Published on May 1, 2015.

THE WAY WE SHOP FOR GOODS TODAY is dramatically different than it was 20 years ago, just as the materials used in the products we buy have also changed.

The recent proliferation of big-box and online retailers has resulted in the need for ever-larger warehouses to store all of these goods, many of which are now made of plastics, composites, and other materials that have the potential to be highly combustible.

Protecting these storage occupancies is more difficult than ever. That reality kept the technical committee for NFPA 13, Installation of Sprinkler Systems, busy during the revision cycle for the 2016 edition of the standard, says Matt Klaus, principal fire protection engineer and liaison to the NFPA 13 technical committees.

“Of the biggest-picture changes we made, a lot of them focused on storage applications,” he said. “Warehousing and distribution have become a huge deal.”

Two of the big changes proposed for the new edition of NFPA 13 include an extensive revision of the commodity classifications, as well as a new protection scheme for Group A exposed expanded plastics stored in racks. Among the other changes to the standard are new rules on installing sprinkler systems for cloud ceiling applications and a move toward approximate metric conversions.

NFPA members will discuss those changes, and more, in detail at the NFPA Conference & Expo in Chicago, June 22–25. They will also discuss the merits of the nine certified amending motions on the docket for the NFPA 13 session.

Here’s a primer on some of the notable changes proposed for the 2016 edition of NFPA 13.

Commodity classification

One critically important change proposed for the 2016 edition is a comprehensive update of the standard’s commodity classification tables—the first in at least two decades.

Chapter 5 and its associated annex material, one of the most frequently referenced parts of the standard, contains nine pages of tables listing hundreds of commodities—everything from boxed frozen fish to filing cabinets—and assigns each a classification based on the relative hazard it creates. Class 1 materials, like granite countertops, don’t burn at all, whereas Class 4 materials, which may contain appreciable amounts of plastics, can be extremely combustible under the right conditions. Class 2 and Class 3, commodities consisting of wood, paper, cardboard, and other materials, have variable combustibility. The most combustible commodities, which go beyond even Class 4, are known as Group A plastics—goods such as Styrofoam, meat trays, packaging peanuts, and many other plastic products.

The accuracy of those classifications is vital for fire protection, Klaus said. “The first decision you make when designing a sprinkler system in a warehouse is figuring out what commodity group you’re storing,” he said. A warehouse full of Styrofoam cups, for instance, requires a much different fire suppression system than a warehouse full of granite.

In some cases, though, the classification information provided in NFPA 13 is nearly 50 years old, written when storage facilities and schemes were vastly different than today. In the 1960s, for instance, a product like aspirin was stored in glass bottles, on wood pallets with paper lining, and on 12-foot-high racks. Today, the same product is stored in highly combustible plastic jugs, on plastic palettes encapsulated in plastic wrapping, and on shelves 40 feet high—a scenario with a much greater fire potential, Klaus said.

To address this issue, a group of committee members spent more than a year meticulously updating classifications for hundreds of new and existing commodities to reflect new research, products, and storage schemes.

NFPA Conference Session
NFPA Conference & Expo, Chicago, June 22-25, 2015

NFPA 13–2016, Installation of Sprinkler Systems, Changes (Panel 1 of 3)
Monday, June 22, 9:30–10:30 a.m.

Matt Klaus, NFPA; Russell Leavitt, Telgian Corporation; Ken Linder, Swiss Re

Sprinkler Technology for Storage Protection
Monday, June 22, 9:30–10:30 a.m.

James Golinveaux, Tyco Fire Protection Products

Sprinkler Protection for Cloud Ceilings
Tuesday, June 23, 9:30–10:30 a.m.

Jason Floyd, JENSEN HUGHES

NFPA 13-2016, Installation of Sprinkler Systems, Changes (Panel 2 of 3)
Monday, June 22, 9:30–10:30 a.m.

Matt Klaus, NFPA; William Koffel, Koffel Associates, Inc.; James Golinveaux, Tyco Fire Protection Products

NFPA 13-2016, Installation of Sprinkler Systems, Changes (Panel 3 of 3)
Wednesday, June 24, 9:30–10:30 a.m.

Matt Klaus, NFPA; Ken Isman, University of Maryland; David Lowrey, City of Boulder Fire Rescue; Kerry Bell, UL

Sprinkler Installation Requirements: A Road Map to NFPA 13, Chapter 8
Wednesday, June 24, 9:30–10:30 a.m.

Audrey Goldstein, NFPA; Chad Duffy, NFPA

ESFR Sprinklers and Obstructions—The Latest Research
Wednesday, June 24, 11 a.m.–noon

Garner Palenske, Aon Fire Protection Engineering

For the first time, the technical committee is also adding a chart that users can reference to help them classify mixed commodities—a wooden entertainment center with plastic knobs and shelves, for example. The chart, which bases classification on the percentage of plastic in the product by weight and volume, will help engineers and designers more accurately classify commodities, which results in the correct suppression system design for their facility, Klaus said.

“How we classify a given commodity, and calculate the resulting sprinkler density required to protect that commodity, can be the difference between a warehouse developer spending a quarter of a million dollars on a fire pump installation, or not,” Klaus said. “It’s a critical part of the design process and a decision not to be taken lightly.”

Exposed expanded plastics

Several commodities in Chapter 5 are not given a classification—lithium ion batteries, for instance—because not enough is known about how they burn to be able to safety recommend an adequate suppression system.

Until the proposed 2016 edition of NFPA 13, that was the case with a common yet challenging material called Group A expanded exposed plastics. The material is used widely in many plastic goods, such as children’s toys and lawn furniture, Klaus said. In recent years, these highly combustible products have been increasingly stored in plastic bags or in plastic wrap—hence the term “exposed”—rather than in cardboard boxes, which offered some protection when dampened by sprinklers, Klaus said.

