Editor’s Note:The design parameters of NFPA 13D allow for the installation of a residential sprinkler system as a part of the water distribution system. As a result, the multipurpose piping system reduces the cost of installation by only having one piping system for both the cold water supply and the sprinkler system, unlike a commercial building with two separate and distinct piping systems.
In the 25 years since the publication of the National Fire Protection Association 13D, “Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes,” not one person has died in a fire in a home that was properly sprinklered. That means that these systems have the capability of saving more than 3,000 lives every year.
The residential sprinkler business can be very profitable, if done correctly. And for a few dollars more, the residents can have peace of mind.
The following article discusses how two contractors used two different ways to pipe such a system.
Nelson Plumbing Co., Vancouver, Wash.“For about 1 percent of the cost of a home,” says Garth Kightlinger, owner of Nelson Plumbing Co., Vancouver, Wash., “the dwelling unit can be protected with a residential sprinkler system.”
Nelson’s first venture into residential fire protection was for a townhouse development in Lake Oswego, Ore. Each townhouse unit was three stories in height with a two-car garage. Because of the location of the garage under the building, sprinklers were also required in the garage area.
The Nelson team ended up choosing CPVC pipe. “It’s just like plumbing,” says Ron Broersma, project superintendent. The main runs of piping are installed using BlazeMaster® pipe with adapter fittings used to connect to FlowGuard Gold® pipe.
To avoid concerns with pressure and flow rates, the sprinkler piping was 1-inch pipe. This avoided a potential problem with inadequate pressure and length of run restrictions. While the system could have been 3/4-inch, the 1-inch mains will provide plenty of water pressure for the plumbing water distribution system.
Different Sizes: One of the initial concerns with a multipurpose piping system in CPVC was the difference in the piping material. BlazeMaster® CPVC pipe is manufactured in IPS, or iron pipe size dimensions. FlowGuard Gold® is manufactured in CTS, or copper tube size. The IPS pipe has a larger diameter, allowing a greater flow of water at the same velocity. To join the two piping materials together, the Nelson crew had to use IPS-to-CTS adapter fittings
“In any multipurpose piping system, you have to adapt between the sprinkler part of the system and the water distribution part,” adds Mike Doty, regional manager for Noveon, Inc. (formerly BFGoodrich Performance Materials). “It is just a matter of what type of adapter you install.”
In addition, BlazeMaster® pipe, which is orange in color, must be joined with one-step solvent cement. The UL listing of the piping system requires the solvent cement to be red in color. FlowGuard Gold® is tan in color with a gold stripe, and a one-step solvent cement that is yellow in color. So what color solvent cement do you use to join the orange BlazeMaster® pipe to the tan-colored adapter fitting?
“That’s easy,” Doty says. “If the pipe is orange, the solvent cement is red!”
Besides selecting pipe, Nelson Plumbing also chose Star concealed residential pendent sprinklers for the project. As the name suggests, these sprinklers are completely concealed in the ceiling. The only indication of there being a sprinkler is the cover plate for the sprinkler.
The versatility of sprinklers was another reason for their selection. One sprinkler can cover a myriad of areas ranging from 12 feet by 12 feet to 20 feet by 20 feet.
“We just use one sprinkler throughout the entire project,” Broersma says. “That way we don’t have to question whether we have installed the correct sprinkler for a given room.”
Each three-story unit took between 2-1/2 to 3 days for a two-man crew to install the combination sprinkler and water distribution piping system. The town homes had some unique features. The architect had different wall configurations, elevated flower walls, sloped ceilings and skylights. This made the sprinkler installation a little more difficult than in a standard townhouse design.
Still, the additional material cost for the sprinkler system was approximately $750 per unit.
There is a learning curve to installing the multipurpose piping system. “We kept getting better,” Broersma says. “The last unit took less time than the previous unit. When the next building breaks ground, we’ll be flying through that building.”
Know Your Costs: “The most important aspect of entering the residential sprinkler business is knowing your costs and what to bid,” Kightlinger says. Most sprinkler installations use a price per square foot number. “But in residential design that can be dangerous. The size and shape of a room determines how many sprinklers must be installed. Using a per square foot number will not provide an accurate number to use when bidding a project.”
Kightlinger discovered it was more precise to use a cost per sprinkler (or head). A room that is sized 9 feet by 10 feet can get by with one sprinkler. Likewise, a room 20 feet by 20 feet may also be able to get by with one sprinkler. While the area would be more than double in size, the sprinkler installation cost could be the same.
