Industry
Overview
INTRODUCTION
TO
HVAC
Technical Development Programs (TDP) are modules of technical training on HVAC theory, system design, equipment selection and application topics. They are targeted at engineers and designers who wish to develop their knowledge in this field to effectively design, specify, sell or apply HVAC equipment in commercial applications.
Although TDP topics have been developed as stand-alone modules, there are logical group-ings of topics. The modules within each group begin at an introductory level and progress to advanced levels. The breadth of this offering allows for customization into a complete HVAC curriculum – from a complete HVAC design course at an introductory-level or to an advanced-level design course. Advanced-advanced-level modules assume prerequisite knowledge and do not review basic concepts.
This TDP provides a general overview of the commercial HVAC industry, providing an awareness of: the design process; participants in the design and construction process; documents involved in construction; a typical timeline of activities in the design and construction process; and how these activities are influenced by the different participants in the process. This industry is also influenced by regulatory agencies and legal concerns that are important to designers of HVAC systems.
© 2005 Carrier Corporation. All rights reserved.
The information in this manual is offered as a general guide for the use of industry and consulting engineers in designing systems. Judgment is required for application of this information to specific installations and design applications. Carrier is not responsible for any uses made of this information and assumes no responsibility for the performance or desirability of any resulting system design.
The information in this publication is subject to change without notice. No part of this publication may be reproduced or transmit-ted in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of Carrier Corporation.
Printed in Syracuse, NY CARRIER CORPORATION Carrier Parkway
Table of Contents
Introduction... 1
Participants... 3
Equipment Supplier Organizations ... 5
Industry Associations... 6
Legal Concerns ... 7
Delivery Methods ... 10
Plans and Specifications (Plan and Spec) ... 11
Design-Build (D-B) ... 12 Construction Management (CM) ... 13 Performance Contracting ... 13 Typical Projects ... 13 HVAC Systems... 15 HVAC Products ... 17 Summary... 18 Work Session ... 19
Work Session Answers ... 25
Glossary ... 27
Introduction to HVAC
1
Introduction
The HVAC (Heating, Ventilating, Air Condition-ing) industry is a large and mature industry that serves many markets. In fact, based on the Commercial Buildings Energy Consumption Survey (CBECS) it is estimated that there were 4,859,000 com-mercial buildings with 71.6 billion square feet of floor space in the United States in 2003. Table 1 summarizes the number of buildings and floorspace based on market segment.
Table 2 further describes these 4.9 million buildings by size. Looking at the table, we can see that over 50 percent of the buildings are between 1,000 and 5,000 square feet and only 1.5 percent are above 100,000 square feet.
Table 1
Number of Buildings and Floorspace by Principal Building Activity, 2003
Number of Buildings (thousands) % of Total Total Floorspace (million ft2) % of Total All Buildings 4,859 - 71,658 - Education 386 8.0 9,874 13.7 Food Sales 226 4.7 1,255 1.8 Food Service 297 6.0 1,654 2.3 Health Care 129 2.7 3,163 4.4 Lodging 142 2.9 5,096 7.1 Mercantile 657 13.5 11,192 15.6 Office 824 17.0 12,208 17 Public Assembly 277 5.7 3,939 5.5
Public Order and Safety 71 1.5 1,090 1.5
Religious Worship 370 7.6 3,754 5.2
Service 622 12.8 4,050 5.7
Warehouse and Storage 597 12.3 10,078 14.0
Other 79 1.6 1,738 2.40
Vacant 182 3.7 2567 3.8
Table 2
Number of Buildings and Floorspace by Size of Building, 2003 (Preliminary)
Number of Buildings (thousands) % of Total Total Floorspace (million ft2) % of Total All Buildings 4,859 - 71,658 - 1,001 to 5,000 2,585 53.2 6,922 9.7 5,001 to 10,000 948 19.5 7,033 9.8 10,001 to 25,000 810 16.7 12,659 17.7 25,001 to 50,000 261 5.4 9,382 13.1 50,001 to 100,000 147 3.0 10,291 14.4 100,001 to 200,000 74 1.5 10,217 14.3 200,001 to 500,000 26 0.5 7,494 10.5 Over 500,000 8 0.1 7,660 10.7
Introduction to HVAC 2
The HVAC market can be looked at or segmented in different ways. This review can be based on the age of the building, the use of the build-ing, the type of equipment or system, or the contracting arrangement. The existing building market is typically two to three times the size of the new construction market.
The new construction market consists of projects in which the HVAC system is installed when the building is originally constructed. This market includes projects in which the shell of the building is constructed separately, with the HVAC system and other finish work installed later under separate contracts after the tenants and their specific needs are identified.
The existing construction market is usually identified as the renovation or replacement market. It includes system replacement projects, in which the air conditioning system re-places a previously installed system, and equipment replacement projects in which some or all of the major equipment is replaced. This market also includes projects in which the air conditioning system is installed many years after the building is constructed and no specific provisions were made for its installation.
Figure 1 By Building Age Figure 2 By Scope of Work
Where market segment is based upon building usage, the customary commercial market segments include offices, schools, manufacturing, retail, healthcare, lodging, and other, which includes entertainment, correctional facilities, religious buildings, airports, warehouses, etc.
By Building Usage % of Market
Other30%
Public Order and Safety 1 % Public Assembly 6% Figure 3 By Building Usage Office 17% Mercantile 13% Education 8%
Food Sales and Service 11%
Where market segment is based upon contracting arrangement, the segments can be design-build, plan and specification (plan and spec), or construction management. In design-build work, the design and the construction are provided by the same organization. In plan-and-specification work, a design organization performs the design and creates design documents (called plans and specifications) that are then used by a separate contractor organization to construct the building.
In construction management work, a third party oversees the design and construction activi-ties to reduce risk and insure project completion, schedule, and cost.
Participants
Many different entitles are m-volved in a typical construction project. Their usual relationships are shown in Figure 4.
