A code based on scientific data

This Issue This is a part of the Building controls feature

By - , Build 161

New Zealand’s Building Code can trace part of its history back to the us small dwelling Code published in 1922. This was the first nationally developed us Building Code and probably the first anywhere to explore going beyond minimum standards.

1932 edition of the US building code.

IN APRIL 1920 , following the impact of World War I, the US Senate established a Select Committee on Reconstruction and Production. It held hearings in 13 cities over 37 days, presenting a 61-page summary report in March 1921 (with 2,360 pages of appendices) and concluding:

‘The building codes of the country have not been developed upon scientific data, but rather on compromises; they are not uniform in principle and in many instances involve an additional cost of construction without assuring more useful or more durable buildings.’

Demand for building code

Soon after, a Division of Building and Housing was established in the National Bureau of Standards with its first task to create such a code. The demand was impressive – of all the US cities with populations over 5,000, 25% lacked a building code or inspector, and of these, half had populations over 10,000.

In 1920, Herbert Hoover was appointed Secretary of Commerce. A focus of his tenure was on improving productivity through fair competition. This included developing the legislative framework leading to the modern Federal Communications Commission, the Federal Aviation Authority and standardisation of a range of products, including building materials, like brick and timber sizes.

Building Code Committee established

By May 1921, Hoover had established a Building Code Committee (BCC) and appointed the chair and six members. The chair was a consulting fire engineer, while the committee included three engineers, two architects and the New York City Superintendent of Buildings (the person in charge of administering the New York City building code).

Averaging 54 years of age, the members were well experienced. However, as they all came from the east or the mid-west, regions known for very cold winters and hot summers, their knowledge of construction in milder climates may have been limited.

They set to work with vigour, travelling regularly from their home cities by train to Washington DC for meetings. In February 1922, they sent out over 1,000 copies of the draft code, receiving back 150 letters of comment mostly from groups or organisations. These were debated and incorporated along with a range of illustrations provided by industry associations and companies.

1932 edition of the US building code.

First US building code in 1922

In July 1922, Recommended minimum requirements for small dwelling construction was published, complete with a letter of approval from Hoover.

It covered brick, concrete block, monolithic concrete and timber-framed buildings up to 30 feet (9.1 m) high accommodating one or two families.

This was the first nationally developed US building code. It brought together the experiences of not only the wider nationwide code community but also the work of researchers at organisations such as the National Bureau of Standards and the Forest Products Laboratory. The final code received wide support from the building industry and was widely distributed.

Code small and prescriptive

The code was divided into nine articles, each with a number of clauses (see Table 1). To those used to working with modern building codes, a surprise is the small number of clauses and pages.

Table 1
1922 US building code clauses and coverage
ARTICLE I GENERAL (2 CLAUSES, 2 PAGES)
  • Limitations, heights and areas
ARTICLE II DWELLINGS WITH SOLID BRICK WALLS (5 CLAUSES, 1 PAGE)
  • Thickness, height and bonding of exterior walls
  • Piers, chases, arches and lintels
  • Material quality
ARTICLE III HOLLOW: BUILDING TILE, CONCRETE BLOCK, BRICK (5 CLAUSES, 3 PAGES)
  • Thickness, height and bonding of exterior walls
  • Piers, chases, bearing for concentrated loads
  • Material quality
ARTICLE IV CONCRETE MONOLITHIC, UNIT OR STRUCTURAL FRAME (5 CLAUSES, 2 PAGES)
  • Monolithic concrete, unit construction
  • Concrete structural frame with enclosing walls
  • Height of concrete exterior walls
  • Floors, floor beams and columns
ARTICLE V FRAME CONSTRUCTION (4 CLAUSES, 2 PAGES)
  • Definition, exterior walls
  • Masonry veneer and stucco on frame construction
ARTICLE VI WOOD FRAMING (6 CLAUSES, 3 PAGES)
  • General requirements, strength of members
  • Beams, joists, girders and rafters, basement columns
  • Bearing partitions, non-bearing partitions
ARTICLE VII PARTY AND DIVISION WALLS AND PARTITIONS (3 CLAUSES, 4 PAGES)
  • Party and division walls, parapet walls, interior partitions
ARTICLE VIII FOUNDATIONS (3 CLAUSES, 2 PAGES)
  • Foundation walls, footings, ventilation
ARTICLE IX MISCELLANEOUS REQUIREMENTS (10 CLAUSES, 2 PAGES)
  • Loads, weight of materials, floor loads, roof loads
  • Plastering, timber in walls
  • Chimneys and surround woodwork, fire-stopping
  • Private garages

Although the code provides some details, for example, a table of allowable stresses permissible for structural timbers by timber species, it is mostly prescriptive. One example is, Wood studding shall be not less than 2 by 4 inches and spaced not to exceed 16 inches on centers.

It is likely the BCC expected those likely to use the code would be well trained, experienced and likely to know their construction materials. These expectations would be buttressed with a good dose of inspection and the potential for legal consequences.

The 1922 code was possibly the first code anywhere that included exploration of going beyond the minimum. It used the research to identify the need for a range of requirements in response to local conditions including wind, snow, earthquakes, moisture, sound, vermin, insects and the correct use of thermal insulation.

Base for other codes, including NZ’s

The BCC code found a major use in the development of the 1927 Uniform Building Code prepared by building officials on the temperate west coast. This, along with other BCC publications, supported the development of the 1945 Standard Building Code widely used in the southern states and the 1950 Basic Building Code used mainly in the north central and eastern states.

In 1997, these three codes merged into the International Building Code, making the 1922 code the grandparent of the modern US building code.

This 1922 US building code also travelled to New Zealand, where it was used to create the first New Zealand national Building Code in 1924 – but that is another story.

Note

This research was funded by a Fulbright New Zealand Scholarship and supported by Victoria University of Wellington.

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Articles are correct at the time of publication but may have since become outdated.

1932 edition of the US building code.

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