Perfecting Firestopping: Materials, techniques, and specifications to reduce building fire fatalities and injuries

Photos courtesy RectorSeal Corp.
Photos courtesy RectorSeal Corp.

By Bill Flynn and Randy Clark
Most construction specifiers, architects, engineers, and contractors are aware of the National Building Code of Canada’s (NBC’s) firestop compliances, but proper materials and application techniques are nevertheless often overlooked. This situation could lead to needless injuries and fatalities in a commercial building fire. However, using the correct firestop materials can save a project thousands of dollars without affecting efficacy 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 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 1970s, fatality and injury statistics from smoke and hot gas inhalation during commercial building fires were drastically higher.

Contractors and distributors need to know firestopping materials and brands differ widely as to storage temperature tolerances and shelf life. As many firestop products are water-based, not all perform up to UL-approved standards if they freeze. Some products are stable after an unintended freeze-thaw period, others become damaged and cannot be used.
Contractors and distributors need to know firestopping materials and brands differ widely as to storage temperature tolerances and shelf life. As many firestop products are water-based, not all perform up to UL-approved standards if they freeze. Some products are stable after an unintended freeze-thaw period, others become damaged and cannot be used.

For example, a 1949 fire in Illinois led to 74 fatalities due to a lack of fire compartments, firestopping, and other standard features of modern fire protection codes. Tony Crimi, P.Eng., president of A.C. Consulting Solutions and a former vice-president and chief engineer at Underwriters Laboratories of Canada (ULC), detailed the catastrophe in a white paper, “Healthcare Fire Safety: Should We Backtrack on 60 Years of Improvement?”1

Today, nearly every country mandates firestopping in its new commercial construction projects. Historically, Europe led firestopping building code development in the 1970s. A decade later, NBC began mandating firestopping practices are compliant with CAN/ULC S115, Standard Method of Fire Tests of Firestop Systems.

All major construction projects in Canada now use the latest firestop technology, according to Gordon Martin, the CEO of Canadian Thermal Technology (CTT), a Winnipeg-based firestopping manufacturer’s representative/contractor. CTT has been instrumental in supplying firestopping to well-known projects such as Winnipeg’s Investors Group Field—home of the Canadian Football League’s (CFL’s) Blue Bombers; and the recently built 14-storey 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 to firestop contractors and building trades contractors that penetrate walls, ceilings, and floors.

NBC requires manufacturers to test not only each of its firestop products, but also 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 (e.g. copper pipe, steel pipe, cable trays, and 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 severe firestopping standards in the world.

N--Hands on seminar for firestopping
Hands-on training is available from many manufacturers, industry groups, and companies such as Canadian Thermal Technology (CTT)—a Winnipeg-based firestopping manufacturers rep/contractor. CTT was instrumental in supplying firestopping to the city’s Investors Group Field—home of the CFL’s Blue Bombers.

Generally, firestop manufacturers either put together test assemblies for in-house laboratories or send it to an outsourced, approved laboratory. After the firestop material cures for up to 21 days, it is burned in a controlled laboratory fire. If passed, 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 does not always equate to proper firestopping, according to Antonio Caramagno, president of Consulco, a Lorraine, Que.-based 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), Québec’s commercial firestopping is installed by contractors that make the penetrations or interior systems, such as plumbing, electrical, HVAC and drywall contractors.

The fact many contractors do not specialize in firestopping makes education even more critical. For example, Caramagno provides many educational seminars to distributors such as plumbing and interior systems specialists in the province. In turn, these distributors continually present educational seminars to their wholesale and contractor clients.

Once a firestop product complies with NBC, a project’s architect or engineer specifies a firestop product be used in a penetration or floor/ceiling joint. Typically, it is the general contractor or the installing trade that chooses a particular brand or method of firestopping the penetration.

Types of firestopping products
Firestopping methods fall under several types, such as:

  • caulking sealants;
  • putties;
  • mortars;
  • pillows;
  • boards;
  • spray-on mastics;
  • pipe collars;
  • intumescent sleeves;
  • joint strips;
  • wrap strips; and
  • pass-through devices.
A still image from the video, “Close Enough is Not Good Enough: A Demonstration of Proper Vs. Improper Firestopping,” produced jointly by UL and the International Firestop Council (IFC). The resource is available for free viewing at www.fi restop.org. Photo courtesy International Firestop Council
A still image from the video, “Close Enough is Not Good Enough: A Demonstration of Proper Vs. Improper Firestopping,” produced jointly by UL and the International Firestop Council (IFC). The resource is available for free viewing at www.firestop.org. Photo courtesy International Firestop Council

Firestopping materials may also be generally classified as ‘intumescent’ or ‘non-intumescent.’ The former expands many times its volume when exposed to a certain temperature. Generally, intumescent materials are used with combustible penetrants such as non-metallic pipes.

Large projects frequently use various firestop methods. For example, CTT’s Martin was instrumental in helping architects and engineers specify a variety of firestopping materials in the challenging 191-room hotel project, Canad Inns Destination Centre on the Winnipeg campus of Health Services Centre—one of the world’s largest teaching hospitals. CTT, which is a member of the 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-storey project for project general contractor, Manshield Construction.

“All the firestop products on the project carry a lifetime warranty,” Martin said.

Highly intumescent wrap strips can be successfully used around large non-metallic pipes. During a fi re, the product’s interior heats up and expands into any void around the hole or pipe.
Highly intumescent wrap strips can be successfully used around large non-metallic pipes. During a fire, the product’s interior heats
up and expands into any void around the hole or pipe.

