An Introduction To Building Information Modeling

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An Introduction To
Building
Information
Modeling (bim)

A Guide for ASHRAE Members

Revised November 3, 2009

Table of Contents

Foreword ………………………………………………………………………………………………………….. 3

BIM Terminology and Narrative Definitions ………………………………………………………… 5

The Benefits of Building Information Modeling …………………………………………………… 8

Getting Started with BIM ………………………………………………………………………………….. 13

What Others are Doing and How to Get Involved ………………………………………………. 17

The Future ………………………………………………………………………………………………………. 19

Conclusion ……………………………………………………………………………………………………… 22

Additional Reading Suggestions ……………………………………………………………………… 23

References ……………………………………………………………………………………………………… 24

Appendix A—BIM Software Guide ……………………………………………………………………. 25

BIM Steering Committee
Charles S. Barnaby
Dave Conover (Chair)
Chuck Gulledge
Dru Crawley
Rob Hitchcock
Stephen Hagan
Steven Rosen
Dennis Knight

Additional Contributors
To this Guide

Brian Emtman
Gordon Holness
Don Iverson

Mark Palmer
Chris Wilkins

© 2009 American Society of Heating Refrigerating and Air-Conditioning Engineers, Inc.
1791 Tullie Circle, N.E., Atlanta, Georgia 30329
www.ashrae.org
All rights reserved.

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Foreword

T his Guide is intended to provide ASHRAE members with an introduc-

tion to Building Information Modeling and Building Information Models
(both known as “BIM”). It is intended to serve as a starting point for those
members considering adopting BIM tools and applications as part of their busi-
ness practices. BIM is about integrating design and construction processes, about
making them interoperable, and about the software tools needed to achieve that.
It explores the benefits, costs, risks and rewards associated with BIM, interoper-
ability and integration. In addition, for those members already applying BIM and
BIM-related technologies, it may provide ideas to help them expand their services
into new markets and unearth new opportunities.

The Guide identifies the current state-of-the-art of the industry with respect to
software applications and related protocols, and provides additional resources and
suggested reading material for members planning a transition to BIM. Because of
the rapid evolution of technology, the Guide is intended to be a living document,
and ASHRAE members are encouraged to share their experience to help update
and improve it over time.

The greatest value of Building Information Modeling to the construction industry
and to ASHRAE members may be its potential to reduce cost, increase productivity,
reduce errors and improve the quality of our work products and to improve the built
environment. As such, it can be a valuable tool in facilitating successful collabora-
tion and coordination during pre-design, design, construction, and operation and
maintenance of both new and existing buildings.

BIM applications will be essential to successful Integrated Building Design (IBD)
and Integrated Project Delivery (IPD). IBD and IPD will also play a critical role
in achieving our goals of reducing energy use, minimizing waste and delivering
better buildings.

BIM will also be valuable to creating a sustainable built environment.
Sustainability is a major focus of the Society as noted in its Strategic Plan and in
all subsequent developments—Vision 2020, Standard 189.1 (High Performance
Green Building Standard), Standard 90.1, the Advanced Energy Design Guide
series (AEDGs), and every other publication and initiative we develop as we aim
toward producing net-zero energy* buildings.

ASHRAE will play a significant role in the evolution of BIM and integration in
the built environment by committing the resources and developing specific goals
to establish comprehensive, consistent HVAC&R terminology, data dictionaries,
rule sets, and schema for its Handbooks, Standards and Guidelines to support the
HVAC&R and building industry. The establishment of an ASHRAE Building In-
formation Modeling and Interoperability Steering Committee (The BIM Steering
Committee) under the Society’s Technology Council is an excellent start. It indicates
recognition by ASHRAE of the role this technology can play in the development
of better buildings.

As new educational programs, technical papers, and other publications are
developed by ASHRAE and others, there is a need to be cognizant of the bigger
picture and the new methods for the design and delivery of high-performance
and sustainable built environment. BIM, interoperability and integration will sig-
nificantly impact almost everything ASHRAE and its members do, as a technical

* See ASHRAE Vision 2020 at: www.ashrae.org/vision2020 for the ASHRAE Vision 2020 Ad Hoc Committee.1

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A n I n t r o d u c t i o n t o B u i l d i n g I n f o r m a t i o n M o d e l i n g ( B I M )

society or as engineers, including the processes of developing, delivering and using
ASHRAE standards and guidelines.

It is a goal of this guide that by reading this material a “light” will come on and
the reader will realize some aspects of that integration already exist in much of
what we do every day, and that BIM, integration and integrated practice can be
implemented now without waiting for someone to “finish it first.” It will never be
finished. There will always be room for improvement and innovation. If we wait,
we will just get left behind.

Return to Table of Contents

A n I n t r o d u c t i o n t o B u i l d i n g I n f o r m a t i o n M o d e l i n g ( B I M )

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BIM Terminology and Definitions

T o explain the benefits and opportunities offered by BIM and integration,

it is essential to develop a consistent vocabulary and set of definitions as
a basis for the discussion.

