International Existing Building Code 2009 (IEBC 2009)

Chapter 1 Scope and Administration

Chapter 2 Definitions

Chapter 3 Prescriptive Compliance Method

Chapter 4 Classification of Work

Chapter 5 Repairs

Chapter 6 Alterations - Level 1

Chapter 7 Alterations - Level 2

Chapter 8 Alterations - Level 3

Chapter 9 Change of Occupancy

Chapter 10 Additions

Chapter 11 Historic Buildings

Chapter 12 Relocated or Moved Buildings

Chapter 13 Performance Compliance Methods

Chapter 14 Construction Safeguards

Chapter 15 Referenced Standards

Chapter A1 Seismic Strengthening Provisions for Unreinforced Masonry Bearing Wall Buildings

Chapter A2 Earthquake Hazard Reduction in Existing Reinforced Concrete and Reinforced Masonry Wall Buildings With Flexible Diaphragms

Chapter A3 Prescriptive Provisions for Seismic Strengthening of Cripple Walls and Sill Plate Anchorage of Light, Woodframe Residential Buildings

Chapter A4 Earthquake Hazard Reduction in Existing Woodframe Residential Buildings With Soft, Weak or Openfront Walls

Chapter A5 A5 Earthquake Hazard Reduction in Existing Concrete Buildings

Appendix A Guidelines for the Seismic Retrofit of Existing Buildings

Appendix B Supplementary Accessibility Requirements for Existing Buildings and Facilities

Appendix B Supplementary Accessibility Requirements for Existing Buildings and Facilities

Resource A1 Fire-Related Performance of Archaic Materials and Assemblies

Resource A2 Building Evaluation

Resouce A3 : Final Evaluation and Design Solution

Resource A4 Summary

Resource A Appendix : Table of Contents

Resource A Appendix: Section I - Walls

Resource A Appendix : Section II - Columns

Resource A Appendix : Section III - Floor/Ceiling Assemblies

Resource A Appendix : Section IV - Beams

Resource A Appendix : Section V - Doors




The International Existing Building Code (IEBC) is a comprehensive code with the goal of addressing all aspects of work taking place in existing buildings and providing user friendly methods and tools for regulation and improvement of such buildings. This resource document is included within the cover of the IEBC with that goal in mind and as a step towards accomplishing that goal.

In the process of repair and alteration of existing buildings, based on the nature and the extent of the work, the IEBC might require certain upgrades in the fire resistance rating of building elements, at which time it becomes critical for the designers and the code officials to be able to determine the fire resistance rating of the existing building elements as part of the overall evaluation for the assessment of the need for improvements. This resource document provides a guideline for such an evaluation for fire resistance rating of archaic materials that is not typically found in the modern model building codes.

Resource A is only a guideline and is not intended to be a document for specific adoption as it is not written in the format or language of ICC’s International Codes and is not subject to the code development process.


The Guideline on Fire Ratings of Archaic Materials and Assemblies focuses upon the fire-related performance of archaic construction. “Archaic” encompasses construction typical of an earlier time, generally prior to 1950. “Fire-related performance” includes fire resistance, flame spread, smoke production, and degree of combustibility.

The purpose of this guideline is to update the information which was available at the time of original construction, for use by architects, engineers, and code officials when evaluating the fire safety of a rehabilitation project. In addition, information relevant to the evaluation of general classes of materials and types of construction is presented for those cases when documentation of the fire performance of a particular archaic material or assembly cannot be found.

It has been assumed that the building materials and their fastening, joining, and incorporation into the building structure are sound mechanically. Therefore, some determination must be made that the original manufacture, the original construction practice, and the rigors of aging and use have not weakened the building. This assessment can often be difficult because process and quality control was not good in many industries, and variations among locally available raw materials and manufacturing techniques often resulted in a product which varied widely in its strength and durability. The properties of iron and steel, for example, varied widely, depending on the mill and the process used.

There is nothing inherently inferior about archaic materials or construction techniques. The pressures that promote fundamental change are most often economic or technological—matters not necessarily related to concerns for safety. The high cost of labor made wood lath and plaster uneconomical. The high cost of land and the congestion of the cities provided the impetus for high-rise construction. Improved technology made it possible. The difficulty with archaic materials is not a question of suitability, but familiarity.

Code requirements for the fire performance of key building elements (e.g., walls, floor/ceiling assemblies, doors, shaft enclosures) are stated in performance terms: hours of fire resistance. It matters not whether these elements were built in 1908 or 1980, only that they provide the required degree of fire resistance. The level of performance will be defined by the local community, primarily through the enactment of a building or rehabilitation code. This guideline is only a tool to help evaluate the various building elements, regardless of what the level of performance is required to be.

The problem with archaic materials is simply that documentation of their fire performance is not readily available. The application of engineering judgment is more difficult because building officials may not be familiar with the materials or construction method involved. As a result, either a full-scale fire test is required or the archaic construction in question removed and replaced. Both alternatives are time consuming and wasteful.

