Most construction specifiers, architects, engineers and contractors are aware of the National Building Code's firestop compliances, but proper materials and application techniques are many times overlooked, which could lead to needless injuries and fatalities in a commercial building fire. Furthermore, using firestop materials economically can save a project tens of thousands of dollars without affecting efficiency or limiting life safety.
Hundreds of lives are saved and thousands of injuries are avoided annually during building fires, because of recent advancements in construction-phase firestopping efforts that minimize the transmission of smoke and other combustion byproducts into abutting areas.
Firestopping is a material or combination of materials used in re-establishing the fire-rated integrity of a wall or floor assembly that has been compromised by the inclusion or exclusion of a penetrant. Walls and floors in commercial buildings are code-compliant to fire ratings. However, if a penetrant, such as a pipe, cable tray or HVAC duct, alters the wall or floor's fire rating, it must be restored with an approved firestopping system. The goal is to eliminate the transmission of a fire's smoke, flames and hot gases from passing through the penetration into another room and buy more time for occupants to escape.
Current State of Firestopping
Firestopping and other fire safety technologies developed in the last half of the 20th Century are saving many lives today. Prior to the 1970's however, fatality and injury statistics from smoke and hot gas inhalation during commercial building fires were drastically higher. For example, a fire April 5, 1949, at St. Anthony’s Hospital in Effingham, Ill. was the worst hospital fire on record. Without fire compartments, firestopping and other standard features of modern fire protection codes, the blaze spread quickly and recorded 74 fatalities, according to Tony Crimi, P. Eng., president of A.C. Consulting Solutions and a former vice president and chief engineer at Underwriters Laboratories of Canada. Crimi detailed the catastrophe in a white paper, "Healthcare Fire Safety: Should We Backtrack on 60 Years of Improvement?" which is now listed on the www.firestop.org website of the International Firestop Council (IFC), a non-profit association of North American manufacturers, distributors and installers of passive fire protection materials and systems.
Today, nearly every country mandates firestopping in its new commercial construction projects. Historically, Europe led the development of firestopping building codes in the 1970's. It wasn't until the late 1980's that Canada's National Building Code (NBC) implemented firestopping codes that today are compliant with the CAN/UL-S115 standard.
All major construction projects in Canada now use the latest firestop technology, according to Gordon Martin, CEO, Canadian Thermal Technology (CTT), a Winnipeg-based firestopping manufacturer's rep/contractor. CTT has been instrumental in supplying firestopping to well-known projects such as Winnipeg's Investors Group Field--home of the CFL's Blue Bombers; and the recently built 14-story glass and brick Pembina Hall Residence on University of Manitoba's campus. Martin, who regularly provides contractors and specifiers with firestopping engineering judgments for projects throughout CTT's territory of western Manitoba, Saskatchewan, British Columbia and Alberta, says education is key to proper firestopping specification and installation. Thus, his firm regularly provides educational seminars on firestopping to firestop contractors and building trades contractors that penetrate walls, ceilings and floors.
The NBC code requires manufacturers to not only test each of its firestop products, but also test them with through every conceivable application. For example, a firestop sealant must pass the standard's test procedures for copper pipe penetrating a concrete wall, a gypsum wall, a wooden floor and other rated assemblies. Each penetrating material, such as copper pipe, steel pipe, cable trays, and today's trend toward more non-metallic or plastic pipe, is tested with various penetrations through walls, floors or ceilings. Therefore, Canada's mandate to test the product and its application makes it one of the most superior severe firestopping standards in the world.
Generally, firestop manufacturers either put together test assemblies with for in-house laboratories or send it to an outsourced approved laboratory. After the firestop material cures for up to 21 days, it's burned in a controlled laboratory fire. If it passes, the system design receives an identification number and is authorized to be specified and installed for that exact application in Canada.
The fact Canada has high standards doesn't always equate to proper firestopping, according to Antonio Caramagno, president of Consulco Inc., Lorraine, Quebec, a manufacturer's representative for firestopping, insulation and other commercial/residential building envelope construction materials. Unlike some of Canada's western provinces which have a proliferation of specialty firestopping contractors, Quebec's commercial firestopping is installed by contractors that make the penetrations or interior systems , such as plumbing, electrical, hvac HVAC and drywall contractors.
