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Motif Articles: Residential Fire Suppression - NFPA 13D Systems

Updated: May 16, 2023

NFPA 13D is a residential sprinkler design standard focused on one- and two- family dwellings and manufactured homes. The intent is to provide an affordable sprinkler system in homes while maintaining a high level of life safety.

Fire suppression in homes are becoming more popular in Austin.

Building a large home in Austin can sometime poses challenges, especially around the lake. Due to the size, fire flow and fire area - some new homes require a fire suppression system to protect the occupants during an event.

For example, our Big Horn project on Lake Austin required a NFPA 13D system per the City of Austin. At first glimpse, we shrugged from the added cost.. however, after meeting with the plan reviewer, talking to several suppliers / contractors / fire marshals... we actually liked the idea and value that the system offered to the new home.

"The provisions in NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, do provide a degree of property protection especially where the fire occurs in a space protected by sprinklers. NFPA research indicates that fire sprinklers can reduce the risk of property damage by 70 percent. However, the standard’s focus is life safety and therefore does not require sprinkler protection in all areas of the home. The standard requires two operating sprinklers discharging for a period of 10 minutes to control the fire — a period considered sufficient for residents to safely escape a home fire." - NFPA.ORG

Why our Big Horn project required a Fire Suppressions System.

Our Big Horn project on Lake Austin had very low hydrant flow. Infact it was so low, it was deemed pretty much pointless. To add to the complexity, the City of Austin's Fire Department would not allow third party testing (as noted below)... however the water district only allowed third party testing (do you see the problem here).

Regardless of the testing, the district was aware of the low flow, so the results wouldn't of been in our favor.

Also, because the lot walls within Lake Austin contours, the City of Austin has jurisdiction over Travis County.. so the permitting process and other code adoptions that City of Austin has - applied to this project.

Action #1 - Understand Fire Area, Fire Flow and the Code Requirements in Austin.

Fire Area: If the Fire Area of a new home in the City of Austin exceeds 3600 SF, the 2021 International Fire Code (IFC) Table B105.1(2) requires at least 1750 GPM Fire Flow for the fire hydrants closest to the property.

Our project was only 3495 SF however the approx. fire area was calculated around 4540 SF, due to the large overhangs and three tiered patio deck.

Fire Flow: Providing water to the responding fire department is a crucial aspect of the overall fire protection and life safety strategy of an entire community. When a new building is developed or an existing building is renovated, it is important to make sure that the proper amount of water is available to the responding fire department to allow for both suppression of the fire in the building, and protection of any exposed buildings. Because of this, NFPA 1, The Fire Code, requires a minimum amount of water be provided based on the type of construction of the building as well as fire flow area.

Fire flow is defined as the flow rate of a water supply, measured at standard residual pressure, that is available for the responding fire department for manual firefighting, typically this is water that is available at the surrounding fire hydrants, but it can be supplied with another approved source such as a static water supply like a tank or pond, or even using a fire department tanker shuttle service.

Options: If the Austin Fire Department has no flow data on file for this area. The available options for compliance with 2021 IFC are as follows:

  • Request a fire flow test at nearest hydrant from the assigned Emergency Services District. Sometimes the available fire flow may not be the same value as the Flow Rate displayed on the ESD hydrant flow test. The City of Austin reviewer will calculate the available fire flow and notify you of the amount of fire flow available and what options are available to comply with the 2021 IFC. Important: AFD Does not accept third party fire flow tests. All fire flow tests must be conducted by AFD or witnessed by AFD unless it comes from another fire department or ESD.

  • If the available fire flow (as shown by the flow test) is less than the required fire flow of at least 1750 GPM, your options for compliance with the IFC 2021 are as follows:

    1. Reduce the fire area of the home to under 3600 SF.

    2. Provide a full fire sprinkler system designed per 2019 NFPA 13D or 2021 IRC Sec. P2904.

Refer to the City of Austin's Municode / NFPA Website for additional information with regards to location, code and application type

Action #2 - Understand the NFPA 13D System

The ordinance is pretty simple once you understand why its was set in place. It defines the MAXIMUM AMOUNT OF DEVELOPMENT PERMITTED on the property, and 2. The ordinance establishes the BUILDABLE AREA within which development must occur.

