What’s new to NFPA 13 and what to expect in future editions

Changes to the 2016 edition of NFPA 13 are evaluated along with what to expect in the 2019 edition.


This article is peer-reviewed.Learning Objectives

  • Review changes made to the 2016 edition of NFPA 13: Standard for the Installation of Sprinkler Systems.
  • Discuss the updated organization to the 2019 edition of NFPA 13.

Standards that are regularly applied in daily practices are developed years in advance of them actually being adopted and enforced. The 2016 edition of NFPA 13: Standard for the Installation of Sprinkler Systems will not be adopted locally until the location’s jurisdiction adopts the 2018 edition of the International Building Code or 2018 edition of NFPA 101: Life Safety Code.

There are some authorities, however, that adopt the most current edition of the standards. Most notably, the U.S. Department of Defense typically applies the most recent edition of the NFPA standards to projects. It may also be advantageous from a risk management perspective to apply the most recent edition of a code to a project. This is because there may be areas addressed in the most recent code that aren’t addressed in previous editions that can influence a design.

The most recent edition of a standard is typically considered to contain the latest and best thought on the subject. However, if there are changes from the actual standard that are being enforced on a project, it is recommended that any deviation from the adopted standard be reviewed with the authority having jurisdiction (AHJ) during the design process.

For product manufacturers and installers, knowing what is coming down the road can also help prepare for implementing the new code requirements. The knowledge also can be used to impact product design or help develop training material for employees who design and install systems.

There are a number of significant changes in the 2016 edition of NFPA 13 that will be evaluated in addition to the new organization of the 2019 edition.

Metric conversions: During the development of the 2016 edition of NFPA 13, the association’s correlating committee established a task group to review the metric conversions within the standard and make recommendations for potential revisions to enhance usability outside of the United States. Previous editions of the standard used an exact conversion between U.S. customary units and metric units. Where it was deemed appropriate by the task group and technical committees, nominal metric equivalents or approximate conversions have been provided. The standard explicitly notes in Section 1.6.3 that it is acceptable to use the exact conversion or the conversion stated in the standard even though they may not be the same. Section A.1.6.3 of Annex A provides explanatory information and examples of conversions.

Storage commodity classification: The criteria for defining Class IV commodities has been expanded to include criteria for cartoned versus exposed products. Class IV commodities can also include limited amounts of Class A plastics (expanded and unexpanded). Figures have been added that note the allowable mixtures (on a percentage by volume basis) of expanded and unexpanded Group A plastics for purposes of defining the commodity classification. (Figures [a] and [b])

Cellulosics, natural rubber, and nylon have been reclassified from Group B to Group A plastics. PVF (polyvinyl fluoride) has been reclassified from a Group C plastic to a Group A plastic.

Treatment of extension fittings: A definition of extension fittings and criteria for their use have been added to the standard. An extension fitting is an adapter that is used to adjust the final fit where sprinklers are installed in a finished ceiling or wall. Previous editions of the standard do not address extension fittings.

A new Section 6.4.8 has been added. Extension fittings are allowed to be used with sprinklers having a K factor of 8 or less in light or ordinary hazard occupancies only. A single extension fitting having a maximum length of 2 in. is allowed and is not required to be included in the hydraulic calculations.

Extension fittings longer than 2 in. are allowed if they are specifically listed and are included in the hydraulic calculations.

Figure 1: This photo shows a dry pipe system being fed from a wet combination sprinkler/standpipe riser. The dry pipe system is extending to an exterior area to protect mechanical equipment on the roof of the building. All graphics courtesy: ArupAir venting: A requirement has been added that each wet-pipe system using metallic pipe be provided with a vent. The vent is required to be located near a high point in the system to allow air to be removed from the system (Sections 7.1.5 and 8.16.6). The vent can consist of a manual valve, an automatic valve, or other approved means. The intent of the requirement is to provide a means for removing trapped oxygen that could fuel corrosion, and that the valve be operated after each drain-and-fill event. Only one vent is required per system. There isn’t an intent that all air that may be trapped in the system be vented. The provision of more than one vent is at the designer’s discretion.

Galvanized pipe in dry systems: The requirement that galvanized steel pipe be used in dry and preaction systems was removed from the standard. The technical committee removed the requirement because there have been instances where galvanized pipe has corroded as quickly as nongalvanized steel pipe.

Sprinklers under skylights: A clarifying section (Section has been added to the standard regarding the placement of sprinklers under skylights. This section notes that for the purpose of determining the distance of a sprinkler to the ceiling, the ceiling plane shall be measured to the ceiling as if the skylight were not present. This is applicable to skylights that are less than 32 sq ft in area.

It is also important to note that the 2013 and 2016 editions allow omission of sprinklers from skylights that are less than 32 sq ft in area when they are located greater than 10 ft from another unprotected skylight or ceiling pocket.

Sprinklers under obstructions: Most designers and installers are aware that obstructions wider than 4 ft require sprinkler protection below the obstruction. Two new criteria have been added to the standard addressing these obstructions. One requirement mandates that sprinklers be installed no more than 12 in. from the bottom of the obstruction and is applicable to all types of sprinklers with the exception of residential sprinklers, which are to be installed in accordance with their listed distance below ceilings (Sections,,, and The other requirement addresses sprinklers below round ducts that are creating an obstruction, stating that the sprinklers be intermediate-level/rack-storage type or otherwise shielded from the discharge of overhead sprinklers. This requirement is applicable to pendant and upright sprinklers as well as residential sprinklers (Sections,, and

Clearance to storage: An allowance has been added to the standard to permit wall-mounted shelving not located directly below a sprinkler to extend above a plane that is 18 in. below the sprinklers. The standard does not limit the height of wall-mounted shelving that is not directly below a sprinkler. Wall-mounted shelves could be installed up to the ceiling (Section

Sidewall sprinklers in soffits and above cabinets: The limitation that sidewall sprinklers be located within 4 in. of the bottom of a soffit to avoid sprinklers below the soffit has been removed. The sidewall sprinkler just needs to be located on the soffit within the spacing limitations from the ceiling (Section

Criteria for sidewall sprinkler installation in soffits above cabinets were previously only applicable to soffits and cabinets in residential areas and occupancies. Limiting the use of these rules in other occupancies has been deleted (Section

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