Residential Fire Sprinkler Systems are becoming more prevalent with each passing year. There is still some resistance to their installation in new home construction due to the perception that homeowners will not want to pay the additional 1 to 2% increase in the final cost of the home. This is about $1.50 to $2.00 per square foot. In existing homes, the installed costs can increase to $2.50 to $5.00 per square foot. Some also argue that the systems are not effective if they are not properly maintained and inspected.
Municipalities must account for the increase in residential systems and ensure that they are being maintained in accordance with current National Fire Protection Association (NFPA) standards. Home fire sprinklers can contain or even extinguish fires in less time than it would take the fire department to arrive at the scene. Combined with the use of smoke detectors, fire sprinklers also reduce the risk of dying in a home fire by 82 percent, as compared to having neither.
Once sprinkler systems are installed, they will actually save money because they can reduce your home insurance rates by 5 to 15 percent. In the event that there is a fire, they will also save money in potential damages. The average cost of damages in homes with sprinkler systems was about $2,100. In comparison, the average cost of damages in homes without sprinkler systems was about $45,000. Before you consider installing a sprinkler system, contact your insurance agent to see what reduction you can expect in your premium. If the reduction is small or if they don’t offer any reduction, consider switching to another insurance company. Even if you don’t save money on your premium, it may still be worth the peace of mind and security to install the fire sprinkler system.
Residential Fire Sprinklers are designed to do the following:
• Activate at 160 F
• Only discharges water from the head that is activated
• Apply water at a rate of 13 to 18 gallons per minute during the initial stages of fire (instead of 120-150 GPM from fire department equipment)
• Provides early fire warning (augments, but does not replace smoke detectors)
• Allows residents to escape from the fire.
Identify the System Components and Location
Shut-Off Valve
The main water meter shutoff outside of your house is the only valve that will shut off water to your sprinkler system. The sprinkler system cannot be shut off independent of the house service.
Riser
Should always be labeled as such. Commonly found in the garage. However, it may be located in utility closets or wall cabinets.
Gauge
Found with the Riser. It records the static pressure of the system.
Inspector Test Valve
Located at the most remote wall (the part of the house that is furthest from the Riser) and should be labeled. It looks like a hose faucet without a handle.
Bell(s)
Found in a visible location at the front or rear of a structure; may be more than one. It should be audible from all sleeping areas.
Interior Alarm Device (optional)
Typically found in the hallway.
Recommended Practices for Homeowners with Existing Systems
• Contact your monitoring company if your system is monitored.
• Test your system monthly: Open the Inspectors test valve and listen for the bell to ring then turn off the valve.
• Know your sprinkler system shut off valve location and communicate this to all occupants of your home.
• Any extensions or alterations of your sprinkler system must be approved by your local Fire Department or Building Inspector prior to any work being done.
• Contact the Fire Department if and when any activation of your sprinkler system occurs (except when testing the system).
• Do not do anything to your sprinkler system that would hinder its performance such as painting or hanging objects from the sprinkler heads. Of course, never turn off or disconnect the system from its water source.
• Do not turn off the sprinkler system in the event of a fire - let the Fire Department perform this task.
POTENTIAL PROBLEMS WITH RESIDENTIAL SPRINKLERS
The most important step in maintaining a sprinkler system during the winter months is also the simplest: keep the heat on. National building codes recommend that a sprinkler protected room be maintained at a minimum of 40 degrees Fahrenheit to avoid freeze-ups. Go below that and you’re flirting with disaster.
If you turn the heat off in a building during below freezing weather, the water in the piping network will freeze. This expands the pipe and places pressure on the fittings till they break. Drafts or missing insulation in concealed areas magnify the potential for freezing. Although in most cases, freezing will occur near the perimeter of the home, if the outside temperature is low enough and cold air is blowing continuously, a water line can freeze almost anywhere.
It’s not unusual for the damage from a sprinkler freeze to reach several thousand dollars. Moreover, as long as a sprinkler system is damaged, its ability to fight fire is greatly compromised, so the building itself is left open to catastrophe.
Fire sprinkler systems freeze faster than plumbing pipe because the water doesn’t flow unless there’s a fire. Low points in a dry pipe sprinkler system where condensation can collect are susceptible to freezing, as are the smaller pipe diameters, such as 1"-2" pipes, in a wet pipe sprinkler system.
Most sprinkler systems employ steel pipe with cast iron fittings and freezing can shatter the cast iron fittings and even dislodge the sprinkler head itself. Plastic pipe turns brittle in cold weather, so entire lengths can shatter if the water inside freezes. For most residential systems, installers are using PVC pipe specially formulated for sprinkler systems.
