CBC · California Building Code

What special inspections and nondestructive tests are required for steel construction?

For steel buildings in California, the CBC requires project‑specific special inspections and nondestructive testing per §1705.2 and the detailed CBC table §1705A.2.1: structural steel follows AISC 360, seismic systems follow AISC 341 (with specified NDT such as UT for certain welds), shop fabrication is inspected unless an approved fabricator exemption applies, and all inspection and testing duties and qualifications must be listed in the Statement of Special Inspections and reported to the building official.

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

The California Building Code requires special inspections and nondestructive testing (NDT) of steel construction to be performed in accordance with the steel-specific provisions of Section §1705.2 and, where the A‑Chapter quality‑assurance path is used, Table §1705A.2.1 and related AISC/AISI/SDI quality‑assurance requirements. Structural steel must follow the quality‑assurance inspection requirements of AISC 360 (§1705.2.1), and seismic force‑resisting steel is subject to AISC 341 quality‑assurance and NDT requirements (§1705.13.1 and §1705.14.1). These requirements include material identification, inspector qualifications, welding inspection, sampling/testing of high‑strength fasteners, and NDT (as specified by the referenced standards) with several explicit exceptions and agency-specific modifications.

Requirements in detail

Scope and controlling sections

  • General requirement for steel special inspection and NDT: §1705.2 (steel construction) and the A‑section equivalent §1705A.2.
  • Structural steel (non‑seismic and general): follow AISC 360 quality‑assurance inspection requirements (§1705.2.1).
  • Structural stainless steel: follow AISC 370 (§1705.2.2).
  • Cold‑formed steel deck welding/inspection: follow SDI QA/QC (§1705.2.3).
  • Seismic force‑resisting systems: special inspections and NDT follow AISC 341 as called out in §1705.13.1 and §1705.14.1.

What must be inspected or tested (decision‑relevant items)

The code organizes required activities by element/type and references specific standards. The table below synthesizes the decision‑relevant dimensions a design/inspection team must check when preparing the Statement of Special Inspections and when planning work.

Element or trigger Typical required activity When continuous vs periodic / who does it Referenced standard(s) Code Reference
Structural steel fabrication & erection Welding inspection, dimensional/material verification, QA procedures Continuous or periodic as specified by AISC 360; performed by approved agency / special inspector AISC 360 (quality assurance) §1705.2.1
Seismic force‑resisting steel (moment frames, collectors, struts, etc.) Special inspections + NDT (UT/RT/etc.) as required by AISC 341 Continuous for welding in many seismic systems; NDT per AISC 341 and CBC table; qualified NDT Level II for exams AISC 341; ASCE 7 where noted §1705.13.1; §1705.14.1
Complete‑joint‑penetration (CJP) groove welds subject to transverse tension Ultrasonic testing (UT) on CJPs in specified Risk Categories and thicknesses (see notes below) Per Table 1705A.2.1 replacement language; performed by QA approved agency AISC 360 / Table 1705A.2.1 (CBC) §1705A.2.1
High‑strength bolts, nuts, washers Sampling and mechanical testing (sampled/tested by approved agency) Periodic sampling/testing per Section 1705A.2.8 and Table 1705A.2.1 ASTM referenced standards; CBC Table 1705A.2.1 §1705A.2.8; Table §1705A.2.1
Shop (fabrication) inspection Shop special inspections during fabrication unless the fabricator is approved to work without special inspection (requires material control procedures and mill test traceability) Continuous during shop operations unless an approved fabricator exemption applies CBC fabrication rules; AISC quality‑assurance references §1705.2 exception; §1704.2.5

Notes on specific decision points:

  • The code explicitly incorporates the quality‑assurance requirements of AISC 360 for structural steel (§1705.2.1) and AISC 341 for seismic systems (§1705.13.1), so the practical extent and type of inspection follow those standards as modified by the CBC.
  • Table 1705A.2.1 in the CBC lists the detailed required inspections/tests for steel construction; CBC text replaces/augments portions of AISC Chapter N and sets UT requirements for CJP welds in certain Risk Categories and for material thicknesses (see §1705A.2.1 discussion).

Inspector qualifications and reporting

  • Welding inspectors and NDT personnel must be qualified as required by the enforcement agency; NDT shall be performed by qualified NDT Level II personnel employed by the approved agency (per CBC annotations). Welding inspector approval may be required by the enforcement agency.
  • The Statement of Special Inspections must identify each special inspection and test, the extent (continuous or periodic), and the responsible approved agency or inspector (§1704.3.1). Reports of inspections/tests and certificates of compliance are required per §1704.2.4/§1704.5.

