Sprinkler Systems

Click Here for a PDF Copy of this White Paper

Minnesota State Fire Chiefs Association
White Paper on Residential Sprinkler Systems

Background:
At the September, 2008 International Code Council hearings conducted in Minneapolis, Minnesota, a proposal to require residential fire sprinklers for one and two family homes was approved (see below) for homes built under the 2009 version of the International Residential Code (IRC).

SECTION R313
FIRE SPRINKLER SYSTEMS

R313.1 General. Effective January 1, 2011, an approved automatic fire sprinkler system shall be installed in new one-and two-family dwellings and townhouses in accordance with NFPA 13D.

The IRC is a model code that each state, or in some cases, local jurisdictions, can adopt as their model building code.  Minnesota has historically adopted the International Building Code, International  Fire Code, and the International Residential Code on a state-wide basis and there is currently no effort underway to change this.

The Department of Labor and Industry (DOLI) is tasked with adoption of the model codes and has issued a letter on June 1, 2009 stating the adoption of all codes; Building, Fire and Residential would be temporarily placed on hold due to the combination of economic conditions and lack of any significant changes in any of the model codes.

The letter states DOLI’s intention of beginning the adoption process with the formation of advisory committees to begin sometime in 2010 or at the latest, the early part of 2011.

Effective Date:
The IRC provision calls for an effective date of no sooner than January 1, 2011.  If the state adopts the IRC by January 1 the provision will apply.  If adoption occurs after January 1, 2011 then only those homes built after adoption will be required to comply.  There is no retroactive provision in the code.

NFPA 13D:
The National Fire Protection Association is a non-profit 100+ year old organization specializing in fire related issues.   Amongst their many activities are the development of education materials, standards, and codes.  The “13” series of their product line are specific to automatic sprinkler systems with the NFPA 13 1 standard for commercial applications, 13R 2 applicable to multi-family structures such as apartments and town homes, and the 13D 3 applicable to one and two family residences.

NFPA 13D standard is the least prescriptive, thus, the most economical. The following table illustrates some of the differences:

Item	13 System	13D System
Pipe	Steel Pipe 1” to 8” diameter	Plastic typically 1” diameter
Coverage	100% of building	Small closets, bathrooms, storage areas exempted if under 55 sq. ft.
Pressure Test	Required	Not Required
Fire Department Connection	Required	Not Required
Alarm	Required	Not Required

There are numerous myths and inaccurate statements about the requirements of 13D, many of these surround water supply and electrical power.  The facts are 13D is a performance standard in which the installer must calculate flow requirements based upon the water supply.  Your certified system designer will obtain water supply information and calculate supply needs and possible pump requirements based upon the structure.

FACT – 13D has no requirement for a water reservoir or pump unless the water supply is inadequate.  In most municipal cases the water supply should be adequate; however, in rural areas with wells, a slightly larger pump (1/4 to 1/3 more horsepower) will adequately supply a single family system.  New sprinkler head technology specific for13D systems allow operation at flows as low as 8 gallons per minute.  NFPA requires a minimum supply of at least two heads, thus 16 gallons per minute.  For comparison, a 5/8” garden hose flows at 17 gallons per minute.

FACT – 13D has no requirement for back-up electrical power of the pump.  If there is a power failure at the same time a fire occurs there is a greater likelihood of significant fire damage.

Cost:
A recent report issued by the Fire Protection Research Foundation 4 which is comprised of fire groups, home builders, and water supply agencies details the cost to install a NFPA 13D compliant system ranges from $.38 per square foot to $3.66 per square foot.  The average cost was $1.61 per square foot.  The Report determined this number by selecting ten representative cities from around the nation and soliciting and acquiring three bids.

Minnesota, with its cold winter climate eliminates certain efficiencies in installation as few circumstances allow any pipe in the attic area.  Cities such as Blaine, Plymouth and Maple Grove have thousands of systems installed in town homes and close to a hundred one and two single family homes.

Their experience reflects the Minnesota Fire Chiefs member’s average of $1.61 for the townhomes and approximately $1.80 for one and two single family homes.

Reductions/Insurance Savings/Financing Costs:
Depending upon the community, there may be certain trade-off or alternatives to other building code requirements if sprinklers are installed.  These are more typical for town homes where street width can be narrowed, lot size reduces, and hydrant spacing increased.  However, these same trade-offs can and have been used in single family housing developments.

Additionally, most community building and fire officials will accept a sprinkler system as an alternate to egress windows from basement locations.  Depending upon your situation, the installation of a sprinkler system would partially or wholly offset the cost of egress window installation.

At least thirteen insurance companies now provide a discount on their homeowner policy ranging from 5% to 15%.  While this is becoming more widely known, the consumer still must shop on the open market to achieve the greatest savings. 5

If one were to finance a $3,500 system (average cost for a 2,000 sq. ft. home); at a 6.5% interest rate the additionally monthly cost in your mortgage would be just under $5 per month.

