proceed. The contractor then obtains construction permits, as
required, from governmental agencies, such as the local building, water, sewer, and
highway departments.
The general contractor plans and schedules construction operations in detail and
mobilizes equipment and personnel for the project. Subcontractors are notified of
the contract award and issued letters of intent or awarded subcontracts, then are
given, at appropriate times, notices to proceed.
Before construction starts, the general contractor orders a survey to be made of
adjacent structures and terrain, both for the record and to become knowledgeable of local conditions. A survey is then made to lay out construction.
Field offices for the contractor are erected on or near the site. If desirable for
safety reasons to protect passersby, the contractor erects a fence around the site and
an overhead protective cover, called a bridge. Structures required to be removed
from the site are demolished and the debris is carted away.
Next, the site is prepared to receive the building. This work may involve grading
the top surface to bring it to the proper elevations, excavating to required depths
for basement and foundations, and shifting of utility piping. For deep excavations,
earth sides are braced and the bottom is drained.
Major construction starts with the placement of foundations, on which the building
rests. This is followed by the erection of load-bearing walls and structural
framing. Depending on the height of the building, ladders, stairs, or elevators may
be installed to enable construction personnel to travel from floor to floor and eventually
to the roof. Also, hoists may be installed to lift materials to upper levels. If
needed, temporary flooring may be placed for use of personnel.
As the building rises, pipes, ducts, and electric conduit and wiring are installed.
Then, permanent floors, exterior walls, and windows are constructed. At the appropriate
time, permanent elevators are installed. If required, fireproofing is placed for
steel framing. Next, fixed partitions are built and the roof and its covering, or
roofing, are put in place.
Finishing operations follow. These include installation of the following: ceilings;
tile; wallboard; wall paneling; plumbing fixtures; heating furnaces; air-conditioning
equipment; heating and cooling devices for rooms; escalators; floor coverings; window
glass; movable partitions; doors; finishing hardware; electrical equipment and
apparatus, including lighting fixtures, switches, outlets, transformers, and controls;
and other items called for in the drawings and specifications. Field offices, fences,
bridges, and other temporary construction must be removed from the site. Utilities,
such as gas, electricity, and water, are hooked up to the building. The site is landscaped
and paved. Finally, the building interior is painted and cleaned.
The owner’s representatives then give the building a final inspection. If they find
that the structure conforms with the contract documents, the owner accepts the
project and gives the general contractor final payment on issuance by the building
department of a certificate of occupancy, which indicates that the completed building meets building-code requirements.

TRADITIONAL DESIGN PROCEDURES

                    TRADITIONAL DESIGN PROCEDURES
Systems design of buildings requires a different approach to design and construction
than that used in traditional design. Because traditional design and construction
procedures are still widely used, however, it is desirable to incorporate as
much of those procedures in systems design as is feasible without destroying its
effectiveness. This will make the transition from traditional design to systems design
easier. Also, those trained in systems design of buildings will then be capable
of practicing in traditional ways, if necessary.
In the basic traditional design procedure, design usually starts when a client
recognizes the need for and economic feasibility of a building and engages an
architect, a professional with a broad background in building design. The architect,
in turn, engages consulting engineers and other consultants.
For most buildings, structural, mechanical, and electrical consulting engineers
are required. A structural engineer is a specialist trained in the application of scientific
principles to the design of load-bearing walls, floors, roofs, foundations, and
skeleton framing needed for the support of buildings and building components. A
mechanical engineer is a specialist trained in the application of scientific principles
to the design of plumbing, elevators, escalators, horizontal walkways, dumbwaiters,
conveyors, installed machinery, and heating, ventilation, and air conditioning. An
electrical engineer is a specialist trained in the application of scientific principles
to the design of electric circuits, electric controls and safety devices, electric motors
and generators, electric lighting, and other electric equipment.
For buildings on a large site, the architect may engage a landscape architect as
a consultant. For a concert hall, an acoustics consultant may be engaged; for a
hospital, a hospital specialist; for a school, a school specialist.
The architect does the overall planning of the building and incorporates the
output of the consultants into the contract documents. The architect determines what
internal and external spaces the client needs, the sizes of these spaces, their relative locations, and their interconnections. The results of this planning are shown in floor
plans, which also diagram the internal flow, or circulation, of people and supplies.
Major responsibilities of the architect are enhancement of the appearance inside
and outside of the building and keeping adverse environmental impact of the structure
to a minimum. The exterior of the building is shown in drawings, called elevations.
The location and orientation of the building is shown in a site plan. The
architect also prepares the specifications for the building. These describe in detail
the materials and equipment to be installed in the structure. In addition, the architect,
usually with the aid of an attorney engaged by the client, prepares the construction
contract.
The basic traditional design procedure is executed in several stages. In the first
stage, the architect develops a program, or list of the client’s requirements. In the
next stage, the schematic or conceptual phase, the architect translates requirements
into spaces, relates the spaces and makes sketches, called schematics, to illustrate
the concepts. When sufficient information is obtained on the size and general construction
of the building, a rough estimate is made of construction cost. If this cost
does not exceed the cost budgeted by the client for construction, the next stage,
design development, proceeds. In this stage, the architect and consultants work out
more details and show the results in preliminary construction drawings and outline
specifications. A preliminary cost estimate utilizing the greater amount of information
on the building now available is then prepared. If this cost does not exceed
the client’s budget, the final stage, the contract documents phase, starts. It culminates
in production of working, or construction, drawings and specifications,
which are incorporated in the contract between the client and a builder and therefore
become legal documents. Before the documents are completed, however, a final
cost estimate is prepared. If the cost exceeds the client’s budget, the design is
revised to achieve the necessary cost reduction.
In the traditional design procedure, after the estimated cost is brought within the
budget and the client has approved the contract documents, the architect helps the
owner in obtaining bids from contractors or in negotiating a construction price with
a qualified contractor. For private work, construction not performed for a governmental
agency, the owner generally awards the construction contract to a contractor,
called a general contractor. Assigned the responsibility for construction of the
building, this contractor may perform some, all, or none of the work. Usually, much
of the work is let out to specialists, called subcontractors. For public work, there
may be a legal requirement that bids be taken and the contract awarded to the
lowest responsible bidder. Sometimes also, separate contracts have to be awarded
for the major specialists, such as mechanical and electrical trades, and to a general
contractor, who is assigned responsibility for coordinating the work of the trades
and performance of the work.
Building design should provide for both normal and emergency conditions. The
latter includes fire, explosion, power cutoffs, hurricanes, and earthquakes. The design should include access and facilities for disabled persons.

