Time to rethink fire sprinkler pipe materials

By By Matthew Kuwatch, Lubrizol

CPVC offers attractive alternative; benefits include cost efficiency and fast, easy, reliable installations.

Today there are more options for designing fire sprinkler systems than ever before. That includes a number of new technologies and piping materials designed to improve the overall performance, reliability and cost efficiency of the system. 

Lubrizol (formerly BFGoodrich Performance Materials) is credited with the invention of chlorinated polyvinyl chloride (CPVC) back in 1959. This high-performance plastic has been successfully used in fire sprinkler applications since the mid 1980s under the BlazeMaster® brand name. During the past 20+ years, it has quickly grown in popularity, largely because of its fast and easy installation process which allows contractors to meet tight deadlines and even tighter budgets. 

Today, BlazeMaster CPVC pipe and fittings are the number-one specified fire sprinkler piping system in the world, having been installed in a wide variety of commercial and residential applications, including high rises, hotels, college dorms, hospitals and single-family homes. 

Considerations When Specifying CPVC
This specialty Listed product is approved for all light hazard, wet systems in accordance with NFPA 13, 13D and 13R. As part of the Listing for use in NFPA applications, it is approved for use in buildings higher than four stories. Having been tested and proven to meet the requirements of UL 1887, BlazeMaster® CPVC piping systems are also approved for installation in return air plenums (UL 1887 is referenced by NFPA 90A and the model codes as the standard for flame and smoke characteristics for nonmetallic fire sprinkler pipe). CPVC meets the requirements of all major model building codes. It is Listed by UL, UL of Canada, the Loss Prevention Certification Board (LPCB) and VdS (German approval). Specifiers should still refer to local jurisdictions for complete code requirements. 

Since CPVC is used in such a wide variety of fire sprinkler applications, each with its own specific requirements, pipe and fittings manufactured today are available in a wide variety of sizes. Specifically, CPVC pipe is produced in SDR 13.5 dimensions according to ASTM F442 and is available in sizes ¾” to 3” (20 mm to 80 mm) in diameter. The pipe is complemented with a full line of solvent weld fittings and transition fittings, which are Schedule 40 or 80 for ¾” to 1-1/4” (20 mm to 32 mm), and Schedule 80 for 1-1/2” to 3” (40 mm to 80 mm). The fittings are manufactured per ASTM F437, F438, and F439.  Since they are not as bulky as iron fittings, they further accommodate tight spaces well.

CPVC pipe and fittings are rated for continuous service of 175 psi at 150°F (12 Bar at 65°C).  As part of the UL Listing requirements the pipe is tested at five times the rated maximum pressure of 175 psi (12 Bar), which is 875 psi (60 bar). 
 
When working with CPVC pipe and fittings, however, it’s important to remember that not all CPVC pipe and fittings are the same. Since the CPVC compounds used to make pipe and fittings are derived from different base resins, performance is not necessarily consistent between manufacturers. Some CPVC resins and compounds are specifically developed to optimize performance for their individual applications and are designed to meet or exceed existing code and approval requirements. CPVC pipe and fittings with extra Listings or approvals can be very valuable to both the engineer and sprinkler contractor due to increased flexibility of product use. BlazeMaster® CPVC fire sprinkler systems, for instance, have more Listings and approvals than any other non-metallic pipe or fittings currently on the market.

Why Specify CPVC?
There are many benefits to using CPVC fire sprinkler pipe and fittings – the greatest being overall installed cost savings.  Why is CPVC less expensive to install? 

• Field fabrication is quick, simple and clean
• Fast installation resulting from a one-step, low VOC, solvent cement joining system
• CPVC pipe is lightweight, so it’s easier to transport and handle on the job site
• No need for shop fabrication. You can fabricate the system right on the job site, which saves time and eliminates costly errors that arise from the prefabrication of steel pipe systems.
• A higher Hazen-Williams C factor often allows for increased flow and pipe downsizing.  Steel pipe has a C factor of 120 when new compared to the C factor of 150 of CPVC. This higher C value produces less friction loss and generally results in a pipe diameter at least one size smaller than that of steel.
• A natural immunity to scale, corrosion and MIC (microbiologically influenced corrosion) means a longer, lower maintenance service life
• More predictable, controlled material costs since, unlike metals with their skyrocketing prices, CPVC pipe and fittings are not a limited natural resource subject to international supply and demand fluctuations
• 50-year life expectancy with a safety factor of 2

One additional advantage worth noting is that nearly all CPVC fire sprinkler systems, including BlazeMaster pipe and fittings, are hydraulically calculated. Compared to more outdated, inefficient pipe schedule systems, these hydraulically calculated systems offer greater efficiencies because pipe size is directly proportionate to the needs of the job to avoid pipe oversizing. (A pipe schedule system relies exclusively on the number of sprinkler heads being fed into the system for determining pipe sizing. A hydraulically calculated system, in contrast, determines the size of the pipe based on the NFPA density required as a result of the available water supply. It takes into account water flows, sprinkler head specifications, static pressures, press loss through friction, and many other factors in order to calculate a given density of water necessary to meet the NFPA-determined fuel load.)

