The information source for design & engineering professionals offering guidance and solutions on general topics relating to structural steel fireproofing.
Focus On Fireproofing
Learn how our innovative products solve the challenges of today’s structural steel fireproofing requirements.
The fire resistance of a steel component is its ability to withstand fire for a period of time under conditions of heat intensity.
Critical failure of steel occurs when the steel reaches 1,000°F (537°C). At this point, unprotected steel is reduced to 60% of its original strength, is prone to bend and deflect and the structural load stability and physical characteristics of steel is compromised.
Passive fire protection materials are designed to safeguard the structural integrity of steel under fire conditions and to maintain safe temperatures for a specified period of time.
Model building codes or building regulations determine fire resistance ratings of the structural elements for various building types, based on the building type and occupancy classifications. Fire ratings range from 1 to 4 hours. Thicknesses of the fire resistive materials are dependent on the type of construction, material being used and the hourly rating required.
In the past, industry defined product classifications as “Cementitious Mixtures” or “Sprayed Fiber” materials. These product classifications have been withdrawn and combined to form a new single product classification called Spray-Applied Fire Resistive Material (SFRM).
The term “cementitious” often misleads design professionals to believe that the product contains cement, when in fact, most commercial density fireproofing products called “cementitious” do not. Ironically, most of the materials that were included in the “Sprayed Fiber” category actually do contain cement.
The industry has categorized SFRMs as either “Wet Spray” or “Dry Spray” materials. These terms better describe the manner in which the material is mixed, conveyed and applied.
Intumescent Fire Resistance Coatings are paint-like coatings that expand and char in a fire to insulate structural steel for up to 4-hours.
Thin Film Intumescent Coatings, such as CAFCO® SprayFilm® / ISOLATEK® Type WB, give Architects the ability to design using structural steel that can be decorative and aesthetically pleasing. Intumescent Coatings can be top coated to match their surroundings and allow steel to be left exposed to view while providing the necessary fire resistance ratings.
CAFCO® 300 / ISOLATEK® Type 300 and BLAZE-SHIELD® II / Type II are specified within the American Institute of Architects (AIA) MasterSpec – Section 07811 for concealed applications of Sprayed Fire Resistive Materials (i.e. above ceilings, behind walls, elevator shafts, etc.).
CAFCO® 400 / ISOLATEK® Type 400, CAFCO ®BLAZE-SHIELD® HP / ISOLATEK Type HP and CAFCO® FENDOLITE® M-II / ISOLATEK Type M-II, high-density SFRM, are specified within the American Institute of Architects (AIA) MasterSpec – Section 07811 for Exposed Sprayed Fire Resistive Material (i.e. parking garage, canopies, and storage areas).
CAFCO-BOARD / ISOLATEK Type CB is a rigid, mineral wool board that is mechanically fastened to structural steel to provide up to 4-hour fire protection.
CAFCO-BOARD / ISOLATEK Type CB is ideally suited to protect structural steel in areas where there is limited clearance around perimeter walls, retrofit applications, seismic activity zones, moment connection framing and abatement projects where speed and dry application are required.
There is no need for tarping, masking, ventilating or heating of the work area since there is no minimum application temperature.
All products manufactured by Isolatek International contain no detectable asbestos. Ensure that all fire protection material suppliers provide independent test verification per EPA/600/R-93/116.
CAFCO® 300 / ISOLATEK® Type 300 or CAFCO 400 / ISOLATEK Type 400 that has been damaged or removed may be repaired by sprayed or hand troweling freshly mixed product to the affected areas. The maximum area that can be patched by hand troweling CAFCO 300 / ISOLATEK Type 300 or CAFCO 400 / ISOLATEK Type 400 is 1 ft.2 (929 cm2). CAFCO FIBER-PATCH / ISOLATEK Type P may be used to patch damaged or removed CAFCO 300 / ISOLATEK Type 300 or CAFCO 400 / ISOLATEK Type 400 in areas not exceeding 1 ft.2(929 cm2)
CAFCO® BLAZE-SHIELD® II or BLAZE-SHIELD® HP / ISOLATEK Type II or ISOLATEK Type HP that has been damaged or removed may be repaired by re-spraying the product to the affected areas. In addition, CAFCO® FIBER-PATCH may be used to hand patch damaged or removed CAFCO BLAZE-SHIELD II or CAFCO BLAZE-SHIELD HP / ISOLATEK Type II or ISOLATEK Type HP in areas not exceeding 3 ft.2 (2,787 cm2)
Depending upon thicknesses, environment conditions (i.e. temperature, air-flow, moisture, etc.), the period required for CAFCO® / ISOALTEK® Spray-Applied Fire Resistive Materials (SFRMs) to fully cure is 14 to 28 days or more.
