A Sprinkling of Expertise
This month's panel of fire protection experts hash out the advantages and disadvantages of steel, copper and CPVC sprinkler systems. CSE: What are the main advantages and disadvantages of copper, steel and chlorinated polyvinyl chloride (CPVC) sprinkler piping materials? SCHULTZ: Steel is the oldest, most common pipe in use.
This month’s panel of fire protection experts hash out the advantages and disadvantages of steel, copper and CPVC sprinkler systems.
CSE: What are the main advantages and disadvantages of copper, steel and chlorinated polyvinyl chloride (CPVC) sprinkler piping materials?
SCHULTZ : Steel is the oldest, most common pipe in use. Copper pipe weighs less and is more hydraulic, but the cost varies dramatically between the two. Plastic provides a light, hydraulically superior pipe that is less prone to microbiologically induced corrosion, but some contractors are not comfortable working with it. In addition, certain municipalities will not allow plastic pipe, or limit the occupancies that it can go into. The contractor must understand the listing to recognize when it must be installed behind a ceiling and when and how it can run exposed.
OLAH : The advantages of traditional metallic sprinkler systems, such as copper and steel, are their familiarities within the industry. There doesn’t seem to be a learning curve associated with these systems, whereas with systems such as CPVC, training must accompany the use of the products.
However, the disadvantages of the traditional metallic systems are numerous. Primarily the longevity of these systems, in relation to the environment that they must reside in, may compromise the system over time—these systems are highly susceptible to both external and internal corrosion, rendering the system inoperable and requiring costly replacements. Other disadvantages are the labor-intensive tools and equipment required to install traditional metallic systems. Usually welding, cutting, soldering and forming devices are required, which make it either necessary to fabricate portions of these systems off-site or bring these devices to the job site.
STUDER : Schedule 40 steel pipe with threaded fittings provides a secure and reliable system with few leaks. However, steel pipe also is the heaviest pipe to install, as Mr. Schultz said, and requires additional time to join pipe together. But with the advent and acceptability of schedule 10 pipe using grooved fittings for larger sizes, steel pipe systems became somewhat lighter and easier to handle and install. It does bring up longevity issues, because schedule 10 pipe has a thinner wall than schedule 40 pipe. Also, the process of grooving pipe requirescloser attention to tolerances to provide an equally secure and reliable joint as a screwed joint.
CSE: When determining which piping technology to use, are certain materials better suited for certain applications?
OLAH : Obviously, the first consideration is whether the system is appropriate for hazard classification, and the fire sprinkler system’s longevity.
SCHULTZ : Plastic pipe seems to be carving a nice niche for itself in college dormitories, due to its ability to be installed over the summer. At the same time, steel pipe remains the product of choice in other commercial applications, including office occupancies. There is a hesitancy on the part of the contractor to install plastic in office buildings, due to a need for future fit-outs. Of course, as long as we continue to sprinkler warehouses and storage occupancies, a market will remain for steel pipe.
STUDER : There are many issues to take into consideration—what goals owners are trying to accomplish. Are they trying to install the cheapest possible acceptable systems to mitigate code violations? Are they trying to safeguard their sensitive equipment from system accidents? Do they want systems that will last as long as possible?
I found that telecommunication switching stations are ideal for schedule 40 steel pipe with screwed fittings as it’s an arrangement with a long reliable track record. However, one wouldn’t use steel pipe for areas such as MRI rooms in hospitals, due to the magnetic conditions caused by equipment operation.
As a side note, often certain pipe materials are used due to location or logistics. For instance, sprinkler systems in the Hawaiian Islands usually are made of copper due to its relative availability and economics.
Another example is the use of CPVC systems in new high-rise residential buildings. The systems are relatively inexpensive and quick to install, and odor is not an issue. The pipe typically is installed in non-accessible ceilings or soffitts where it is not susceptible to damage.
CSE: What’s the latest with sprinkler head technologies?
STUDER : New technologies continue to address specific conditions. In the recent past, early suppression fast response (ESFR) sprinklers were developed to protect various rack storage conditions without requiring in-rack sprinklers. Window sprinklers were developed to provide the equivalent rating to windows installed in rated walls. And more recently, we have seen the development of attic sprinklers to better accommodate unique roof configurations. I understand that there is interest in developing a sprinkler for use in confined spaces where standard sprinklers are obstructed from developing their normal spray patterns and are ineffective. Another example is the development of the water mist system, which is used for various application-specific conditions, such as deep fat fryers, flammable liquid storage and electrical switchgear.
SCHULTZ : It seems as if the continual introduction of new sprinklers has slowed. Maybe it is time for the industry to take a break and see where we are. I am sure we are coming up to another sprinkler renaissance, but as of now, the introduction of new technology has slowed.