  • To meet compliance, the drawings must note: A full residential sprinkler system designed, installed and tested in accordance with the 2019 NFPA 13D or the 2021 IRC P2904 standards will be installed in this property.

  • The plans for the sprinkler system must be designed and installed by a Texas Licensed Sprinkler contractor for NFPA 13D systems or a Texas Licensed Plumber with the Multipurpose Residential Fire Protection Sprinkler Specialist (MRFPSS) endorsement.

  • The Sprinkler plans must be submitted, reviewed, approved, tested and inspected by AFD prior to covering the walls and ceilings.

  • A flow test of the most demanding area will be required.

"The 13D system not only adds a peace of mind to your family, its also adds value to your house and reduces insurance premiums. " – Rachel

Action #3 - Understand the benefits of a NFPA 13D System

Cost: At the present time, cost of a home sprinkler system is targeted at approximately $1 per square foot in new construction. It is hoped that the cost will decrease as the use of home fire protection grows. It is also possible to retrofit existing homes with sprinkler systems.

Minimal Installation Work: When homes are under construction or being remodeled, a home sprinkler system will require minimal extra piping and labor.

Good Investment: Home sprinkler systems offer both safety and financial advantages to home buyers, a rare combination.

Insurance Discount: Insurance from homeowner underwriters will vary depending on type of coverage. The discounts now range between 5-15%, with a projected increase in available discounts.

Action #4 - FAQ's about the System

We have added a few FAQ's from NFPA's website below, that we believe will help with most questions.

Can a plumber install an NFPA 13D sprinkler system?

Local licensing laws typically specify who is allowed to install home fire sprinklers. These laws can vary significantly from jurisdiction to jurisdiction. NFPA 13D does not establish professional qualification requirements. Because fire sprinkler system components can be highly specialized for fire protection purposes, even jurisdictions that permit plumbers to install residential fire sprinkler systems typically require some certification confirming fire sprinkler system knowledge.

How large is the tank?

The tank size depends on your system. For our Big Horn project, the home was designed to 3495 SF however the approx. fire area was calculated around 4540 SF. The owner decided to utilize the H2Home Tank Kit (approx.. $5k) thus resulting in closet roughly 3'-0" x 7'-0" in size.

How do I prevent pipes freezing during a winter event?

Where system piping is located in areas not maintained above 40 degrees Fahrenheit, the pipe shall be protected against freezing by use of one of the following methods:

  1. Dry pipe system and preaction systems in accordance with NFPA 13D

  2. Antifreeze system in accordance with provisions in NFPA 13D

  3. Listed standard dry pendent or dry sidewall sprinklers extended from pipe in heated areas into unheated areas not intended for living purposes

  4. Listed heat tracing provided that it is installed and insulated in accordance with manufacturer’s instructions. Heat tracing is an electrical system used to maintain or raise the temperature of the sprinkler pipe so that the water in the pipe does not freeze.

  5. Listed residential dry pendent or dry sidewall sprinklers extended from pipe in heated areas into unheated areas

Consultation with the general contractor and/or owner is recommended to ensure proper methods and materials are used to make sure 40 degrees Fahrenheit will be maintained.

Are you ready to get started on your lake house design?

We're dedicated to helping you tell that story in the best way possible. That means creating a custom lake house that's not only beautiful but also fits your personality and lifestyle perfectly - no matter where it is.

We specialize in designing contemporary custom homes on one-of-a-kind sites, whether that be a lakeside, hillside, remote, or other distinguished sites. Our goal is to design a site-sensitive, integrated dwelling that complements the natural beauty of the surrounding landscapes whilst simultaneously creating a home that celebrates its occupants.

​We aspire to create unforgettable lake homes that are in harmony with their natural surroundings, conserve resources, and are ultimately efficient in use.

This article is building code information and should not be seen as code advice. You should consult with an architect, builder or code expert before you rely on this information. The blog published by Motif Architects PLLC is available for informational purposes only and is not considered legal and or building code advice on any subject matter. By viewing blog posts, the reader understands there is no architect-client relationship between the reader and the blog publisher. The blog should not be used as a substitute for legal or building code advice from a licensed professional architect / interior design, and readers are urged to consult their own legal counsel on any specific legal questions concerning a specific situation.

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