1 Scope
NOTE This standard governs the materials, surface preparation, application, thickness, density, bond, and field verification of applied fireproofing systems installed on structural steel, structural concrete, and composite steel deck to achieve the hourly fire-resistance ratings required by the International Building Code and the contract documents. (1.1)
NOTE Applied fireproofing is the field-applied insulating layer that allows a structural element to maintain its load-carrying capacity for a specified duration of fire exposure; it is the "passive" fire protection that buys time for occupants to evacuate and for the fire service to respond. (1.2)
NOTE Two material families fall within this scope. (1.3)
NOTE Spray-applied fire-resistive materials (SFRM) are wet-mix or dry-mix products applied by pneumatic spray to a substrate, building up a porous, low-density insulating layer in thicknesses typically from 3/8 inch to several inches. (1.4)
NOTE SFRM is the dominant solution for concealed structural steel in commercial construction because it is rapidly applied, economical, and tested under a wide library of UL fire-resistance designs. (1.5)
NOTE Intumescent fire-resistive materials (IFRM) are paint-like or mastic-like coatings that, when exposed to fire, swell to many times their applied thickness to form an insulating char layer. (1.6)
NOTE IFRM is the dominant solution where structural steel is left exposed to view and an architectural finish is required, because its applied dry-film thickness is measured in mils rather than inches and it can be top-coated to match a finish color. (1.7)
NOTE The selection of SFRM type, IFRM type, applied thickness, and tested design is driven by the fire-resistance rating required for each structural element, by the geometric properties of that element (the W/D ratio for columns and beams, the A/P ratio for tubular sections, the slab thickness and reinforcement cover for floor assemblies), by the substrate environment (interior concealed, interior exposed, exterior, semi-exposed), by impact and abrasion exposure, and by surface preparation constraints. (1.8)
NOTE The applied thickness for any given UL design is not a single number — it varies element by element based on the section size and the rating required. (1.9)
1.10 The Contractor shall calculate or otherwise determine the required thickness for every structural element protected under this scope.
1.11 The Contractor shall document the required thickness in a fireproofing thickness schedule submitted to the Architect of Record before application begins.
1.12 Scope Coordination
NOTE Coordinate this scope with
Structural Steel Framing for the steel framing receiving fireproofing, including the shop primer and any tested primer compatibility, with
Steel Deck for composite floor decks where fireproofing is applied to the underside of the deck and to supporting framing, with
Steel Joists for open-web steel joists protected by fireproofing in joist-floor assemblies, with
Gypsum Board Assemblies for membrane-protected fire-resistive assemblies that do not require applied fireproofing of the framing, and with
Firestopping for through-penetration and joint protection of the rated assemblies once they are constructed.
(1.12.1) 1.12.2 Applied fireproofing and firestopping shall not be combined under a single subcontractor unless that subcontractor independently qualifies for both.
NOTE Applied fireproofing and firestopping are separate scopes with separate qualifications, separate products, and separate inspection regimes. (1.12.2.1)
2 Referenced Standards
2.1 All materials, applications, and field verification shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the following standards.
2.2 Where the contract documents or a referenced standard impose a more stringent requirement than the minimum of any other standard, the more stringent requirement governs unless the Architect of Record directs otherwise in writing.
2.3 Referenced Standards Table
| Standard |
Title |
| ASTM E119 |
Standard Test Methods for Fire Tests of Building Construction and Materials |
| ASTM E84 |
Standard Test Method for Surface Burning Characteristics of Building Materials |
| ASTM E605 |
Standard Test Methods for Thickness and Density of Sprayed Fire-Resistive Material Applied to Structural Members |
| ASTM E736 |
Standard Test Method for Cohesion/Adhesion of Sprayed Fire-Resistive Materials Applied to Structural Members |
| ASTM E761 |
Standard Test Method for Compressive Strength of Sprayed Fire-Resistive Material Applied to Structural Members |
| ASTM E859 |
Standard Test Method for Air Erosion of Sprayed Fire-Resistive Materials Applied to Structural Members |
| ASTM E937 |
Standard Test Method for Corrosion of Steel by Sprayed Fire-Resistive Material Applied to Structural Members |
| ASTM E2652 |
Standard Test Method for Behavior of Materials in a Tube Furnace with a Cone-Shaped Airflow Stabilizer |
| ASTM G21 |
Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi |
| AWCI Technical Manual 12-A |
Standard Practice for the Testing and Inspection of Field Applied Sprayed Fire-Resistive Materials — An Annotated Guide |
| AWCI Technical Manual 12-B |
Standard Practice for the Testing and Inspection of Field Applied Thin Film Intumescent Fire-Resistive Materials — An Annotated Guide |
| ICC-ES AC23 |
Acceptance Criteria for Sprayed Fire-Resistive Materials |
| UL Fire Resistance Directory |
UL Listed Fire-Resistance Designs (Volumes 1 and 2) |
| IBC |
International Building Code, Chapter 7 — Fire and Smoke Protection Features |
| IBC |
International Building Code, Chapter 17 — Special Inspections and Tests |
| NFPA 251 |
Standard Methods of Tests of Fire Endurance of Building Construction and Materials |
| NFPA 286 |
Standard Methods of Fire Tests for Evaluating Contribution of Wall and Ceiling Interior Finish to Room Fire Growth |
| AMPP SP 2 (SSPC-SP 2) |
Hand Tool Cleaning |
| AMPP SP 3 (SSPC-SP 3) |
Power Tool Cleaning |
| AMPP SP 6 (SSPC-SP 6) |
Commercial Blast Cleaning |
| AMPP SP 7 (SSPC-SP 7) |
Brush-Off Blast Cleaning |
| AISC 360 |