An owner provides the money to construct a project, and assumes most of the financial risk. A developer pro-vides the concept and the business plan, and usually manages the overall project. The owner and developer functions are frequently provided by the same organization and referred to as the Owner/Developer.
Introduction to HVAC
Figure 4
Typical Construction Project Organization
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The prime contractor is usually responsible for coordinating all construction activity and other contractual items relating to project cost and timing. Large or critical projects are frequently constructed on a fast-track schedule when the major equipment is purchased and the construction work is begun before the overall project design is completed. These projects may have a project manager or a construction manager. A project manager coordinates the entire project, including both design and construction work. A construction manager coordinates the construction activi-ties, that must begin before the prime contract is awarded and continues until the project is complete. Large developers and general contractors usually have project or construction man-agement departments that operate independently of their normal business.
An architect provides the building design services for the project. The design of the HV AC, structural, electrical, plumbing and other trades is provided by engineers in each specialty, by contract with the architect. If these engineers are employed by the architect, the architect becomes an Architect/Engineer.
Contractors provide the construction work. The contract for a prime contractor is a purchase commitment from the owner or developer. A subcontractor has a contract with the prime con
-tractor or a higher-level subcon-tractor. The prime con-tractor usually assumes responsibility for all work at the job site, performs some of the work with his own employees, and provides the rest of the work through use of subcontractors.
A general contractor is usually the prime contractor on a project. If the majority of the work is of a special nature, such as replacement of air conditioning, the mechanical contractor may serve as the prime contractor, with the general contractor becoming a subcontractor to the me-chanical contractor.
The general contractor usually performs the work of constructing the building shell, such as foundations, masonry and concrete work. The mechanical contractor, electrical contractor and automatic controls contractors are typical subcontractors. Subcontractors also perform some work, and arrange for other items through additional subcontractors. The test and balance subcon-tractor may work for the HV AC subconsubcon-tractor, who works for the mechanical subconsubcon-tractor, who works for the prime contractor, etc.
The construction contract usually includes the commissioning, or startup phase of a project. A commissioning agent or contractor is sometimes employed directly by the owner to provide a more objective effort to identify and correct errors made during construction. Test and balance contractors are specialists in measuring air and water flows and checking the performance of equipment after it is placed in service. The startup of some equipment, especially chillers and boilers, is performed by or supervised by a representative of the manufacturer, who is expected to be most familiar with the proper procedures.
The building operations manager is responsible for the operation and maintenance of the HVAC system. This is usually done by contract with a building management service on small buildings. Large buildings usually have a full-time HV AC operation and maintenance staff on site.
Service contractors provide either preventative maintenance or emergency repairs after the system is in operation. Most construction contracts provide a 12-month warranty period. The construction contractor must correct all failures or deficiencies, which are identified during the warranty period, without charge.
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Introduction to HVACTurntotheExperti.
Equipment Supplier Organizations
Every HVAC product is produced by a manufacturer and sold to an "end user." The end user
is the person or entity that finally pays for and uses the product, such as a homeowner or a shop
-ping center operator. Some end users
have enough purchase volume to jus
-tify a direct purchase relationship
between the manufacturer and the end
user, but most users are better served
by purchasing the equipment through
a supply chain which can furnish the
marketing, warehousing, installation
and service functions which are
re-lated to the purchase. Some of the
common supply chain organizations
are shown in Figure 5.
Manufacturers provide design,
production and marketing (product
concept, advertising, sales literature,
etc.) for their products. Sometimes
they maintain warehouses for finished
products or provide their own sales staff, but an "equipment supplier"
usually provides these functions in the local sales area.
Manufacturer
Design, Production, Marketing Warehouse
Sales Representative
Figure 5
Direct Sales
HVA C Equipment Suppliers
Distributor Sales & Marketing
Equipment suppliers handle the sale of equipment for a project. The supplier may be a direct sales office of the manufacturer, or a manufacturer's representative, who is an independently
owned company that typically sells several different types of equipment made by several different
manufacturers. A typical manufacturer's representative may sell pumps from one manufacturer,
fans from another, etc.
A distributor buys equipment in large quantities from a manufacturer, and resells them to
dealers or independent contractors. Distributors tend to emphasize the products of one
manufac-turer and provide warehousing of products, marketing and training for their dealers. Some
distributors are independently owned, while some are owned by manufacturers.
Dealers are independently owned contractors who are franchised by distributors to install equipment purchased from the distributor. The franchise arrangement may require the dealer to be exclusive, in which case they buy all their equipment from one distributor in return for marketing, training and financial assistance from that distributor.
Introduction to HVAC
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5
Industry Associations
Industry associations are formed to provide cooperative solutions to industry wide problems that are best solved by collective effort. The following associations are typical of those involving the HV AC industry.
ASHRAE (American Society of Heating, Refrigeration and Air Condi-tioning Engineers) is primarily concerned with creating information for the design of projects. They pub-lish the ASHRAE Handbook and create many of the recommended minimum standards, which influence project design.
@
®ARI (Air Conditioning and Re-frigeration Institute) is primarily concerned with creating standards for testing and rating the various types of
equipment. Equipment ratings, which Figure 6
American Society of Heating, Refrigerating and Air Conditioning
llD~ Air Conditioning
.~
.. U
& Refrigeration Institutef':'M
National Firel
•
J
Protection Association NFPA®Iii:\
Underwriters'\:!!:J
Laboratories • International Code Council L\."ffll'-\lll.IX.U. cout:wt:xueare ARI certified, are more likely to Industry Associations
be correct and less likely -to be
mis-leading. ARI also provides marketing statistics for air conditioning equipment manufacturers.
NFPA (National Fire Protection Association) addresses building fire and smoke concerns, in-cluding fire and smoke dampers, duct and equipment construction materials and range hood
exhaust systems.