Exceptions & special cases

  • Fabrication with no welding/thermal cutting/heating operations: special inspections of the fabrication process are not required if the fabricator submits a material‑control procedure and mill test traceability for main stress‑carrying elements (§1705.2 exception).
  • Railing systems made of structural steel: special inspection is limited to welding at the base of cantilevered rail posts (§1705.2.1 exception).
  • Seismic/NDT exceptions: in some lower seismic categories or where certain ASCE 7/AISC design allowances are used, NDT or special inspections may not be required (see the exceptions in §1705.14.1 for specific SDCs and R‑value conditions). Always check §1705.14.1 for the applicable exception language.
  • State agency modifications: OSHPD and DSA jurisdictions impose additional restrictions (for example, certain AISC Chapter N provisions are not permitted) and may require specific replacements to AISC language; verify the project authority (OSHPD/DSA) and apply the CBC amendments shown in §1705 and §1705A.2.1.

Common mistakes

  • Treating AISC/AISI/SDI referenced QA documents as optional: the CBC adopts those quality‑assurance requirements by reference for many steel items, so you must follow the referenced standard requirements unless the CBC specifically modifies them (§1705.2.1 and §1705A.2.1).
  • Omitting required NDT for CJP welds in applicable Risk Categories or wrong thickness threshold: the CBC replacement language tied to Table 1705A.2.1 establishes UT requirements for CJPs in certain Risk Categories and thicknesses—don’t assume all CJPs are exempt. Check Table §1705A.2.1.
  • Assuming shop fabrication is automatically exempt: the CBC permits shop exemption only if the fabricator is approved and has documented material control and is acceptable to the authority; otherwise shop inspections are required (§1704.2.5 and §1705.2 exception).
  • Not specifying inspection type/extent in the Statement of Special Inspections: the registered design professional must list materials, inspection types (continuous/periodic), and tests as required by §1704.3.1.

Worked example — 6‑story office building, seismic force‑resisting moment frames

Scenario:

  • 6‑story office building in Seismic Design Category D, Risk Category II.
  • Steel moment frames are the seismic force‑resisting system. Main beam‑to‑column connections use CJP groove welds in plate members 1/2" thick (0.5" > 5/16").

How the CBC applies (step‑by‑step):

  1. Determine that steel seismic force‑resisting systems are present → apply §1705.13.1 and §1705.14.1: AISC 341 quality‑assurance and NDT requirements govern special inspection and testing.
  2. Check Table §1705A.2.1 / replacement language: for Risk Category II (and III/IV) the CBC replacement requires UT on all CJP groove welds subject to transverse tension where material thickness is 5/16" (8 mm) or greater. Since the plate thickness is 1/2", UT is required on those CJPs. The UT must be performed by the approved QA organization and qualified NDT personnel.
  3. Welding inspection during fabrication/erection: provide continuous or otherwise appropriate welding special inspection per AISC 341/AISC 360 as adopted by the CBC; document that in the Statement of Special Inspections. Inspector qualifications and who does UT (NDT Level II) must be listed.
  4. Deliverables: inspection reports and UT reports showing acceptance/rejection, and final certificate(s) of compliance submitted per §1704 reporting requirements.

Bottom line numeric decision: Because thickness (0.5") > 5/16" and the structure is SDC D with moment frames in Risk Category II, UT of CJPs subject to transverse tension is required per the CBC Table §1705A.2.1 replacement language.

Related provisions

  • §1704.3 — Statement of Special Inspections (content and preparation requirements).
  • §1704.2.5 — Special inspection of fabricated items (shop inspection and fabricator approval).
  • §1705.13 — Special inspections for seismic resistance (overall seismic inspection rules).
  • §1705.14 — Testing for seismic resistance (nondestructive testing rules and exceptions).
  • §1705A.2.8 — Special inspection and tests of high‑strength fastener assemblies.
  • Table §1705A.2.1 — Required special inspections and tests of steel construction (detailed itemization and CBC modifications).

Code references

Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:

  • CBC § 1705.2 High relevance — show source text

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    SPECIAL INSPECTIONS AND TESTS

    1705.2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

    Exception: Special inspections of the steel fabrication process shall not be required where the fabrication process for the entire building or structure does not include any welding, thermal cutting or heating operation of any kind. In such cases, the fabricator shall be required to submit a detailed procedure for material control that demonstrates the fabricator’s ability to maintain suitable records and procedures such that, at any time during the fabrication process, the material specification and grade for the main stress-carrying elements are capable of being determined. Mill test reports shall be identifiable to the main stress-carrying elements where required by the approved construction documents.

    1705.2.1 Structural steel. Special inspections and nondestructive testing of structural steel elements in buildings, structures and portions thereof shall be in accordance with the quality assurance inspection requirements of AISC 360. [OSHPD 1R, 2 & 5] and this code.

    Exception: Special inspection of railing systems composed of structural steel elements shall be limited to welding inspection of welds at the base of cantilevered rail posts.

