NFPA 13 is the industry standard for all matters related to sprinkler systems in the U.S., and the first version was published more than a century ago in 1896. It is important to note, however, that state and local authorities frequently introduce additional requirements. For example, fire sprinkler systems in New York must also meet local amendments to NFPA 13, along with additional requirements set forth in the New York Building Code and New York Fire Code.
The NFPA 13 standard is almost 500 pages long and is very detailed in requirements and specifications. This article will provide an overview of the main points covered, but is in no way a substitute for the full document. Also remember that automatic fire sprinkler installations in New York can only be approved if a Registered Design Professional (RDP) submits construction documents, and the work permit is only issued to a qualified and licensed contractor – a plumber licensed master (LMP) or Licensed Fire Suppression Contractor (LFSC).
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Local Law 26 of 2004 makes fire sprinklers mandatory for all commercial occupancies where the building is at least 100 feet tall. If a New York property is covered by LL26/04, the deadline to install an automatic sprinkler system is July 1, 2019. Because these projects can be time-consuming and capital-intensive in large buildings, the best advice we can give is : Get started as quickly as possible and with the assistance of qualified engineering consultants.
The most recent editions of NFPA 13 are not retroactive in most cases, meaning there is no need to update existing installations that were in compliance at the time of installation. If any specific requirements are retroactive, this is clearly stated in the current version of NFPA 13.
General Definitions and Requirements
Because the design of fire extinguishers involves many technical concepts, NFPA 13 devotes its Chapter 3 to defining the key terms that are used throughout the document. An automatic sprinkler is defined as “a fire suppression or control device that operates automatically when its heat-activated element is heated to its heat rating or higher, allowing water to be discharged over a specific area.” There is a common misconception that automatic sprinklers are activated by smoke, but they actually respond to heat.
The general requirements apply to all sprinkler systems, regardless of building type or specific configuration, unless there is a direct exception in the code. If a building uses fire extinguishers, NFPA 13 requires full coverage for the entire property unless the standard clearly indicates that a specific building area is optional.
NFPA 13 Occupancy Classification
NFPA 13 classifies occupations by hazard level. It is important to note that this only applies to fire sprinkler systems and is not a general classification. The general classification for occupancy groups is in the New York Building Code.
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OCCUPANCY CLASSIFICATION |
DESCRIPTION |
|
Mild Danger |
Low combustibility of contents and low heat release expected from a fire. |
|
Common Danger |
Group 1: Low combustibility, moderate amount of combustible materials, stocks are no more than 2.5 meters high and moderate heat release is expected in a fire. Group 2: Combustibility and amount of content vary from moderate to high. Contents with moderate heat release are not stacked more than 12 feet high, and contents with high heat release are not stacked more than 8 feet high. |
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Extra Danger |
Group 1: The combustibility and quantity of contents are very high, and there are compounds such as dust or lint present, which can accelerate a fire if it occurs. The rate of heat release from a fire is high, but combustible and flammable liquids are only present in small amounts or not present at all. Group 2: Moderate to large amounts of flammable or combustible liquids. Also includes occupations with extensive combustible shielding. |
In addition to classifying occupancy, NFPA 13 has a classification for stored materials, called “commodities” in the standard. There are four classes, I to IV, where Class I is the least vulnerable to fire and Class IV is the most vulnerable. Classification is determined based on both the materials stored and the containers used (boxes, pallets, crates, etc.).
Fire Sprinkler System Components and Installation
The main content of NFPA 13 is a description of all components used in automatic sprinkler systems and a description of their correct installation procedure and mechanical support requirements. The standard establishes requirements for all system components depending on their material and type. NFPA 13 provides general requirements and application-specific requirements.
NFPA 13 provides detailed requirements for each type of sprinkler system.
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TYPE OF SPRAYING SYSTEM |
DESCRIPTION |
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Wet tube |
Permanently filled with water. |
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Dry tube |
Filled with pressurized gas, it allows water to enter the system when a sprinkler is activated. |
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PRE-action |
It fills with water upon an alarm signal from an independent heat or smoke sensor, and water is released when individual sprinklers are activated. |
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Flood |
All sprinklers are open and controlled by sensors. When a fire is detected, all sprinklers discharge water at once. |
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Dry tube and pre-action combined |
Filled with pressurized air, but activates as a pre-action system. |
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Multicycle |
Can be activated many times consecutively. |
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Antifreeze |
A wet piping system where water is mixed with an antifreeze compound. |
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Circulating in a closed circuit |
A wet piping system that can be used to circulate water for heating and cooling purposes. |
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Grid |
Sprinkler system with parallel connections between crossed networks, so that each sprinkler receives water from both sides of the pipe when active. |
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Looped |
Sprinkler system where many cross networks are connected together to provide multiple paths for water. |
|
Piping Schedule |
Sprinkler system where pipe size is determined by occupancy classification. |
Note that a sprinkler system can be of more than one type. For example, a wet piping system may be configured as an antifreeze or circulating closed loop system.
Conclusion
The NFPA 13 standard is demanding in its requirements, but this is necessary considering the important role of automatic sprinkler systems in fire protection. Keep in mind that New York codes establish additional requirements for fire sprinkler systems while also amending NFPA 13. The best way to ensure compliance is to work with qualified fire protection engineers.