This guideline and the accompanying Appendix are designed to help fill this information void. By providing the necessary documentation, there will be a firm basis for the continued acceptance of archaic materials and assemblies.



This guideline does not specify the level of performance required for the various building components. These requirements are controlled by the building occupancy and use and are set forth in the local building or rehabilitation code.

The fire resistance of a given building element is established by subjecting a sample of the assembly to a “standard” fire test which follows a “standard” time-temperature curve. This test method has changed little since the 1920s. The test results tabulated in the Appendix have been adjusted to reflect current test methods.

The current model building codes cite other fire-related properties not always tested for in earlier years: flame spread, smoke production, and degree of combustibility. However, they can generally be assumed to fall within well defined values because the principal combustible component of archaic materials is cellulose. Smoke production is more important today because of the increased use of plastics. However, the early flame spread tests, developed in the early 1940s, also included a test for smoke production.

“Plastics,” one of the most important classes of contemporary materials, were not found in the review of archaic materials. If plastics are to be used in a rehabilitated building, they should be evaluated by contemporary standards. Information and documentation of their fire-related properties and performance is widely available.

Flame spread, smoke production and degree of combustibility are discussed in detail below. Test results for eight common species of lumber, published in an Underwriter’s Laboratories’ report (104), are noted in the following table:

Flame Spread

The flame spread of interior finishes is most often measured by the ASTM E 84 “tunnel test.” This test measures how far and how fast the flames spread across the surface of the test sample. The resulting flame spread rating (FSR) is expressed as a number on a continuous scale where cement-asbestos board is 0 and red oak is 100. (Materials with a flame spread greater than red oak have an FSR greater than 100.) The scale is divided into distinct groups or classes. The most commonly used flame spread classifications are: Class I or A*, with a 0-25 FSR; Class II or B, with a 26-75 FSR; and Class III or C, with a 76-200 FSR. The NFPA Life Safety Code also has a Class D (201-500 FSR) and Class E (over 500 FSR) interior finish.

These classifications are typically used in modern building codes to restrict the rate of fire spread. Only the first three classifications are normally permitted, though not all classes of materials can be used in all places throughout a building. For example, the interior finish of building materials used in exits or in corridors leading to exits is more strictly regulated than materials used within private dwelling units.

In general, inorganic archaic materials (e.g., bricks or tile) can be expected to be in Class I. Materials of whole wood are mostly Class II. Whole wood is defined as wood used in the same form as sawn from the tree. This is in contrast to the contemporary reconstituted wood products such as plywood, fiberboard, hardboard, or particle board. If the organic archaic material is not whole wood, the flame spread classification could be well over 200 and thus would be particularly unsuited for use in exits and other critical locations in a building. Some plywoods and various wood fiberboards have flame spreads over 200. Although they can be treated with fire retardants to reduce their flame spread, it would be advisable to assume that all such products have a flame spread over 200 unless there is information to the contrary.

Smoke Production

The evaluation of smoke density is part of the ASTM E 84 tunnel test. For the eight species of lumber shown in the table above, the highest levels are 275-305 for Yellow Pine, but most of the others are less smoky than red oak which has an index of 100. The advent of plastics caused substantial increases in the smoke density values measured by the tunnel test. The ensuing limitation of the smoke production for wall and ceiling materials by the model building codes has been a reaction to the introduction of plastic materials. In general, cellulosic materials fall in the 50-300 range of smoke density which is below the general limitation of 450 adopted by many codes.

Degree of Combustibility

The model building codes tend to define “noncom- bustibility” on the basis of having passed ASTM E 136 or if the material is totally inorganic. The acceptance of gypsum wallboard as noncombustible is based on limiting paper thickness to not over 1/8 inch and a 0-50 flame spread rating by ASTM E 84. At times there were provisions to define a Class I or A material (0-25 FSR) as noncombustible, but this is not currently recognized by most model building codes.

If there is any doubt whether or not an archaic material is noncombustible, it would be appropriate to send out samples for evaluation. If an archaic material is determined to be noncombustible according to ASTM E 136, it can be expected that it will not contribute fuel to the fire.






Western White Pine




Northern White Pine




Ponderosa Pine




Yellow Pine




Red Gum




Yellow Birch




Douglas Fir




* Some codes are Roman numerals, others use letters


One of the earliest forms of timber construction used exterior load-bearing masonry walls with columns and/or wooden walls supporting wooden beams and floors in the interior of the building. This form of construction, often called “mill” or “heavy timber” construction, has approximately 1 hour fire resistance. The exterior walls will generally contain the fire within the building.

With the development of dimensional lumber, there was a switch from heavy timber to “balloon frame” construction. The balloon frame uses load-bearing exterior wooden walls which have long timbers often extending from foundation to roof. When longer lumber became scarce, another form of construction, “platform” framing, replaced the balloon framing. The difference between the two systems is significant because platform framing is automatically fire-blocked at every floor while balloon framing commonly has concealed spaces that extend unblocked from basement to attic. The architect, engineer, and code official must be alert to the details of construction and the ease with which fire can spread in concealed spaces.