Specification for Structural Steel Buildings (shop primer compatibility) |
NOTE ASTM E119 and NFPA 251 are technically equivalent fire test methods for assemblies; UL designs are tested under ASTM E119. (2.3.1)
NOTE AWCI Technical Manual 12-A is the controlling document for field inspection of SFRM and is referenced by the International Building Code as the basis for special inspection of installed sprayed fire-resistive materials. (2.3.2)
NOTE ICC-ES AC23 establishes the acceptance criteria under which SFRM products are evaluated by the ICC Evaluation Service and is the basis of the ESR (Evaluation Service Report) that documents the product's allowable uses. (2.3.3)
NOTE Surface preparation standards are referenced by the AMPP (formerly SSPC) designation. (2.3.4)
3 Submittals
3.1 Action Submittals
3.1.1 The Contractor shall submit the following for the Architect's review prior to procurement and application:
- Product data for each fireproofing product proposed, including the manufacturer's published technical data sheet, the current ICC-ES Evaluation Service Report (ESR), ASTM E84 flame-spread and smoke-developed indices, density at the application thickness, cohesion/adhesion per ASTM E736, compressive strength per ASTM E761, air erosion per ASTM E859, corrosion of steel per ASTM E937, and any service-environment qualifications (interior, exterior, semi-exposed, high-humidity)
- A UL design schedule cross-referencing each structural element type (beam mark, column mark, deck type) to a specific UL fire-resistance design number for which the manufacturer's product is listed, including the design rating, the construction type modeled, the substrate condition, and the controlling section geometry parameter (W/D, A/P, or design-specific)
- A fireproofing thickness schedule listing, for every structural element, the element designation, the required hourly rating, the W/D or A/P ratio, the UL design number, and the required applied dry thickness, organized by floor, area, and element type
- Primer compatibility documentation for each shop primer applied to steel that will receive SFRM or IFRM
- Applicator qualification documentation, including manufacturer training certificates for the specific products proposed, evidence of completed projects of similar scope, and the names and qualifications of the field crew leaders who will supervise application
- Mock-up product data and procedures where a mock-up is required by the contract documents
- Material safety data sheets (SDS) for all products to be used on the project
☑ Product data and ICC-ES Evaluation Service Reports
☐ UL design schedule (element type to UL design number)
☐ Fireproofing thickness schedule (calculated W/D and A/P, required thickness)
☐ Primer compatibility documentation
☐ Applicator qualification documentation
☐ Mock-up product data and procedures
☐ Material safety data sheets (SDS)
3.1.2 Application of any fireproofing system shall not begin until the corresponding submittals have been reviewed and returned.
3.1.3 The UL designs cited shall match the field conditions in all controlling variables; designs that differ in substrate, primer, deck profile, or geometry shall not be substituted.
3.1.4 The fireproofing thickness schedule shall be reproduced on the project record drawings or in a stand-alone protected schedule that the inspector and applicator can reference during the work.
3.1.5 The fireproofing manufacturer shall provide written confirmation, based on testing or published data, that the proposed shop primer is compatible with the fireproofing product and does not require removal or surface preparation beyond the manufacturer's standard.
3.1.6 Where the shop primer is not on the fireproofing manufacturer's accepted list, the surface shall be prepared by removal of the primer or by other treatment as specified by the fireproofing manufacturer.
3.2.1 Manufacturer's published mixing and application instructions shall be available on the job site during the work.
3.2.2 The Contractor shall submit a copy of the mixing and application instructions to the Architect on request and shall confirm that the applicator's field practice conforms to those instructions.
3.2.3 Test reports from the field inspection program shall be submitted as the work progresses, not solely at closeout.
3.2.4 Thickness measurements per ASTM E605, density measurements per ASTM E605, and cohesion/adhesion testing per ASTM E736 shall be reported within five business days of testing so that deficiencies can be corrected before the work is concealed.
3.3 Closeout Submittals
NOTE Provide the following closeout submittals at substantial completion: (3.3.1)
- As-installed fireproofing thickness records identifying each structural element by its drawing mark, reporting the actual measured thickness, density (where measured), and cohesion/adhesion (where measured) for each tested location, organized by floor and area
- Field inspection reports prepared by the special inspector, with deficiencies and their resolution clearly identified
- Manufacturer warranty documentation for each product installed
- Manufacturer's maintenance instructions covering patching of damage during the building's service life, including the proper repair procedure, the acceptable damage size for field patching, and the conditions under which a damaged area must be cut out and reapplied to the full thickness
☑ As-installed fireproofing thickness records
☑ Field inspection reports (special inspector)
☑ Manufacturer warranty documentation
☑ Manufacturer's maintenance instructions
3.3.2 The as-installed thickness record shall serve as the basis of acceptance.
4 Quality Assurance
4.1 Applicator Qualifications
● Manufacturer-certified applicator with documented project experience
○ Manufacturer-certified applicator with no minimum experience requirement
○ Any qualified applicator acceptable to the Architect
4.1.1 Applied fireproofing shall be installed by an applicator qualified in the specific products proposed and trained by the manufacturer for the application methods and quality control procedures of those products.