The following definitions are given in the context of their use in this Guide.
Definitions used in this document are presented to promote understanding in a nar-
rative fashion and in a manner such that they build upon and support one another
in the description of BIM, integration and interoperability. They are not presented
in alphabetical order and do not try to describe every possible use of the word or
term. Where the definition has been taken or adapted from a dictionary or other
published material, the specific reference is indicated at the end of this Guide.

Building
Information
Model

A Building Information Model is a digital representation of the physical and the
functional characteristics of a facility. As such it serves as a shared knowledge
resource for information about a facility, forming a reliable basis for decisions
during its life cycle from inception onward.2 Creating a BIM is different from
making a drawing in 2-D or 3-D CAD (see subsequent definitions). To create a
BIM, a modeler uses intelligent objects to build the model.3

Building
Information
Modeling

3-D BIM

Building Information Modeling is the human activity of using BIM software and
other related software, hardware and technologies to create and use in a building
information model.4

See the definition of Building Information Model. A model that includes three
dimensional (3-D) shape information and does not include the 4-D and 5-D char-
acteristics described below.

4-D BIM

A 3-D BIM that has objects and assemblies that have schedule and time constraint
data added to them. The information can be contained in the BIM or can be linked or
otherwise associated (integrated and/or interoperable) with project design and con-
struction activity scheduling and time sensitivity estimating and analysis systems.3

5-D BIM

A 4-D BIM that has objects and assemblies that have a cost dimension added to
them. The cost information can be contained in the BIM or can be linked or oth-
erwise associated to the building objects.3

2-D/3-D CAD

Two dimensional or three dimensional, Computer Aided Drafting is equivalent
to conventional drafting, only performed on a computer. Unintelligent points,
lines and symbols are used to convey design intent or detail construction means
and methods. Most often plotted onto paper media and published in that form for
drawings and specifications and delivered to the owner, contractor and reviewing
authorities and agencies for approval and actual construction.3

Parameter

A quantity that is constant under a given set of conditions (rule set), but may be dif-
ferent under other conditions. For example: a duct penetrates a non-rated steel stud
and gypsum board wall, and the annular space of the penetration is sealed only with
caulk. If you change the wall to a 2-hour rated concrete fire barrier (new parameter)
the duct still penetrates the wall, but in a different way, with a UL listed fire damper.5

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Intelligent Object

The object (or set of objects) represents not only the geometry required to rep-
resent the component or assembly graphically (visually) but also has the ability
to have much more information about that object associated with it or related to
other intelligent objects associated with it. Think of the geometric parameters of
the object as being only one of many fields in a database that describes the visual
features and characteristics of the object. Other parameters might include variables
such as how the object may change (a rule set) when something with which it is
associated changes. For example, if a relationship is established between a duct
and a diffuser that are connected in the model and assigned a specified airflow and
the modeler (engineer, designer, etc.) decides to change the specified airflow of the
diffuser then the duct size and diffuser, neck size automatically (parametrically)
are adjusted to accommodate the new specification, and pressure loss calculations
throughout the entire duct system are automatically updated at the same time.

Parametric

Rule based relationships between intelligent objects that enable related properties
to be updated when one property changes.

Integrated

Integrated data processing is that which has been organized and carried out
as a whole, so that intermediate outputs may serve as inputs for subsequent
processing with no human intervention. The same can be said for any human
activity or process (see integrated practice). Note that integrated and interop-
erable are not mutually exclusive, but they can be. A system or process can
be integrated within its own boundaries, yet still not be interoperable with
other external systems or processes that could benefit from the use of data or
information contained within the first system.5

Human activities and data processing—The incorporation of working practices,
methods, processes, and tools that creates a culture in which individuals and orga-
nizations are able to work together efficiently and effectively.4
Uses early contributions of knowledge through utilization of new technologies,
allowing Architects (Engineers, Owners, Contractors, Manufacturers, Firms,
Individuals, Communities) to realize their highest potential as designers and
collaborators while expanding the value they provide throughout the project life
cycle (adaptation of definition in original publication cited). Essential to integrated
practice is the elimination of waste and duplication by capturing knowledge and
information one time, using it for any purpose necessary without losing it in the
process and adding to it (creating new knowledge) over time.4

Integration

Integrated Practice

Interoperability

In the context of BIM, IBD (Integrated Building Design) and IPD (Integrated Project
Delivery), defined as the ability to manage and communicate electronic product
and project data between collaborating firms’ and within individual companies’
design, procurement, construction, maintenance, and business process systems.6

Data Exchange
Specification

Data Exchange
Standard

An electronic file format specification for the exchanging of digital data. They can
be proprietary or open source and can be developed and promulgated by anyone.

A data exchange specification developed and balloted by a standards developing
organization for the purpose of standardizing electronic data transmitted between
different software applications.

