It’s a proven fact – fire sprinklers save lives and protect property by controlling fires. According to a study by the US National Fire Protection Association (NFPA) the civilian death rate was 87% lower in properties with sprinklers compared to those without fire-suppression systems. Equally important, the average firefighter injury rate was 67% lower where fire sprinklers were in use.
In designing a fire-sprinkler system for new construction or a retrofit, planners must make an early decision on which type of pipe to use – a decision that usually comes down to steel versus chlorinated polyvinyl chloride (CPVC). Steel has been the traditional choice since sprinkler systems were invented in the 19th century.
But today CPVC offers a variety of advantages based on cost, performance, system longevity and environmental impact. That’s why it is a popular choice for both new construction and retrofits of offices, schools, high rises, hospitals, nursing homes and many other applications. It is listed by Underwriters Laboratories (UL) for use in any light-hazard occupancy as defined by the NFPA.
Facts about CPVC
CPVC is different from other thermoplastics – when installed per its listings, it resists heat and fire and maintains its structure when directly exposed to a flame. That’s because the base PVC polymer is fortified with extra chlorine molecules and additives that enable the pipe to withstand intense heat and pressure. In a UL test, a leading brand of CPVC was exposed to a fire plume between 698°F and 901°F (370°C and 483°C) and continued to perform.
When CPVC is exposed to a fire, a charring layer forms on the outside of the pipe and fittings. This serves as a thermal barrier that reduces heat conduction. Water flowing through the pipe cools the inside to further resist heat. When installed per its listing, CPVC maintains its structure to ensure delivery of water to extinguish a fire. In addition, the molecular structure of CPVC limits smoke generation.
As you consider options, here are five advantages for CPVC over steel pipe:
1. CPVC is less expensive
CPVC offers advantages in both the cost of material and labour. In fact, savings can reach up to 30% depending on the type and size of the project.
CPVC’s superior hydraulics is part of the cost advantage. The smoothness of a pipe’s surface has a direct impact on ensuring enough water reaches a fire to suppress it. The interior surface of CPVC is smoother than steel pipe, creating less friction to interfere with water flow. As a result, planners may be able to specify smaller-diameter pipe to reduce overall material costs.
2. CPVC installation is faster and easier
CPVC also offers substantial savings on labour costs because it is easier to install. Steel pipe is 84% heavier than CPVC, which means crews need special equipment and additional workers just to move it around the site. Special rigging may be needed on multi-story projects because steel may not fit in the elevator to be transported to upper levels. Parts of the system may need to be fabricated off-site, which slows the installation process.
By contrast, lightweight CPVC is installed with a quick, simple joining process that allows one person to cover an area using basic hand tools along with a quick, one-step solvent cement welding process. Fabrication can be completed on the spot. It is also easier to accommodate design alterations during construction. Changes that would require refabricating a steel project can be readily made on-site.
CPVC’s easy installation is especially valuable in retrofits. Because it is rigid, steel is difficult to manoeuvre through tight and hard-to-reach areas. Lightweight, flexible CPVC pipe is easy to fit into confined spaces commonly found in retrofit projects.
For instance, a Sacramento-area contractor started a 24,000sq. ft office retrofit with steel pipe, but quickly realized CPVC installation would be less expensive. In this case, the project required fitting pipe between trusses, which was cumbersome using steel pipe. Using CPVC instead of steel reduced labour by about 35% which saved about 100 man-hours on the project. Overall, use of CPVC saved the building owner $21,000.
3. CPVC lowers maintenance costs
Unlike steel, CPVC will not corrode, which eliminates costly repairs and reduces total cost of ownership.
With steel pipe, the combination of water, water treatment chemicals and oxygen can cause corrosion to start quickly – potentially in less than two years. A study by a German fire-safety firm found that 35% of wet systems have significant corrosion issues after 25 years. Corrosion eats away at the interior of the pipe to cause pinhole leaks and create friction along the pipe surface, which slows water flow if fire strikes. Steel pipes are also prone to mineral build-ups that attach to the pipe (scaling), often near fittings and corners. Over time, scaling can restrict or even stop the flow of water.
The roughness along a pipe is calculated through the Hazen-Williams C Factor formula. The higher the number, the smoother the pipe. For instance, BlazeMaster CPVC has a C Factor of 150 – and that remains stable throughout its life because it naturally resists corrosion and scaling. By comparison, new steel pipe has a C Factor of just 120, but performance declines over time as the surface corrodes.
In addition to slowing water flows, corrosion and scaling inevitably lead to expensive repairs. By contrast, CPVC pipe naturally resists corrosion and scaling for the life of the system, even in challenging environments with salt air or with fluctuating pH balances in the water. If repairs are needed, neither hot work nor messy cutting oils are needed, minimizing the disruption to building occupants.
4. CPVC offers a greener solution
Green building is a top priority as developers choose products that mitigate environmental impacts, and CPVC offers significant advantages over steel pipe. An ISO-compliant life-cycle assessment found that a leading brand of CPVC is much less harmful to produce and has half the climate change impact of steel pipe. CPVC outperformed steel in 12 out of 13 categories such as human toxicity, mineral and water depletion, non-renewable energy use and others.
5. For retrofits, CPVC installation is less disruptive for building occupants
Installing steel fire sprinkler systems is a noisy process that creates unpleasant odours. Open-flame torches require special permits and create a fire hazard. Noisy threading machines are needed to fabricate and connect the system. As a result, tenants must typically be relocated during a retrofit.
CPVC installation is cleaner and quieter, which creates minimal disruption for building occupants. For instance, if installers work in an office overnight, they can leave the site cleaned up so the business can be open as usual in the morning. With steel installation, there would be much more clean-up required and heavy equipment would need to be relocated.
CPVC’s simpler, quieter installation process can help meet challenging deadlines. For instance, the University of Texas was faced with the need to retrofit the largest residence hall in North America. Because students were living there, it wasn’t practical to close the dorm, or even sections. With CPVC, the contractor was able to retrofit the dorm rooms during daytime hours when students were unlikely to be there. As a result, the contractor was able to install sprinklers over more than 1 million sq. ft in 11 months without relocating students.
Ensuring a successful project
Once you decide to go with CPVC for your project, it is important to carefully evaluate brands, as not all orange CPVC is the same. Key items to consider include:
- Broad approvals. Ensure the brand you choose meets and exceeds global performance and manufacturing standards in addition to having the proper local approvals.
- Burst and impact resistance. Look for independent testing that assesses these critical metrics for ensuring dependable long-term performance.
- Partner manufacturers. Ensure the CPVC you choose is made by a manufacturer with a proven track record of maintaining consistent quality and strict standards.
- Chemical compatibility programme. Choose a brand that has a robust, extensive compatibility programme to ease the burden associated with researching and selecting accompanying construction products. Look for a programme that offers extensive information on compatible and incompatible brands and products and, most importantly, requires suppliers to complete third-party validation and audits of manufacturing sites.
- Training and support. Rigorous training for contractors ensures your project will be completed safely to a high standard. Be sure to choose a supplier that offers high-quality support to help resolve technical issues and keep the project moving forward.
Following these guidelines will allow you to make the right choice for your next project and ensure the fire-sprinkler system works as designed to protect people and property.
For more information, go to www.blazemaster.com