4.1.2 The applicator shall be a single firm responsible for all fireproofing on the project; partial scopes shall not be split between firms unless the Architect approves in writing.
4.1.3 The applicator's field crew leaders shall have a minimum of three years of documented experience applying the proposed product family on projects of comparable scope and substrate condition.
4.2 Single-Source Responsibility
● Yes — all fireproofing products from one manufacturer
○ Multiple manufacturers permitted with compatibility documentation
4.2.1 To the extent practical, all SFRM and IFRM products on the project shall be obtained from a single manufacturer with a complete product line covering the substrate, exposure, and rating conditions encountered.
NOTE Single-source responsibility consolidates technical support, primer compatibility data, repair procedures, and warranty administration with one party, and avoids the boundary-condition problems that arise where adjacent products from different manufacturers meet at construction interfaces. (4.2.2)
4.3 Pre-Application Conference
4.3.1 Before fireproofing application begins, the Contractor shall convene a pre-application conference with the Owner's representative, the Architect, the structural steel erector, the fireproofing subcontractor, the trades responsible for surface preparation and primer compatibility, the special inspector, and the manufacturer's technical representative.
4.3.2 The conference shall review the UL design schedule, the thickness schedule, the surface preparation requirements, the primer compatibility documentation, the sequence of application, the schedule for field inspection, and the protection of in-place work from damage by subsequent trades.
4.3.3 Issues identified at the pre-application conference shall be resolved before application proceeds.
4.4 Field Mock-Up
○ Yes — one of each major substrate condition
● No
4.4.1 Where the contract documents require a mock-up, the Contractor shall apply one representative installation of each major condition — typical beam, typical column, typical metal deck soffit, and any specialty condition such as exterior or exposed-to-view IFRM — at locations directed by the Architect.
4.4.2 The mock-up shall demonstrate the surface preparation, application method, applied thickness, surface texture, top-coat (for IFRM), and identification labeling exactly as the production work will be executed.
4.4.3 The mock-up shall be tested for density and cohesion/adhesion before production application begins, and shall be retained as the field benchmark for acceptance.
4.5 Field Inspection by Special Inspector
NOTE The International Building Code (Chapter 17) requires special inspection of applied fireproofing in buildings of certain construction types and occupancy classifications, including most Type I-A, I-B, II-A, and high-rise construction. (4.5.1)
● Yes — per AWCI 12-A (SFRM) and 12-B (IFRM) as applicable
○ No — not required by code or contract
4.5.2 Where special inspection is required by code or by the contract documents, the special inspector shall verify compliance in accordance with AWCI Technical Manual 12-A for SFRM and AWCI Technical Manual 12-B for IFRM.
NOTE Both manuals prescribe a thickness sampling rate, a density sampling rate, and a cohesion/adhesion sampling rate, and require visual inspection of all accessible installations. (4.5.3)
5 Environmental and Service Conditions
5.1 Substrate and Ambient Conditions During Application
5.1.1 Most water-mix cementitious SFRM products require ambient and substrate temperatures above 40 °F (4 °C) during application and through the initial cure period, with substrate temperatures not less than the ambient and free of frost; mineral-fiber SFRM with adhesive binders may have wider temperature ranges.
NOTE Intumescent coatings typically require ambient temperatures from 50 °F (10 °C) to 95 °F (35 °C) and relative humidity below 85% during application and cure. (5.1.2)
5.1.3 SFRM and IFRM products shall be applied only when ambient and substrate temperatures, relative humidity, and substrate moisture content fall within the ranges published by the manufacturer.
5.1.4 The Contractor shall verify the published limits for each product and shall provide temporary heat, dehumidification, ventilation, or shade as necessary to maintain acceptable conditions for the duration of cure.
5.1.5 The structure shall be enclosed against the weather before interior SFRM is applied.
5.1.6 The building envelope, the roofing membrane, and exterior glazing shall be in place and the building shall be reasonably watertight so that newly applied SFRM is not wetted by rain or condensation during cure.
5.1.7 Wind speeds during application of any sprayed product shall be controlled by enclosure or by deferring exposed work, both to maintain transfer efficiency and to prevent overspray contamination of adjacent finishes.
5.2 Ventilation During Application and Cure
5.2.1 The water released during cure must be removed from the space or the SFRM will not develop its tested density and cohesion.
5.2.2 Adequate ventilation shall be maintained during application and through the initial cure of water-mix SFRM.
5.2.3 Ventilation shall provide a minimum of four air changes per hour during application and at least one air change per hour for the duration of cure as specified by the manufacturer.