Operation:
All sprinkler heads including residential sprinkler heads are activated by heat.  Meaning that only those heads closest to the fire will activate.  Most residential heads are designed to activate at 155 degrees.  In close to 90% of fires in which a sprinkler head activates, a single head will control or extinguish the fire.6

Accidental discharge of sprinkler heads is rare.   Factory Mutual, a nationally recognized testing laboratory reports the chance of an accidental discharge from a sprinkler is “the odds that rival winning the California State Lottery.”  Water filled sprinkler heads and pipes are subject to freezing, however, no more or less than your domestic water supply.  No evidence or data exists indicating more water damage due to frozen sprinkler pipes  versus frozen water pipes.

Water damage from sprinklers is minimal given that one to two sprinklers typically control the fire.  This equate to 15 to 20 gallons per minute.  Comparatively, upon arrival the fire department will employ a minimum of two firefighting lines discharging 150 to 200 gallons per minute each or a total of 300 to 400 gallons of water per minute.

Unlike most other systems in your home; lawn sprinklers, heating and cooling and plumbing; there is virtually no maintenance for residential systems.  A periodic check of the pressure gauge and ensuring the main valve is never turned off is typically all that is required.

In their 100+ year history, sprinklers have proven to be extremely effective in controlling and extinguishing fire.  There are few other examples of technologies more effective in minimizing death and destruction as sprinklers. 

Comparatively, traditional fire suppression is the least effective method of controlling fire and the United States, despite having some of the best training, equipment, and technology, ranks amongst the worst when compared to the world in fire property and death statistics.

Fire Facts:
According to the United States Fire Administration for the calendar year 2007;

• There were 399,000 structure fires in the United States
• 2,865 civilians were killed, a disproportionate number of them young children and elderly people.
• There were 13,600 civilian injuries.
• Over $7.4 billion worth of property was destroyed.
• Over 100 firefighters were killed.
• According to a National Institute of Standards and Technology study, a family had 17 minutes to escape a residential fire in the 1970’s. 7  Today, due to changes in construction, finishing materials, and the large amount of synthetics and plastics in the contents of the home, that time has been reduced to as few as 3 minutes! 8

Policy Issues:
Communities can significantly reduce their overall fire protection costs through the adoption and use of codes requiring the use of automatic sprinkler systems.  A community using this approach transfers the responsibility directly to the property owner who receives the benefits of reduced insurance costs, a vastly improved response in the event of a fire, significantly reduced loss of personal property, and reduced infrastructure costs (taxes).  In communities where sprinklers are an integral part of the overall fire protection plan, it is possible to save millions of dollars per year of property tax dollars via the use of a combination, volunteer, or smaller career department.  Minnesota cities such as Bloomington, Plymouth, Woodbury Eden Prairie, and Maple Grove are just a few of many examples of cities who have been able to maintain predominantly volunteer departments at significant cost savings in large part due to sprinkler requirements.

Lightweight construction, specifically the dominate use of trusses and floor trusses are emerging as a firefighters greatest threat.  First introduced about twenty years ago, they are almost exclusively used in all new home construction.  Any fire that penetrates and impinges on the truss assembly almost immediately weakens the assembly and has resulted in a greater frequency of firefighter injuries and fatalities as they have fallen through the floor. 

Numerous scientific studies have been completed on this issue with two of the more recent ones being; National Institute of Standards and Technology in January of 2007 and Uderwriters Laboratories in conjunction with Michigan State University in November of 2008.  Both studies reported results of significant failure of the truss assembly when exposed to fire, sometimes within minutes of the fire starting. 9

Opponents argue that smoke detectors are more than sufficient to protect a family in a residential occupancy.  However, statistics again reveal that while smoke detectors have a marvelous record in having helped to reduce the number of deaths over the years, they simply are not adequate or effective in all cases.  Disabled, disconnected and poorly maintained detectors are present in over 25% of residential structures.  Furthermore, as mentioned earlier, the young and old are especially vulnerable and given the speed at which fire grows, smoke detector activation has proven to be inadequate.

Finally, the Insurance Services Office (ISO) just released a Residential Sprinkler ISO Fact Sheet stating:

• Premium credit of 13% for fully sprinklered homes and 8% for partial
• Leakage coverage is included in the basic policy, there is no extra charge.
• If the requirement of the International Residential Code (2009) for automatic sprinkler protection is removed by legislative or local ordinance the ISO Building Code Effectiveness Grading Schedule would not provide full recognition for adoption of the code.

Summary:
Installing residential sprinklers in newly constructed one and two family homes will have a profound impact on the fire service, local governments, and society.