“This is one of the more common storage schemes we’re seeing right now, and the standard has historically been silent on it,” Klaus said. “How can we be the go-to source for information on automatic sprinklers if we aren’t addressing what is now one of the most common storage arrangements?”

Researching how commodities burn and testing various suppression schemes and methods is one of the main focuses of the Fire Protection Research Foundation. The technical committee approached the Foundation in 2008 about the gap in knowledge related to the protection of facilities storing exposed expanded Group A plastics. The Foundation coordinated with Underwriters Laboratories on a series of fire tests using various combinations of ceiling and storage rack heights, different sprinklers, ignition locations, and other variables. Each burn test used expanded polystyrene meat trays stored in plastic bags as the commodity, because these are particularly combustible, Klaus said. Based on the information gathered from these tests, the NFPA 13 technical committee approved new protection schemes for Group A expanded exposed plastics, which consider the use of K-25 sprinklers at the ceiling with vertical barriers in the racks. The new schemes will be published in the 2016 NFPA 13.

“The K-25 is a big honking sprinkler,” Klaus said. “The joke is that the next step up is putting 10 fire hoses on your ceiling, because that is how much water you get out of these sprinklers.” 

Cloud ceilings

Another increasingly popular trend today is a building design feature known as cloud ceilings—essentially arrays of ceiling panels suspended below the actual structural ceiling. Cloud ceiling designs vary greatly; panels come in many shapes, sizes, and configurations, and the space between panels can vary as well. Each panel has open space on all four sides, giving it the illusion of floating in space. Cloud ceilings are found in many large spaces with high ceilings—airports, museums, concert halls, restaurants, office buildings, and more.

While they can hide unsightly heating, ventilation, air conditioning systems, and piping, and can even improve acoustics, cloud ceiling arrays can also create problems for sprinklers. “This is a design feature we’ve seen more and more of in the past five years, and we get the question on a weekly basis: ‘How do I address cloud ceilings?’” Klaus said. “Historically there haven’t been a lot of exceptions to the installation requirements, so we said the standard requires that you put sprinklers both above, at the structural ceiling, and below, at the cloud ceiling, because there are too many potential ceiling designs and the standard couldn’t address how sprinklers would react in each case.”

Most developers have opposed that solution, arguing that the requirement adds unnecessary cost and could create safety problems. It is possible that, in some cases, the weight of the water from the sprinklers on the structural ceiling could collect on a cloud ceiling panel and cause it to collapse.

Once again, the NFPA 13 technical committee turned to the Fire Protection Research Foundation for help. The Foundation organized fire tests to determine when sprinklers on the cloud ceilings were enough to suppress a fire and when they were not.

Based on the research, the NFPA 13 technical committee came up with a design approach that allows designers to have a gap between cloud ceiling panels that is one inch wide for every vertical foot of height between the floor and the cloud ceiling panel. For instance, in a space with 12 feet of clearance from the floor to the bottom of the ceiling panel, the maximum gap between cloud ceiling panels must be 12 inches or less, or else sprinklers above would be required. If the floor to cloud ceiling is eight feet, the gap between clouds can only be up to eight inches, and so on.

“This is important, because it shows that the sprinkler industry is working with architects and designers, trying to make this work,” Klaus said. “It’s something we are seeing the design community move toward, and we are trying to answer the bell.”

Metric conversions

Users of NFPA 13 in the United States might not notice, but there is a proposed change to the code that will have a major impact in the Middle East and other international locales where NFPA 13 adoption is widespread.

Over the course of many months, NFPA associate fire protection engineer Audrey Goldstein and seven NFPA 13 committee members, hailing from countries all over the globe, meticulously changed the code’s rigid metric conversions from exact conversions to more approximate figures that correspond with actual product dimensions found in the real world. The change is critical for increasing the usability of the standard in places outside of the U.S., Klaus said.

NFPA 13 is filled with measurements—pipe diameters, water volumes, areas, pressures, and more—and the conversion of these base values into metric values has been an afterthought to those not working in inches, gallons, square feet, and pounds per square inch. The exact metric conversions are printed in the current edition of NFPA 13, but in many instances are not usable, Klaus said. A three-inch pipe, for instance, converts exactly to 76.2 millimeters. A sprinkler installer in Dubai can’t walk into the local hardware store and buy 76.2 millimeter piping—it just doesn’t exist. That leaves contractors to make a judgment call; do they go with 75 millimeter diameter piping or 80 millimeter?

“It is a huge problem,” Klaus said. “Contractors are being forced to have to make engineering decisions about the rounding principles in the standard.”

Simply rounding to the nearest real metric number isn’t always practical or safe, so the committee needed to develop rounding rules before it could change the thousands of figures in the document. If the standard says you need 2,000 gallons to put out a fire, for example, the exact translation would be 7,570.824 liters. But rounding to an even 7,500 liters would mean that slightly less than 2,000 gallons of water would go on a fire. “Do we know that’s going to work? Not in every case,” Klaus said. “We are confident that 2,000 gallons will put the fire out because we have test data that says so. In that case, in Europe and elsewhere we have to round up so we know they are at least going to hit that minimum value.”

In other cases, rounding down was deemed acceptable because equivalent strengths had been verified by the International Organization for Standardization. That was the case with a half-inch hanging rod, where the 12.7-millimeter exact equivalent was changed to 12 millimeters.

“We care how our documents are used internationally,” Klaus said. “It’s very important and it’s a real benefit to show the metric world, which is most of the world, that we do consider how they use our standards and that we are committed to improving their experience with the document.”

Click here for more on NFPA 13 and on the process used to update the 2016 edition of the standard.

JESSE ROMAN is staff writer for NFPA Journal. He can be reached at jroman@nfpa.org.