NOTE Inadequate ventilation is a frequent cause of soft, friable, low-density SFRM that fails cohesion/adhesion testing and must be removed and reapplied. (5.2.3.1)
5.3 Protection of Installed Fireproofing
5.3.1 Installed fireproofing shall be protected from physical damage, water exposure, and abrasion until the building is enclosed and substantially complete.
5.3.2 The Contractor shall coordinate the sequence of trades so that mechanical, electrical, plumbing, and ceiling work is executed without damaging the SFRM in place, or so that damage is repaired promptly by the fireproofing applicator before the work is concealed.
NOTE SFRM is friable and is readily damaged by trades working overhead — by ladder placement, by lift contact, by cable pulling, and by the storage of materials against protected members. (5.3.2.1)
5.4 Service Conditions
NOTE SFRM products are classified by their tested service environment. (5.4.1)
NOTE Interior products are suitable for protected, dry, conditioned spaces and are not rated for exterior exposure or for elevated humidity. (5.4.2)
NOTE Exterior products and semi-exposed products carry additional qualifications under ICC-ES AC23 for resistance to water, air erosion, and freeze-thaw cycling. (5.4.3)
NOTE IFRM products are classified similarly, with thin-film intumescent coatings rated as interior, exterior, or weathering-grade depending on the topcoat system and the manufacturer's testing. (5.4.4)
Interior — concealed, conditioned (above ceilings, in shaftwalls)
Interior — exposed (where IFRM finish is required)
Semi-exposed (parking garages, unconditioned interior)
Exterior (canopies, exterior columns, weather-exposed)
Per drawings
5.4.5 The product selected for each substrate location shall match the service environment at that location.
NOTE Interior products applied at exterior locations — even temporarily, during construction — will degrade and fail. (5.4.6)
6 Materials and Selection
6.1 Material Type Selection
NOTE The selection between SFRM (cementitious or mineral-fiber) and IFRM (thin-film or mastic) is driven by the visibility of the protected element, the required hourly rating, the substrate geometry, the service environment, and the construction schedule. (6.1.1)
NOTE SFRM is the default for concealed structural steel and concrete in commercial construction because of its low cost, rapid application, and broad UL design library. (6.1.2)
NOTE IFRM is selected where structural steel is exposed to view and an architectural finish is required, because the applied dry-film thickness is measured in mils rather than inches and the surface can be top-coated. (6.1.3)
NOTE Mastic intumescent coatings — heavier-bodied trowel or spray applications — are selected for higher ratings (typically 2 hours and above) on exposed exterior or industrial steel. (6.1.4)
● SFRM — cementitious (Portland cement / gypsum based)
○ SFRM — mineral fiber
○ IFRM — thin-film intumescent coating (interior, exposed-to-view)
○ IFRM — intumescent mastic (exterior or higher ratings)
Per drawings
NOTE Cementitious SFRM uses Portland cement, gypsum, or both as the binder with vermiculite, perlite, or proprietary lightweight aggregates. (6.1.5)
NOTE Cementitious products typically have densities of 15 to 22 pcf for medium-density formulations and 22 to 50 pcf or higher for high-density formulations used in semi-exposed or impact-exposed locations; cementitious SFRM is hard, dust-resistant, and tolerates moderate handling after cure. (6.1.6)
NOTE Mineral-fiber SFRM uses mineral wool or slag wool fibers with an inorganic binder and an organic adhesive booster; typical densities are 12 to 22 pcf, and the cured material is softer and more compressible than cementitious. (6.1.7)
NOTE Mineral-fiber SFRM is generally faster to apply, generates less rebound, and is preferred for retrofits and for very large floor decks where application speed governs. (6.1.8)
NOTE Thin-film intumescent coatings (IFRM) are applied at dry-film thicknesses from about 10 mils to several hundred mils depending on the rating and the section geometry; the applied film is essentially a paint and can be topcoated to match an architectural color. (6.1.9)
NOTE Mastic intumescent coatings are heavier-bodied and are applied by trowel, putty knife, or specialty spray; they are used where dry-film thicknesses exceed the practical limit of thin-film products or where the service environment requires a more robust topcoat. (6.1.10)
6.2 Density Classification
NOTE SFRM products are commonly categorized by density into low-density, medium-density, and high-density formulations. (6.2.1)
● Standard density (15 to 22 pcf) — concealed conditioned interior
○ Medium density (22 to 30 pcf) — semi-exposed, elevated impact
○ High density (30 to 50+ pcf) — exterior, parking garage, industrial
○ Not applicable — IFRM coating
Per drawings
6.2.2 The in-place density tested per ASTM E605 shall equal or exceed the minimum density required by the UL design for the product.
NOTE The density category does not by itself determine suitability — the controlling parameter is the listed density required by the specific UL design — but the density category influences impact resistance, abrasion resistance, and dust generation in the finished installation. (6.2.2.1)
NOTE A product applied at a density below the listed minimum has not been tested in that condition and does not carry the design's rating. (6.2.2.2)
6.3 Surface Burning Characteristics
6.3.1 All applied fireproofing products shall have a maximum flame-spread index of 25 and a maximum smoke-developed index of 50 when tested in accordance with ASTM E84.