UL (Underwriters' Laboratories) is a non-profit organization divided into two parts. The first section develops standards for the design and testing of product safety. These standards are widely accepted as the benchmarks to be used in product safety testing. The second section of UL is responsible for certification of products to the safety standards. Products may be tested by UL for certification are listed in the UL directory and bear the UL label. Products tested to UL stan-dards by an organization other than UL, such as CSA (Canadian Standards Association), AGA
(American Gas Association), and Intertech (ETL) are called UL accepted and are listed in that organization's directory and bear the label of the listing organization. UL may also test products for specific applications that are not listed in its directory. These products are known as UL recognized products. Local code officials generally accept the testing of these agencies to UL standards as meeting the requirements for safety testing.
The International Code Council (ICC) is a non-profit association of building code officials who develop building safety, energy efficiency, and fire prevention codes used for residential and commercial construction. ICC has replaced other model code writing agencies such as Building Officials and Code Administrators (BOCA), Southern Building Codes Congress (SBCC), and the
International Conference of Building Code Officials (ICBCO). The ICC model code is now used as the basis of most all state and local building energy codes.
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Introduction to HVACTurn to the Experts.- - - -- -
Legal Concerns
The importance of legal issues to an equipment supplier depends upon the amount of money
involved and the organizational relationship of the HY AC supplier on the particular project. The
responsibilities of the supplier must be clearly identified.
The construction and operation of a building must be in accordance with the applicable local
and state building codes. These codes are usually based upon one of the model codes such as
ICC, which are written and sponsored by various associations of building code officials. The Na
-tional Electric Code (NEC) is an example of a model code, which is written by an industry
association. Codes also include reference standards, which are written by industry associations
such as ASHRAE and ARI. ASHRAE Standard 15, for example, is the refrigeration safety
stan-dard that governs the design and installation of refrigeration systems. A model code or a reference
standard becomes part of the state or local building code when it is legally adopted by the
appro-priate governing body. The designer is responsible for meeting the elements of the design codes,
the contractor for meeting the construction elements of the codes, etc. The equipment supplier is
generally responsible for meeting HY AC equipment safety codes. This responsibility is absolute
when the construction documents identify the codes that must be met and when the purchase
or-der for the equipment requires that the equipment be furnished in compliance with the
construction documents.
The official having jurisdiction is the government official who is responsible for enforcement
of the code item being considered. This official may be the fire marshal, the building inspector,
etc. Their interpretation of a code item is final, and they have the authority to enforce their
deci-sion by refusing to issue a certificate of occupancy for the building, which is necessary before the
building can be placed in use.
The HVAC systems are addressed
in a number of building construction
codes, mainly relating to life safety,
layout, design features, and
perform-ance (energy conservation). Across the
United States, the International Code Council's family of publications has
been adopted almost universally. It is
safe to say that familiarity with the
International Building Code (IBC),
International Mechanical Code (IMC),
International Energy Conservation
Code (IECC), and International Fire
Code (IFC) will cover most of the
code-related requirements for HY AC systems. See Figure 7. Always verify
your general understanding of the code
requirements with the specific project
program before finalizing system
se-lection or closing out a design phase.
Introduction to HVAC
Figure 7
Codes, Standards, and Guidelines
(Reproduced with permission of ICC. All rights reserved.)
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Figure 8 shows the relationships
involved in building codes.
Licenses and pem1its for work at
the job site are usually obtained by the contractors. The equipment supplier is generally not responsible unless job site labor is included and a special
license is required for this labor.
The construction documents for a
project are prepared by the designers of the project, and include the plans
(drawings) and specifications. Archi -tects and engineers who are properly
registered by the local authorities to
perform such work must sign the con- Figure 8 struction documents for large projects.
Legal Issues - Codes Equipment specifications and equip
-Equipment Manufacturer
ment selection criteria are included in the construction documents for "plan and specification"
projects, but may be issued separately for design-build projects.
Rather than copying the entire codes and reference standards that apply to a project, a typical
specification will simply state that all equipment must comply with the requirements related to
that item. The codes and reference standards for a project are usually listed at the beginning of
each major section of the specifications.
An addendum is a change or addition to the construction documents for a project.
Adden-dum #1 might change the capacity of a chiller, for example, and Addendum #2 might add an electronic variable speed drive to the air-handling unit. Failure to identify addendums and include
the changes in a quotation for the project may result in the delivery of the wrong equipment to the
job. The resulting expense and construction delay will create a very difficult situation for every
-one involved.
A contract is the legal agreement between the participants on a project. A contract can be
created by the purchaser writing a purchase order that identifies the conditions of the sale.
Accep-tance of this purchase order by a vendor constitutes an agreement by the seller to all of these
conditions. A contract can also be created by the supplier making a proposal (an offer to sell), which identifies the conditions of the sale. Acceptance of this proposal by a buyer constitutes an agreement by the buyer to all of these conditions. The terms and conditions of proposals and pur-chase orders include the "fine print," which is usually on the back of the first page. Contractors and equipment suppliers who do a lot of business together usually agree upon a standard proposal
and purchase order format.
A change notice is a revision to the contract between the owner and the prime contractor. A change notice may include the changes resulting from several addenda that have been issued by the designers of the project. For example, Change Notice 1 may include Addenda 1, 3, 4, and 9, while Change Notice 2 may include Addenda 2 and 5 through 8. Some addenda are issued, but never incorporated into the project because the cost is excessive or for some other reason.
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Introduction to HVACTurntotheExpertS:-- -- - - --
-8
Submittals and approvals are required for large projects, in order to confirm that the equip-ment being furnished is in accordance with the plans and specifications. The submittal and approval requirements are described in the project specifications. The equipment being submitted may have been the "basis of design," which is the exact equipment that the designer used to de-termine the size of the mechanical room, the arrangement of the piping and wiring, and the features described in the specifica
-tions.
