Construction Inspection in the US: Model Code and Special Inspections

1. The same question, a different architecture

In DEN-01 we described construction inspection in Turkey: a central law, one nationwide framework, inspection firms assigned by the Ministry. In the US the question is the same (was the building built as calculated?), but the architecture of the system differs. There is no single nationally binding building code; the International Building Code (IBC) is a model code written by a private body, the International Code Council (ICC), and takes effect only when a state or city adopts it.

2. How does a city adopt a code?

Ordinance 1246 of the City of Southlake, Texas, is a concrete example. The city council adopts the 2021 IBC, with selected appendices, as the city’s building code, but excludes one- and two-family dwellings (a separate residential code covers them). Amendments are collected in a separate exhibit and rest on regional amendments developed by a regional body (the North Central Texas Council of Governments, NCTCOG) through a year of open review. The ordinance was approved on two readings in April 2022.

One amendment concerns inspection directly: Southlake rewrites the IBC definition of special inspector locally, as a qualified person employed or retained by an approved agency, who proves competence to the satisfaction of the registered design professional in responsible charge and is approved by the building official. Enforcement is local too: fines up to $2,000 for violations involving zoning, fire safety or public health, up to $500 for others; each day a violation exists is a separate offense.

3. IBC Chapter 17: Special inspections and tests

The heart of inspection is IBC Chapter 17. In the 2024 edition its sections are: 1701 General, 1702 New Materials, 1703 Approvals, 1704 Special Inspections and Tests, Contractor Responsibility and Structural Observations, 1705 Required Special Inspections and Tests, 1706 Design Strengths of Materials, 1707 Alternative Test Procedure, 1708 In-Situ Load Tests, 1709 Preconstruction Load Tests. Section 1705 is the longest (about nine pages in print): the list of work requiring special inspection.

The logic differs from Turkey’s: the building’s designer defines the scope of inspection in a statement of special inspections; a special inspector of an approved agency carries it out; and for certain structures the designer or a representative also visits the site for structural observation.

4. The DoD reading

When the U.S. Department of Defense adapts the IBC to its projects, it redefines these relationships for its own contract structure (UFC 3-301-01 §2-5):

• "Building official" and "owner" are read as the Authority Having Jurisdiction (AHJ), "permit applicant" as the contractor; when DoD advertises a project, the building permit is effectively implied.
• The structural engineer of record (SER) prepares the statement of special inspections; templates are public.
• Structural observation is required for Risk Category III and IV structures, by the SER or a designated registered design professional. It does not replace special inspections.
• The contractor retains a licensed professional engineer as Special Inspector of Record, a third-party quality-assurance agent; at the end, the inspector submits a signed and sealed final report confirming that all nonconforming work was resolved.
• For nonstructural seismic systems (plumbing, mechanical and electrical components), walk-down inspections by design professionals are required; the SER performs the final walk-down.

The last item ties directly to the lesson of DEP-04: what stops a hospital from working is often its nonstructural elements.

5. Lessons from two systems

1. Who defines the scope of inspection? In the US the designer, through the statement; in Turkey the legislation and the inspection firm. In both, the designer’s knowledge is the starting point.
2. Independence is secured in two ways: in Turkey by electronic assignment of the firm, at DoD by a third-party special inspector.
3. Nonstructural elements belong in inspection. DoD makes it an explicit rule.
4. Local adoption means local variation. In the US, before applying a provision, check which edition, with which amendments, the place where the building stands has adopted.