Steel and Polybutylene Provide Sprinkler System for Fire Station
FEATURES
FIRE PROTECTION
As part of a major renovation of its 56-year-old station, the Takoma Park, MD, Volunteer Fire Department, in conjunction with Montgomery County’s Department of Fire and Rescue Services, installed a full sprinkler system in its fire station.
The quick response sprinkler system with polybutylene piping was chosen over standard sprinkler systems for a couple of reasons. First, the design of this quick response sprinkler head with a large surface to mass metallic vane type heat collector operates much faster than sprinkler heads with smaller temperature sensitive elements. Also, support of this technology could assist other county facilities seeking to invest in fire protection systems.
Takoma Park’s fire station’s sprinkler system is a combination of thin wall steel and polybutylene pipe. Because polybutylene is only labeled/approved for sizes up to two inches, a four-inch steel riser with a three-inch steel cross main feeds the main floor of the station. The cellar area is fed by a three-inch main along the side of the structure. To attach the polybutylene pipes and fittings to these steel mains, steel to polybutylene reducers were used, and polybutylene pipe and fittings were joined with heat fusion before installation of the sprinkler system could begin. Fleat fusion also made repairs of a few faulty joints (revealed by hydrostatic testing) much easier. Sprinkler heads were then screwed into a polybutylene fitting equipped with a metal insert.
Due to the long runs of piping necessary for proper protection, many additional hangers were installed to both eliminate characteristic pipe sagging and to ensure that all heads would be in a level plane.
Having been involved in numerous sprinkler system installations, I must say that the number of leaks with this polybutylene piping system were much less than those of steel systems, and any necessary repairs and/or modifications were made much easier. For example, several existing building obstacles were not reflected on the fire station’s architectural plane. As the polybutylene system was being installed, several sections had to be rerouted and field modifications had to be made to shorten or lengthen head spacing. By simply cutting the existing pipe, adding or removing the necessary section with the use of polybutylene couplers, changes were made rapidly.
Why the quick response sprinkler system?
The best method of combatting fires is by early detection and extinguishment. It’s not always easy to reach a fire with hose streams, and water pails, standpipes, and hose equipment are inadequate unless the fire is discovered in its early stages. The forerunners of the automatic sprinkler, the perforated pipe and the open sprinkler, were installed in a number of mill properties from 1850 to 1880. The first practical application of automatic sprinklers began about 1878, whereby heat from a fire opened one or more sprinklers and allowed water to flow.
First designed to meet the fire protection needs of rapidly growing industrial, commercial, and mercantile structures, advocates of automatic suppression have proposed transferring this highly reliable technology to residential and office properties. Those efforts initially met with great resistance.
In 1979, under a U.S. Fire Administration (USFA) program, a new sensing element was developed. This gave rise to the quick response sprinkler head that operates at low water volume. Tied hand in hand to the quick response sprinkler head was the need for a piping system that would permit easy, economical retrofit of existing properties and that could be readily and inexpensively installed in new construction.
The USFA sponsored a research program at Factory Mutual (FM) that led to an FM product acceptance standard and approval of polybutylene pipe. Grinnell Fire Protection Systems Company Inc. introduced a prototype quick response sprinkler later that year.
Field tests of the prototype were conducted in Los Angeles, CA, and Charlotte, NC, under a USFA program. This field test program led to the development of Underwriters Laboratories Standard 1626, the product acceptance standard for residential quick response sprinkler, and to the adoption of a new National Fire Protection Association (NFPA) 13D-1980, Standard for the Installation of Sprinkler Systems in Oneand Two-Family Dwellings and Mobile Homes.
Following the adoption of this NFPA standard, further tests and demonstrations with the quick response sprinkler and polybutylene pipe were conducted in cities throughout the United States, and results indicated that the quick response sprinkler system will save lives, reduce injuries and property damage, and greatly reduce the toxicity problem.
Community uses
Following tests with the quick response heads and alternative piping systems, Cobb County, GA, Fire Chief Dave Hilton had a voluntary residential sprinkler installation ordinance passed. Within 18 months of this voluntary code, Chief Hilton reported three life and property saving incidents. To date, over 15,000 Cobb County residences are protected by sprinklers.
Even before the widespread focus on residential sprinklers came about, Chief Ron Coleman of San Clemente, CA, had a residential sprinkler ordinance adopted in 1975, using the old NFPA 13D system (which uses the slower standard response head). Chief Coleman is now attempting to have this ordinance updated.
The Marriott Hotels have taken the lead in use and application of the quick response heads and alternative piping systems. At present, 15 hotels across the nation have been fitted with the quick response sprinkler system. Marriott’s goal is to sprinkler every existing and every new hotel.
Marriott Fire Protection Engineer John Scarff has spoken often on the progress of such work. While one floor can be completed in a day with the polybutylene system, the retrofit of one floor with black iron took 14 days. Because of the ease of assembly with the heat fusion process, work proceeds at a rapid rate. Sprinkler contractors may pre-cut pipe in the parking lot, roll the pipe into easily handled sections, and then carry these sections to the floors (via elevators) for final assembly.
Industrial applications
Will this concept work in industry? If the initial results of recent Factory Mutual testing are any clue, there could be a revolution in the way industrial properties are protected.
Dual testing with quick response and standard sprinkler systems was conducted at the FM test center on 20-foot high rack storage of a plastic commodity. A conventional standard sprinkler system required 18 heads and 2,500 gpm to control the fire. When the test was repeated with the quick response heads, the same fire required only three heads and 250 gpm for extinguishment.
As research continues, changes and advances may result in even greater protection. Changes such as the wiring of each sprinkler head to an annunciator panel, providing emergency service personnel with the exact location of a fused head and the use of large drop heads will see more industrial applications.
Summary
For years, industry has used steel pipe to deliver water; and manufacturers of steel piping continue to promote the fire resistivity of that material while downplaying alternatives in the plastic families as fire spreaders and toxic smoke producers. Toxicity studies are finding that fires are extinguished with quick response heads before uninhabitable atmospheres exist.
Fire protection is a key responsibility of the fire service; and the Takoma Park Volunteer Fire Department is taking a big step in this responsibility by protecting its station with the most up-to-date technology available. It’s been proven that automatic sprinklers, when properly installed and maintained, do save lives and property—and isn’t that what the fire service is all about?
While much is being said about the alternatives to steel piping, including copper, polybutylene, pvc (polyvinyl chloride), or whatever else might come forth, one thing is sure—they do work.
Photo courtesy of Takoma Park. MD, Fire Department
