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Building Codes and Historic Preservation: An Overview 

12-09-2015 17:35

Most state and local building codes in the United States are adopted from one of three models: BOCA National Building Codes (Building Officials and Code Administrators International), Standard Building Codes (Southern Building Code Congress International) and Uniform Building Codes (International Conference of Building Officials). Some states and localities develop their own codes. The goal of each of these code groups is to write regulations that can be consistently and uniformly interpreted. The situation is complicated by the fact that people interpret the codes differently.

Building codes have to keep up-to-date with modern materials and methods of construction. If not, the code would be unwieldy and full of unused information. One problem is that the code does not contain information on the methods of construction used in historic structures. Thus building officials have no information regarding the fire resistance or structural capacity of archaic materials.

Building code compliance for historic buildings has long been a problem under this system. However, application of building codes to historic structures has evolved dramatically over the past decade. Building codes have been amended to encourage reuse of structures. Building officials have been more flexible on code enforcement and in accepting alternative compliance methods.

In 1974, the National Trust for Historic Preservation, in conjunction with 11 other key national organizations, made an early attempt to address the issue by sponsoring a Preservation and Building Codes Conference. People interested in preserving buildings while achieving appropriate levels of safety got together and papers from the conference were published by the National Trust as Preservation & Building Codes.

These concerned parties were able to introduce into the model codes provisions relative to historic buildings and the authority of building officials to not require of such structures full compliance with current codes. Working with building officials, the National Trust lobbied for this result within the model code change cycle.

In 1976, our firm did the Survey of Building Code Provisions for Historic Structures under a contract from the National Bureau of Standards. Some interesting regulatory facts relative to historic buildings were found. A number of states had statewide legislation. A considerable number had adopted regulations permitting authority for states to work with compliance alternatives. We also surveyed major cities, finding that many jurisdictions had cultural heritage or historic preservation boards with authority to grant alternatives or waivers.

Further research focused on the larger problem of all existing buildings, not just landmark structures. The idea of "existing level of performance" evolved. If an existing building has performed adequately and safely, improvements should be permitted to be made to it without requiring the building arbitrarily to meet requirements for upgrade to current code level required for new construction. Codes formerly contained a provision that any structure altered in excess of 50% of its value had to "be brought up to the current code." Almost all modem codes have eliminated this provision.

Exceptions to the existing level of safety concept would be an obviously unsafe condition or a change of occupancy. The Massachusetts code, Article 22, is an early example of handling the change of occupancy situation. A numeric system rating the hazard increase was employed for change of occupancy. If you change the building`s use and move up in this number scale, you have to comply with current codes. If you don`t move up more than a certain percentage, the existing building is considered adequate.

The Department of Housing and Urban Development (HUD) funded the development of a series of guidelines for rehabilitation of buildings, published by HUD in 1980 as Rehabilitation Guidelines. The multi-volume work covers a gamut from administrative provisions to liability to technical provisions such as egress, fire safety, electrical and plumbing. Several other volumes, dealing with structural assessment and building inspection, have subsequently been published.

Some states have adopted statewide pre-emptive historic building codes. California has a statewide state historic building code that, although touted by many as an important document, in my opinion doesn`t really give much guidance in resolving problems. It`s a "meet and confer" type of document.

The International Conference of Building Officials published the Uniform Code for Building Conservation (UCBC) in 1985. The UCBC is intended for use for existing buildings undergoing alterations, improvements or a change in occupancy, or for historic structures. It was adopted by the Uniform Building Code membership and is now being adopted by jurisdictions around the country, either by ordinance or for guidance for administrative implementation of compliance alternatives.

The purpose of the UCBC is to encourage the continued use or reuse of legally existing buildings and structures. The code makes the fundamental statement of "non-conforming rights"--that existing buildings, legally constructed under previous codes, may remain as long as all unsafe conditions are corrected. Improvements may be made without requiring that the building comply with the current code.

Provisions regarding compliance alternatives are included, allowing conformance with the code`s intent, using means, materials or design features that can be demonstrated to the satisfaction of the building official to perform in a manner equivalent to those specifically required by the code. A method encouraging the use of alternatives where necessary is important for historic preservation, due to the type of construction and renovation work involved. To aid in defining standards, the UCBC includes HUD`s rehabilitation guidelines.

The Uniform Building Code has a provision stating that when buildings undergo a change of use, the building official can authorize deviations from full compliance with the current code if there is no increase in the fire and life risk. To handle this complex situation, UCBC has a hazard ranking by certain features of the building, rather than simply considering categories of occupancy change. The kind of issues examined include height and area, exit systems, separation of occupancies, exterior walls, earthquake, wind, light and ventilation.

Other sections of the code deal such topics as relocated buildings, special change of occupancy provisions, handicapped access and a building conservation advisory and appeals board.

The codes continue to be updated with new, positive approaches to dealing with fire and life safety issues in existing and historic buildings. The BOCA Code recently adopted a new Article 25 (Article 32 in the 1987 edition) covering rehabilitation of existing buildings. Previously, changes of use, minor additions or major alterations required that an existing building be brought up to the code for new building construction. The Southern Building Code Congress is planning to publish code changes in this area.

Publication Date: Spring 1988


Author(s):Mel Green