6.3.2 Products exceeding the ASTM E84 indices shall not be installed in plenums, concealed spaces, or exposed locations subject to building-code finish-rating limitations.
7 Ratings, UL Designs, and Thickness Determination
7.1 Hourly Fire-Resistance Rating
NOTE The required hourly fire-resistance rating for each structural element is determined by the construction type of the building and by IBC Table 601 (Fire-Resistance Rating Requirements for Building Elements). (7.1.1)
NOTE The Architect of Record establishes the rating for each element on the contract documents; this standard governs how the rating is achieved through applied fireproofing. (7.1.2)
1 hour
1.5 hours
2 hours
3 hours
4 hours
Per drawings
7.2 UL Design Number
NOTE The UL design is the unit of acceptance — the design number defines the substrate, the product, the section geometry, the rating, and the required applied thickness as a complete tested system. (7.2.1)
● UL (Underwriters Laboratories) — UL Fire Resistance Directory
○ Intertek — Directory of Listed Products
○ FM Approvals — FM Approval Guide
7.2.2 For every structural element to be protected, a specific UL Fire Resistance Directory design shall be cited in the thickness schedule.
7.2.3 The Contractor shall not interpolate between designs, shall not substitute substrates within a design, and shall not adjust applied thickness below the design minimum based on field judgment.
7.3 W/D Ratio (Wide-Flange Beams and Columns)
NOTE For wide-flange steel sections, the required SFRM thickness for a given UL design and rating is a function of the W/D ratio of the section — where W is the weight of the section in pounds per linear foot and D is the heated perimeter in inches. (7.3.1)
NOTE The W/D ratio expresses the thermal mass of the steel relative to its surface area; heavier sections (high W/D) heat more slowly than lighter sections (low W/D) and therefore require less applied fireproofing for the same rating. (7.3.2)
NOTE UL designs list applied thickness as a function of W/D, often with a controlling minimum-W/D condition that defines the lightest section the design is tested for. (7.3.3)
0.34
Default: 0.6 lb/ft per in
Per drawings
7.3.4 The Contractor shall calculate the W/D ratio for each beam and column type protected and shall include the calculated value in the thickness schedule.
7.3.5 Where a UL design lists a thickness only for a controlling minimum W/D, that thickness shall apply to all sections in the design with W/D at or above the listed minimum unless the design provides a thickness adjustment formula.
7.4 A/P Ratio (Hollow Structural Sections)
NOTE For hollow structural sections (HSS) and tubular sections, the thermal mass parameter is the A/P ratio, where A is the cross-sectional area of the section in square inches and P is the heated perimeter in inches. (7.4.1)
NOTE UL designs for HSS sections list applied thickness as a function of A/P. (7.4.2)
7.4.3 The Contractor shall calculate the A/P ratio for each HSS column and brace protected.
7.5 Applied Dry Thickness
NOTE The applied thickness is the dry, cured thickness measured per ASTM E605. (7.5.1)
NOTE The wet-applied thickness during application will be greater than the dry thickness due to water release during cure for cementitious products. (7.5.2)
7.5.3 The applied dry thickness for each element shall match the value listed in the cited UL design for that element's W/D or A/P ratio.
7.5.4 The Contractor shall determine the required thickness for every element type and shall record it in the fireproofing thickness schedule.
7.5.5 Thickness shall be measured per ASTM E605 at the frequencies established in AWCI Technical Manual 12-A.
7.5.6 The Contractor shall control the wet application to deliver the required dry thickness after cure.
7.6 IFRM Dry-Film Thickness
NOTE For intumescent coatings, the required dry-film thickness (DFT) is determined by the manufacturer's loading chart or design listing for the section geometry, the rating, and any specified topcoat. (7.6.1)
7.6.2 Thin-film IFRM is measured in mils, not inches; the DFT may range from about 10 mils for short ratings on heavy sections to 400 mils or more for higher ratings on light sections.
7.6.3 IFRM applied DFT shall be measured with a calibrated wet-film gauge during application (with the wet-to-dry conversion published by the manufacturer) and verified with a calibrated dry-film thickness gauge after cure.
7.7 Cohesion/Adhesion Threshold
NOTE The default minimum required by IBC Section 1705.14 is 150 psf for cementitious SFRM and 150 psf for most mineral-fiber SFRM in buildings 75 feet and below in height; higher thresholds (typically 430 psf) apply in high-rise buildings and where required by the controlling jurisdiction. (7.7.1)
150 psf — buildings 75 ft and below
430 psf — high-rise (above 75 ft) and where required by code
Per UL design and AHJ — exceeds 430 psf
Per drawings
7.7.2 The cohesion/adhesion of installed SFRM shall meet or exceed the minimum required by the project's UL designs and by AWCI Technical Manual 12-A, tested in accordance with ASTM E736.
7.7.3 Where cohesion/adhesion tests fail in a representative sample, the affected area shall be removed and reapplied with the cause of failure identified and corrected.