IFC

Industry Foundation Classes (IFC) is a vendor neutral, open data exchange speci-
fication. It is an object oriented file format developed for the building industry and
is commonly used in Building Information Modeling to facilitate interoperability
between software platforms. IFC was originally developed in 1995 by a group of
American and European AEC firms and software vendors through the International

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Alliance for Interoperability (IAI). Since 2005 it has been maintained by building
SMART International.7

XML

Extensible Markup Language (XML) is a general-purpose electronic text tagging
specification for creating custom markup languages. XML was recommended by
the World Wide Web Consortium (W3C) as an internet standard in 2008. It is classi-
fied as an extensible language, because it allows the user to define the markup tags.
XML’s purpose is to aid information systems in sharing structured data, especially
via the Internet, to encode documents, and to serialize data. XML is a free and
open standard. There are many extensions and proprietary adaptations that exist.

gbXML

The Green Building XML schema (gbXML) was developed to facilitate the trans-
fer of building information stored in CAD building information models, enabling
integrated interoperability between building design models and a wide variety of
engineering analysis tools and models available today. gbXML has the industry sup-
port and wide adoption by the leading CAD vendors and HVAC software vendors.
With the development of export and import capabilities in several major engineering
modeling tools, gbXML has become a defacto industry standard schema. Its use
dramatically streamlines the transfer of building information to and from engineer-
ing models, eliminating the need for time consuming plan take-offs. This removes
a significant cost barrier to designing resource efficient buildings and specifying
associated equipment. It enables building design teams to truly collaborate and
realize the potential benefits of Building Information Modeling.

LCA

Life-Cycle Assessment is the process of evaluating a component, product, assembly,
building, etc., and their development from the moment of extraction of raw materi-
als, transportation, processing, manufacturing, use, recyclability and disposal and
assigning a value or assessment of its cumulative and ultimate social, environmental
and economic costs, benefits and impacts. This is often referred to as a “cradle to
grave” or “cradle to cradle” assessment.

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A n I n t r o d u c t i o n t o B u i l d i n g I n f o r m a t i o n M o d e l i n g ( B I M )

The Benefits of Building Information

T o understand the benefits of BIM to our industry and ASHRAE, we must

explore some of the global benefits of BIM and discuss the direct benefits
to ASHRAE and its members of embracing and adopting BIM, integration

and interoperability.

Globally one of the great advantages of Building Information Modeling is the
ability to create an accurate model that is useful throughout the entire life of the
building, from initial design through occupancy and operation (see definitions).
Ideally, a BIM would be created in the early stages of the design, updated as the
design is refined and used by the construction team, and refined continuously as
the facility is built. Post-occupancy, the BIM would be used by the owner and
owner’s maintenance team to improve understanding of building operation and
to make adaptations, renovations, additions and alterations to the building faster
and for less cost than through traditional processes. Future benefits may include
linking manufacturers’ R&D databases, which will be discussed later in this guide.
In addition, operating level BIMs may be linked through integrated and interoper-
able pipelines to local and national emergency response and disaster management
systems to help improve life-safety, save lives and mitigate damage.

The power of BIM can be realized though its ability to allow the whole building
to be optimized in lieu of optimizing individual components. Each discipline and
trade benefits through integration and optimization within a BIM and becomes
more efficient by providing parametric responses to single discipline changes
through the use of consistent data sets for calculation and decision making. The
work of the HVAC industry has an impact on every other design and construction
discipline and trade including the following: architecture, electrical engineering,
lighting design, roof and envelope consultation, food service, fire protection, civil
engineering, structural engineering, security consultants, acoustical engineering
and others. BIM can benefit these associated and complimentary disciplines and
trades through precise interdisciplinary coordination using parametric geometric
modeling. However, much of the existing software, such as load calculation, plumb-
ing, piping, lighting design and life-cycle assessment tools, only receive input data
from the BIM at this time and are not fully parametric. Software and hardware
developments that will allow adjustments and fine tuning of the calculations via
changes in the BIM and vice versa that would result in optimizing the BIM in real
time will be available in the near future.

The benefits of BIM are evident in its capability of capturing, organizing, integrat-
ing, maintaining and growing the vast amount of knowledge, data and information
required to conceive, plan, design, construct, operate, maintain, adapt, renovate and,
finally, beneficially deconstruct a building at the end of its life cycle.

The HVAC&R industry impacts building owners, users, regulatory agencies,
legal, finance, operation and maintenance, the environment, and community. BIM
can benefit project participants and these entities through improved multidiscipline
collaboration to achieve optimal solutions, interference checking prior to construc-
tion, reduced errors and omissions, automated code/regulatory reviews, accelerated
permitting, and earlier beneficial occupancy, leading to enhanced return on invest-
ment (ROI) for the building owner/developer.

Real-time monitoring of a building’s temperature, humidity, ventilation, air
quality, pressurization, isolation, compartmentation, and occupant location inte-
grated into the BIM can benefit first responders in public health, safety, fire, law