Equipment, which was not the ba-sis of design, will almost always be different in some respect. These items should be resolved during the bidding and submittal processes. Considerable experience is necessary in order to identify what constitutes a significant deviation, and how to either obtain approval of the deviation or modify the equipment to meet the specified requirements. If incorrect equipment is installed, it may have to be removed and replaced without charge by the contractor, probably at the expense of the supplier.
Construction Documents (Plans and Specifications) Proposal or
Quotation
Figure 9
Legal Issues - Purchase Contract
Addendums to Construction Documents
Figure 9 shows the relationship of the various documents that are most frequently encoun-tered by equipment suppliers.
Introduction to HVAC
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Delivery Methods
There are many different methods of taking a project from the needs identification phase to
the completed building. The various design elements are not always completed in the same se-quence or by the same members of the design team. Design is a shared, ongoing process that is
not always done by the HV AC designer. System selection needs to be responsive to this fact, along with the many other criteria placed upon the process. Four common methods are shown below. Features are shown in Figure 10.
Typical Projects All types of Complex or schedule Complex or budget Energy conservation
buildings constrained constrained or system retrofits
When are Design Before bidding for Completed after Before or after Completed after
Details Worked construction bidding bidding bidding
Who Works on HVAC Designer and Either HVAC
HVAC Designer Designer or Contractor
Them? Contractor
Contractor
Who is Responsible Either HVAC
HVAC Designer D-B Contractor Designer or Contractor
for HVAC Design? Contractor
Level of Design Complete through Can become May change during Depends on
Team Continuity process fragmented process Contractor control
Who Controls Controlled by Often forced to adjust Often forced to
adjust to competing Contractor
Integrity of Design? HVAC Designer to competing needs
needs Degree of Process
Greatest Less than Normal Moderate to High Least Burden
Level of Owner
Highest Moderate Moderate to Limited Very Limited Involvement
Length of Schedule 1 to 4 years typical 15 to 25% less than Like Plan and Spec 3 to12 Months
Plan and Spec
Relative Cost to Average to High - Greatest -caused by Average to High - Least - paid out of depends on bidding CM fees and bidding
Owner climate shortened schedule
climate savings
Figure 10
Comparison of the Features of Delivery Methods
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Introduction to HVACTmnroilieExperts.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Plans and Specifications (Plan and Spec)
A typical Plan and Spec project organization is shown in Figure 11. This delivery method has dominated the public money segments of the industry for quite some time. A detailed set of contract drawings and specifications
are prepared by the HV AC designer, then bid by mechanical contractors, either publicly or by invitation. Once a contract is awarded, the construction team executes the design and turns
over the building to the client for use. Other Desi ners HVAC Design Engineer Figure 11 Other Subcontractors HVAC Subcontractors therVendor HVAC Equipment Supplier
Typical Construction Project Organization
HVAC Service
Plan and Spec project delivery offers system selection as an up-front activity led by the HV AC system designer (Figure 12). The designer completes drawings and specifications that document what will eventually be
provided by the construction contrac -tor, often with minimal input by the architect and client, and seldom if at all from the eventual occupants.
Introduction to HVAC
Plan and Spec Project Structure (Fig 11)
Figure 12
Plan and Spec Project Structure
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A negative feature of Plan and Spec is that only during bidding does the potential construction contractor have a chance to review the design and communicate concerns to the de-signer. Changes to the design are difficult to bring about.
Design-Build (D-B)
Q,) C) c: (I) .s::. 0 0 ~ :i ~ i5 'O c: (I) tl 0 0During System
Design
Process
Criteria System Concept Design Calculations and Equipment Selection Figure 13
Cost and Difficulty of Making Changes
Plans and Specs
Design-Build differs from Plan and Spec in that the construction bidding phase is moved up
to the front of the design process (Figure 14). Properly done, the client prepares building systems performance plans and specifications
that are bid by contractor teams with design capability that carry forward with the design process, meshing it with the construction activities to shorten the overall project delivery schedule.
The HV AC system selection oc-curs right up front, along with the other building systems, as the per-formance documents are prepared. If good communication and documenta-tion occurs during the performance phase, the initial system selection will
Owner-Prepared "Performance" Bid Package
Review of Contractor Bid Packages and Contract Award J E~~ineerj Single-Line Layouts Equipment Selections Completion Dates Update Layout, Coordinate Contractor Drawings Confirm Equip. Selections ' - - - - . . i Owner Approval
I
Possible 3rd Party Reviews - Arch/EngrV
carry forward in the remaining phases Figure 14
of the design process and be properly Design-Build Project Structure
implemented during construction.
Of-Warranty Period Owner Takes Beneficial Occupancy
Equipment Installation
ten, the original architect and engineer who worked on the performance specifications, if not on the winning bid team, will be retained as consultants to ensure that the client's needs are met as the building design takes shape and construction is completed.
o•
Introduction to HVACTw-n to the
Construction Management
(CM)
In the construction management delivery method, an additional person is added to the team -the construction manager (also called -the CM). Traditionally hired by -the client, the CM oversees the design and construction process, streamlining both efforts. The construction manager relieves the client of watching over the complexities of the project and ensures that the design process and construction results will be responsive to the client's program. Many times the CM will operate at risk, having guaranteed an overall project maximum cost or a construction schedule, or both.
When a client hires a construction manager, the final selection of the architect and engineers may be the decision of the CM.
Performance Contracting
The performance contracting method of project delivery puts the greatest amount of deci-sion-making in the contractor's hands. Usually a client is interested in lowering their energy costs by replacing or upgrading a building system (like lighting, HVAC, or high-use motors), but is not
willing or able to provide the capital financing. Performance contracting transfers the financing
responsibility from the client to the contractor, who is then paid a percentage of the future savings
in energy costs.
Potential savings in energy costs are discovered during an energy audit of the facility and
proposed to the client by the contractor. HV AC systems are often a source of the energy savings, both because of how much energy they use, and the savings that occur through improvements in maintenance and operations. When significant upgrades in HV AC systems or a retrofit to another system are suggested, the client needs to carefully review the impact on their employee comfort
and productivity to make sure it is a net gain. Many clients will bring in an HV AC systems
con-sultant to review the recommended changes before authorizing the performance contractor to
proceed with the work.