The fact that many contractors that don't specialize in firestopping makes education even more critical. For example, Caramagno provides many educational seminars to distributors such as plumbing specialist Fibro-Drain, Boisbriand, Quebec; and interior systems specialist, Up Drywall, Terrebonne, Quebec. Both distributors continually present educational seminars to their wholesale and contractor clients.
Once a firestop product complies with the NBC, a project's architect or engineer specifies that a firestop product is to be used in a penetration or floor/ceiling joint. Typically it's the general contractor or the installing trade that chooses a particular brand or method of firestopping the penetration.
Types of firestopping products
Firestopping products fall under several types such as caulking sealants, putties, mortars, pillows, boards, spray-on mastics, pipe collars, intumescent sleeves, joint strips, wrap strips, pass-thru devices and other products. Firestopping materials may also be generally classified as ‘intumescent’ or ‘non-intumescent’. An ‘intumescent’ material is one which will expand many times its volume when exposed to a certain amount of heat. Generally, intumescent materials are used with combustible penetrants such as non-metallic pipes.
Large projects many times use a variety of firestop methods. For example, CTT's Martin was instrumental in helping architects and engineers specify a variety of firestopping materials in the very challenging 191-room hotel project, Canad Inns Destination Centre on the campus of Health Services Centre, Winnipeg, one of the world's largest teaching hospitals. CTT , which is a member of the Hillside, Ill.-based Firestop Contractors International Association (FCIA), installed several firestop materials and devices to help comply with NBC construction codes and also save the project money with selections of the compliant materials at the least cost, according to Martin. CTT installed pass through devices, caulking, spray caulking and collars in the 14-story project for project general contractor, Manshield Construction, Winnipeg. "All of the firestop products on the project carry a lifetime warranty," Martin said.
Specifying firestopping products
Specifying firestopping products is a four step process. The engineer typically chooses a firestop method once the following is determined:
- the construction details of the floor or wall. --For example, concrete floor, gypsum wall, precast planks, etc..
- size of the opening--The annular space of the penetration may be too large to accept a caulking type solution and instead a collar or a sleeve might be more applicable;
- the penetrating item(s)--The major consideration is differences between metallic piping, such as copper or steel and non-metallic or plastic pipe, which typically will melt in a fire and therefore require a material that expands into the void the pipe once occupied before the fire;
- the hourly rating of the wall or floor--Hourly ratings typically range from one to four hours, therefore the proper firestopping system must match;
The firestopping material choice many times reflects on project costs. Several options, such as caulking sealants, collars or sleeves all perform well around a steel pipe during a fire. However, a specifier may make the mistake of choosing a more expensive solution, such as a collar, when a caulking sealant might be equally effective and at a significantly lower cost.
Firestopping costs can be reduced by selecting one type of caulking material to do more than one type of application on the job. For example, using the same product design that's UL Listed for both sealing the joint between curtain walls and floors, plus piping penetrations and cable trays, could save money and eliminate mistakes of using the wrong material on an application. Remember, no one product is good for ALL applications, be sure to select the right product and system design for each application.
Caulking the gap between a hole and pipe, cable tray, ductwork or whatever else might be penetrating a wall, ceiling or floor, is typically an effective method that is usually less costly when compared to other methods. In firestopping curtain wall, for example, the material choice can potentially save a project tens or hundreds of thousands of dollars in materials and labor. A recent Saudi Arabian project had more than 120 kilometers of curtain wall joints to seal. Choosing a UL-approved system design that utilized half the thickness of sealant than that of competitors, saved the project nearly 50-percent on firestopping materials and labor.
Project environments also dictate firestopping choice. The high humidity of an indoor pool, vibration in of a compressor, chemicals storage areas, seismic effects, building wind load, extreme temperatures and other environmental factors all dictate different firestopping material choices.
Another consideration is noise attenuation. Many projects require a firestopping system design that has been tested under ASTM E90 standards for a particular sound transmission class (STC) classification. Firestopping materials are rated typically between 55 and 65-STC. The higher the STC number, the better the sound attenuation. The NBC doesn't require STC rated firestopping designs, however an architect or engineer may specify a particular rating. For example, in a hotel environment where sound transmission between rooms is an important design factor, an architect might specify a high STC rating for the firestopping system design..
