Building Codes

ContentsAnalysis of the organization, intent and use of codes in general and the International Building Code IBC in particular

Reasons why the codes exist and how they form an integral part of the design criteria for every building project.

The more you know about the code, the more it can become a tool for design rather than an impediment. The better the underlying criteria for code development and the reasons for code provisions are understood, the easier it is to create code-compliant designs.

Early understanding and incorporation of code-compliant design provisions in a project reduces the necessity for costly and time-consuming rework or awkward rationalizations to justify dubious code decisions late in project documentation, or even during construction.

Brief History

If a builder builds a house for someone, and does not construct it properly, and the house which is built falls in and kills its owner, then that builder shall be put to death. (Hammurabi’s Code of Laws, ca. 1780 BC)

Chicago developed a building code in 1875 to placate the National Board of Fire Underwriters who threatened to cut off insurance for businesses after the fire of 1871.

The first model codes were written from the point of view of insurance companies to reduce fire risks. Model codes are developed by private code groups for subsequent adoption by local and state government agencies as legally enforceable regulations.

Three Model-Code Agencies

The first major model-code group was the Building Officials and Code Administrators (BOCA), founded in 1915, currently located in Country Club Hills, IL

The International Conference of Building Officials (ICBO) was formed in 1922, presently located in Whittier, CA. The first edition of their Uniform Building Code was published in 1927.

The Southern Building Code Congress International (SBCCI) was founded in 1940, Birmingham, AL. They publish the Southern Building Code.

The ICBO Uniform Building Code was used West of Mississippi

The BOCA National Building Code was used North-central, North-east

The SBCCI Standard Building Code was used Southeast

International Code Council and the IBC

International Code Council (ICC) was formed in 1994 with representatives from three major model-code groups. Their first achievement, despite differences, was that the organization of each code became the same, thus allowing direct comparisons.

International Building Code (IBC) published and maintained by representatives of three agencies, the International Code Congress, in Falls Church, VA

In addition

International Residential Code (IRC)

Americans with Disabilities Act (ADA). It is a federal civil-rights legislation, an enforced law, rather than just a code. ADA Accessibility Guidelines (ADAAG)

Federal Fair Housing Act (FFHD)

Adoptions of Codes by States, Counties and Cities

The three major regional differences still exist. For instance, until the IBC was adopted, Georgia adopted more codes according to the Standard Building Code

Larger cities such as Los Angeles, New York City, Chicago and San Francisco adopt many revisions to the model codes, sometimes having no basis on the model-codes.

It is imperative to check first what kinds of codes or regulations are adopted by the county, city or the state in which the project is located.

Specialized Codes | the AHJs

Life Safety Code (NFPA-101) published by the National Fire Protection Association. This codes serves as the basis for the egress portion of other model codes. Hospital and federal projects use NFPA-101.

Fire codes are typically considered maintenance codes. They are intended to provide for the public safety and the daily operation of a structure.

Planning, zoning, fire and building officials that have something to say about building are known as Authorities Having Jurisdiction (AHJ). Often, there are overlapping or duplicity of jurisdictions.

It is imperative to determine first which codes and standards are to be enforced for a project and by which agency.

Legal Basis for Codes | Standard of Care | Priorities

The model codes have no force of law unto themselves. Only after being adopted by a governmental agency, do they become enforceable under the police powers of the state, county or city.

Determine what kinds of construction require application of code. Some remodeling work is exempt from code regulations.

One exception is the ADA which is a civil-rights law and is not enforced by building officials, while still not relieving the owner from obligations under the ADA.

Codes are legally and ethically considered to be the minimum criteria to be met.

The basis for building-code development is the safeguarding of the public, while having a strong component of property protection. Sprinklers help both public and buildings. Security measures against burglary might interfere with life safety of occupants.

Future Trends | Performance vs. Prescriptive Codes

At the present condition, the IBC is prescriptive in nature. It is developed to mitigate concerns by creating specific and prescribed responses to problems that have been identified. For instance, an assumed problem is falling over an edge higher then 30” above the adjacent grade. The solution – guardrails of 42” height are required for differences in grade exceeding 30”. Note: a handrail is not a guardrail.