Deep Freeze Protection
Measures taken to protect sprinkler piping exposed to brief periods of freezing weather are the same as those recommended for standard water pipes — insulate using specialized material or cloth. If the pipe continues into a heated area, this may be enough. Then again, it may not. If you have doubts, call your contractor and get a professional’s advice.
For extended exposure to cold, it’s better to install a sprinkler system that can withstand the elements. Your design options include: Dry pipe valves; Preaction systems; Antifreeze loops; and Dry pendant sprinklers. Many new products are available today, including alarm and heat-tracing equipment that have been created specifically to help protect sprinkler systems from the cold. The fall season is the ideal time to have your sprinkler system inspected before freezing weather sets in. A thorough inspection of your sprinkler system by a qualified contractor will detect any leaks or system deficiencies before it’s too late. While there, your contractor can also test the system’s antifreeze, drain any water buildup in the piping’s low points, and point you towards cost-effective solutions for maintaining and protecting your fire suppression investment against cold weather.
CONNECTION TO MUNICIPAL WATER SUPPLY
At the present time, most municipalities require that the sprinkler connection to the municipal water supply must occur after the water meter. This creates a few problems:
1. Most existing standard or typical residential water meters are not designed or intended to handle the types of flows which are seen for sprinkler systems.
2. The pressure loss through standard 5/8 or ¾ inch water meters can be very high. It is not unusual to have 15-25 PSI of friction loss through a standard-sized meter. The friction loss can be substantially reduced by going to a larger size meter but that can affect the cost of installation and the minimum monthly water fee as some municipalities charge a fee based on the size of the meter.
3. Sprinkler systems have always had check valves to prevent the stagnant water in the system from back flowing into the potable water. Growing concern about contamination of potable water has caused health officials to push for a more sophisticated and expensive device called a reduced-pressure principal backflow preventer. Backflow preventers can add up to $600 to total cost. Cities are more likely to have annual inspection requirements for backflow preventers.
Multipurpose Systems
Multipurpose sprinkler systems have been available for some time, but the lower cost of backflow prevention and recent changes to NFPA 13D, Installation of Sprinkler System in 1- and 2-Family Dwellings and Manufactured Homes, are making them more popular. A multi-purpose sprinkler system shares its pipe with the plumbing system. Using the same pipe for both systems means less pipe and fittings.
The biggest cost saving these systems offer is the deletion of backflow prevention devices, which add about $6oo to the cost of a residential sprinkler system. Growing concern about contamination of potable water has caused health officials to push for a more sophisticated and expensive device called a reduced-pressure principal backflow preventer.
Multipurpose sprinkler systems eliminate the need for backflow prevention because the water in the sprinkler system isn’t stagnant. Since the same water supplies the plumbing fixtures and the sprinklers, each time water flows in the plumbing system it refreshes the water in the sprinkler system. The piping supplying the sprinkler heads and plumbing fixtures creates a network where the water can flow to the sprinkler heads from different directions in the piping.
There are two methods for installing multipurpose sprinkler systems; one can be called a sprinkler/plumbing system and the other a plumbing/sprinkler system. The difference is in the pipe that’s used. The sprinkler/plumbing system uses sprinkler pipe, and the plumbing/sprinkler system uses plumbing, or copper, pipe.
Both systems share pipes, fittings and water supply, but there are two big differences: the pipe size and pressure rating. A lot of plumbing pipe is 1/2-inch in diameter. This smaller diameter pipe has a higher friction loss, which means that the standard T sprinkler fitting can’t be used. Although it supplies water from two directions, this isn’t enough to overcome the friction loss in 1/2-inch pipe. Sprinkler systems typically use 3/4-inch or larger pipe.
The plumbing/sprinkler system overcomes the friction loss problem by using a multiport fitting to supply additional flow. NFPA 13D requires that systems using 1/2-inch pipe supply water to each head from a minimum of three directions. The multiport fitting has four ports, thus allowing water to be supplied from four directions. If the hydraulic calculations show that three ports will provide enough flow, the fourth port is used to supply a plumbing fixture or a port on another sprinkler fitting.
The resulting layout of pipe can look more like a web than a grid because of pipe going to the additional ports. On the surface it would look like this system would cost more to install since this design appears to need much more piping, but the savings is in the fittings, which are the expensive parts of a sprinkler system.
The plumbing/sprinkler system reduces the number of fittings by using a manifold at the water service entrance. Each manifold outlet supplies one plumbing fixture, so each pipe doesn’t need joints to split the water supply between fixtures. The only breaks in a pipe are where there’s a sprinkler fitting, and the water continues out of the fitting through the fourth port to a plumbing fixture.
Whatever your decision is, there is compelling evidence for installing residential fire sprinkler systems to protect your home and family.
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