Sprinkler Myths & Facts

There are some common misconceptions when it comes to fire sprinkler systems. Here are some myths people often believe, as well as the facts to hopefully clear up some of those myths.
   
  • When a fire occurs, every sprinkler head goes off.   
  • Water damage from a sprinkler system will be more extensive than fire damage.   
  • Sprinklers steal water from the fire department hoselines.   
  • Sprinklers are designed to protect property, but are not effective for life safety.   
  • The added cost of sprinklers will make housing unaffordable to first-time buyers.   
  • Sprinklers are ugly, and I don't want them in my space.


  • MYTH: When a fire occurs, every sprinkler head goes off.
  • FACT: Sprinkler heads are individually activated by fire. Residential fires are usually controlled with one sprinkler head, and 90 percent of all fires are controlled with six or fewer heads. A study conducted in Australia and New Zealand covering 82 years of automatic sprinkler use found that 82 percent of the fires that occurred were controlled by two or fewer sprinklers.


  • MYTH: Water damage from a sprinkler system will be more extensive than fire damage.
  • FACT: Water damage from a sprinkler system will be much less severe than the damage caused by water from firefighting hoselines or smoke and fire damage if the fire goes unabated. Quick response sprinklers release 8 to 24 gallons of water per minute compared to 50 to 125 gallons per minute released by a firehose. Sprinklers are highly reliable devices that are activated by heat. They will only go off if there is a fire which increases the heat beyond the sprinkler trigger point (typically 135 to 165°F (57.2 to 73.9°C)). Preaction systems employ additional safety features. Research has demonstrated that only 1 in 16 million heads ever activates by accident. Sprinkler systems can be connected to an alarm monitoring company or an external alarm that will notify neighbors or passersby of a water flow. This will facilitate the prompt notification of the fire department and will minimize that amount of water damage.


  • MYTH: Sprinklers steal water from the fire department hoselines.
  • FACT: A properly designed sprinkler system (for commercial structures) includes water supplies for the system and fire department hose streams. MYTH: Sprinklers are designed to protect property, but are not effective for life safety. FACT: Sprinklers provide a high level of life safety. Statistics demonstrate that there has never been any multiple loss of life in a fully sprinklered building. Property losses are 85 percent less in residences with fire sprinklers compared to those without sprinklers. The combination of automatic sprinklers and early warning systems in all buildings and residences could reduce overall injuries, loss of life, and property damage by at least 50 percent.


  • MYTH: The added cost of sprinklers will make housing unaffordable to first-time buyers.
  • FACT: A sprinkler system costs one to two percent of the total construction costs. The cost of a sprinkler system is comparable to what many people pay for carpet upgrades, a paving stone driveway, or a whirlpool bath.


  • MYTH: Sprinklers are ugly, I don't want them in my space.
  • FACT: Residential and commercial sprinkler heads come in a variety of unobtrusive styles and models and in designer colors. Some can be mounted flush with the ceiling line, and concealed behind protective covers.




Based on the unique floor plan of the home you’re building, the sprinkler designer determines the piping design and the appropriate number, type and layout of sprinklers along the piping. Since sprinklers cover a minimum 12 x 12 foot area, while extended sprinklers can cover up to a 20 X 20 foot area, in many rooms you’ll have a single sprinkler. Larger areas will be protected by additional sprinklers or special extended coverage sprinklers. For example, in a typical unfinished basement, three pendent sprinklers would be used to protect the far sides of the area and near the center stairway. The NFPA 13D standard permits positioning sprinklers in basements to anticipate future ceiling finishing – a flexibility selling point for your buyers who are thinking ahead. If you finish the basement, concealed sprinklers can be used immediately. When you get up into the finished areas of the home, concealed sprinklers can be used in the ceilings. Wall-mounted, semi-recessed sprinklers are used when you want to avoid placing pipes in an unfinished attic.




TYPICAL RESIDENTIAL WATER SPRINKLER SUPPLY

CONCEALED SPRINKLER

SPRINKLERS

TYPICAL residential PIPING SETUP

DESCRIPTION

DELUGE SYSTEMS

DOUBLE INTERLOCKED PREACTION SYSTEM

The Double-Interlocked Preaction System utilizes a detector system and pressurized air or gas in the sprinkler piping. This system utilizes the deluge valve and is arranged so that the valve will open only when both pressure reduced in the sprinkler piping and the detection system operates. If the detection system operates due to fire, damage, or malfunction, the valve will not open, but an alarm will sound. If the sprinkler piping is damaged or sprinkler is broken or fused, the valve will not open but a supervisory alarm will sound. The operation of both a sprinkler and a detector (or release) is required before the valve will open, allowing water to enter the system piping. Because pressurized air or gas is available in the output piping, the system is usually supervised. The Double-Interlocked Preaction System is commonly used in freezers where flooding of the pipe can have serious consequences and in system applications where it is important to control accidental discharge of the system.


