Smaller + Smarter
Fire engineering and alternatives to full-scale testing
NFPA Journal®, January/February 2013
In 2005, I gave a presentation at a Society of Fire Protection Engineers conference that included a challenge for the audience: “Can we design a sprinkler system for a given ignition scenario, commodity, and configuration, without a full-scale fire test?”
I believe the answer will one day be an unequivocal yes, but for now progress is incremental. That said, there are significant research initiatives underway by insurers, universities, the sprinkler industry, and others to approach this challenge from a fundamental scientific and engineering approach. This work is exploring new means of classifying commodities, of characterizing the spray patterns of sprinklers, and of modeling the effectiveness of sprinklers for commodity protection — all through emerging testing protocols that are more strategic and less expensive than classic full-scale testing.
A big feature of the Foundation’s research portfolio over the past five years has been full-scale testing to determine protection criteria for emerging commodities. And I mean big: a typical full-scale sprinklered commodity test might generate a 25-megawatt fire and cost $100,000 or more. Many of these tests involve a lot of cleanup, which is an increasingly large share of fire testing costs. But because resources are scarce, the technical panels that review the scope and details of our research programs are always asking us if there’s some way, through our increasing knowledge of fire growth and the effects of sprinklers, to reduce the number and/or magnitude of the tests required to develop appropriate protection criteria.
In 2012 we completed two major projects that illustrated innovative engineering-based approaches towards “smart” full-scale testing, a critical step in the evolution of new testing methods. The first project, designed to understand how boxed small-format lithium-ion batteries (PDF, 355kb) — the kind you find in your cell phone or laptop computer — perform relative to other cartoned commodities, was undertaken at FM Global’s research facility. Using only a limited amount of the commodity, and placing it strategically, FM’s engineers were able to characterize the flammability of the stored product and compare it to other commodities, providing valuable insight into required protection. Another project, conducted at Underwriters Laboratories, explored the possibilities of ceiling-only protection for stored non-cartoned expanded plastics (PDF, 65kb), an increasingly common commodity in today’s warehouses and big-box stores. Again, using an “engineered” approach to full-scale testing of the storage configuration — limited commodity, strategically placed—engineers were able to study sprinkler protection criteria for the commodity.
Each test saved tens, if not hundreds, of thousands of dollars in commodity and cleanup costs. Even with those savings, the cost of these two test programs together was well in excess of $1 million and represented a major commitment from the sprinkler, insurance, and facility communities to support NFPA standards.
There are many more challenges ahead of us. New commodities, new storage configurations, and new protection solutions are emerging every day, and the Foundation’s Automatic Sprinkler Research Advisory Council, which meets each year to identify research priorities for NFPA 13, Installation of Sprinkler Systems, has long lists of topics to address in each of these categories. It is my hope that the Foundation can continue to help provide a bridge between these increasingly sophisticated predictive approaches and the “smart” full-scale test programs that are emerging. We have come a long way, but we have a long way to go to prepare for the storage fire protection challenges of the future.
Kathleen H. Almand, P.E., FSFPE, is the executive director of the Fire Protection Research Foundation.