This assumes that ventilation is properly provided, particularly when spraying in enclosed areas such as basements, stairwells, shafts, and small rooms. A minimum of 4 complete air exchanges per hour is required until the material is dry.
Traditionally sprayed fireproofing is applied to bare steel. Gypsum based products tend to be less chemically aggressive than cement –based products. Where using cement based products, care must be taken when applying to specific primer type, such as alkyd primers. The primer coating must be identified and approved by Isolatek prior to fire protection
Isolatek International has tested a wide array of paints/primers for compatibility with our fireproofing products to be used on wide flange beams and columns. A painted/primed beam or column must achieve a minimum average measurement of 80% and a minimum individual measurement of 50% of the manufacturer’s published bond strength on a clean uncoated 1/8 inch thick plate when tested in accordance with ASTM E736; the beam flange must not exceed 12 inches; the column flange must not exceed 16 inches; and the beams and column web must not exceed 16 inches. If the painted/primed members do not meet all of the above conditions, mechanical reinforcement (metal lath, steel studs) must be fastened to the substrate prior to fire protection.
Contact Isolatek Technical Services Department to determine compatibility of the primer used.
Isolatek has evaluated the compatibility of primers under laboratory conditions in accordance with ASTM D4541-95 (Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers). Results of our investigation indicate that certain primers are compatible with the intumescent basecoat, provided SprayFilm / Type WB 3, WB 4 or WB 5 are applied in accordance with our written application/installation instructions and primer manufacturer guidelines are followed. You can find a copy of our complete primer list by visiting our Product Information Section.
In following industry practice, the direct application of Intumescent Coatings over zinc-rich primers without the use of an approved barrier / tie coat is not recommended. When left exposed for long periods, zinc rich coatings may form a layer of zinc salts on the surface which may inhibit adhesion of the Intumescent Topcoat. Contact Isolatek International Technical Services for further information.
If a steel deck is to be painted/primed, it must be listed in the specified Underwriters Laboratories, Inc. (UL) Design as a classified painted deck for the particular fire protection product and certified for fire test compatibility by the deck manufacturer for the exact deck designation. CAFCO® BOND-SEAL / ISOLATEK® Type EBS (mixed as an adhesive) is required on the underside of all roof deck.
The deck manufacturer must provide written confirmation that the paint/primer and the deck supplied to the project are those which are classified by UL. In addition, the deck must be listed in the UL roof assembly being utilized and Isolatek must confirm paint/primer adhesion compatibility.
CAFCO-BOARD® / ISOALTEK Type CB is an ideal solution to painted roof decks and a wider variety of project sequencing issues that typically result in time and material patching. Include CAFCO-BOARD / ISOLATEK Type CB in all your SFRM base specifications.
For situations where the deck utilized on a project is painted, contact the deck manufacturer and/or Isolatek International to determine if the deck and paint is UL Classified.
Our dry mix, portland cement based CAFCO® BLAZE-SHIELD® II / ISOLATEK® Type II and BLAZE-SHIELD HP / ISOLATEK Type HP are the only commercial density (low density) and medium density SFRMs that have been subjected to advanced exterior exposure conditions at Underwriters Laboratories, Inc. and have shown satisfactory physical and fire resistance performance, resulting in a “Investigated for Exterior Use” classification by UL.
CAFCO® FENDOLITE® M-II / ISOLATEK Type M-II, high density SFRM, is also classified by UL as “Investigated for Exterior Use”.