An average homeowner will pay less than $4,000 for the installation of the system and will, in most cases, recoup that investment through the combination of insurance savings, possible construction trade offs, and reduced property taxes.

The same homeowner will enjoy an immeasurably greater level of safety, with respect to fire, as compared to reliance on traditional fire suppression response which has proven time and time again to be woefully inadequate due to the speed at which fire grows.

_________________________________________________________________________________

1 National Fire Protection Association, Standard for the Installation of Sprinkler Systems
2 National Fire Protection Association, Standard for the Installation of Sprinkler Systems in Residential Occupancies up to and Including Four Stories in Height
3 National Fire Protection Association, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes
4 Fire Protection Research Foundation, Home Fire Sprinkler Cost Assessment, 2008, http://www.nfpa.org/assets/files//PDF/Research/FireSprinklerCostAssessment.pdf
5 Insurance Services Office, Inc., Residential Sprinklers ISO Fact Sheet, www.isomitigation.com
6 NFPA, Fast Facts About Home Fire Sprinklers
7 NIST, Technical Note 1455
8 NIST, Technical Note 145
9 NIST, A Study of Metal Truss Plate Connectors When Exposed to Fire
UL, Fire Test Report: Wood Truss Members with Steel Plate Connectors Used in Floor-Ceiling Assemblies

Click Here for a PDF Copy of the Policy

Minnesota State Fire Chiefs Association
Model Policy for Residential Sprinkler Systems for One & Two Family Dwellings

The following is a model policy for the installation of residential sprinkler systems in one and two family dwellings. This model policy was developed in an effort to encourage the installation of residential sprinkler systems and to remove regulatory road-blocks to residential sprinkler installations. It combines the requirements and allowances from the Minnesota State Fire Code and NFPA 13-D with life safety experiences and best practices from several communities into a simple easy-to-follow document for code officials to use as a guideline in their communities. This document was a joint effort between the Minnesota State Fire Chiefs Association, the Fire Marshals Association of Minnesota, and the Minnesota State Fire Marshal Division.

SECTION I – SITE ISSUES

A. Road Width:

• Road widths may be reduced when approved by the authority having jurisdiction in a fully sprinklered development.
  

B. Hydrant Spacing:

• Hydrant spacing is allowed to be increased to 800 feet spacing (no more than 400 feet from a hydrant).

C. Dead-End Roads & Turn-Arounds:

• Dead end roads up to 300 feet in length are allowed without turn-around provisions (such as a cul-de-sac or hammerhead).

D. Water Supply Taps from Municipal Supply to Homes:

• A minimum 1” water supply shall be provided from the municipal water supply to the home (this includes a 1” tap and 1” line). See Section II – Item C for more information

SECTION II – SPRINKLER COVERAGE AND INSTALLATION REQUIREMENTS

A. Appropriate Design Standard:
The appropriate design standard for residential sprinkler systems is NFPA 13-D (Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes). This standard should be followed except as modified herein.

• Sprinklers shall be listed for residential use and shall be used in accordance with their applicable spacing and listing criteria (except for garage protection below).

B. Areas That Can be Exempted from Having Sprinklers Installed:
NFPA 13-D allows certain areas with a limited fire loss history from having sprinkler protection. These areas include:

• Bathrooms of 55 ft2 and less.
• Clothes closets, linen closets, and pantries not exceeding 24 ft2 or 3 ft in the least direction. The closet or pantry must not contain any mechanical equipment, electrical equipment, or electrical appliances (including washers or dryers).
• Open attached porches, carports, and similar structures.
  Attics, crawl spaces, and other concealed spaces that are not used or intended for living purposes.
• Covered unheated projections of the building at entrances/exits as long as there is another means of egress from the dwelling unit.
• Closets on exterior balconies, regardless of size, as long as there are no doors or unprotected penetrations from the closet directly into the dwelling unit.

C. Water Supplies – Municipal Systems:

• Sprinkler flows shall be hydraulically calculated using the most demanding sprinkler flow. Two design sprinklers are required for NFPA 13-D systems.
• For NFPA 13-D systems the recommended water supply to the dwelling unit is 1 ½ inch (in some cases, a 1 inch supply may be acceptable if it can be proven hydraulically).
• The preferred method is to split the water supply as soon as it enters the building into domestic and fire protection. It is recommended that no meter be installed on the fire protection side. If a meter is required by the water utility, there are two options:
  • o Size the meter for the incoming supply (1” or 1 ½”),
  • o Provide separate meters (one for domestic; one for fire protection).
• A check valve is required immediately following the tap for the fire protection system.
• In the case of a multi-purpose sprinkler system (combined piping for domestic and fire protection use), a separate meter and check valve would not be required.
  
