Apr 2016

The Top 13 Changes to NFPA 13, Standard for the Installation of Sprinkler Systems

The first edition of NFPA 13 came out in the year 1896. NFPA 13 is on a three year revision cycle, with the last edition in 2013. Revisions for the 2016 edition occurred in August 2013 and June 2014. A vote for changes occurred June 2015 and the 2016 edition, which is 486 pages, was published October 2015.

Back in August 2015, Risk Logic provided a sneak peek at the changes to the 2016 edition of NFPA 13.

Below you will find a detailed review of the Top 13 changes to the 2016 edition of NFPA 13.

    1. In Rack Automatic Sprinklers (IRAS) – NFPA 13 now allows for the use of larger orifice sprinklers and higher water flow rates for IRAS. The number of IRAS needed for an installation will be greatly reduced. Instead of using the traditional K5.6 sprinklers at a flow rate of 22 to 30 gpm, K14.0 and higher sprinklers can be used at flow rates of 60 gpm. Traditional IRAS installations limit the storage height above the top level of sprinklers to 10 ft. and also use a vertical spacing between levels of IRAS ranging from 10 to 15 feet. This is due primarily to the smaller K-factor sprinklers and their relatively low design flow rates. The new extended coverage pendent IRAS uses a nominal K factor of 25.2 and allows for much more increased spacing both vertically and horizontally as compared with conventional IRAS. The old conventional IRAS had a max K-factor of 11.2, which resulted in closely spaced IRAS 5 ft. – 10 ft. apart horizontally.

A recent fire test by NFPA was set up as follows:

      • Exposed Expanded Group A Plastics (polystyrene trays) in Double Row Racks (DRR)
      • Racks to 35 ft. in a 40 ft. building
      • One extended coverage IRAS was located in each bay of the longitudinal flue on 8.25 ft. horizontal spacing and 12 ft. vertically
      • IRAS designed for 30 psi
      • A horizontal barrier was provided above the IRAS
      • Ceiling K25.2 ESFR designed for 12 @ 60 psi
      • Fire was started at the base of the commodity at the aisle which was the most remote location between IRAS

Results of the test (Based on UL199 criteria) were successful

      • Fire contained within the two initial rack bays
      • Two IRAS activated
      • One ceiling head activated
      • One minute average steel temperature above the fire was limited to 102 F.

So why do Extended Coverage IRAS provide a better option than the old conventional IRAS?

      • Lower cost by reducing the amount of piping and number of sprinklers
      • Less chance of a damaged IRAS since face sprinklers are not needed
      • Reduced water supply requirements
      • Unlimited storage and building heights
      • Limited impact on the slope of the roof
      • Limited impact on ceiling level obstructions
      • More flexibility with open top plastic totes

Now the requirement will have IRAS at a lower hydraulic demand:

      • 6 flowing IRAS calculated to discharge 60 gpm for SRR
      • 8 flowing IRAS calculated to discharge 60 gpm for DRR
    2. An important advantage of this new IRAS criterion is that the IRAS demand is not added to the ceiling demand. This can be useful at an existing building where the ceiling demand is not adequate and an IRAS water demand will be less than 500 gpm, because the IRAS demand is separate from the ceiling demand, often without upgrading the water supply. Also this design can be used where a higher commodity hazard is stored in only several racks. In this design the IRAS and horizontal barriers must be extended one pallet position.
    3. Another very important change to NFPA 13 is the new protection criteria for Expanded Uncartoned Plastics (UEP). In the past when there has been expanded exposed uncartoned plastics in racks the only prescriptive standard was FM Global Data Sheet 8-9, Storage of Class 1, 2, 3, 4 and plastic commodities. Now NFPA 13 has added a new protection scheme for exposed expanded uncartoned Group A plastics in racks. This new design criterion is in Chapter 17. Below are some of the highlights:
      • The maximum storage height shall be 25 ft.
      • The maximum ceiling height shall be 40 ft.
      • Sprinklers shall be intermediate temperature rated ESFR pendent sprinklers with a nominal K-factor of 25.2
      • The design area shall consist of the most hydraulically demanding area of 12 sprinklers
      • The minimum operating pressure shall be either 30 psi or 60 psi based upon the applicable storage and ceiling height for the installation as follows:
        • 30 psi for storage heights up to 25 ft. with a maximum ceiling height of 30 ft.
        • 60 psi for storage heights up to 25 ft. with a maximum ceiling height of 40 ft.
      • The minimum aisle width shall be 8 ft.
      • The rack shall have a solid vertical barrier of 3⁄8 in. plywood or particleboard, 22 gauge sheet metal, or equivalent, from face of rack to face of rack, spaced at a maximum of 16.5 ft. intervals
      • The vertical barrier shall extend from a maximum of 4 in. above the floor to the maximum storage height
      • The plan area of storage between vertical barriers and aisles shall not exceed 124 sq. ft.
    4. All of the commodity classification tables in the Chapter 5 Annex have been updated for the first time in over 30 years. There are clear examples of Ordinary & Extra Hazard Group 1 and 2 occupancies. There are also 17 pages of hundreds of examples of commodities, both liquids and solids. Many Group B plastics are now classified as Group A.
    5. New language has been added to Chapter 8 that will allow sprinklers to be omitted above certain cloud ceilings. Automatic sprinklers heads need to be quick response and not sidewall heads.
    6. The 2 in. main drain sizing has been changed so there are no restrictions on the size of the drain. The reason for this change is that backflow preventers can now be tested through the main drain. A problem you may need to look out for is the drainage area may not be able to handle the additional waterflow with the increase in size of the 2 in. drain.
    7. A new requirement has been added that will require listed window sprinklers to be used where glazing assemblies are used as an alternative to fire resistive rated construction.
    8. Revisions were made to Chapter 9 for the use of concrete anchors.
    9. An alternative storage protection scheme has been added for certain storage, which will look similar to the Scheme A allowance in NFPA 30.
    10. In Chapter 11 the Adjacent Hazards or Design Methods section has been changed. A barrier is needed between occupancy classes or the higher protection design scheme should be maintained an additional 15 ft.
    11. In Chapter 8 there is a clearer understanding when protection can be omitted in concealed spaces.
    12. All new wet systems are required to have an air vent. The intent is to cut down on potential corrosion to the piping.
    13. All of the conversions for metric have been rounded from exact to approximate to make the document more useable.

The main changes to NFPA 13 deal with the increased capacity of IRAS and the new protection criteria for expanded uncartoned plastics. If you need additional help in understanding the new changes to NFPA 13 or would like to know the difference between NFPA 13 and FM Global DS 8-9 please contact Risk Logic. We have trained PE’s that have over 25 years’ experience with deciphering these standards.