Fire Protection of Unfinished Basements
In May 2010, the International Code Council (ICC) approved the new fire protective membrane provisions for the 2012 International Residential Code (Section R501.3) with the intent to ensure a minimum level of fire performance for floors in one- and two-family dwellings that were not otherwise required to be fire-resistance rated.
The same requirements carried over into the 2015 IRC Section R302.13 from the 2012 IRC Section R501.3:
R501.3 Fire protection of floors. Floor assemblies, not required elsewhere in this code to be fire resistance rated, shall be provided with a 1/2 inch gypsum wallboard membrane, 5⁄8 inch wood structural panel membrane, or equivalent on the underside of the floor framing member.
1. Floor assemblies located directly over a space protected by an automatic sprinkler system in accordance with Section P2904, NFPA13D, or other approved equivalent sprinkler system.
2. Floor assemblies located directly over a crawl space not intended for storage or fuel-fired appliances.
3. Portions of floor assemblies can be unprotected when complying with the following:
3.1 The aggregate area of the unprotected portions shall not exceed 80 square feet per story.
3.2 Fire blocking in accordance with Section R302.11.1 shall be installed along the perimeter of the unprotected portion to separate the unprotected portion from the remainder of the floor assembly.
4. Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater than 2-inch by 10-inch nominal dimension, or other approved floor assemblies demonstrating equivalent fire performance.
This fire protective provisions apply to not only I-joist floors but all residential floor assemblies, including all floor trusses and light-gauge steel framing, and less than 2-inch by 10-inch nominal dimension lumber and structural composite lumber. They will become effective when adopted by the local jurisdiction. However, not all local jurisdictions have elected to adopt these provisions.
In the U.S. there are currently 28 states which have adopted the fire performance requirements for floors as first outlined in the 2012 International Residential Code. Adoption of the provision came as either a full, un-amended, adoption of the 2012 or 2015 IRC, or as a state-wide adoption of the “fire performance” language listed in the 2012 IRC. There are currently 6 additional states which are set to adopt the fire performance provisions of the code by the end of 2018.
Overall, the International Residential Code is in use or adopted in 49 states, the District of Columbia, Guam, Puerto Rico and the U.S. Virgin Islands.
As a model code, the IRC is intended to be adopted in accordance with the laws and procedures of a governmental jurisdiction. When adopting a model code like the IRC, some jurisdictions amend the code in the process to reflect local practices and laws.
Source: ICC Code Adoption Map, May 2017
Strategies to Meet Floor Assembly Fire-protection Provisions
The floors constructed with 2x10 dimension lumber, structural composite lumber, or their dimensional equivalent, as well as the floor assemblies located directly over a space protected by an automatic sprinkler system do not require a fire protective membrane. Another exception is when only a small area of the floor is unprotected (less than or equal to 80 square feet per story), provided code-required fire blocking is in place to separate the unprotected portion from the remainder of the floor assembly. Finally, enhanced fire protection is not required for floors over crawl spaces, provided the crawl space is not intended for storage or contains fuel-fired appliances.
In addition to the ½-inch gypsum or 5/8-inch wood structural panel protection, there are several methods of fire assemblies for prefabricated wood I-joists that have demonstrated equivalency to Exception 4 of the 2012 IRC Section R501.3 and 2015 IRC Section R302.13, in accordance with ICC-ES AC-14 requirements.
Method 1. PinkWood's WEBshield – FRI Assembly
With the introduction of the FRI assembly, PinkWood was able to offer the building community a code approved, cost effective, easy to use, wood based protection system which meets specific requirements outlined in AC14. PinkWood’s FRI assembly option is the easiest and most convenient way to meet the IRC provisions for unfinished basements. The FRI assembly is made up of our PKI Joist series (11 7/8" and deeper) plus our WEBshield panels and pre-defined spacing. The designer must also use a moment reduction factor of 0.82. The WEBshield panels can be installed during the manufacturing process or in the field. The builder and framing contractor find this the easiest compliance method because the contractor does not need to coordinate a new trade or change the order of their sub-contractors.
In addition, the panels are easy to inspect by the code authority and in the end the panels provide a visual assurance to the new homeowner that extra measures are in place for their safety. Mechanical, plumbing and electrical trades find it very easy to work around the panels and can perform customary penetrations in numerous unprotected regions of the joist. Please see below.