  

  Intent: A sufficient water supply is necessary; this is generally verified through hydraulic calculations. A 1 inch water supply is generally considered as the minimum and 1 ½ inch water supply is generally preferred. Water meters are discouraged on the fire protection system due to friction loss in the meter. If meters are required by the municipality or the water utility provider, the meter should be upsized to match the incoming water supply size or separate meters should be provided.

D. Water Supplies – Private Systems:

• NFPA 13-D allows for a water sources, supplied from a well, and the use of an automatically operated pump.
• The water supply components used for an NFPA 13-D sprinkler system do not need to be listed for fire protection (pump, well, tank, etc.).
• The size of the stored water supply is based on the demand of the sprinkler system and the duration.
• Typically the sprinkler demand for NFPA 13-D systems is 13 gpm for two sprinklers (26 gpm total). The use of extended coverage sprinklers may increase this demand.
• NFPA 13-D requires a 10-minute duration for a home over 2,000 sq. ft. in size (26 gpm times 10 minutes = 260 gallons). For smaller homes (under 2,000 sq. ft. in size) a 7 minute duration is allowed (26 gpm times 7 minutes = 182 gallons).
• The following types of water supplies are acceptable:
  • Stored supplies:
    • Pressure tank,
    • Bladder tank,
    • Storage tank (indoor or underground),
    • Cistern
    • Wells.
• •If the water supply is from a well only, the well must be capable of providing the required flow for the intended duration including normal domestic use.
• No back-up electrical power supply is required for NFPA 13-D systems.

Intent: The intent of NFPA 13-D is to allow for the installation of sprinkler protection using the types of materials commonly used in residential construction. Homes and buildings constructed in areas with no municipal supply have options for providing their own water supply through a combination of well, tanks, and/or pumps. Other than adding in the supply needed for the duration of time required, this section imposes no additional requirements on the water supply.

E. Attached Garages:
Sprinkler systems in single family dwellings and similar residential structures having attached garages require a single sprinkler (dry sidewall type) installed above the door between the garage and the dwelling unit to protect the structure from a fire originating in the garage. This sprinkler does not need to be hydraulically calculated nor does it need to meet the listed spacing or protection criteria.

Intent: The garage to house separation is critical to protect occupants from a fire originating in an attached garage. Most sidewall sprinklers are not listed to protect the entire garage area. This allows a relatively inexpensive means of preventing fire spread through the opening (i.e. door) between the attached garage and the house.

F. System Attachments for NFPA 13-D Systems:

• No fire department connection is required.
• No hydrostatic test (i.e. 200 PSI for 2 hours) is required since the system lacks a fire department connection.
• No off-site monitoring of flow or tamper conditions is required.
  

Intent: NFPA 13-D requirements.

G. Exterior Alarms:

• An outside audible flow alarm is strongly recommended for NFPA 13-D systems.
• A separate water meter is not required by NFPA 13-D if an outside flow alarm is provided but some municipalities may still require it.

Intent: NFPA 13-D does not require an outside alarm but encourages it to prevent unnecessary water damage. Water meters need not be provided if there is an outside flow alarm as theft of water would be detected by the outside flow alarm.

SECTION III – INSPECTIONS, TESTING & MAINTENANCE

A. Inspections:

• Acceptance inspection – final inspection should be conducted.
• Acceptance test consists of the following:
  • Apply water pressure at normal operating pressure to the system.
  • Visually inspect for leaks.
  • Operate all valves to ensure proper operation (control, drain, and test valves).
  • Test operation of outside flow alarm, if provided.
  • Perform other tests that may be required by the manufacturer.
• Additional inspections (such as “rough-in”) may be performed if deemed necessary.
• Sprinklers are allowed to be installed at proposed finished ceiling heights (in unfinished areas).

B. System Maintenance:

• Contractor to leave maintenance instructions (these should be a simple, easy to follow set of instructions for on-going maintenance of the system).
• Contractor to leave emergency repair telephone contact numbers at the system riser.
• Annual maintenance by an outside contractor is not required.

SECTION IV – PERMITS & PLAN REVIEWS

A. Permits:

• Waive permit and plan review fees for single family dwellings or charge minimal fees.

B. Plan Reviews:

• Allow prototype plan review for similar floor plan structures in which hydraulic calculations suffice.

SECTION V – ALTERNATIVE MATERIALS AND METHODS

The following building and fire code provisions could be waived subject to the approval of appropriate code officials (building and fire code officials) as the installation of a residential sprinkler system has been deemed to provide an equivalent level of life safety.

A. Smoke Alarms:

• In lieu of hard-wired and interconnected smoke alarms, allow battery-powered smoke detectors in sleeping rooms.
• Smoke alarms are still required in hallways giving access to sleeping rooms.

B. Second Means of Escape:

• Egress Windows are not required from sleeping rooms located on the main floor and above stories.
• At least one second means of escape (egress window or door) is required for below grade or basement areas having sleeping.