Our CAFCO® SprayFilm® WB 4 / ISOLATEK Type WB 4Intumescent Coating is a water-based, intumescent coating consisting of polyvinyl acetate resins and inorganic fillers for the fire protection of structural steel. CAFCO® SprayFilm® WB 4 / ISOLATEK Type WB 4, in conjunction with CAFCO® SprayFilm®Topseal / ISOLATEK Type Topseal, is a water-based system investigated by UL for exterior applications. An additional protective topcoat, CAFCO®Sprayfilm® Topseal / ISOLATEK Type Topseal, is applied over the CAFCO® SprayFilm® / ISOLATEK Type WB in conjunction with an exterior finish coat. The topcoat material can be any color match to provide a durable, decorative, architectural finish.
Surface coatings such as water-based latex, vinyl acrylic, urethane or chlorinated rubber coatings may be used as overspray on CAFCO / ISOLATEK Types D-C/F, II, II HS, HP, 300, 300AC, 300ES, 300HS, 300N, 3000, 3000ES, 400AC, 400ES, 400, M-II, TG and M-II/P. If used, the coatings are intended for surface coloring only. Their application must be controlled so that the coatings do not saturate the Spray-Applied Fire Resistive Material (SFRM) and thus influence the bond between the SFRM and the steel substrate. Unless specifically indicated above, these systems have not been investigated for exterior use. The flame spread index of the surface coating shall be less than 200 as determined by the test method in ANSI/UL 723 (ASTM E84 and NFPA 255). Surface Burning Classifications are contained in the Building Materials Directory.
In areas where there is expected to be a greater than normal amount of air movement such as elevator shafts or areas adjacent to exhaust fans, it is recommended that our CAFCO® BOND-SEAL / ISOLATEK® Type EBS & X be applied as a sealer. Otherwise, a sealer or topcoat is considered optional, as we do not require a sealer in maintaining the fire rating or physical properties of the SFRM.
Thickness of the fire protection material is dependent upon the assembly in which it is being applied. The following is a partial list of the basic information required by the estimator to determine the proper Underwriters Laboratories (UL) assembly or fire test assessment.
- Type of deck and depth of metal deck
- Type of topping on deck (i.e. concrete or insulation type and thickness)
- Beam sizes supporting deck
- Type of column and column sizes
- Hourly rating required
Once an assembly is determined and a UL Design is selected, the design will list the proper thicknesses required.
Before applying CAFCO SprayFilm / ISOLATEK Type WB 3, WB 4 or WB 5 to structural steel, the steel must be primed with a suitable primer. This is a requirement by Underwriters Laboratories, Inc. (UL) in the specific design. The primer must be applied in accordance with the primer manufacturer’s written instructions.
It is an industry standard for Spray-Applied Fire Resistive Materials (SFRMs) that the temperature at the job site must be greater than 40°F (4°C). A minimum substrate and ambient temperature of 40°F (4°C) shall be maintained prior to, during, and for a minimum of 24 hours after the application.
For CAFCO® SprayFilm® / ISOLATEK® Type Intumescent Coatings, the minimum ambient temperature must be between 50°F (10°C) and 100°F (38°C). A minimum substrate and ambient temperature of 50°F (10°C) shall be maintained prior to, during and a minimum of 72 hours after application.
If necessary, tarp enclosures and temporary heat may be utilized to maintain the proper temperature and humidity levels in the application areas.
These are the standards called out and accepted by the Association of the Wall and Ceiling Industries – International (AWCI) as wells as The National Fireproofing Contractors Association (NFCA).
CAFCO / ISOLATEK fireproofing materials are purchased and installed only by applicators and companies who are recognized by Isolatek International.
You can obtain Technical Letters, Submittal Information and Engineering Judgments by contacting Isolatek Technical Services via our Hotline at 800-631-9600 (Option 1), Fax at 973-347-6730 or email at .
All Isolatek International technical related letters and documentation must be issued through the Isolatek International Corporate Technical Services Department.
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Determining Nozzle Cup Weight
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