More information on PinkWood’s FRI Assembly
The structural and fire resistance properties of the PKI joist(the structural member of the FRI Assembly) evaluated for compliance with ASTM D5055. PinkWood chose IAPMO as its evaluation services agency as a highly respected organization with all the required ISO certification and engineering expertise to evaluate the product and, in particular, the compliance to the provisions outlined in AC14 for Fire Performance.
FRI Assembly offers equivalent fire performance to 2-inch by 10-inch nominal dimension lumber and are recognized for installation without the prescribed minimum ½-inch-thick gypsum wallboard or ⅝-inch-thick wood structural panel membrane in accordance with Exception 4 to 2012 IRC Section R501.3 or 2015 IRC Section R302.13, when installed in accordance with the PinkWood FRI Installation Guide.
The web sections of the PKI I-joists are uncoated when used in the FRI Assembly. WEBshield panels are 2-foot-long OSB panels cut to just fit between the top and bottom flanges and fastened to the webs of the PKI I-Joists using staples. WEBshield panels are factory coated in accordance with the FRI quality supplement with PS5005-PK Shield, a coating formulated for fire resistance at a thickness defined in the FRI quality supplement.
PinkWood chose Intertek as simply the most trusted and the most used certification company in the world when it comes to fire to certify PinkWood FRI series joists and WEBshield panels.
Overall, the PinkWood FRI assembly solution provides the best tested system on the market today.
Method 2. Factory-applied Proprietary Coatings and Thermal Barriers
Factory-applied fire protective coatings and thermal barriers are also used to enhance the fire resistance of I-joists. These methods are applied in a factory setting with stringent quality controls ensuring a permanent bond to the joists and reliable performance when exposed to high temperatures. These coatings must meet ICC-ES Acceptance Criteria AC14, which includes fire endurance and durability provisions. In most case these types of protective technologies are cost prohibitive and require the manufacturer to subsidize the cost of the technology in order to effectively market the technology. While these technologies provide compliance to the fire performance provision of the code, they often come at the cost of significant product weight, limited availability, limited product series and depths and in one case, a protective system which completely eliminates access to the joist web. This can create significant issues when trying to fasten electrical wire support clips and other miscellaneous hardware designed for wood based connections.
Method 3. Field-applied Fire Protective Coatings
A field-applied fire protective coating also complies with the IRC provisions. These coatings must meet the fire endurance portion of ICC-ES Acceptance Criteria AC14, but are not designed to meet the durability portion as these solutions are only allowed once the house or structure is dried in. Field-applied solutions also require the applicator or coating manufacturer to re-certify all components being sprayed, as most engineered products (I-joists, OSB, Plywood, Glulams, etc.) are required to remain dry per the manufacturers specifications. Overall, field applied fire protective coatings require the construction process to slow down in order to schedule additional trades, special inspections and other field related tasks to ensure the protective sprays are not rendered “non-compliant” due to mechanical, electrical and plumbing trade involvement.
Method 4. 1/2-Inch Gypsum Board Installed on Top of the Bottom Flange
Installers can add one layer of ½-inch gypsum board cut to fit between the I-joist webs and sized to lie on the top of the bottom flange of the I-joist. The minimum I-joist flange dimension must be 1-1/8 inches by 2 inches. No fasteners or adhesives are required to secure the gypsum. A maximum gap of 5/16 inch between the edge of the gypsum and the I-joist web is allowed. This option can be used when joist spacing is 19.2 inches on center or less.
Similar to ½-ince gypsum board, a layer of 5/8-ince gypsum board cut to fit between the I-joist webs and sized to lie on top of the bottom flange of the I-joist can be installed, where joists are spaced up to 24 inches on center. The minimum I-joist flange dimension must be 1-1/8 inches by 2 inches and a maximum gap of 5/16 inch between the edge of the gypsum and the I-joist web is allowed.
These methods work well for unfinished basements where builders or homeowners prefer not to have a finished gypsum membrane covering the ceiling. However, electrical wires and water lines ran close to the bottom flange will eliminate the ability to use this solution. In addition, inconsistent on center spacing of floor joists and/or plumbing offsets create “special” panel widths requiring field modification.