Specifying firestopping products
Specifying firestopping products is a four-step process. The engineer typically chooses a firestop method once the following is determined:

  • construction details of the floor or wall (e.g. is the material concrete floors, gypsum walls, or precast planks?);
  • opening size (e.g. annular space of the penetration may be too large to accept a caulking type solution—instead a collar or sleeve might be more applicable);
  • penetrating items (e.g. major consideration is differences between metallic [like copper or steel] and non-metallic 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); and
  • hourly rating of the wall or floor (e.g. hourly ratings typically range from one to four hours, therefore the proper firestopping system must match).

The firestopping material choice often reflects on project costs. 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 significantly less costly.

Firestopping costs can be reduced by selecting one type of caulking material to perform more than one kind of job application. For example, using the same product design that is CAN/ULC-approved for both sealing the joint between curtain walls and floors, along with piping penetrations and cable trays, could save money and eliminate mistakes of using the wrong material on an application. Given no single product can be comprehensive for all applications, proper selection is critical.

Caulking the gap between a hole and pipe, cable tray, ductwork, or whatever else might be penetrating a wall, ceiling, or floor, is usually less costly when compared to other methods. In firestopping curtain wall, for example, the material choice can potentially save a project hundreds of thousands of dollars in materials and labour. A recent Saudi Arabian project had more than 120 km (75 mi) of curtain wall joints to seal. Choosing a CAN/ULC-approved system design employing half the thickness of sealant versus competing products, saved the project nearly 50 per cent on firestopping materials and labor.

Some manufacturers test their own products in-house with highly trained chemists and quality control personnel under CAN/ULC S115 requirements. Here a company tests its materials in-house to carefully monitor all areas of production.
Some manufacturers test their own products in-house with highly trained chemists and quality control personnel under CAN/ULC S115 requirements. Here a company tests its materials in-house to carefully monitor all areas of production.

Project environments also dictate firestopping choice. The high humidity of an indoor pool, vibration of a nearby compressor, chemical 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, Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements, 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.

NBC does not require STC-rated firestopping designs, but 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, the design professional might specify a high STC rating for the firestopping.

The increasing popularity of non-metallic piping, such as polyvinyl chloride (PVC), can be problematic in a fire because it will be consumed. Therefore, a melted pipe’s surrounding firestopping material must have the ability for expansion to fill the hole.

Although some firestop sealants are intumescent for larger non-metallic pipes, a more effective product may be a pipe collar filled with intumescent material. The pipe collar holds the intumescent material in such a manner its chemical expansion is directed toward the pipe. As the pipe softens from the heat of the fire, the intumescent material shears it in half while its expansion closes the void. Consequently, the rapid expansion of the intumescent material seals the hole so no smoke, flame, or hot gasses can escape to the next room. Some firestop products are capable of an expansion of up to a 37:1 ratio. CAN/ULC testing and approval has proven the effectiveness of these materials.

Product may be applied by several methods; in this photo, it is sprayed for quick and efficient coverage.
Product may be applied by several methods; in this photo, it is sprayed for quick and efficient coverage.

Intumescent materials have uses other than floor, ceiling, or wall penetrations. They are also applied to fire doors, dampers, and joints between ceilings and walls.

Fire-rated collars can accommodate 50 to 356-mm (2 to 14-in.) diameter non-metallic pipes. Collars are required on both sides of a wall because the fire could begin on either side. Floor/ceiling penetrations typically require a bottom-side collar.

Intumescent sleeves are gaining in popularity because they may eliminate the need for installing collars on each side of the penetration. Instead, the sleeve penetrates the wall’s entire width and intumesces 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 cost-savings.

Cutting costs with firestopping selection
Choosing the right firestopping material is important for efficacy, but it can also be important for project costs and value engineering. Fortunately, most firestopping manufacturers offer software for calculating how much material is needed. These proprietary programs prompt for product type, 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 firestopping materials and brands differ widely as to storage temperature tolerances and shelf life. Temperatures can range from 2 to 49 C (35 to 120 F), 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 CAN/ULC-approved standards if they freeze. Some products are stable after an unintended freeze/thaw period, while others become damaged and cannot be used. However, freeze/thaw periods usually do not affect firestop stability or efficacy after application and curing.

Quick, effective and easy installation can be accomplished with the electrical box guard products that are available in all box configurations.
Quick, effective and easy installation can be accomplished with the electrical box guard products that are available in all box configurations.

Shelf life is also critical; it can range anywhere from nine months to three years on caulking materials according to individual product data sheets. Materials with longer shelf lives are preferred when they are shipped long distances, or stored for extended 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.

Conclusion
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 CAN/ULC-approved technologies and methods.

Notes
1 The white paper is now listed on www.firestop.org—the 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. (back to top)

rs Headshot Randy ClarkRandy Clark is firestop technologies manager for the international division of RectorSeal, a manufacturer of firestop, chemical, HVAC/R, and plumbing products with worldwide distribution. He has 30 years of industry experience, consulting specifiers, contractors, and end-users of all commercial construction projects on using the correct firestopping materials and techniques for optimal code compliance and fire safety. Clark can be reached via e-mail at randyclark@rectorseal.com.

 

rs Headshot Bill FlynnBill Flynn is RectorSeal’s vice-president of international hardware and OEM sales. He has more than two decades of experience in firestopping. Flynn can be reached at billflynn@rectorseal.com.

 

To read the sidebar “Three Most Common Specification Mistakes,” click here.

To read the sidebar “Three Most Common Installation Mistakes,” click here.

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