Performance codes define the problem and allow the designer to devise a solution. The word ‘performance’ refers to the problem definition and to setting parameters for deciding if a solution solves the problem. For instance, ‘the building shall allow all of its prospective occupants to safely leave the building in case of fire’. The language of modern performance based codes is an objective-based one.

Objective: What is to be accomplished? (Example, prevention from falling 30”)

Functional Statement: Why do we want this? (We want to safeguard occupants from accidentally falling from a height that might result in injury)

Performance requirement: How is this to be accomplished? Guardrails. (might become prescriptive)

2 | Navigating the CodeThe key word to remember about how all building codes are developed and how they work is intent. The intent of the author of a building code section is to solve a specific design problem with prescriptive words.

Designers also have intent as they are trying to achieve certain functional or formal goals in the design of the building. Designers should measure their own intent for the design against their interpretations of the intent of the code. When examined together, the intent of the code and that of the design solution should be concurrent.

The responsibility for understanding, applying and fulfilling the requirements of the code always rests with the design professional. Approvals by the AHJ do not relieve the designer of social and licensing responsibilities to maintain the health, safety and welfare of society.

Intent and Interpretation

Each section of the code was developed to solve a certain problem.

Sections are organized into chapters based upon common themes, but usually are developed in isolation from one another with little attention to continuity of the whole document.

Code language usually arises from a specific issue the code writer wishes to address based on experience or upon a construction or life safety issue. The writer then makes the requirements general so that they apply to more typical conditions than the specific instance that generated the concern.

The intent of the code is a crucial idea to understand. Why is a much more important question that what when you are puzzled by the actual language of a code passage.

Do not try to memorize passages from the code, rather learn the organization of the code.

Alternate Means and Methods

The alternative is to be approved when “the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in the code in quality, strength, effectiveness, fire resistance, durability and safety. ( § 104.11)

Alternate Means

and Methods

Code interpretations

Designers and code officials approach interpretations from quite different perspectives.

The designer is trying to make his design solution compliant with the code while satisfying project requirements.

The AHJ examines the solution for compliance with the code being unaware about the practical requirements of the building design.

When differences occur, the designer and AHJ work together to reconcile the intent of the design solution with the intent of the code

Documenting Code interpretations

Every project should receive a detailed code analysis that is recorded as a permanent part of the permit documents

All code interpretations and citations should have a reference to the code sections in order to allow retracting steps in the code analysis

This figures shows the minimum required items

Also, site plan, floor plan, detail egress requirements, exit discharge paths, exit quantities and locations.

Using the Code

1 Classify the building according to occupancy, type of construction, location of property, floor area, height and number of stories.

2 Review the building for conformity with occupancy requirements

3 Review the building for conformity with the type of construction requirements

4 Review the building for conformity with egress requirements

5 Review the building for other detailed code regulations

6 Review the building for conformity with structural engineering regulations and requirements for materials of construction

A B C D E

1A Occupancy Classification

Determine the occupancy group that the use of building or portion thereof most nearly resembles.

Compute the floor area and occupant load of the building or portion thereof.

See appropriate sections in Chapter 3 for buildings with mixed occupancies.

Classifying the Building

1B Type of Construction

Determine the type of construction by the materials used and the fire-resistance of the parts of the building.


1C Location on Property

Determine the location of the building on the site and clearances to property lines and other buildings from the plot plan.

Determine the fire-resistance requirements for exterior walls and wall-openings requirements based on proximity to property.


1D Allowable Floor Area

Determine the allowable floor area of the building.

Use basic allowable floor area (tabular area) based on occupancy group and type of construction.

Determine allowable floor area of multistory buildings.

Determine allowable increases based on location on property and installation of an approved automatic fire-sprinkler system.


1E Height and Number of Stories

Compute the height of the building and determine the number of stories.

Determine the maximum height and number of stories permitted based on occupancy group and type of construction.

Determine allowable height and story increase based on the installation of an approved automatic fire-sprinkler system.


Occupancy Type

Projects are almost always defined based on occupancy type. A client asks a designer for facility with a defined need. The use of that facility determines the occupancy group to which it belongs.

Each occupancy group has specific requirements related to allowable area, height and means of egress with potential construction types growing out of these requirements.

The codes are fundamentally use (occupancy) based.