Typical
Projects
Residential projects are usually design-build projects handled by air conditioning dealers and
contractors. The purchaser is usually a developer in new construction, or a homeowner for exist
-ing build-ings.
New small commercial systems are also design-build projects by air conditioning dealers and contractors. The purchaser is usually a developer in new construction, and a business owner or tenant for existing buildings. New large systems, above 100 tons, are usually plan and specifica -tion projects. The equipment sale is usually to a contractor, but the owner and the designer can be
very influential in determining the equipment supplier. In some cases, the equipment is purchased
directly by the owner.
Introduction to HVAC
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Equipment replacement projects are usually negotiated between the owner and a service con
-tractor.
Regardless of the type of project, the sequence of events is as shown in Figure 15, which is sometimes referred to as the "time line" of a project. The initial phase is an organizational phase, in which the owner or developer
identify the major participants and decide how the project will be organized (negotiated, plan and specification with competitive bids, etc.).
The conceptual phase begins with the identification of the pur-pose and general criteria for the project by the owner. Each of the design professionals then deter-mines which general concepts are most appropriate to meet the
es-ORGANIZATION PHASE
Organization Typo:
Design/Build Plan and Spec
Construction Management Purchase Method: Competitive Bid Negotiation Create Project Team
tablished criteria. The Figure 15
CONCEPT PHASE Project Criteria: Comfort Level Costs Appearance System Choice Coordination: Space Budgets
requirements for each trade are Typical HVAC Project Timeline
coordinated. Using the HVAC
DESIGN PHASE Load Calculations Equipment Selection Air Distribution Water Distribution Automatic Controls Construction Documents Coordinate Details
CONSTRUCTION WARRANTY AND PHASE SERVICE PHASE
Pricing Award of Contracts Equipment Purchase Submittal and Approval Installation Commissioning Resolve Equipment Failure and System Operational Problems
system as an example, the equipment and duct space is allocated by the architect, the preliminary electrical power requirements are provided to the electrical engineer, the equipment weights to the structural engineer, etc. The budgets for each trade and for the entire project are established.
The HV AC system design phase is dominated by the HV AC designer, either an independent consulting engineer or an employee of the design-build contractor. The designer confirms the cri-teria for the HV AC system, calculates the cooling and heating loads, selects the equipment,
designs the air, water and refrigerant distribution systems and the HV AC control system. Each item must meet the space, cost and service requirements that were agreed upon during the concept phase, or the designer must coordinate the new requirements with all of the affected parties. De-sign changes become increasingly difficult during this phase.
The constmction phase is dominated by the contractor. It includes the purchase of equipment, installation of equipment, air and water distribution and control systems and the commissioning of the HV AC system. To the contractor, timing is extremely important. Delays in equipment
submittals or deliveries can result in substantial increased cost to the contractor that may lead to legal damage claims.
The warranty and service phase involves the owner and, for commercial projects, the building
management and service contractors as well. Everyone, including owner, tenants, contractor, a r-chitect and engineer, becomes aware of problems that affect or prevent operation of the HV AC system. Prompt and fair resolution of any problems is extremely important.
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Introduction to HVACTurn to the Expert$
HVAC Systems
Many types of HV AC systems have been developed to serve a wide range of different mar-kets and performance requirements. The choice of a suitable type of system is a logical first step toward providing a satisfied client. The choice should be based on the priorities that have been
established for that individual project. These priorities include functional performance, costs and many other considerations.
HV AC systems differ widely in their ability to provide the normal air conditioning functions, which include the control of temperature, humidity, air motion, air quality (ventilation and air purity) and sound level. Costs include the initial construction cost of the system; the cost of en-ergy, makeup water, water treatment and disposal; the cost of operation labor, maintenance,
repair and equipment replacement; the cost of system modification to serve future tenants; and the construction cost of building space for ductwork, piping and mechanical rooms. Other considera-tions include the architectural appearance of visible system elements, the probability and impact . of HV AC system failures and the disruption of tenant activities related to maintenance of items in
tenant areas.
From the above, it should be obvious that the lowest construction cost system is inappropriate
for most applications. Most owners and system designers are very interested in providing appro-priate systems, and are relatively open to discussion of these items. To be successful, these discussions must occur before or during the concept phase of the project.
HV AC systems are generally classified by the type of refrigeration and by the type of air system.
Refrigeration systems are either direct (called DX for "direct-expansion") or indirect. The cooling coil in a DX system is cooled directly by the expansion of refrigerant inside the tubes of the coil. The cooling coil in an indirect system is cooled by chilled water or brine that is circu-lated through a piping system between a water chiller and the cooling coil.
Packaged DX systems with a single refrigeration compressor, cooling coil and condenser in close proximity to each other generally have low initial cost, and can be very efficient if the com-ponents are selected for high efficiency. They are usually simple and trouble-free. Split system
DX systems become more complex and prone to refrigerant leakage with increasing numher of
components and the length of piping. A single leak can result in loss of the entire refrigerant
charge of a system.
Chilled-water systems are generally preferred if one or two central water chillers can replace
a large number of separate DX systems, or if the refrigeration equipment must be remote from the
cooling coils. Water piping between the chiller and the cooling coils is simpler than refrigerant
piping. The refrigerant piping system can be factory-installed and tested on practically any size
chiller, and the possibility of refrigerant leakage is minimized.
Air systems are generally classified as either single or multiple zone systems. Single-zone systems can serve any size building area as long as a single temperature control zone can provide reasonable temperatures throughout the area served by that system. A window air conditioner and a 50,000 cfm central system serving an exhibition hall are examples of single-zone systems. Mul
-tiple single-zone systems can be installed to provide separate zones within the building area, with a separate temperature control for each single-zone unit.