CSE: Is there a shortage of qualified sprinkler system designers and installers? How can this problem be addressed?
STUDER : Yes, there is a constant shortage of fire protection engineers, designers and fitters. Few schools have fire protection engineering programs and the graduates from these schools are in high demand. One way our company copes is by recruiting engineers from the mechanical and electrical fields and cross-training them. Practical sprinkler system design is more likely taught to individuals by contractors or consultants.
SCHULTZ : It doesn’t appear that there is a shortage of installers, but there appears to be a serious shortage of qualified designers. College graduates have an opportunity to work as consultants or code officials, so few seem to be willing to get into contracting.
The other problem that has occurred is a change in how designers are trained. In years past, one would put in time at one of the “big” contractors such as Grinnell or Viking. These firms had formalized training programs and spent time teaching design. Now these firms either do not exist, or are not providing the same training or are retaining their personnel, but the trained designer is not out in the marketplace.
We need to educate the graduate engineer as to what is important. There are no massless pulleys, infinitely long wires or frictionless surfaces and until the designer starts to understand the intent of what is being done, we will continue to deal with nit-picking little issues.
The unions have to stay active. There is always some reluctance to train new people under a belief that they will take jobs away from existing members. This is a fine line that must be watched.
CSE: Are there a sufficient number of experienced maintenance personnel to address copper, steel and plastic sprinkler systems issues?
STUDER : Unfortunately, it is costly to establish maintenance programs or hire outside maintenance personnel. But the importance of regular maintenance—for proper system operation—needs to be emphasized. Although many municipalities require documentation of yearly tests, other weekly or monthly requirements are ignored or are unknown by the owners. And sometimes the consultant or the contractor does not emphasize the importance of maintenance when the systems originally are installed. Again, continuing education is critical.
OLAH : I believe that fire system maintenance over time will be better addressed by incorporating new and improved materials into fire sprinkler systems. Although periodic checks always will be necessary to validate the integrity and operability of a system, more reliable materials requiring less maintenance will be added assurance that these systems will function. With more reliable systems in place, routine system checks can be done by other qualified individuals.
CSE: In general, what other trends are you witnessing in the realm of sprinkler systems?
OLAH : There is a growing awareness about the importance of fire sprinkler systems in residential applications. The public is becoming more cognizant of the need for fire sprinkler systems in all dimensions of residential use and is readily asking for and accepting systems.
SCHULTZ : A disturbing trend ties itself back to my earlier response about a general lack of understanding on what we are trying to accomplish and a belief that by following the letter of the standard, one is protected from litigation.
For example, an existing warehouse with rack supports on 10-ft., 6-in. centers locates the flues at that point. But NFPA 13 states that rack sprinklers are to be on 10-ft. centers, so rather than place the sprinklers in the flue, which would space them more than 10 feet, the designer places the sprinklers on 10-ft. centers. Yet from a fire protection standpoint, would it not be more appropriate to locate the sprinklers in the flues, which is where the heat is going to be?
Another example: The contractor wants to use a k11 sprinkler at 15 psi. However, the standard states that rack sprinklers are to be a k5.6 or a k8.0 at 15 psi. The designer does not allow the larger sprinkler, which would flow more water, because it wasn’t allowed by the standard.
At some point in time, everyone must remember that the goal is to put the blue stuff on the red stuff and use common sense.
Technical Manager BlazeMaster Fire Safety Products NoveonCleveland
Gerald R. Schultz
Principal The Fire Protection InternationalConsortiumDowners Grove, Ill.
Vice President Rolf Jensen & Assocs. Brea, Calif.
NFPA 25 May Neglect IT&M
Regarding the “inspection, testing and maintenance” (IT&M) topic, as required by NFPA 25, this remains one of those items that we all talk about, but nobody wants to address. The problem is that NFPA 25 requires that the individual performing the inspection must be qualified, i.e., having adequate knowledge, but does not define what constitutes adequate knowledge.
The biggest issue is that the owner is paying for IT&M and operating under the belief that the system he has installed in the building is adequate for the hazard, but who is making the subsequent inspection to evaluate the adequacy of the system? NFPA 25 does not require this to be done because it recognizes that the individual addressing the normal maintenance testing issues is not capable of determining if the design is adequate for the hazard. This is the hole in the system and is one of those items that we don’t talk about. Is the AHJ coming into the existing building, inspecting the system and evaluating adequacy? Ultimately, the owner believes that the system is properly designed because the inspection report identifies no deficiencies.
In a nutshell, a broken hanger is not as critical as an underdesigned system, yet we inspect for one and are silent on the other.
— By Gerald R. Schultz, Principal, The Fire Protection International Consortium, Downers Grove, Ill.