NOTE Cohesion/adhesion failure is the most common reason fireproofing is rejected at field inspection; common causes include incompatible shop primer, contaminated substrate, low-density application from undermixing or insufficient cure ventilation, freezing during cure, and excess thickness in a single coat. (7.7.4)
8 Substrate Preparation
8.1 General Substrate Conditions
○ Bare structural steel — mill finish, no primer
● Shop-primed structural steel — primer tested compatible with fireproofing
○ Shop-primed structural steel — primer not on manufacturer's accepted list
○ Galvanized structural steel
○ Steel deck — galvanized or painted
○ Concrete — formed or troweled finish
○ Concrete — sprayed or shotcrete finish
Per drawings
8.1.1 Substrates to receive applied fireproofing shall be clean, dry, structurally sound, free of frost, oil, grease, form-release agents, loose mill scale, loose rust, dirt, and any contaminant that would impair adhesion.
NOTE The condition required varies by product and substrate — SFRM applied over unprimed mill-finish steel has different requirements than SFRM applied over a tested-compatible shop primer, which has different requirements than IFRM applied over a tested-compatible primer system. (8.1.2)
8.2 Shop Primer Compatibility
● None beyond clean and dry (primer accepted by manufacturer)
○ Bond enhancer or accelerator applied per manufacturer
○ Brush-off blast (SSPC-SP 7) where primer not accepted
○ Commercial blast (SSPC-SP 6) — required for some IFRM
Per drawings
8.2.1 Shop primers applied to structural steel under Structural Steel Framing shall be selected for compatibility with the fireproofing product. 8.2.2 Primers not on the fireproofing manufacturer's accepted list shall be either removed in the receiving areas or treated with the manufacturer's specified surface preparation (acid wash, bonding agent, or mechanical abrasion).
8.2.3 The Architect and the fireproofing manufacturer shall coordinate primer selection with the structural fabricator during the steel submittal phase.
NOTE The fireproofing manufacturer publishes a list of accepted primers for which testing has demonstrated adequate bond of the fireproofing to the primed steel. (8.2.4)
NOTE Primer-compatibility problems discovered after steel is erected on site are expensive to remedy and frequently delay the fireproofing schedule. (8.2.5)
8.3 Surface Preparation for IFRM
NOTE Intumescent fire-resistive materials require a higher standard of surface preparation than SFRM because they bond directly to the steel as a coating system and rely on the substrate bond for their tested performance. (8.3.1)
8.3.2 Most thin-film IFRM products require SSPC-SP 6 (commercial blast cleaning) prior to application of the manufacturer's tested primer; some products are listed over compatible shop primers with no blast.
8.3.3 The IFRM manufacturer's published surface preparation shall govern; field deviation from the published preparation shall not be permitted.
8.4 Surface Preparation for Concrete Substrates
8.4.1 Concrete substrates shall be cured per the concrete manufacturer's instructions before SFRM application.
8.4.2 Form-release agents shall be removed by mechanical means or by chemical cleaning.
8.4.3 Laitance, loose surface paste, and dust shall be removed.
8.4.4 Smooth troweled finishes may require a bonding agent or mechanical roughening to develop adequate bond; the Contractor shall confirm the required preparation with the SFRM manufacturer for the specific substrate condition.
NOTE Uncured concrete continues to release moisture and alkali that prevent SFRM bond. (8.4.4.1)
8.5 Surface Preparation for Steel Deck
8.5.1 Composite steel deck and form deck receiving SFRM on the underside shall be clean, dry, and free of release agents from the concrete placement above.
8.5.2 Galvanized deck substrates require an SFRM product tested over galvanized steel; not all SFRM products are listed for this condition, and the Contractor shall verify compatibility before application.
9 Application
9.1 Application Method
NOTE Wet-mix products are pumped through a hose to a spray nozzle where the material is atomized and applied. (9.1.1)
NOTE Dry-mix products are conveyed through a hose under air pressure and mixed with water at the nozzle. (9.1.2)
● Wet-mix pumped spray — cementitious products
○ Dry-mix conveyed spray — mineral-fiber and some cementitious
○ Trowel or hand application — patching and small areas only
9.1.3 SFRM shall be applied by pneumatic spray equipment of the type and configuration required by the manufacturer.
9.1.4 The Contractor shall use the manufacturer-specified equipment, nozzle configuration, mix water rate, and spray pressure; deviations from the manufacturer's published procedure can produce densities and cohesions outside the tested range.
9.1.5 IFRM shall be applied by airless spray, conventional spray, brush, or roller as specified by the manufacturer for the product.
9.1.6 Wet-film thickness shall be measured during application with a calibrated comb gauge to confirm that the target dry-film thickness will be achieved after cure.
NOTE Spray application is the standard for production work; brush and roller are used for cut-in work and for patching. (9.1.6.1)
9.2 Multiple Coats
9.2.1 SFRM may be applied in a single coat or in multiple coats depending on the total thickness required and the manufacturer's specifications.
9.2.2 SFRM coats shall be applied before the prior coat has cured to a tack-free condition that prevents intercoat bond, unless the manufacturer specifies an intercoat delay.