Introduction to HVAC
«+4&
- -- - - -Turn to the Expert$.
Multiple-zone systems provide several or many temperature control zones from the same cen
-tral equipment. One central air handler can serve over a thousand separate temperature control
zones. Many of these systems use room terminal units to serve each zone. Multiple-zone systems
are sub-classified in several ways, as shown below.
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Constant Volume Reheat Laboratory · 3 3 I 3 I 5 ! 5 ! 5 2Figure 16
Multiple Zone System Characteristics
' -'--' 2 1 1
All-air systems are systems in which a central air system provides all of the cooling effect to
the individual zones. All-water systems do not have a central cold air system, but provide a
sepa-rate chilled-water fan-and-coil unit to serve each zone. Combination air-water systems provide a
central conditioned air system to do a portion of the zone cooling and also provide a chilled-water
coil in each zone to supply the remaining zone cooling load. The performance and costs of the
multiple-zone systems vary widely and are beyond the scope of this discussion.
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Introduction to HVACTurn to the EXpertS
HVAC
Products
Products are also classified in many ways, beginning with the type of HV AC system for
which it is intended. A "room type chilled-water fan-coil unit" is obviously intended for use as
the room terminal of that type of system.
Products are classified by the degree of factory design, either factory-engineered or
custom-designed; and by the degree of factory assembly, such as single-piece, split-system, or
field-assembled component. The design of a factory-engineered system has the advantages of being tested before it is produced for sale and of continual improvement in response to product failures
of units previously manufactured. The fabrication of a factory-fabricated system has the
advan-tage of production using properly trained labor with the optimum tooling and materials, plus
quality testing of the finished product.
A single-piece, factory-engineered assembled unit is inherently the most reliable and least
expensive. Split-systems provide the ability to locate the elements in more appropriate locations,
but with the possibility of poor refrigerant piping connections. Factory-engineered package
equipment is usually designed for the mass market, with commensurate lower equipment price.
Field-assembled components provide the ultimate in design flexibility for projects with unusual
needs such as extremely low energy consumption or extremely high fabrication quality.
Products are classified by the type of condenser, either air-cooled, water-cooled, or
evapora-tive. Air-cooled units have greater electricity demand and consumption, but require much less
maintenance and do not require any makeup water, treatment, or disposal. The type of compres
-sor is usually part of the classification, such as reciprocating, scroll, rotary screw, or centrifugal.
Finally, products are classified by
the components in the product. A
condensing unit includes a condenser
and a compressor, in order to
con-dense the refrigerant that evaporates
in a remote DX cooling coil. A
pack-age water chiller is a complete
assembly of compressor, chiller, con
-denser, controls and wiring.
The CSI (Construction
Specifica-tions Institute) format is used by most
specification writers. The above
dis-cussion generally follows the CSI
classifications of HV AC equipment.
Introduction to HVAC
Indoor Unit AHU (Fan Coil)
Figure 17
Typical Components of Air-Cooled Split System
Indoor Unit Furnace And Coil
- - - -- - - -Turn to the Experts':
17
Summary
The HV AC industry is a challenging and diverse marketplace. The size of the market is huge considering the 4.9 million building base that might require some type of new HV AC system or
upgrade. Selection systems for this varied base can be complicated further by the multiple types
of systems that are available and the potential unique requirements of each building. Each partici-pant in the design process is critical in assuring properly functioning systems are delivered to building owners. Compliance with building codes and specifications are also the responsibility of
all members of the design and construction team.
The HV AC industry is an exciting business to be a part of. Customer requirements continu-ally evolve and drive industry standards. Designers, manufacturers, and contractors must constantly upgrade their knowledge to meet their customers' needs. The Technical Development Program series is presented to help all players in the industry to develop, maintain, and upgrade their skills in meeting customer needs.
«<f,M@
Introduction to HVAC
Turn to the Experts:·
Work Session
MARKETS
1. For the HV AC industry, identify the two market segments that are based upon the age of the buildings involved.
2. Identify the market segments that are based upon the usage of the building.
3. Identify the market segments that are based upon the type of design and contracting method.
PARTICIPANTS
4. Match the following participants in the HV AC industry:
Engineer Contractor Architect Owner Developer Commissioning Agent Dealer Service Contractor
Equipment Sales Distributor
Equipment Sales - -- - Representative
Building Operations
Manager Introduction to HVAC A. B. C. D. E. F. G. H. I. J. K.
provides the money and assumes the primary
finan-cial risk of the project.
provides the concept and business plan for the
pro-ject. May also provide the project management. provides the architectural design of the building, and coordinates the design services of the engineers and
other design specialists for the project.
provides the design services for technical portions of the project, such as HV AC, electrical, structural.
provide the construction work of purchasing and
in-stalling the items needed for the project.
places the equipment and systems in operation after they have been installed by others. A Test and Bal -ance Contractor is a commissioning agent.
operates and maintains the HV AC and other building
systems.
provides maintenance and repair service for the HV AC and other building systems.
handles the sale of equipment to the contractor. Usu-ally sells products manufactured by several different
manufacturers.
an equipment sales representative who provides local warehousing of products. Often provides training and marketing services for a dealer network.
a contractor with a formal ongoing relationship with an equipment distributor.
··-- ··-- ··-- ··-- ··-- ··-- ··-- ··--- - - -- - -- - - - -- - - -- - Turn to the Expert$.
INDUSTRY ASSOCIATIONS
5. What is ASHRAE's primary mission?
6. What is NFPA's primary mission?
7. What is UL's primary mission?
LEGAL CONCERNS
8. Which entity (contractor, engineer, equipment supplier, etc.) has the primary responsible for meeting the following requirements?