A wet pipe sprinkler system may be installed in any structure not subject to freezing to automatically protect the structure, contents, and/or personnel from loss due to fire. The structure must be substantial enough to support the piping system filled with water. Using water as its extinguishing agent, one wet system may cover as much as 52,000 square feet in a single fire area. The system should be designed by qualified fire protection engineers in conjunction with insuring bodies. Sprinkler systems are engineered to meet the standards of National Fire Protection Association (see N.F.P.A. Pamphlet 13, “The Installation of Sprinkler Systems”), Factory Mutual (F.M.), Loss Prevention Council (FOC), Assemblee Pleniere, Verband der Sachversicherer or other similar organizations, and also with the provisions of governmental codes, ordinances, and standards where applicable. Small unheated areas of a building may be protected by a wet system if an antifreeze-loop or auxiliary dry system is installed. For rules and limitations, see appropriate codes and standards.


A wet pipe sprinkler system is fixed fire protection using piping filled with pressurized water supplied from a dependable source. Closed heat sensitive automatic sprinklers spaced and located in accordance with recognized installation standards are used to detect a fire. Upon operation, the sprinklers distribute the water over a specific area to control or extinguish the fire. As the water flows through the system, an alarm is activated to indicate the system is operating. Only those sprinklers immediately over or adjacent to the fire operate, minimizing water damage.


APPLICATIONS

DESCRIPTION

HERE ARE SOME BASIC DESCRIPTIONS AND DIAGRAMS OF THE DIFFERENT FIRE SPRINKLER SYSTEMS WE INSTALL:

CRAWFORD Sprinkler COMPANY

WHAT ARE HOME FIRE SPRINKLER SYSTEMS?

Using quick response sprinklers and approved piping, homes can be built or even retrofitted to include low-cost automatic sprinkler systems connected to the domestic water supply.

  •     Sprinkler systems offer advantages to the homebuilder:

  •     A low-cost reliable safety option that would attract many buyers.

Trade-offs between sprinklers and code requirements that can result in lower construction costs, more units per area of land, etc.
For homeowners, the advantages include assurance of a safer environment for their families, protection of their investment and irreplaceable family possessions, and lower insurance rates 5 to 15 percent.


residential SYSTEMS

OPERATION

This preaction system utilizes a deluge, which may be opened either by the fusing of a sprinkler in the sprinkler piping or by the operation of the detection system. The sprinkler piping contains air or gas under pressure. If the detection system does not operate, the sprinkler system will operate as a dry pipe system. If the sprinkler piping is broken or the sprinkler operates, the valve will open and water will flow. If the detection system operates due to fire, damage, or malfunction, the valve will open, but the water will be contained in the sprinkler piping. The system is supervised to indicate low air pressure. The objective of this system is to fill the sprinkler piping with water prior to the fusing of a sprinkler, thereby permitting more rapid fire attack.

GENERAL DESCRIPTION

There are several types of preaction systems, but all employ closed sprinklers in the sprinkler piping. The detection system may be hydraulic, pneumatic or electric, and may be actuated by manual, fixed-temperature, rate-of-temperature-rise or other means. Detection systems operate before the sprinklers fuse and give an alarm. Because preaction systems are often used in freezing areas, electrical and pneumatic detection systems are by far the most common. Preaction systems are usually supervised. The purpose of supervision is to monitor the integrity of the system. Air or gas under pressure is maintained in the sprinkler and release piping. If the sprinkler or release piping or a sprinkler head is broken, the pressure will be reduced and an alarm will sound. There will also be an alarm due to low air or gas supply pressure. Electrical equipment can be similarly supervised. Hydraulic release system or supply pressure may also be supervised.

PREACTION SYSTEMS

A Dry Pipe System is primarily used to protect unheated structures or areas where the system is subject to freezing. Under such circumstances, it may be installed in any structure to automatically protect the structure contents and/or personnel from loss due to fire. The structure must be substantial enough to support the system piping when filled with water. One system may protect as much as 52,000 sq. ft. (4830.8m2) in a single fire area. The system should be designed by qualified fire protection engineers in conjunction with insuring bodies.