For the town homes, Kightlinger found that his bid price came to approximately $240 per sprinkler for the multipurpose piping system. In other words, if a unit required the installation of 15 sprinklers, the bid for that unit was $3,600. If the same size unit had a floor arrangement that required only 12 sprinklers, the cost of the installation would be lowered to $2,880.
One of the differences in the unit design was the size and shape of the bathrooms and closets. If a bathroom is less than 55 square feet, the room does not have to be sprinklered. However, some of the master bathrooms readily exceeded this size limitation. Likewise, if a closet had the smallest dimension greater than 3 feet, then the closet would have to be sprinklered. Hence, any walk-in closet required sprinkler protection. A standard 2 foot by 10 inch by 8 foot closet with bi-fold doors did not have to be sprinklered.
Kightlinger knows contractors could get into trouble when they enter the residential sprinkler business. Most importantly, if contractors generalize the installation costs in a price per square foot, they can get into financial trouble. The particulars for each given project must be known. Where can the pipe be installed? How much water pressure is in the street? How are the rooms laid out? What type of floor construction is used? These are a just a few of the variables that must be understood.
RCR Cos./AMPAM, Las Vegas, Nev.Besides CPVC, another alternative to piping a multipurpose system is to go with PEX. After the city of North Las Vegas, Nev., passed an ordinance mandating multipurpose sprinkler systems in new construction, RCR Cos./AMPAM selected Aquasafe, a combination PEX system patented by Wirsbo.
The contractor had already installed the company’s Aquapex plumbing system in thousands of single-family homes and apartments. “It was an easy transition to go from one to the other,” says Rick Meyers, general superintendent at RCR. “It made cross-training our crew very easy.”
The RCR crew’s first multipurpose system installation was at the Genevieve Court, a housing developing featuring 1,200 square feet single-family homes.
The Aquasafe system uses an interconnected grid of PEX tubing that feeds both the sprinklers and the plumbing fixtures. The sprinkler head is attached to a stainless steel four-port fitting. A cold water manifold feeds the 1/2-inch Aquapex tubing directly to the four-port fittings. The fittings and supply lines are part of the home’s plumbing system. Each time a plumbing fixture draws water, water is drawn to the sprinkler head.
“When the homeowner does the dishes, washes their car or gets a drink of water,” says Tom Walls, RCR’s field superintendent, “they have piece of mind that the fire sprinkler system is working correctly.”
According to Wirsbo, this is one product benefit that separates its system from other multipurpose solutions.
“The Aquasafe system provides a completely nonstagnant plumbing and sprinkler system, says Franz Haase, Wirsbo’s Aquasafe installation manager. “Because every plumbing fixture is tied into the sprinkler system, water moves throughout the entire system each time a plumbing fixture is used. Other multipurpose systems that we have seen typically run only a few lines to a plumbing fixture, which doesn’t appear to eliminate stagnant water issues in the same way that the Aquasafe system does.”
Each home required about 1,600 feet of PEX and 19 sprinkler heads. To further cut down on installation time, the Aquasafe sprinkler heads come assembled and ready to mount. “Other systems we’ve seen require the heads to be assembled in the field,” Meyers adds. “It took just two installers one day to pipe both the cold side potable and the fire sprinkler system.”
According to Wirsbo, the average home fire sprinkler system adds approximately 1 percent to 1.5 percent of the total building cost in new construction. According to RCR’s calculations, the combination system is 15 percent less than a stand-alone system. Some locales, however, may end making a combination system even less by comparison. For example, North Las Vegas has also passed an ordinance requiring that backflow preventers on stand-alone systems must be buried in yards and installed in a freeze-proof enclosure.
Residential Sprinkler Facts
- In 2000, the National Fire Protection Association reported there were 379,500 fires in residential buildings. That averages out to a residential fire every 83 seconds in the United States.
- In that same year, 3,445 people died in residential fires. Of those fire deaths, 2,920 occurred in one- and two-family dwellings.
- Looking at all types of structures, one- and two-family dwellings accounted for 72 percent of the total fire deaths.
- Statistics from the Home Sprinkler Coalition show that a sprinkler system used together with a smoke detector reduce the risk of fire-related deaths by 82 percent.
- Ninety percent of fires are contained by the operation of one sprinkler. Sprinklers can discharge approximately 12-14 gallons of water per minute. Meanwhile, fire department hoses typically discharge about 200 gallons of water per minute. Most people don’t realize that excessive water and smoke can be more damaging than the fire itself.
- The odds of a sprinkler accidentally discharging due to a manufacturing defect are one in 16 million.