A. Building design codes
B. Building construction work codes C. Equipment construction codes D. Building licenses and pennits
9. What is a "national" building code or standard?
10. What is a "local" building code?
11. What are "Construction Documents"?
12. What is an Addendum to the construction documents?
13. Describe two ways of creating a contract to purchase HVAC equipment.
14. In question 13 above, why does it make any difference?
15. What is a Change Notice?
16. What is the purpose of an equipment submittal?
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Introduction to HVACTurn to the Experts:- - - -- - - - -- - -
TYPICAL PROJECTS
17. What are the 5 phases of a typical project?
18. Identify some reasons to become involved early in a project.
HV AC SYSTEMS
19. There are many different types of HVAC systems - direct expansion or chilled-water, central
or unitary, etc.; and many different applications - offices, hotels, residences, shopping
cen-ters, etc. Is any one of these types of systems better than all of the others for all of the
different applications?
20. What is a DX system?
21. What is a chilled-water system?
22. What is likely to be different if one type of HY AC system is chosen instead of another type?
23. What is a "single-zone" system?
24. What is a "multiple-zone" system?
HV AC PRODUCTS
25. Name some typical benefits of a "factory-engineered" product compared to a "custom
design" using standard components.
26. Name some typical benefits of a "factory-assembled" product compared to a "field assembly"
of components.
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Commercial HVAC Systems- - - -- - - - -Turn to the Experts:
27. Name an advantage of air-cooled equipment. 28. Name an advantage of water-cooled equipment.
HV AC DESIGN PROCESS
29. Why might a system designer be reluctant to change the concept of a system after it has been
agreed upon?
30. Why might a system designer be reluctant to change the selection of HVAC equipment after
it has been done?
31. Why might a system designer be reluctant to change the construction documents for a system
after they have been issued?
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Introduction to HVACTurn to the Experts:· - - - -- - -
Notes
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Work Session Answers
MARKETS 1. A. New Construction B. Existing Buildings 2. A. Residential B. Commercial C. Office D. IndustrialE. Institutional (schools, hospitals, prisons)
3. A. Design/build
B. Plan and specification
PARTICIPANTS
4. Describe the following participants in the HV AC industry:
D Engineer K Dealer
E Contractor H Service Contractor
C Architect J Equipment Sales Distributor
A Owner I Equipment Sales Representative
B Developer G Building Operations Manager
C Commissioning Agent
INDUSTRY ASSOCIATIONS
5. create HVAC design information 6. create fire and smoke safety standards 7. test products for safety
LEGAL CONCERNS
8. A. Building design codes the designer of the item or system involved, usually the architect
and engineer
B. Building construction work codes contractor C. Equipment construction codes equipment supplier
D. Building licenses and permits contractor
9. A design or construction code prepared by a national code authority, such as ICC, UL,
ASHRAE, NFP A, NEC, etc. .
10. A legal document enacted by the local governing body, such as a city, county or state, that
describes the minimum requirements for building construction. A local code usually "refers"
to the various national codes and standards, instead of copying the items into the local
document.
11. Drawings and specifications prepared by the designer of a project to describe the construction work. They are used to obtain building permits and as the basis for construction contracts. 12. a document issued by the designer to describe a change in the drawings or specifications
13. A. The buyer accepts a proposal from a seller
B. The seller accepts a purchase order from a buyer
14. The "terms and conditions" of a purchase order usually favor the buyer, while those of a
proposal usually favor the seller.
15. A revision to the contract in which the contractor agrees to make the changes described in an Addendum in return for an agreed upon change in the contract price.
16. It is to confirm that the equipment to be furnished is in conformance with the construction
documents. The objective is to avoid the project delay and expense that will result if the
«fMQ
i
- - - -Commercial HVAC Systems Turn to the Expert&
wrong equipment is shipped to the job site and must be removed and replaced at the
supplier's expense.
TYPICAL PROJECTS
17. A. Organize: decide who does what
B. Concept: decide what is to be built and the appropriate budget
C. Design: determine capacity, arrangement and construction detail
D. Construction: Build and commission the project E. Warranty and Service: Prevent or correct problems
18. A. If you have done good work with one of the organizers (owner, engineer, contractor) on a
previous project, they can influence the others to favor you when close decisions must be made.
B. You may be able to identify situations, which would place you at a competitive disadvan-tage, and suggest changes to improve your position without hurting the overall cost or performance of the project.
HV AC SYSTEMS 19. NO
20. A system in which refrigerant circulates "directly" through the cooling coil.
21. A system in which a water chiller is ·used to cool water. The chilled-water is circulated
through the cooling coils in the air-handling units.
22. A. functional performance: temperature, humidity, air quality and sound level
B. costs: design and construction, energy consumption, water and water treatment, operation
and maintenance
C. space: for duct, piping, equipment rooms D. architectural appearance
23. A system that serves an area with one thermostat.
24. A system that serves several different areas and provides a separate temperature control zone
for each area.
HV AC PRODUCTS
25. less design cost, less chance of design errors
26. lower cost because of tooling and production quantity; better quality because of better
supervision and testing.
27. no water consumption or chemical water treatment is necessary 28. lower electricity consumption
HV AC DESIGN PROCESS
29. The other designers, such as the architect or electrical engineer, may have to change work they have already done in order to accommodate the new concept.
30. The designer will not be paid for the time required to make the change, and there is risk that this change will require changes to other items that have already been completed.