9.2.3 The manufacturer's maximum single-coat thickness shall be observed.
NOTE Excess single-coat thickness in some products causes sagging, slumping, or loss of cohesion as the coat cures. (9.2.3.1)
9.2.4 IFRM is typically applied in multiple coats with intercoat dry times specified by the manufacturer.
9.2.5 The maximum single-coat wet-film thickness for thin-film IFRM is typically 20 to 40 wet mils, with several coats required to build to the total DFT.
NOTE Insufficient intercoat dry time produces solvent entrapment, blistering, and poor cohesion that will fail field inspection. (9.2.6)
9.3 Application to Beams and Columns
9.3.1 Beams shall be sprayed to encapsulate all four sides of the flange and web.
9.3.2 Columns shall be sprayed on all sides to the full perimeter; columns embedded in walls shall be sprayed before the wall is constructed.
9.3.3 Box columns, built-up columns, and HSS columns shall be sprayed on all exterior surfaces.
9.3.4 Stiffeners, connection plates, gusset plates, and other appurtenances within the heated area shall be coated to the same thickness as the parent member.
9.4 Application to Underside of Composite Deck
9.4.1 The underside of composite deck and the supporting beams shall be coated continuously, with the SFRM applied to fill the ribs of the deck profile where required by the UL design.
NOTE The deck profile and rib geometry are part of the UL design — substituting a different deck profile invalidates the design even if the deck weight and span are equivalent. (9.4.1.1)
9.5 Application to Concrete
9.5.1 SFRM applied to concrete shall fully cover the substrate to the required thickness, with no thin spots, voids, or skips.
9.5.2 Where SFRM is applied to soffits of cast-in-place concrete slabs, the substrate shall be clean and the surface texture shall be receptive to the SFRM.
9.6 Cutting in at Edges and Penetrations
9.6.1 The fireproofing shall be continuous at all edges, ends of members, connection plates, and penetrations.
9.6.2 Penetrations through the protected member, through the soffit, or through the protected wall shall be cut in cleanly with the firestop or sleeve in place; the firestop scope (see Firestopping) governs the seal around the penetration. 9.6.3 The fireproofing applicator shall coordinate with the firestop applicator so that fireproofing is continuous to the firestop boundary and is not damaged or interrupted by subsequent firestopping work.
10 Field Verification
10.1 Thickness Measurement per ASTM E605
NOTE AWCI Technical Manual 12-A prescribes the sampling rate, location, and acceptance criteria. (10.1.1)
NOTE A measurement is the average of multiple readings at a sampling location, and a sampling location is one of multiple locations along a member. (10.1.2)
● Per AWCI 12-A — minimum frequency by element type and floor area
○ Project-specific frequency as directed by special inspector
Per drawings
10.1.3 The applied dry thickness of SFRM shall be measured in accordance with ASTM E605 using a calibrated thickness gauge.
10.1.4 The average of thickness measurements shall equal or exceed the required thickness; individual measurements may be below the required thickness by a defined tolerance (typically 1/4 inch or 25% of the required thickness, whichever is less) provided the average meets or exceeds the requirement.
10.1.5 Thickness measurements that fail to meet the required average shall result in additional application to bring the area to the required thickness, or in removal and reapplication where additional application would exceed the maximum single-coat thickness or would not bond to the existing material.
10.2 Density Measurement per ASTM E605
10.2.1 The in-place density of cured SFRM shall be measured in accordance with ASTM E605 by cutting a sample of known volume from a representative location and weighing it.
10.2.2 Density measurements shall be conducted at the frequency required by AWCI 12-A — typically one sample per several thousand square feet of applied product or per floor, whichever is greater.
10.2.3 The measured density shall equal or exceed the minimum listed by the UL design and the manufacturer.
10.2.4 Areas with failing density shall be removed and reapplied.
NOTE Low density indicates that the applied product did not develop its tested mass per unit volume during cure; common causes include insufficient mix water, excessive mix water, inadequate ventilation during cure, freezing during cure, or improperly mixed product. (10.2.4.1)
10.3 Cohesion/Adhesion Testing per ASTM E736
NOTE A test pad is attached to the SFRM surface, allowed to cure, and pulled perpendicular to the substrate; the force at failure divided by the bonded area gives the cohesion/adhesion. (10.3.1)
10.3.2 The test is destructive — the SFRM is damaged at the test location and must be patched after the test.
Per AWCI 12-A — minimum one test per floor per major element type
Per project special inspector — typically more frequent
10.3.3 The cohesion/adhesion of applied SFRM shall be tested in accordance with ASTM E736.
10.3.4 The Contractor shall investigate failed cohesion/adhesion tests and shall remove and reapply the affected area with the cause identified and corrected.
NOTE Failed cohesion/adhesion tests indicate either a substrate bond problem (incompatible primer, contaminated substrate, frost or moisture at application) or a product condition problem (low density, freeze damage, incompatible coat thickness). (10.3.5)
10.4 IFRM Dry-Film Thickness Verification
10.4.1 Cured IFRM dry-film thickness shall be measured with a calibrated electronic DFT gauge per the IFRM manufacturer's procedure.
10.4.2 IFRM dry-film thickness measurements shall be taken at the frequency specified by AWCI 12-B and the manufacturer, with the average of multiple readings at each location compared to the required DFT.