The increasing popularity of non-metallic piping (e.g. PVC) can be is problematic in a fire because it will be consumed. Therefore a melted pipe's surrounding firestopping material must be able to expand to fill the hole (intumesce). Although, some firestop sealants are intumescent, for larger non-metallic pipes, a more effective product may be which utilizes a pipe collar filled with intumescent material. The pipe collar holds the intumescent material in such a manner that its chemical expansion is directed toward the pipe. As the pipe softens from the heat of the fire, the intumescent material expands to shears the pipe in half closing it as it expands into the void. Consequently, it seals the hole so that no smoke, flame or hot gasses can escape to the next room due to the intumescent material’s rapid expansion. Some firestop products are capable of an expansion up to a 37:1 ratio. UL testing and approval has proven the effectiveness of these materials.
Intumescent materials have uses other than floor, ceiling or wall penetrations. These materials may also be applied to fire doors, dampers and joints between ceilings and walls.
Fire-rated collars can accommodate two-inch to 14-inch diameter non-metallic pipes. Collars are required on both sides of a wall because the fire could begin on either side of the wall. Floor/ceiling penetrations require a collar on only one side, usually the bottom side.
Intumescent sleeves are gaining in popularity because they may eliminate circumvent the need for installing two collars on each side of the penetration. Instead, the sleeve penetrates the entire width of the wall and intumesces during a fire to seal the opening. Specifying and installing a collar for every pipe size can be expensive and logistically difficult on large projects. Since sleeves can adapt to several pipe diameters within a range, specifying just one or two sleeve sizes, versus many different separate collars, can result in a cost savings for the project.
Cutting costs with firestopping selection
Choosing the right firestopping material is important for efficiency, but it can also be important for project costs and value engineering. Fortunately, most firestopping manufacturers offer website software for calculating how much material is needed. The software programs prompt for the type of product, hole shape, penetrating item size, hole diameter, product depth and the quantity of applications. The calculation reveals the total cubic inches of firestop material required and the number of containers needed.
Contractors, as well as distributors, need to know that firestopping materials and brands differ widely as to storage temperature tolerances and shelf life. Temperatures can range from 35F to 120F (2C to 49C), but not all materials boast that range. Products with a narrower range can become unstable when storage facility temperatures surpass the range. Many firestop products are water-based, therefore not all products will perform up to UL-approved standards if they freeze. Some products are stable after an unintended freeze/thaw period, others become damaged and can't be used. However, freeze/thaw periods usually don't affect firestop stability or efficiency after application and curing.
Shelf life, which can range anywhere from nine months to three years on caulking materials according to individual product specifications, is critical as well. Products with longer shelf lives are preferred when they are shipped long distances, or stored for long periods during project delays.
Backing materials, such as mineral wool, are used in annular spaces too large for caulking materials, which have a limitation as to the width of the hole they can fill. They are also used to conserve more expensive firestopping materials in a hole. Backing materials must also be specified within the approved design. Contractors should be knowledgeable in not only the use of the specified firestopping material, but also backing materials. Using non-compliant materials can compromise the fire rating of the wall, ceiling or floor.
Firestopping is a proven method of reducing fatalities and injuries during commercial building fires. However, it can only perform under its design standards when the proper materials are specified and installed competently under UL-approved technologies and methods.
Sidebar: Three Most Common Firestopping Specification Mistakes
- Putting too many penetrants through the same hole in a floor, ceiling or wall.
- Mixing penetrant types in the same hole, such as pipe and steel pipe. Different penetrant types may need different firestopping materials and installation techniques.
- Specifying a firestopping material or device that is not a UL-approved as a product or as a product for a particular application.
Sidebar: Three Most Common Installation Mistakes
- Using a code-compliant firestop systems, but not for UL-approved for the application.
- Not properly tooling a sealant into the void around a penetrant.
- Using backing materials to fill a hole that isn't UL-approved.
Randy Clark, manager of firestop technologies--international division; and Bill Flynn, v.p. of international hardware and OEM sales; have a combined 53 years in the firestop industry and 51 years at RectorSeal®, Houston, a manufacturer of firestop, chemical, HVAC/R and plumbing products with worldwide distribution.
Clark consults specifiers, contractors and end-users of all commercial construction projects on using the correct firestopping materials and techniques for optimum code compliance and fire safety. RectorSeal is one of the few manufacturers that tests its own firestop products with a certified in-house laboratory under the CAN/UL-S115 standards. RectorSeal is a leading manufacturer of firestop products under the Metacaulk™ and Bio FireShield™ tradenames