31. Addendums are time consuming and expensive. They also raise the issue of who is to blame for the change.
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Introduction to HVACTurn to the Expert$.- - - -- -- - - -- -- - --
-26
Glossary
addendum air-water system all-air system all-water system architect ARI ASHRAE building operations manager change notice commissioning agent construction management construction manager contract contractor dealerschange or addition to the construction documents for a project
an air conditioning system that controls space conditions by supplying a
combination cooled and dehumidified, heated, or neutral, and
conditioned air and chilled or heated water from a conditioning unit and
central plant equipment located outside the conditioned zone.
an air conditioning system that controls space cooling . conditions by
supplying cooled, dehumidified, and conditioned air to the zone from a
conditioning unit normally located outside the conditioned zone; heated air may also be provided for heating control.
an air conditioning system that controls space cooling conditions by
supplying chilled-water to the zone from a chiller outside the
conditioned zone; heated water may also be provided for heating control.
participant in a typical construction project who provides the building
design services; when employing the engineers is called Architect/
Engineer
Air Conditioning and Refrigeration Institute; concerned with creating standards for testing and rating equipment; provides marketing statistics for air conditioning equipment manufacturers
American Society of Heating, Refrigerating, and Air Conditioning engineers; organization concerned with creating information for the design of projects; publishes the ASHRAE handbook and establishes minimum standards that influence project design
responsible for the operation and maintenance of the HV AC system revision to the contract between the owner and the prime contractor employed by the owner to provide an objective perspective to correct errors made during construction
delivery method where an oversight contractor controls the design,
bidding, and construction activities, most often paralleling the sequence
used in plan and spec
participant in a typical construction project who is responsible for coordinating the construction activities that must begin before the prime contract is awarded and continues until the project is complete; common in a "fast-track" schedule
legal agreement between the participants of a project; can be created by a
purchase order, or proposal
participant in a typical construction project who provides the construction work
independently owned contractors who are franchised by distributors to
install equipment purchased from the distributor; this arrangement may
require the deal to be exclusive
«<ii@•
- - - - -Turn to the Expert$.Commercial HVAC Systems
design-build developer direct expansion (DX) distributor engineer equipment replacement project equipment supplier fast-track schedule ICC
Multiple wne system
new construction market NFPA owner Performance Contracting Plan and Specification
«<fihi+
delivery method where building systems performance criteria are
documented in a minimal set of drawings and text; contractors bid on the
completed building, finished the design while executing the requirements, and then tum over a completed project
participant in a typical construction project who provides the concept and the business plan and typically manages the overall project;
commonly the same entity as the owner and referred to as owner/developer
cooling process in which the refrigerant is used directly in the indoor coil.
buys equipment in large quantities from a manufacturer and resells the to dealers or independent contractors
participant in a typical construction project who design the HVAC,
structural, electrical, plumbing, and other trades in their specialty; when employed by the architect is called Architect/Engineer
subcategory of the replacement market in which some or all of the major HV AC equipment is replaced
handles the sale of the equipment for a project
construction project schedule typical of large or critical projects in which
the major equipment is purchased and the construction work is begun before the overall project design is completed
International Code Council; association dedicated to building safety and
fire prevention; develops codes used to construct residential and commercial buildings; has replaced other model code writing
organizations
an HV AC system with multiple thermostats controlling temperatures in various spaces served by a single air-handling unit
market consisting of projects in which the HVAC system is installed
when the building in originally constructed
National Fire Protection Association; writes standards,;addresses
building fire and smoke concerns
participant in a typical construction project who provides the money for
the construction and assumes most of the financial risk; commonly the same entity as the developer and referred to as Owner/Developer
Delivery method where an oversight contractor controls the design, bidding, and construction activities of a normally focused set of upgrades
or retrofits to an existing building
delivery method where building systems criteria are documented in a set of construction drawings and specifications that are bid by contractors who then execute the requirements and tum over a completed project
Introduction to HVAC
TurnroilieExperts:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
prime contractor project manager reference standards replacement market service contractors subcontractor test and balance contractors UL
participant in a typical construction project responsible for coordinating all construction activity and other contractual items relating to project cost and timing; often the general contractor but may be a subcontractor if most of the work is in their specialty
-participant in a typical construction project responsible for coordinating the entire project, including design and construction work
standards created by organizations such as ARI arid ASHRAE that govern the design, manufacture, and installation of HV AC equipment and systems
market consisting of projects in which a previously installed system or equipment is replaced
provide either preventative maintenance or emergency repairs after the system is operational
participant in a typical construction project who has a contract with the prime contractor or a higher-level subcontractor
specialists in measuring air and water flows and checking the performance of equipment after it is placed in service
Underwriters' Laboratories; concerned with product safety requirements; a UL label denotes that equipment has been tested to comply with safety standards
«<flip
Commercial HVAC Systems
- - - -- - - -- - - -TurntotheExperti.
References
2003 International Building Code. Copyright 2002. Falls Church, Virginia: International Code
Council, Inc.
2003 International Energy Conservation Code. Copyright 2003. Falls Church, Virginia:
Interna-tional Code Council, Inc.
2003 International Mechanical Code. Copyright 2003, Falls Church, Virginia: International Code
Council, Inc.
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Introduction to HVACTurntotheExpertS:- - - -- -- -- - - -- -- - -
None
Learning Objectives:
After reading this module, participants will be able to:
Describe the commercial and how its market is served.
Describe the participants in the construction process and total HVAC life cycle influencers in the various market categories.
Understand the steps in the construction process of typical commercial projects.
Describe the commercial new construction process and influencers, plan and specification and design build.
Describe the commercial retrofit, replacement and renovation market and how they are in-fluenced by the construction process and decision makers.
Understand how codes and regulatory influences impact building decision.
Be able to identify how different industry organizations influence HVAC design. Understand how influencers and regulatory influences affect system selection.
Understand how various players in the process can work together.
Appreciate who does what design in each method of going to market and know when it is their turn to perform.
Supplemental Material:
Book TOP No. Cat. No. TDP-701 796-067 Instructor Information Instructor CD Cat. No. 797-067 Title System Selection
Each TDP topic is supported with a number of different items to meet the specific needs of the user. Instructor materials consist of a CD-ROM disk that includes a PowerPoint™ presentation with convenient links to all required support materials required for the topic. This always includes: slides, presenter notes, text file including work sessions and work session solutions, quiz and quiz answers. Depending upon the topic, the instructor CD may also include sound, video, spreadsheets, forms, or other material required to present a complete class. Self-study or student material consists of a text including work sessions and work session answers, and may also include forms, worksheets, calculators, etc.
Form No. TDP-101
Supersedes Form No. TDP-50
Carrier Corporation Technical Training