STATter 911

Thirty-two townhomes were destroyed during a fire in Raleigh, NC on February 22nd. Now our friends at FireNews.net have alerted us to the report this week that explains the factors leading to such destruction and what is needed to prevent a similar firestorm in the future.

You can read the report the 50-page by Schirmer Engineering of Charlotte here.

This is an excerpt from the introduction:

Schirmer Engineering Corporation has been retained by the City of Raleigh to perform an independent study to recommend changes to applicable codes and ordinances to mitigate future fire losses. The study has been requested by Mayor Charles Meeker and the City Council in response to a fire on February 22, 2007 at the Pine Knoll townhomes subdivision that destroyed 32 townhomes. This loss is an example of the current most common conflagration scenario, a wildland/urban interface fire. The classic conflagration scenario of the past century that involved narrow streets and closely spaced buildings has been replaced by a brush or forest fire that spreads to nearby buildings.

According to the National Fire Protection Association, virtually every wildland/urban interface fire includes the combination of dry vegetation, combustible construction, and high winds. These conditions existed at the Pine Knoll Townhomes on the day of the fire. Once an ignition source as introduced, the fire was soon uncontrollable. The cause of the fire was reported as a carelessly discarded cigarette that ignited landscaping pine straw. Fire spread up vinyl siding through vinyl soffits into attics,negating the presence of fire-rated walls between residential units. Strong winds (ie, 35 mph) caused air-borne embers to ignite pine straw and dry grass near multiple buildings as well as buildings on the opposite side of Capitol Blvd.

An excerpt from the executive summary listing contributing factors for the rapid fire spread:

1. Weather (pages 16-18): High winds (ie, 35 mph) caused air-borne embers to ignite pine straw and dry grass near multiple buildings as well as dry grass on the opposite side of Capitol Blvd. Many of the buildings were ignited via this method and were destroyed before the fire department could extinguish them.

2. Combustible construction (pages 19-25): The effect of combustible soffits was a major influence to fire spread. Vinyl siding melted and exposed fire-resistant underlayment, whereas vinyl soffits melted and exposed combustible attics. The study concludes that vinyl is suitable for siding when it has a maximum flame spread rating of 25 and it is installed over fire-resistant sheathing, but vinyl is not suitable for eaves and soffits. Fire protection objectives for soffits must be balanced with the need to release hot air and moisture from attics.

3. Combustible landscaping (pages 26-28): Fire spread to multiple buildings when air-borne fire embers ignited dry grass and pine straw. In addition to pine needles being the probable point of origin for the Pine Knoll Townhome fire, dry grass provided a medium to transfer flames between buildings. As concluded by prominent research facilities, pine straw (ie, pine needles) should not be used close to structures. It is one of the most highly flammable landscape materials.

Click above to see WRAL-TV's coverage on the report and video from the fire. Click here to see a slide show of images from February 22nd.

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