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What does a third-party firestop inspection to ASTM E2174 and ASTM E2393 involve?

By Corey Beckett, Founder & Principal · Published 28 October 2026

Who is involved

• The authorizing authority (AA): the designated person or organization that administers the inspection, for example the responsible architect, engineer or building owner, or their representative (ASTM E2174 and E2393, clause 3.2.3).
• The authority having jurisdiction (AHJ): the official who enforces the building or fire code (clause 3.2.2). The inspection documents have to be acceptable to both the AA and the AHJ (clause 7.1).
• The installer, who builds the firestop systems and repairs deficiencies.
• The inspector, who must be acceptable to the AHJ and qualify by one of the routes in the standard (in ASTM E2393, the routes for a contract inspector), for example ASTM E3038, or at least two years of construction field inspection experience with education, credentials and experience acceptable to the AA (ASTM E2174, clause 6.1; ASTM E2393, clause 6.2.1).

The ASTM E3038 route asks for a prerequisite, such as four years of full-time experience selecting or installing firestop systems, a score of at least 80% on a firestop industry examination that the AHJ or AA accepts, and firestop training (ASTM E3038, clauses 6.2 and 6.3). ASTM E3038 names the UL Qualified Firestop Contractor Program, which uses the UL Firestop Exam, among the programs that offer such an examination (Note 9). IAS AC291, the accreditation criteria for special inspection agencies, lists the UL Firestop Examination, the FM Firestop Examination and the IFC third-party Firestop Special Inspector Examination among its recommended credentials for inspectors of fire-resistant penetrations and joint systems, for use where the AHJ sets no qualification requirements or in addition to them (AC291, clause 6.8 and Table 2).

Independence is a requirement, not a selling point. The inspector must be completely independent of, and divested from, the installer, the contractor, and the manufacturer and supplier of any material being inspected, and must not be a competitor of any of them. The inspector submits notarized statements of that independence to the AA and a written request for acceptance, and the AA confirms acceptance in writing (ASTM E2174, clauses 6.2 to 6.4; ASTM E2393, clauses 6.2.2 to 6.2.5). Under ASTM E2393, a contract inspector also provides proof of any insurance required by statute, the AA or the AHJ (clause 6.2.4).

Before installation starts

• The AA gives the inspector a complete set of inspection documents at least ten working days before the inspection. The inspector reviews them first and gets written clarification of any conflict or gap before inspecting (clause 7.3).
• The documents include a listed design for every firestop or joint system, or, where no listed design exists, a judgment issued by the manufacturer or an accredited testing laboratory and acceptable to the AHJ (clause 7.4).
• The inspector and installer agree a schedule of notifications, including the start of installation and the anticipated completion of inspection; the installer notifies any change within one working day (clauses 9.1 and 9.3).
• The inspector checks the materials on arrival and records construction details that the installation will hide (clauses 10.4 and 10.5). For joints, the standard's examples are the free movement area, the rated floor thickness, the width of the opening and the wall construction (ASTM E2393, Note 5).
• The inspector does not supervise or direct any part of the installation, including handling and mixing materials or preparing substrates (clause 10.6).

The standard's non-mandatory appendix recommends a pre-construction meeting of the owner, the general contractor, the trades that create penetrations or openings, the firestop installer and the inspector (ASTM E2174, appendix X1.2).

How much gets inspected

Each standard offers two methods. The AA may set the types and increase the numbers above these minimums.

A “type” is typically a unique combination of the penetrating item or joint type, the firestop material or system, and the substrate (ASTM E2174, Note 4; ASTM E2393, Note 7).

What destructive verification means

The inspector cuts into or opens a completed firestop to check what cannot be seen from the surface: sealant depth, the packing or forming material behind it and the annular space, against the listed system. Guidance from the International Firestop Council recommends measuring at several points around each seal, at the points where the sealant adheres to the item and the assembly, and checking packing or forming material for type, density, compression, fibre orientation and depth. The opened area is then repaired following the manufacturer's procedures, and the repair has to comply with the inspection documents (clause 10.16).

At PFS, the inspector opens and measures the sampled systems; the installer repairs every opened area, and PFS re-inspects the repair. PFS does not repair any system and takes no samples.

When something does not comply

• Every deficiency is documented on the inspection form, and its location is physically identified on site (clause 10.14).
• A system that does not comply is repaired or replaced and re-inspected, and one full additional sample of that type is inspected (clause 10.13; in ASTM E2174 this applies to the post-installation method).
• The 10% rule: if non-compliance reaches 10% of the quantity of a type inspected, inspection of that type stops. The installer inspects its own work and repairs or replaces those systems in the area before inspection resumes (clause 10.13).
• ASTM E2393 requires the inspector to advise the contractor of deficiencies within one working day (clause 10.15). ASTM E2174 requires the installer and inspector to agree the communication method and the minimum notice time before installation (clause 10.15).
• Completed work is inspected within two working days of the installer's notice (clause 10.7). Repairs are re-inspected within two working days of the installer's notice; ASTM E2174 requires this and ASTM E2393 recommends it (clause 10.17).

The paperwork

Inspection forms are written, numbered in sequence from 1, cover one type of system each, and go to the AA and the installer within one working day after an area is inspected (ASTM E2174, clauses 10.18 and 11; ASTM E2393, clauses 10.18 and 11).

At the end, the inspector issues a final report with a cover page naming the project, the inspector, the installer (and the prime contractor if different), the AA and the AHJ; a summary page with the types and quantities of systems in the inspection documents, the verification method used, the quantity inspected with the inspector's notarized statement that it meets the minimum, and the deficiency percentages by type and overall; and copies of everything submitted to the AA and every inspection form in chronological order (clause 12).

How the US standards apply in Canada

ASTM E2174 and ASTM E2393 were written around US test methods: their materials clauses name ASTM E814 and UL 1479 for penetrations, and ASTM E1966 and UL 2079 for joints (clause 8.1). In Canada the NBC names CAN/ULC-S115 for penetration and joint firestops and ASTM E2307 for the joint between a floor and an exterior wall, so on Canadian projects the inspection documents (the project specification and the approved submittals) name systems listed to those standards, and the inspection compares the installation with them. The National Research Council's Best Practice Guide on Fire Stops and Fire Blocks (2007) points those who want best practice in firestop installation to independent inspectors working to ASTM E2174 and ASTM E2393 (section 7.9).

What the inspection is not

It does not select installers or products and does not set performance criteria for the systems inspected (ASTM E2174, clauses 5.3 and 5.4). It is not a design review, it does not create or approve a judgment, and it is not acceptance by the authority having jurisdiction.

This page explains the national code and the inspection standards in general terms. It is not a code interpretation, a design opinion or engineering advice for a particular building. The code in force in your province or territory governs, and the authority having jurisdiction decides what is acceptable on a project. PFS is not an engineer, an architect or the authority having jurisdiction, and does not issue, request or procure engineering judgments.