    [OSHPD 1R, 2 & 5] The following provisions of AISC 360, Chapter N are not permitted: 1. N5, Item 3 (Coordinated Inspection). 2. N6 (Approved Fabricators and Erectors).

    Notes: [OSHPD 1R, 2 & 5]

    1. Quality assurance requirements in AISC 360, AISC 341, AISC 358, AISO S240, SDI QA/QC and AISC 370 are equivalent to special inspection and testing requirements in this code and are provided by approved agencies employed by the Owner. 2. Chapter 22 requires the steel fabrication and erection, including quality control, to be in accordance with the AISC 360, AISC 341, AISC 358, AISI S240, SDI QA/QC and AISC 370.

    1705.2.2 Structural stainless steel. Special inspections and nondestructive testing of structural stainless steel elements in buildings and portions thereof shall be in accordance with the quality assurance inspection requirements of AISC 370. [OSHPD 1R, 2 & 5] and this code.

    [OSHPD 1R, 2 & 5] The following provisions of AISC 370, Chapter N are not permitted: 1. N5, Item 3. (Coordinated Inspection). 2. N6 (Approved Fabricators and Erectors).

    1705.2.3 Cold-formed steel deck. Special inspections and qualification of welding special inspectors for cold-formed steel floor and roof deck shall be in accordance with the quality assurance inspection requirements of SDI QA/QC. [OSHPD 1R, 2 & 5] and this code.

    [OSHPD 1R, 2 & 5] SDI QA/QC Section D3 (Coordinated Inspection) is not permitted.

  • CBC § 1704.6.1 High relevance — show source text

    1704.6.1 Structural observations for structures. Structural observations shall be provided for those structures where one or more of the following conditions exist:

    1. The structure is classified as Risk Category III or IV.
    2. The structure is a high-rise building.
    3. The structure is assigned to Seismic Design Category E, and is greater than two stories above grade plane.
    4. Such observation is required by the registered design professional responsible for the structural design.
    5. Such observation is specifically required by the building official.

    SECTION 1705—REQUIRED SPECIAL INSPECTIONS AND TESTS

    1705.1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705.1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

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    1705.2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

    Exception: Special inspections of the steel fabrication process shall not be required where the fabrication process for the entire building or structure does not include any welding, thermal cutting or heating operation of any kind. In such cases, the fabricator shall be required to submit a detailed procedure for material control that demonstrates the fabricator’s ability to maintain suitable records and procedures such that, at any time during the fabrication process, the material specification and grade for the main stress-carrying elements are capable of being determined. Mill test reports shall be identifiable to the main stress-carrying elements where required by the approved construction documents.

    1705.2.1 Structural steel. Special inspections and nondestructive testing of structural steel elements in buildings, structures and portions thereof shall be in accordance with the quality assurance inspection requirements of AISC 360. [OSHPD 1R, 2 & 5] and this code.

    Exception: Special inspection of railing systems composed of structural steel elements shall be limited to welding inspection of welds at the base of cantilevered rail posts.

    [OSHPD 1R, 2 & 5] The following provisions of AISC 360, Chapter N are not permitted: 1. N5, Item 3 (Coordinated Inspection). 2. N6 (Approved Fabricators and Erectors).

    Notes: [OSHPD 1R, 2 & 5]

  • CBC § 26.6.4 High relevance — show source text
    1. Reports of material properties verifying compliance with the requirements of AWS D1.4 for weldability as specified in Section 26.6.4 of ACI 318 for reinforcing bars in concrete complying with a standard other than ASTM A706 that are to be welded.
    2. Reports of mill tests in accordance with Section 20.2.2.5 of ACI 318 for reinforcing bars complying with ASTM A615 and used to resist earthquake-induced flexural or axial forces in the special moment frames, special structural walls or coupling beams connecting special structural walls of seismic force-resisting systems in structures assigned to Seismic Design Category D, E or F.

    1704 A .6 Structural observations. The owner shall employ a registered design professional to perform structural observations. The structural observer shall visually observe representative locations of structural systems, details and load paths for general conformance to the approved construction documents. Structural observation does not include or waive the responsibility for the inspections in Section 110 or the special inspections in Section 1705 A or other sections of this code. Prior to the commencement of observations, the structural observer shall submit to the building official a written statement identifying the frequency and extent of structural observations. At the conclusion of the work included in the permit, the structural observer shall submit to the building official a written statement that the site visits have been made and identify any reported deficiencies that, to the best of the structural observer’s knowledge, have not been resolved.

    [DSA-SS, DSA-SS/CC] Reference to Section 110 shall be to the California Administrative Code instead.

