Standards: Installing Sprinklers

The National Fire Protection Association standard for installing sprinklers has greatly expanded in the past few years, but not all building codes have caught up.

Although the 1996 Edition of National Fire Protection Association (NFPA) Standard 13, “Installation of Sprinkler Systems,” is still used by many jurisdictions, significant changes have been incorporated into both the 1999 and 2002 editions — enough changes that the volume has more than doubled in size, expanding from 133 to 342 pages.

Designers of sprinkler systems will want to follow the latest issue of the standard as a matter of due diligence. In doing so, they will be assured that the design complies with the most recent scientific test results and field experience.

For example, the 2002 edition of NFPA 13 incorporates data on new large flow sprinklers that have been specially designed and tested to meet the challenges of big box stores. Additionally, after test results of some residential sprinklers by Underwriters’ Laboratories showed their failure to meet area flow density requirements, the standard has discontinued listing residential sprinklers with flows less than 0.05 gpm/ft2. Features like these are major safety considerations that a designer would wish to address to ensure their clients are adequately protected.

1999 Edition

Major changes incorporated into the 1999 edition of NFPA 13 included:

The scope was expanded to address all sprinkler system applications.

Information for special hazards from more than 40 NFPA documents was drawn into the standard.

Design requirements for on-floor and rack storage of all commodities including plastics, rubber tires, baled cotton, and roll paper previously found in NFPA 231 were incorporated.

A new classification concept for occupancy hazards and storage of commodities was introduced that now determines design requirements.

Obstruction rules for early suppression fast response sprinklers and rules for locating sprinklers in concealed spaces were revised. These allow for the sprinklering of only the area where combustibles are stored in these concealed spaces.

New limitations were placed on sprinkler sizes in storage applications. The provisions limit the size of large flow sprinklers in storage areas as it was found that the large flows disrupted the spray patterns and thus system effectiveness.

2002 Edition

The major changes in the 2002 Edition were meant to further refine the document into a single reference standard for sprinkler installations. These changes included:

Increased protection requirements needed for commodities being stored on plastic pallets.

The incorporation of all underground piping requirements into a new chapter.

A separate chapter with new design methodologies for protecting storage facilities.

A new chapter for all non-storage design requirements and approaches.

Changes to address how to account for irregular ceilings and architectural features when designing the sprinkler layout.

Changes in the design areas for residential sprinklers in all types of applications, including the provision not to list sprinklers below 0.05 gpm/ft2 flow.

Discrepancy and conformance

A problem sometimes arises when a local building official does not wish to accept a design done according to the newer standard. Some local regulations and building codes still cite the older standard, so building officials are concerned that they may be exposed to liability if they accept a design made to the new standard and not according to the older standard cited in their code.

The building officials may not even be aware of the changes incorporated in the new NFPA 13 standard and the rationale behind them. Since it is ultimately the official’s decision whether to accept the design or not, the consulting engineer or other party that has designed the system has to communicate up front with them and provide the rationale for using the latest standard.

As consulting engineers you should never go wrong by referencing the latest edition of the standard. NFPA is attempting to advise municipalities of the need to update to the latest reference standards, and is making presentations to brief them on the changes. The organization also has prepared a CD-ROM to allay concerns and convince the authorities to adopt the 2002 edition.

Sean Tracey, P.Eng. in Ottawa is Canadian Regional Manager of the National Fire Protection Association, Tel. 613-830-9102, e-mail stracey@nfpa.org