Method 5. 1/2-Inch Gypsum Board or 5/8-inch Wood Structural Panel Ceiling Membranes
Installer can add a layer of ½ -inch gypsum board to the bottom of the flange. There are several benefits to installing drywall to the underside of I-joist. Drywall is readily available in the market and the drywall does not have to be mud or tapped to meet the fire performance requirements. No special trades are required. Drywall performs very well in fire conditions.
There are a few challenges when using the drywall option: 1) The drywall is generally not finished or painted, therefore, the basement looks poorly to possible new home buyers. 2) As the basement is usually unfinished, in many cases the drywall needs to be taken down to introduce new mechanical, electrical and framing elements in the finishing process. 3) Generally, the cost to finish the basement with drywall is higher than using other methods.
Method 6. 1/2-Inch Gypsum Board Attached to I-joist Web Only
Installers can add a layer of ½-inch gypsum board directly to both sides of the I-joist webs. The minimum flange size for this option is 1-1/2 inches x 2 inches. This method is acceptable for unfinished basements where builders or homeowners prefer not to have a gypsum membrane covering the ceiling.
However, there are some disadvantages to this assembly: mechanical, electrical and plumbing components are harder to run. Connection hardware, previously designed for direct “wood” attachment must be extended to pass through ½-inch gypsum before connecting I-joist web material. The labour component is not ideal and generally the drywall trades are not interested in conducting this work.
Method 7. 1/2-Inch Gypsum Board Attached to Entire I-joist Depth
Installers can add a layer of ½-inch gypsum board directly to both sides of the flange to cover the entire I-joist depth. This method can be used with I-joists that have a relatively small flange size (min. 1-1/8 inches x 1-3/4 inches).
This method is acceptable for unfinished basements, where builders or homeowners do not want a gypsum membrane covering the ceiling. The disadvantage of this assembly is that mechanical, electrical and plumbing components are extremely hard to run. Connection hardware, previously designed for direct “wood” attachment cannot even reach the wood material of the I-joist web.
Method 8. Mineral Wool Batts
Installers can add a 3-inch-thick layer of 2.5 lb/ft3 nominal mineral wool fiber insulation to the top of the bottom flange between I-joists with a minimum flange size of 1-1/8 inches thick x 1-3/4 inches wide. The insulation is secured with insulation stay wires spaced no more than 24 inches apart and no more than 4 inches from ends of the batts.
This assembly can minimize noise transfer between the basement and the first floor living space. However, mineral wool thickness minimizes available space for HVAC duct work. If installation is desired for Energy Code Conservation, the available duct space is completely eliminated. In addition, electrical wires and water lines ran close to the bottom flange will eliminate the ability to use this solution.
Method 9. Ceramic Fiber Blanket Insulation
Installers can add a proprietary ¾-inch ceramic fire blanket insulation at a minimum of 4 lb/ft3 nominal, in compliance with ASTM C892 Type III or higher. This assembly can be used with I-joists having a minimum flange size of 1-1/2-inces thick x 2.3 inches wide. This solution is acceptable for unfinished basements where builders or homeowners do not want to use gypsum.
However, there are some disadvantages to this assembly: the use of screws and/or foams for component connections to the web will cause insulation to catch on threaded fasteners and “spool” material. In addition, the ability to cut through the fiber blankets for mechanical, electrical and plumbing penetrations is nearly impossible to accomplish with any efficiency.
Source: Fire Protective Options for I-Joist Floor Systems. APA Construction Guide, as of January 2016.
1. How do you demonstrate ‘equivalent performance’ to a 2 x 10?
The term “equivalency” was used in the 2012 IRC language. The AWC (American Wood Council), APA, Evaluation services and WIJMA jointly produced a document titled “Basis of IRC Membrane Protection Provisions” to help explain the nature of the provision and the basis for “equivalent” performance.
2. Why was 15 minutes 30 seconds time used to demonstrate equivalency?
The "Basis of IRC Membrane Protection Provisions" document outlines the 15-minute 30 second standard. The time was calculated based on the three sided burn time of a 2 x 10 solid sawn joist.
3. Why is the loading only 50% of design capacity?
The document "Basis of IRC Membrane Protection Provisions" represents a conservative estimate of in-service residential loads.