    SECTION 1705 A —REQUIRED SPECIAL INSPECTIONS AND TESTS

    1705 A .1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705 A .1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

    1705 A .2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

    Exception: Special inspections of the steel fabrication process shall not be required where the fabrication process for the entire building or structure does not include any welding, thermal cutting or heating operation of any kind. In such cases, the fabricator shall be required to submit a detailed procedure for material control that demonstrates the fabricator’s ability to maintain suitable records and procedures such that, at any time during the fabrication process, the material specification and grade for the main stress-carrying elements are capable of being determined. Mill test reports shall be identifiable to the main stress-carrying elements where required by the approved construction documents.

    1705 A .2.1 Structural steel. Special inspections and nondestructive testing of structural steel elements in buildings, structures and portions thereof shall be in accordance with the quality assurance requirements of AISC 360 and this code.

  • CBC § 1.1 High relevance — show source text

    1705 A .1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705 A .1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

    1705 A .2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

    Exception: Special inspections of the steel fabrication process shall not be required where the fabrication process for the entire building or structure does not include any welding, thermal cutting or heating operation of any kind. In such cases, the fabricator shall be required to submit a detailed procedure for material control that demonstrates the fabricator’s ability to maintain suitable records and procedures such that, at any time during the fabrication process, the material specification and grade for the main stress-carrying elements are capable of being determined. Mill test reports shall be identifiable to the main stress-carrying elements where required by the approved construction documents.

    1705 A .2.1 Structural steel. Special inspections and nondestructive testing of structural steel elements in buildings, structures and portions thereof shall be in accordance with the quality assurance requirements of AISC 360 and this code.

    Exception: Special inspection of railing systems composed of structural steel elements shall be limited to welding inspection of welds at the base of cantilevered rail posts.

    The following provisions of AISC 360, Chapter N are not permitted: 1. N5, Item 3 (Coordinated Inspection). 2. N6 (Approved Fabricators and Erectors). 3. [DSA-SS, DSA-SS/CC] Quality assurance application of: a. N5, Item 2 (Quality Assurance). b. N5, Item 4 (Inspection of Welding). c. N7 (Nonconforming Material and Workmanship).

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    [DSA-SS, DSA-SS/CC] Additionally, the requirements of Table 1705A.2.1 of the California Building Code shall apply.

    [DSA-SS, DSA-SS/CC] References to specified standards in Table 1705A.2.1 apply only to those structural systems and elements required to comply with those by this code.

    [DSA-SS, DSA-SS/CC] Replace AISC 360, Section N5.5(b), as follows:

  • CBC § 2.5. High relevance — show source text

    1705 A .10 Structural integrity of deep foundation elements. Whenever there is a reasonable doubt as to the structural integrity of a deep foundation element, an engineering assessment shall be required. The engineering assessment shall include tests for defects performed in accordance with ASTM D4945, ASTM D5882, ASTM D6760 or ASTM D7949, or other approved method.

    1705 A .11 Fabricated items. Special inspections of fabricated items shall be performed in accordance with Section 1704 A .2.5.

    1705 A .12 Special inspections for wind resistance. Special inspections for wind resistance specified in Sections 1705 A .12.1 through 1705 A .12.3, unless exempted by the exceptions to Section 1704 A .2, are required for buildings and structures constructed in the following areas:

    1. In wind Exposure Category B, where basic wind speed, V, is 150 mph (67 m/sec) or greater.
    2. In wind Exposure Category C or D, where basic wind speed, V, is 140 mph (62.6 m/sec) or greater.

    1705 A .12.1 Structural wood. Continuous special inspection is required during field gluing operations of elements of the main windforce-resisting system. Periodic special inspection is required for nailing, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including wood shear walls, wood diaphragms, drag struts, braces and hold-downs.

    1705 A .12.2 Cold-formed steel light-frame construction. Periodic special inspection is required for welding operations of elements of the main windforce-resisting system. Periodic special inspection is required for screw attachment, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including shear walls, braces, diaphragms, collectors (drag struts) and hold-downs. [DSA-SS, DSA-SS/CC] Requirements specified in Section 1705A.2.9 shall also apply.

    1705 A .12.3 Wind-resisting components. Periodic special inspection is required for fastening of the following systems and components:

    1. Roof covering, roof deck and roof framing connections.
    2. Exterior wall covering and wall connections to roof and floor diaphragms and framing.

    1705 A .13 Special inspections for seismic resistance. Special inspections for seismic resistance shall be required as specified in Sections 1705 A .13.1 through 1705 A .13.9, unless exempted by the exceptions of Section 1704 A .2.

    1705 A .13.1 Structural steel. Special inspections for seismic resistance shall be in accordance with Section 1705 A .13.1.1 or 1705 A .13.1.2, as applicable.

    1705 A .13.1.1 Seismic force-resisting systems. Special inspections of structural steel in the seismic force-resisting systems in buildings and structures assigned to Seismic Design Category D, E or F shall be performed in accordance with the quality assurance requirements of AISC 341 and this code.