Chapter 3 includes the definitions about occupancy classification

Code Components

Construction Type

Construction types are categorized with regard to their resistance to fire in structural applications.

Construction type gives some indication about the amount of time available for evacuation. (wood, steel, reinforced concrete). More resistant construction types are allowed to have more occupants, larger area, and more stories.

Rule of thumb: occupancy quantities and construction costs will both decrease with building type from Type I to Type V.

Chapter 6 and Table 601 gives a synopsis of the minimum fire requirements of each main construction element

Code Components

Building or Floor Area

After one knows the occupancy group and construction type, it is important to establish the permissible area for each floor, for each use and for the entire building.

Some types of construction are limited in size based on occupancy and concentration of people.

Allowable height and areas are tabulated in Table 503.

Section 506 shows allowable increases based on location on the property and allowance for installation of automatic fire-sprinkler systems.

Code Components

Exits / Egress

Determining egress requirements and provision of safe means of egress is one of the most important functions of building codes.

There are specific requirements for size, spacing and travel distances for all components such as floor plans, doors, corridors and stairs.

In simple terms a means of egress consists of three main components: an exit access, an exit and and exit discharge.

Code Components

Building Separation and Shafts

In case of mixed occupancies, codes require fire-rated partitions separating the occupancies.

Separations may also be used to allow more area for a particular occupancy on a single floor in certain types of construction where otherwise such sizes of use would not be permitted.

Openings between floors such as for stairs, elevators and mechanical shafts can allow the passage of smoke, heat and flames. Hence, codes have requirements based on occupancy, building type and building height related to shaft protection.

Chapter 7

Code Components

Fire Protection

Fire protection is divided in two broad categories passive or active protection.

Passive protection is the one built into the structure, either inherent or added as part of protective membranes (wood, steel, reinforced concrete – combustible or non-combustible)

Active protection is the one where the fire causes a reaction in the systems that serve to combat the fire (e.g., sprinklers). Code analysis and design often includes trade-offs between active and passive systems.

to be continued

Code Components

Fire Protection Standards continued

Fire Resistive Standards Include:

1 Structure Hour Rating: Requirements of how long it takes for a fire to weaken a structural element to the point of failure. Minimum time for evacuation and fire-fighting response.

2 Area or Occupancy Separation Rating: Requirements of how long it will take for a fire to penetrate a wall partition, floor or roof assembly.

3 Flame Spread and Smoke Generation:

Requirements of how long it takes a fire to move along the surface of the building and how much and what toxicity of smoke is generated.

Chapters 7 and 8

Code Components

Fire Extinguishing Systems

Fire sprinklers, standpipes, fire detection and fire-alarm systems are an integral part of many buildings. Use of such systems often results in trade-offs for additional height or area.

Trade-offs only apply when the systems are not otherwise required by the code. The idea of a trade-off recognizes that this is a mitigation measure over and above basic code requirements to achieve the desired level of safety different from those spelled out in the code.

Chapter 9

Code Components

Engineering Requirements

One of the bases of codes is structural adequacy of building for both static loading such as occupants and equipment as well as dynamic loading such as earthquakes, snow and wind

Chapters 16-18 deal with forces, inspections and foundations

Chapters 19-23 deal with materials: concrete, lightweight materials, masonry, steel and wood.

Code Components

Every Project, no matter how small , should have a code analysis performed!

Wherever possible consult with the building department and other Authorities Having Jurisdiction prior to design.

Do not expect the code official to do the analysis work for you. Remember, compliance is the responsibility of the designer, not the code official.

However, codes are subject to interpretation. So it’s always in your best interest to determine what, if any, interpretations will be needed for a project.

REMEMBER: DO NOT TRY AND MEMORIZE PARTS OF THE CODE!!! As sections change and interpretations alter meanings, such memorization is a recipe for future trouble.

Clients may expect you to rattle off code requirements, but it’s not in the best interest of project or client to do so and possibly make”snap” code decisions.

DO NOT PROCEED ON MEMORY OR ANALOGY FROM OTHER JOBS! Remember where to look up information and check your decisions each time you apply them.

Even seasoned code professionals use the index to locate familiar phrases and locations of information, especially since items are often relocated as the code evolves.

Code Analysis

Building Codes

Documents

Transcript of Building Codes