SYSTEMS DESIGN AND ANALYSIS

                                 SYSTEMS DESIGN AND ANALYSIS
Systems design comprises a logical series of steps that leads to the best decision
for a given set of conditions. The procedure requires:
Analysis of a building as a system.
Synthesis, or selection of components, to form a system that meets specific
objectives while subject to constraints, or variables controllable by designers.
Appraisal of system performance, including comparisons with alternative systems.
Feedback to analysis and synthesis of information obtained in system evaluation,
to improve the design.
The prime advantage of the procedure is that, through comparisons of alternatives
and data feedback to the design process, systems design converges on an
optimum, or best, system for the given conditions. Another advantage is that the
procedure enables designers to clarify the requirements for the building being designed.
Still another advantage is that the procedure provides a common basis of
understanding and promotes cooperation between the specialists in various aspects
of building design.
For a building to be treated as a system, as required in systems design, it is
necessary to know what a system is and what its basic characteristic are.
A system is an assemblage formed to satisfy specific objectives and subject to
constraints and restrictions and consisting of two or more components that are
interrelated and compatible, each component being essential to the required performance
of the system.
Because the components are required to be interrelated, operation, or even the
mere existence, of one component affects in some way the performance of other
components. Also, the required performance of the system as a whole, as well as
the constraints on the system, imposes restrictions on each component.
A building meets the preceding requirements. By definition, it is an assemblage
(Art. 1.1). It is constructed to serve specific purposes. It is subject to constraints
while doing so, inasmuch as designers can control properties of the system by
selection of components (Art. 1.9). Building components, such as walls, floors,
roofs, windows, and doors, are interrelated and compatible with each other. The
existence of any of thee components affects to some extent the performance of the
others. And the required performance of the building as a whole imposes restrictions
on the components. Consequently, a building has the basic characteristics of a
system, and systems-design procedures should be applicable to it.

             PRINCIPLES OF ARCHITECTURE
A building is an assemblage that is firmly attached to the ground and that provides
total or nearly total shelter for machines, processing equipment, performance of
human activities, storage of human possessions, or any combination of these.

• Building design is the process of providing all information necessary for construction

of a building that will meet its owner’s requirements and also satisfy public
health, welfare, and safety requirements. Architecture is the art and science of
building design. Building construction is the process of assembling materials to
form a building.
Building design may be legally executed only by persons deemed competent to
do so by the state in which the building is to be constructed. Competency is determined
on the basis of education, experience, and ability to pass a written test of
design skills.

• Architects are persons legally permitted to practice architecture. Engineers are

experts in specific scientific disciplines and are legally permitted to design parts of
buildings; in some cases, complete buildings. In some states, persons licensed as
building designers are permitted to design certain types of buildings.
Building construction is generally performed by laborers and craftspeople engaged
for the purpose by an individual or organization, called a contractor. The
contractor signs an agreement, or contract, with the building owner under which
the contractor agrees to construct a specific building on a specified site and the
owner agrees to pay for the materials and services provided.
In the design of a building, architects should be guided by the following principles:
1. The building should be constructed to serve purposes specified by the client.
2. The design should be constructable by known techniques and with available
labor and equipment, within an acceptable time.
3. The building should be capable of withstanding the elements and normal usage
for a period of time specified by the client.
4. Both inside and outside, the building should be visually pleasing.
5. No part of the building should pose a hazard to the safety or health of its
occupants under normal usage, and the building should provide for safe evacuation
or refuge in emergencies.
6. The building should provide the degree of shelter from the elements and of
control of the interior environment—air, temperature, humidity, light, and acoustics—
specified by the client and not less than the minimums required for safety
and health of the occupants.
7. The building should be constructed to minimize adverse impact on the environment.
8. Operation of the building should consume a minimum of energy while permitting
the structure to serve its purposes.
9. The sum of costs of construction, operation, maintenance, repair, and anticipated
future alterations should be kept within the limit specified by the client.
The ultimate objective of design is to provide all the information necessary for the
construction of a building. This objective is achieved by the production of drawings,
or plans, showing what is to be constructed, specifications stating what materials
and equipment are to be incorporated in the building, and a construction
contract between the client and a contractor. Designers also should observe construction
of the building while it is in process. This should be done not only to
assist the client in ensuring that the building is being constructed in accordance
with plans and specifications but also to obtain information that will be useful in design of future buildings.