  • CBC § 1704.5 High relevance — show source text

    At completion of fabrication, the approved fabricator shall submit a certificate of compliance to the owner or the owner’s authorized agent for submittal to the building official as specified in Section 1704.5 stating that the work was performed in accordance with the approved construction documents.

    1704.3 Statement of special inspections. Where special inspections or tests are required by Section 1705, the registered design professional in responsible charge shall prepare a statement of special inspections in accordance with Section 1704.3.1 for submittal by the applicant in accordance with Section 1704.2.3.

    Exception: The statement of special inspections is permitted to be prepared by a qualified person approved by the building official for construction not designed by a registered design professional.

    1704.3.1 Content of statement of special inspections. The statement of special inspections shall identify the following:

    1. The materials, systems, components and work required to have special inspections or tests by the building official or by the registered design professional responsible for each portion of the work.

    2. The type and extent of each special inspection.

    3. The type and extent of each test.

    4. Additional requirements for special inspections or tests for seismic or wind resistance as specified in Sections 1705.12, 1705.13 and 1705.14.

    5. For each type of special inspection, identification as to whether it will be continuous special inspection, periodic special inspection or performed in accordance with the notation used in the referenced standard where the inspections are defined.

    6. Deferred submittal items that require a supplemental statement of special inspections.

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    1704.3.2 Seismic requirements in the statement of special inspections. Where Section 1705.13 or 1705.14 specifies special inspections or tests for seismic resistance, the statement of special inspections shall identify the designated seismic systems and seismic force-resisting systems that are subject to the special inspections or tests. [OSHPD 1R, 2 & 5] Where Section 1705.13 or 1705.14 specifies special inspections or tests for seismic resistance, the statement of special inspections shall identify the equip- ment/components that require special seismic certification and seismic force-resisting systems that are subject to the special inspection or tests.

    1704.3.3 Wind requirements in the statement of special inspections. Where Section 1705.12 specifies special inspection for wind resistance, the statement of special inspections shall identify the main windforce-resisting systems and wind-resisting components that are subject to special inspections.

    1704.4 Contractor responsibility. Each contractor responsible for the construction of a main wind- or seismic force-resisting system, designated seismic system or a wind- or seismic force-resisting component listed in the statement of special inspections shall submit a written statement of responsibility to the building official and the owner or the owner’s authorized agent prior to the commencement of work on the system or component. The contractor’s statement of responsibility shall contain acknowledgement of awareness of the special requirements contained in the statement of special inspections.

  • CBC § 3.1 High relevance — show source text

    [DSA-SS, DSA-SS/CC] The exception is not permitted by DSA.

    1704 A .3.1 Content of statement of special inspections. The statement of special inspections shall identify the following:

    1. The materials, systems, components and work required to have special inspections or tests by the building official or by the registered design professional responsible for each portion of the work.

    2. The type and extent of each special inspection.

    3. The type and extent of each test.

    4. Additional requirements for special inspections or tests for seismic or wind resistance as specified in Sections 1705 A .12, 1705 A .13 and 1705 A .14.

    5. For each type of special inspection, identification as to whether it will be continuous special inspection, periodic special inspection or performed in accordance with the notation used in the referenced standard where the inspections are defined.

    6. Deferred submittal items that require a supplemental statement of special inspections.

    1704 A .3.2 Seismic requirements in the statement of special inspections. Where Section 1705 A .13 or 1705 A .14 specifies special inspections or tests for seismic resistance, the statement of special inspections shall identify the equipment/components that require special seismic certification and seismic force-resisting systems that are subject to the special inspections or tests.

    1704 A .3.3 Wind requirements in the statement of special inspections. Where Section 1705 A .12 specifies special inspection for wind resistance, the statement of special inspections shall identify the main windforce-resisting systems and wind-resisting components that are subject to special inspections.

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    SPECIAL INSPECTIONS AND TESTS

    1704 A .4 Contractor responsibility. Each contractor responsible for the construction of a main wind- or seismic force-resisting system, installation of equipment/components requiring special seismic certification or a wind- or seismic force-resisting component listed in the statement of special inspections shall submit a written statement of responsibility to the building official and the owner or the owner’s authorized agent prior to the commencement of work on the system or component. The contractor’s statement of responsibility shall contain acknowledgement of awareness of the special requirements contained in the statement of special inspections. [DSA-SS, DSA-SS/CC] The contractor’s statement is required only when specified on the approved construction documents.

    1704 A .5 Submittals to the building official. In addition to the submittal of reports of special inspections and tests in accordance with Section 1704 A .2.4, reports and certificates shall be submitted by the owner or the owner’s authorized agent to the building official for each of the following:

    1. Reserved.

    2. Reserved.

    3. Certificates of compliance for equipment/components requiring special seismic certification in accordance with Section 1705 A .14.3.