DRY PIPE SYSTEMS

COMMERCIAL SYSTEMS

WET PIPE SYSTEMS

Based on the unique floor plan of the home you’re building, the sprinkler designer determines the piping design and the appropriate number, type and layout of sprinklers along the piping. Since sprinklers cover a minimum 12 x 12 foot area, while extended sprinklers can cover up to a 20 X 20 foot area, in many rooms you’ll have a single sprinkler. Larger areas will be protected by additional sprinklers or special extended coverage sprinklers. For example, in a typical unfinished basement, three pendent sprinklers would be used to protect the far sides of the area and near the center stairway. The NFPA 13D standard permits positioning sprinklers in basements to anticipate future ceiling finishing – a flexibility selling point for your buyers who are thinking ahead. If you finish the basement, concealed sprinklers can be used immediately. When you get up into the finished areas of the home, concealed sprinklers can be used in the ceilings. Wall-mounted, semi-recessed sprinklers are used when you want to avoid placing pipes in an unfinished attic.


The deluge valve prevents water from entering the system piping until required. The deluge valve is kept closed by a pressurized upper valve chamber. The pressure is maintained through a restriction on the service side. This upper chamber is also connected to the release line. When the pressure is relieved from the upper chamber through the release line, the clapper is lifted by the water pressure under the clapper. Water floods the system and rings alarm.


Regular Deluge Systems may be required to protect extra-hazard occupancies by creating a fire buffer zone or by cooling surfaces to prevent deformation or structural collapse. Examples: storage or process areas containing substances having a low flash point; areas in which fire may spread rapidly; tanks containing combustible solutions, transformers, equipment pits or product handling systems. Systems should be designed by qualified fire-protection engineers in conjunction with the approving bodies having jurisdiction. Foam-water deluge systems are those using foam-water sprinklers or spray nozzles and an air-foam concentrate which is introduced into the water at controlled rate on the system side of the deluge valve. Foam water systems are used to control and/or extinguish fires which require a smothering and cooling agent. Examples are: extraction plants, aircraft hangars and areas where flammable-liquid spill fires may occur.


The single interlocked preaction system requires operation of the detection system to trip the deluge valve and fill the system with water. It also utilizes supervisory air pressure in the system piping. Water will then be discharged on the fire when the sprinklers fuse. If the sprinkler piping or sprinkler is broken, a supervisory alarm will sounds, but the valve will not open. If the detection system operates due to fire, damage, or malfunction, the valve will open, but the water will be contained in the sprinkler piping. If the detection system does not operate, the valve will not open. Supervision is generally used since control of accidental discharge is usually desired. The single interlocked preaction system is commonly used where it is desirable to have water available at the sprinkler when the sprinkler fuses and where the sprinkler piping is subject to damage. The most common applications are large dry systems that exceed the capacity normally permitted on a dry valve, and in a system applications where it is important to control accidental water discharge due to damaged sprinkler piping.


Preaction systems operate in several of ways and perform a variety of functions. A summary of the most common types of preaction systems follows:

NON-INTERLOCKING PREACTION SYSTEM

DESCRIPTION

APPLICATIONS

ADVANTAGES OF NEWLY DESIGNED HOME SPRINKLER SYSTEMS

  • Fast Response

Residential sprinklers, listed by Underwriters Labs, are now available. They are designed to respond to a fire much faster than currently available standard commercial and industrial sprinkler systems. The new home sprinklers react automatically to fires more quickly because of their improved sensitivity.

  • Low Cost

At the present time, cost of a home sprinkler system is targeted at approximately $4.00 to $5.00 per square foot of occupied space where there is a public water supply available. It is hoped that the cost will decrease as the use of home fire protection grows. It is possible to integrate sprinkler systems in new construction, or in retrofitting existing homes.

  • Small Size

For residential systems, the sprinklers will be smaller than traditional, commercial, and industrial sprinklers, and can be aesthetically coordinated with any room decor. Minimal Installation Work When homes are under construction or being remodeled, a home sprinkler system will require minimal extra piping and labor.

  • Low Water Requirement

These systems will require less water than the systems installed in industrial or commercial establishments and can be connected to the domestic water supply.  If there is no public water supply at the home site, the sprinkler system can be supplied by a residential water storage tank and fire pump located within the dwelling.

  • Piping Requirements

In addition to metallic pipe, the use of plastic pipe has brought down the cost of installation in new construction and the retrofit of existing structures.


A Deluge System is a fixed fire-protection system which totally floods an area with pressurized water through a system of piping and open nozzles or sprinklers. The system piping is empty until the Deluge Valve is activated by a hydraulic, pneumatic, electric or manual release system.


APPLICATIONS

SINGLE INTERLOCKED PREACTION SYSTEM

TYPES AND APPLICATIONS

A Dry Pipe Sprinkler System is a fire-protection system which utilizes water as an extinguishing agent. The system piping from the Dry Pipe Valve to the fusible sprinklers is filled with pressurized air or nitrogen. An air check system is a small dry system which is directly connected to a wet pipe system. The air check system uses a dry valve and an air supply but does not have a separate alarm. The alarm is provided by the main alarm valve.


SIDEWALL SPRINKLER

PENDENT SPRINKLER