10.5 Visual Inspection
10.5.1 In addition to instrumented testing, all accessible fireproofing installations shall be visually inspected for continuity, surface texture, bond to substrate at edges and penetrations, presence of voids or thin spots, surface damage, and consistency with the mock-up or approved sample.
10.5.2 Visual deficiencies shall be repaired before subsequent construction conceals the work.
11 Repair and Patching
11.1 Damage During Construction
11.1.1 Fireproofing damaged by subsequent construction — by trades working overhead, by lift contact, by material storage, or by mechanical or electrical penetrations made after fireproofing — shall be repaired by the qualified fireproofing applicator.
11.1.2 The damaged area shall be cleaned, the substrate exposed and prepared as required for original application, and the fireproofing reapplied to the original thickness, density, and bond.
11.1.3 Patches larger than the threshold specified by the manufacturer (typically 36 to 144 square inches, depending on product and substrate) shall require full substrate preparation including any required bond enhancer or accelerator.
11.1.4 Small patches may be applied directly to the cut-back edge of the existing fireproofing per the manufacturer's procedure.
11.2 Modifications by Other Trades
11.2.1 Mechanical, electrical, plumbing, and ceiling trades shall not cut, drill, drive fasteners through, or otherwise modify in-place fireproofing without authorization from the Architect and without coordination with the fireproofing applicator.
11.2.2 Where modifications are required — for example, to install a new hanger anchor in a beam protected by SFRM — the fireproofing shall be cut back, the anchor installed, and the fireproofing patched by the qualified applicator.
11.2.3 The trade responsible for the modification shall bear the cost of the patch.
12 Identification and Labeling
12.1 Identification of Installed Fireproofing
12.1.1 Each fireproofing installation shall be documented in the as-installed thickness schedule with the location, element designation, UL design number, required thickness, measured thickness, and date of application.
12.1.2 Where required by the contract documents or the Authority Having Jurisdiction, durable labels or stencils shall be applied at the entry to each enclosed area (mechanical room, electrical room) identifying the rating of the surrounding construction and the UL design protecting the structure.
13 Delivery, Storage, and Handling
13.1 Delivery
13.1.1 Fireproofing products shall be delivered in the manufacturer's original sealed packaging with all labels, lot numbers, and manufacturing dates visible.
13.1.2 Products with expired shelf life as marked by the manufacturer shall not be installed.
13.1.3 The Contractor shall maintain a delivery log showing the lot number and date of each container received and shall correlate lots with the areas of application to support traceability if a product issue is identified after installation.
13.2 Storage
13.2.1 SFRM bagged product shall be stored in a clean, dry, weather-protected, ventilated location off the ground on pallets.
13.2.2 SFRM bags shall be stacked no higher than the manufacturer's recommended limit (typically 10 bags or less for cementitious products) to prevent compaction and segregation of the dry mix.
13.2.3 Cementitious bags exposed to rain, ground water, or condensation shall not be installed.
13.2.4 IFRM containers shall be stored within the manufacturer's published temperature range.
NOTE Cementitious products are damaged by exposure to moisture. (13.2.4.1)
NOTE Water-based intumescents are damaged by freezing; solvent-based products generally tolerate freezing but shall not be applied below the manufacturer's minimum application temperature. (13.2.4.2)
13.3 Handling
13.3.1 Bags and containers shall be handled to prevent damage to the packaging.
13.3.2 Partially used containers of IFRM shall be tightly resealed to prevent skinning or solvent loss.
13.3.3 Mix water for cementitious SFRM shall be potable; non-potable or contaminated water can interfere with cure and cause density or cohesion failures.
14 Warranty
14.1 Manufacturer's Warranty
14.1.1 Fireproofing products shall be warranted by the manufacturer against defects in materials and against failure to perform as tested for the period stated in the manufacturer's published warranty, which is typically a minimum of one year for SFRM and may extend to five years or longer for IFRM.
14.1.2 The manufacturer's warranty shall remain in effect provided the products are installed in conformance with the listed UL design, are not subjected to conditions beyond their tested service environment, and are not modified by others.
14.2 Applicator's Warranty
1 year from substantial completion
2 years from substantial completion
5 years from substantial completion (IFRM only)
14.2.1 The Contractor shall warrant the fireproofing application against defects in workmanship for the project warranty period.
14.2.2 The Contractor shall correct workmanship defects at no cost to the Owner during the warranty period and shall coordinate any product replacement with the manufacturer.
NOTE Workmanship defects include, but are not limited to, deviation from the cited UL design; thickness less than the required minimum; density below the required minimum; cohesion/adhesion below the required minimum; missing coverage at edges, ends of members, or penetrations; and incompatible substrate preparation. (14.2.3)
14.3 Conditions Voiding Warranty
14.3.1 The manufacturer's and the applicator's warranty are voided by subsequent modifications by others without authorized patching, by exposure to conditions outside the tested service environment (sustained wet exposure of interior products, chemical contamination, temperatures outside the service range), and by damage caused by other trades that is not promptly repaired by the qualified applicator.
14.3.2 The Contractor shall document any conditions observed during application that may affect the durability or performance of installed fireproofing and shall bring them to the Architect's attention before completing the work.