    4. Reports of preconstruction tests for shotcrete in accordance with ACI 318 and Section 1705A.3.9.2.

    5. Certificates of compliance for open web steel joists and joist girders in accordance with Section 2207 A. 5.

  • CBC § 1705A.2.1 High relevance — show source text

    [DSA-SS, DSA-SS/CC] Welding inspector approval by the enforcement agency shall occur when specified in the California Administra- tive Code. Nondestructive testing shall be performed by qualified NDT Level II personnel employed by the approved agency. Additionally, the applicable portions in Table 1705A.2.1 of the California Building Code shall apply.

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    1705A.2.8 Special inspection and tests of high-strength fastener assemblies. Special inspections and tests for high-strength fasteners shall be in accordance with this section and Section 1705A.2.1. High-strength bolts, nuts and washers shall be sampled and tested by an approved agency for conformance with the requirements of applicable ASTM standards [OSHPD 1 & 4] and in accor- dance with Section 2216A.1.

    [DSA-SS, DSA-SS/CC] The minimum requirements for a qualified high-strength bolting special inspector shall be an International Code Council certified Structural Steel and Bolting Special Inspector (S1). Additionally, the requirements in Table 1705A.2.1 of the California Building Code shall apply.

    1705A.2.9 Special inspection and tests of cold-formed steel light-frame construction. [DSA-SS, DSA-SS/CC] Special inspections and tests for cold-formed steel light-frame construction shall be in accordance with quality assurance requirements of AISI S240 and this code. Additionally, the applicable portions in Table 1705A.2.1 of the California Building Code shall apply.

    Quality assurance application is not permitted for the following AISI S240, Chapter D Sections: 1. D6.4 (Quality Assurance Inspection Tasks). 2. D6.5 (Coordinated Inspection). 3. D6.7 (Inspection of Welding). 4. D6.8 (Inspection of Mechanical Fastening). 5. D6.9 (Inspection of Cold-Formed Steel Light-Frame Construction). 6. D6.10 (Additional Requirements for Lateral Force-Resisting Systems). 7. D7 (Nonconforming Material and Workmanship).

    Basic frame inspection provisions of AISI S240, Chapter D are not permitted and inspector of record inspections shall be in accor- dance with the California Administrative Code.

    1705 A .3 Concrete construction. Special inspections and tests of concrete construction shall be performed in accordance with this section and Table 1705 A .3.

    Exception: Special inspections and tests shall not be required for concrete patios, driveways and sidewalks, on grade.

  • CBC § 1704A.2.4. High relevance — show source text

    If they are not corrected, the discrepancies shall be brought to the attention of the building official and to the registered design professional in responsible charge prior to the completion of that phase of the work. A final report documenting required special inspections and tests, and correction of any discrepancies noted in the inspections or tests, shall be submitted at a point in time agreed upon prior to the start of work by the owner or the owner’s authorized agent to the building official. [OSHPD 1R, 2 & 5] Report requirement shall be per 1704A.2.4.

    1704.2.5 Special inspection of fabricated items. Where fabrication of structural, load-bearing or lateral load-resisting members or assemblies is being conducted on the premises of a fabricator’s shop, special inspections of the fabricated items shall be performed during fabrication, except where the fabricator has been approved to perform work without special inspections in accordance with Section 1704.2.5.1.

    1704.2.5.1 Fabricator approval. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. Special inspections during fabrication are not required where the work is done on the premises of a fabricator approved to perform such work without special inspection. Approval shall be based on review of the fabricator’s written fabrication procedures and quality control manuals that provide a basis for control of materials and workmanship, with periodic auditing of fabrication and quality control practices by an approved agency or the building official. At completion of fabrication, the approved fabricator shall submit a certificate of compliance to the owner or the owner’s authorized agent for submittal to the building official as specified in Section 1704.5 stating that the work was performed in accordance with the approved construction documents.

    1704.3 Statement of special inspections. Where special inspections or tests are required by Section 1705, the registered design professional in responsible charge shall prepare a statement of special inspections in accordance with Section 1704.3.1 for submittal by the applicant in accordance with Section 1704.2.3.

    Exception: The statement of special inspections is permitted to be prepared by a qualified person approved by the building official for construction not designed by a registered design professional.

    1704.3.1 Content of statement of special inspections. The statement of special inspections shall identify the following:

    1. The materials, systems, components and work required to have special inspections or tests by the building official or by the registered design professional responsible for each portion of the work.

    2. The type and extent of each special inspection.

    3. The type and extent of each test.

    4. Additional requirements for special inspections or tests for seismic or wind resistance as specified in Sections 1705.12, 1705.13 and 1705.14.