During retrofits, all of the above-referenced benefits apply.  In addition, CPVC offers these additional retrofit advantages:
• Faster completion time means less down time which helps increase occupancy rates and maximizes revenue during the retrofit
• Less occupant disruption since installation process is quieter and cleaner
• Design flexibility which allows CPVC piping systems to be installed on walls or ceilings (and even in tight spaces since extra space is not required for a pipe wrench to turn)
• Scheduling flexibility since contractors can stop or start anywhere on the job site (not possible when using steel due to the threaded fittings)
• Space savings since CPVC pipe and fittings can be strapped to ceilings or walls (Code requires metal pipe to be hung)
• Ability to avoid asbestos and major cleanup costs in older buildings since CPVC is lightweight enough to be strapped to the wall and avoid contact with asbestos

More Stringent Testing Ensures High Performance
As a specialty Listed product, CPVC piping systems have undergone more rigorous testing and been subject to more scrutiny than many other traditional piping products, such as steel or copper. Neither steel nor copper pipe have been subject to the same requirements relative to their ability to withstand extreme stress, temperatures or pressure. They have been grandfathered in most codes and “assumed” to be acceptable.

BlazeMaster CPVC piping systems, in contrast, have undergone numerous performance tests in order to obtain their FM approval and UL Listings including:
• Hydrostatic pressure tests to confirm the system won’t leak (when properly installed) even after being exposed to 375 psi (26 Bar) continuous pressure at 150°F (65°C) for 1,000 hours
• Pressure cycling tests where the pipe and fittings are subjected to pressures ranging from zero to twice the rated pressure (350psi / (24 Bar)) for 3000 cycles. This test sample is then subjected to 875 psi (60 Bar) for one minute.
• Temperature cycling test where the pipe and fittings are subjected to temperatures ranging from 35°F (2°C) to the rated temperature (150°F / 66°C). Five temperature cycles are conducted with the pipe and fittings being held for 24 hours at each temperature, for a total of 10 days. This test sample is then subjected to 875 psi (60 Bar) for one minute.
• Quick burst test ensures that the pipe can meet a minimum 1,000 psi (69 Bar) of pressure at room temperature
• Actual performance testing under fire conditions is also conducted.

With specific regard to fire performance, there are a number of misperceptions that must be rectified so that CPVC can accurately be considered a safe material option. Consider the following facts:
• CPVC has a high flash ignition temperature of 900°F (482°C). This is the lowest temperature at which sufficient combustion gas is evolved that can be ignited by a small external flame.  Many other building materials, such as wood, ignite at 500°F (260°C) or less. So it is unlikely, if not impossible, that the temperature within a wall cavity would ever reach that of CPVC ignition temperature.
• CPVC resists burning due to its high Limiting Oxygen Index (LOI).  LOI is the percentage of oxygen needed in an atmosphere to support combustion.  This means CPVC will not sustain burning because of its high LOI of 60.  Since the Earth’s atmosphere is only 21 percent oxygen, CPVC will not burn unless a flame is constantly applied.  It stops burning when the ignition source is removed. 
• CPVC offers low smoke toxicity. Testing at Underwriters Laboratories of Canada has shown that CPVC produces only one-third the smoke of kiln-dried wood.
• CPVC has a low flame/smoke spread development rating. Since CPVC meets the required values for flame spread index and smoke density index when tested in accordance with UL 1887, it is allowed within air plenums.
• CPVC features low thermal conductivity. Since it is an insulator, CPVC pipe transfers considerably less heat than metallic pipe. So in the event of a fire, CPVC pipe will not transport heat from one room to another.
• Firestopping can be accomplished with CPVC as any other accepted piping material. All firestopping systems must comply with ASTM E814 standards whether they are used with CPVC or copper. So even if a fire spreads beyond the control of the CPVC sprinkler system, the intumescent seal of the firestop would expand to seal off the area around the pipe – CPVC or metal – and protect the building, its contents and its occupants

Conclusion
It’s important to realize that, today, specifiers and contractors do have choices when it comes to piping materials. CPVC is a prime example of a newer technology that offers numerous advantages when used in residential and commercial fire sprinkler applications. It has been proven, through both lab tests and actual installations, to offer greater cost efficiencies, as well as superior reliability. Especially in light of skyrocketing metal prices that have consistently pounded profit margins for the past five years, it is in the best interests of both the specifier and the client to become knowledgeable on all the available options and make the most cost-efficient choice.

Although CPVC is still not approved for all environments, it has been proven to be highly effective for light hazard and residential occupancies. In some cases, the decision to convert to CPVC means that other considerations should be factored into the design phase. That’s why it’s important to choose a product manufacturer that provides the type of technical expertise and field support to help guide you through the design and installation process. 

By understanding the various design parameters of CPVC, you will be in a better position to leverage the product’s benefits and design the most cost-efficient, reliable system to the benefit of your clients.

For more information about the benefits of CPVC pipe and fittings for fire sprinkler systems, visit www.blazemaster.com.  To contact the author, call (216) 447-6331 or matthew.kuwatch@lubrizol.com.

Matthew Kuwatch has been the Global Marketing Manager for BlazeMaster® CPVC Fire Sprinkler Systems since 2000. He has spent more than 16 years in the construction materials field with more than eight years involving the fire sprinkler industry in market development positions.
 
Mr. Kuwatch holds a Bachelor of Business Administration from Kent State University in Kent, Ohio. He also holds a Master of Business Administration from The Weatherhead School of Management, Case Western Reserve University in Cleveland, Ohio.
 
Mr. Kuwatch is a member of the National Fire Protection Association, National Fire Sprinkler Association, American Fire Sprinkler Association, International Fire Sprinkler Association, Society of Fire Protection Engineers, and The Home Fire Sprinkler Coalition. He is also the Executive Director and Chairman of the Board of Trustees for The Ohio Fire Safety Coalition.