4. Why are builders not using the drywall solution?
a) Cost of materials is significant, and installation adds time to the construction process.
b) In its unfinished state, the drywall panels often show foot marks and construction related scuffs.
c) Drywall panels can cause damage to the joists bottom flange when the home owner wants to remove them in order to finish the basement at a later date. In addition, these panels simply become waste afterwards.
5. Why not to use sprinklers instead of FRI Assembly (PKI Joists plus WEBshield)?
a) The cost of sprinklers is prohibitive.
b) Home Owners' Insurance may be increased because of potential damage from accidental flooding.
c) Permit fees are greatly increased because separate water lines and meters must be installed.
d) The sprinkler system can be turned off if the house is not occupied.
6. I see it is possible to use drywall strips or infill panels. Why not use these solutions?
These solutions, along with some other generic options, have been tried and abandoned by many builders. See PinkWood’s website www.pinkwood.ca for detailed explanation.
7. Why does PinkWood not apply a continuous strip of WEBshield panels?
The proprietary intermittent design invented by PinkWood provides the required protection at a lower cost, and allows for the installation of mechanical ducting, wiring and piping between the WEBshield panels.
The WEBshield protected panels are manufactured and coated in a factory environment, and the stringent quality control systems are audited by Intertek Testing Services.
8. How does your product handle the wear and tear on-site versus competitive products?
The WEBshield protection is a wood based protection, which allows for customary handling of I-joists. No paper, foam or other items are used in the WEBshield solution.
9. Do you have installation details?
Yes. The installation details are shown on our website www.pinkwood.ca.
10. How do you handle mechanical penetrations? Does this change the fire performance?
Because the FRI Assembly with WEBshield panels is non-continuous, mechanical penetrations are achieved in the un-protected areas of the I-joist.
11. I see PinkWood uses IAPMO Evaluation Service. Why?
IAPMO UES is an accredited evaluation service that evaluates building materials, components and systems, reports on their compliance with national codes and standards, and provides assurance of their suitability for use in building construction. Evaluation reports issued by IAPMO UES provide solid evidence that products or systems comply with the provisions of these codes and standards. Recognition of Pinkwood FRI Assembly (PKI Joists with WEBshield panels) as equivalent in fire performance to 2-inch by 10-inch nominal dimension lumber is based on review of proprietary information, test reports issued by accredited laboratories demonstrating that the acceptance criteria contained in AC14 was satisfied, and surveillance of Pinkwood’s manufacturing operations.
IAPMO is a well-respected, nationally accepted Evaluation Service.
12. Can you use simple spans and multi-span design conditions?
Yes. There are no span (simple/multiple) restrictions.
13. Do you have the product approved in the other PinkWood joist series?
Yes. The FRI Assembly can be used for the 20, 23, 35+, 40 and 50 series PKI joists. Depth restrictions are from 11-7/8” minimum depth to 24”.
14. How do you design with FRI series in the design software?
The FRI Assembly is listed within the various software design systems. You simply select the PKI designated joist with the FRI extension when designing the main floor/basement joist spans. By choosing the FRI extension this automatically applies the moment reduction factor.
15. Does your system have intellectual property protection, patent, and industrial design?
Yes. Due to innovative non-continuous protection offered by the WEBshield system, PinkWood has both Canadian and International Patent filings. PinkWood also has secured industrial design protection on the system.
16. Why did you choose Intertek as your Quality Assurance agency?
From Intertek’s website, “For more than 130 years, companies around the world have depended on Intertek to help ensure the quality and safety of their products, processes and systems.” They are the most trusted and most used certification company in the world when it comes to fire.
17. Where are your products available?
We have Wholesale distribution coast to coast in the United States and in Western Canada. Please visit our website www.pinkwood.ca for a list of wholesale distributors.
18. Do your protective coatings contain Formaldehyde?
No. Our coatings are Formaldehyde free.
19. What is the benefit of a structurally reinforced system versus light duty protection?
The PinkWood Fire Rated joist creates a more solid and firm floor, in addition to providing fire protection.
20. What is the E119 test and how does it compare to an actual basement fire? How are proprietary construction products evaluated against the code?
ASTM E-119-16a “Standard Test Methods for Fire Tests of Building Construction and Materials” is the test protocols outlined and accepted by the industry to determine product performance in a fire. With the requirement to burn “floor systems” instead of parts or pieces, it provides a repeatable test set up that can compare fire assembly performance.