    5. For each type of special inspection, identification as to whether it will be continuous special inspection, periodic special inspection or performed in accordance with the notation used in the referenced standard where the inspections are defined.

    6. Deferred submittal items that require a supplemental statement of special inspections.

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  • CBC § 1705.14.3.1 High relevance — show source text

    1705.14.3.1 Special seismic certification. [OSHPD 1R, 2 & 5] Special seismic certification shall be required in accordance with Section 1705A.14.3. for all of the following: 1. Life-safety components, such as emergency and standby power systems, mechanical smoke removal systems and fire sprinkler/fire protection systems. 2. Medical, mechanical and electrical equipment and components required for life support for patients. 3. On-site power resources (PVs, batteries, fuel cells, etc.) provided to replace, in whole or in part, the public or private elec- tric utility service. 4. [OSHPD 2] Alternate power systems including:

    a. Generators.

    b. UPS and batteries.

    c. Renewable electrical generation and control equipment. d. Panelboards as defined in the California Electrical Code (CEC) Article 100.

    e. Manual and automatic transfer switches.

    f. Switchgear and switchboards.

    1705.14.4 Seismic isolation systems. Seismic isolation systems in seismically isolated structures assigned to Seismic Design Category B, C, D, E or F shall be tested in accordance with Section 17.8 of ASCE 7.

    [BF] 1705.15 Sprayed fire-resistive materials (SFRM). Special inspections and tests of sprayed fire-resistive materials (SFRM) applied to floor, roof and wall assemblies and structural members shall be performed in accordance with Sections 1705.15.1 through 1705.15.6. Special inspections shall be based on the fire-resistance design as designated in the approved construction documents. The tests set forth in this section shall be based on samplings from specific floor, roof and wall assemblies and structural members. Special inspections and tests shall be performed during construction with an additional visual inspection after the rough installation of electrical, automatic sprinkler systems, mechanical and plumbing systems and suspension systems for ceilings, and before concealment where applicable. The required sample size shall not exceed 110 percent of that specified by the referenced standards in Sections 1705.15.4.1 through 1705.15.4.9.

    [BF] 1705.15.1 Physical and visual tests. The special inspections and tests shall include the following to demonstrate compliance with the listing and the fire-resistance rating:

    1. Condition of substrates.

    2. Thickness of application.

    3. Density in pounds per cubic foot (kg/m [3] ).

    4. Bond strength adhesion/cohesion.

    5. Condition of finished application.

    [BF] 1705.15.2 Structural member surface conditions. The surfaces shall be prepared in accordance with the approved fireresistance design and the written instructions of approved manufacturers. The prepared surface of structural members to be sprayed shall be inspected by the special inspector before the application of the SFRM.

    [BF] 1705.15.3 Application. The substrate shall have a minimum ambient temperature before and after application as specified in the written instructions of approved manufacturers. The area for application shall be ventilated during and after application as required by the written instructions of approved manufacturers.

    [BF] 1705.15.4 Thickness. Not more than 10 percent of the thickness measurements of the SFRM applied to floor, roof and wall assemblies and structural members shall be less than the thickness required by the approved fire-resistance design, and none shall be less than the minimum allowable thickness required by Section 1705.15.4.1.

  • CBC § 1705.14.3. High relevance — show source text
    1. Certificates of compliance for designated seismic systems in accordance with Section 1705.14.3.
    2. Reports of preconstruction tests for shotcrete in accordance with ACI 318.
    3. Certificates of compliance for open web steel joists and joist girders in accordance with Section 2207.5.
    4. Reports of material properties verifying compliance with the requirements of AWS D1.4 for weldability as specified in Section 26.6.4 of ACI 318 for reinforcing bars in concrete complying with a standard other than ASTM A706 that are to be welded.
    5. Reports of mill tests in accordance with Section 20.2.2.5 of ACI 318 for reinforcing bars complying with ASTM A615 and used to resist earthquake-induced flexural or axial forces in the special moment frames, special structural walls or coupling beams connecting special structural walls of seismic force-resisting systems in structures assigned to Seismic Design Category B, C, D, E or F.

    1704.6 Structural observations. Where required by the provisions of Section 1704.6.1, the owner or the owner’s authorized agent shall employ a registered design professional to perform structural observations. The structural observer shall visually observe representative locations of structural systems, details and load paths for general conformance to the approved construction documents. Structural observation does not include or waive the responsibility for the inspections in Section 110 or the special inspections in Section 1705 or other sections of this code. Prior to the commencement of observations, the structural observer shall submit to the building official a written statement identifying the frequency and extent of structural observations. At the conclusion of the work included in the permit, the structural observer shall submit to the building official a written statement that the site visits have been made and identify any reported deficiencies that, to the best of the structural observer’s knowledge, have not been resolved.

    1704.6.1 Structural observations for structures. Structural observations shall be provided for those structures where one or more of the following conditions exist:

    1. The structure is classified as Risk Category III or IV.
    2. The structure is a high-rise building.
    3. The structure is assigned to Seismic Design Category E, and is greater than two stories above grade plane.
    4. Such observation is required by the registered design professional responsible for the structural design.
    5. Such observation is specifically required by the building official.

    SECTION 1705—REQUIRED SPECIAL INSPECTIONS AND TESTS

    1705.1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705.1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

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    1705.2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

  • CBC § 1705.10 High relevance — show source text

    1705.10 Structural integrity of deep foundation elements. Whenever there is a reasonable doubt as to the structural integrity of a deep foundation element, an engineering assessment shall be required. The engineering assessment shall include tests for defects performed in accordance with ASTM D4945, ASTM D5882, ASTM D6760 or ASTM D7949, or other approved method.

    1705.11 Fabricated items. Special inspections of fabricated items shall be performed in accordance with Section 1704.2.5.

    1705.12 Special inspections for wind resistance. Special inspections for wind resistance specified in Sections 1705.12.1 through 1705.12.3, unless exempted by the exceptions to Section 1704.2, are required for buildings and structures constructed in the following areas:

    1. In wind Exposure Category B, where basic wind speed, V, is 150 mph (67 m/sec) or greater.
    2. In wind Exposure Category C or D, where basic wind speed, V, is 140 mph (62.6 m/sec) or greater.

    1705.12.1 Structural wood. Continuous special inspection is required during field gluing operations of elements of the main windforce-resisting system. Periodic special inspection is required for nailing, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including wood shear walls, wood diaphragms, drag struts, braces and hold-downs.

    Exception: Special inspections are not required for wood shear walls, shear panels and diaphragms, including nailing, bolting, anchoring and other fastening to other elements of the main windforce-resisting system, where the lateral resistance is provided by structural sheathing and the specified fastener spacing at panel edges is more than 4 inches (102 mm) on center.

    1705.12.2 Cold-formed steel light-frame construction. Periodic special inspection is required for welding operations of elements of the main windforce-resisting system. Periodic special inspection is required for screw attachment, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including shear walls, braces, diaphragms, collectors (drag struts) and hold-downs.

    Exception: Special inspections are not required for cold-formed steel light-frame shear walls and diaphragms, including screwing, bolting, anchoring and other fastening to components of the windforce-resisting system, where either of the following applies:

    1. The sheathing is gypsum board or fiberboard.
    2. The sheathing is wood structural panel or steel sheets on only one side of the shear wall, shear panel or diaphragm assembly and the specified fastener spacing at the panel or sheet edges is more than 4 inches (102 mm) on center (o.c.).

    1705.12.3 Wind-resisting components. Periodic special inspection is required for fastening of the following systems and components:

    1. Roof covering, roof deck and roof framing connections.
    2. Exterior wall covering and wall connections to roof and floor diaphragms and framing.

    1705.13 Special inspections for seismic resistance. Special inspections for seismic resistance shall be required as specified in Sections 1705.13.1 through 1705.13.9, unless exempted by the exceptions of Section 1704.2.

    Exception: The special inspections specified in Sections 1705.13.1 through 1705.13.9 are not required for structures designed and constructed in accordance with one of the following: 1.

Frequently asked questions

Do I always need NDT on welded steel connections?

Not always. NDT requirements depend on the type of connection, the seismic design category, the response modification/detaling used, the element’s role in the seismic force‑resisting system, and thickness thresholds specified in CBC Table §1705A.2.1 and §1705.14.1. Always check those sections and the referenced AISC quality‑assurance provisions.

Can a fabricator avoid shop special inspections?

A fabricator can be approved to perform fabrication without ongoing special inspections only if the authority accepts the fabricator’s written fabrication procedures and quality control manual and periodic auditing (see shop exemption language). If not approved, shop inspections are required. (§1705.2 exception; §1704.2.5).

Who must perform NDT (UT, RT, etc.)?

Nondestructive testing must be performed by qualified NDT personnel; the CBC notes that NDT shall be performed by qualified NDT Level II personnel employed by the approved agency and welding inspectors may require enforcement‑agency approval.

Where do I find the list of required items for steel?

Use §1705.2 / §1705A.2 and especially Table §1705A.2.1 in the CBC (it lists required continuous and periodic inspections and referenced standards). The table also contains CBC modifications to AISC quality‑assurance language.

If the project is in a DSA/OSHPD jurisdiction, do the rules change?

Yes. The CBC includes agency‑specific modifications and some AISC provisions are not permitted in those jurisdictions; always verify the applicable agency amendments in the CBC text for OSHPD or DSA.

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Material- and System‑Specific Required Special Inspections

California Building Code