NIST And FEMA Research On Protecting Structures From Wildfire Embers And Fire Exposures

4 primary areas where embers can lead to structure ignition are:

• Landing on the structure
• Entering the structure
• Landing on the landscape surrounding the structure
• Landing on nearby fuels (fences, sheds, woodpiles, etc.)

Management 

It is important to make sure that the home and parcel surrounding the home are routinely mitigated

Make sure these areas are routinely and carefully mitigated. During a wildfire, embers can land on buildings and the surrounding landscape. Also, embers can reach a building's interior through a point of entry, such as a window or vent.

During a wildfire, millions of embers can land on a home and the landscape surrounding the home. That is why it is so important to make sure that the home and parcel surrounding the home, including landscape, fences, outbuildings, etc., are routinely and carefully mitigated.

Interdependent factors

Residents must meticulously protect every potential part of the home and parcel that could become a point of entry for embers.

Many interdependent factors influence the fire spread. An ember ignition can start a catastrophic chain of events. A single home catching fire can result in neighborhood destruction.

Smoldering

Sometimes embers smolder in flammable materials for many hours before leading to the ignition of fire on areas such as a roof or deck or areas outside the structure of a home or commercial building.

Visible flames may not appear until hours after the wildfire flame front has passed.

Ember research helps with understanding and mitigation

To protect lives and property, it is important to continue research about the way embers can ignite structures to understand the following:

• Their trajectory
• How they can be generated
• The size of embers that can be lofted during a wildfire event

Recently an ember generated by the Marshal Fire in Colorado was examined. The ember, part of a child's plastic playhouse, was 3 feet wide. It landed in vegetation surrounding a business in Superior, Colorado, a one-quarter mile away from the wildfire, and started a fire in the mulch.

ember research

Current NIST ember research includes:

• A Case Study of the Camp Fire Timeline PDF
• Studies using a barometer
• Wind-Driven Fire Spread to a Structure from Fences and Mulch

Other organizations performing ember research include the U.S. Forest Service Rocky Mountain Research Station and the Insurance Institute for Business and Home Safety.

Mitigation improvements

Mitigation improvements will be incorporated into land use and building code development

More research about embers generated during wildfires could help to develop even more effective mitigation improvements in building and home construction and outbuilding and landscape maintenance, including new types of building materials to be used in home and commercial construction. It will also be incorporated into land use and building code development in wildfire-prone areas.

In addition, researching fire spread at the parcel level to make sure fire in some cases started by embers does not destroy structures could result in communities that are much more resilient (sustaining less damage and recovering more quickly) from wildfire events.

What to do 

Help community members understand the threat that embers represent, even to areas miles away from a wildfire. Residents and business owners cannot control the number of incoming embers from wildfires, but they can control their exposure by hardening their property, structures, and other interdependent factors against the embers.

Implementing current knowledge of hardening for embers, if done in conjunction with addressing fire hazards, will very significantly reduce structure losses, Alex Maranghides, NIST.

Steps 

Guide them with practical, affordable steps they can take to make their buildings and homes safer with proven fire mitigation measures highlighted in NIST's research PDF including:

• Replacing window screens with metal screens
• Caulking or sealing all openings in the structure
• Use metal or stone fence materials where a house and wooden fence meet; 5 feet from the house to the wooden fence

Users can also show them that ember hardening should not be viewed as a structure-only activity. The parcel should also be assessed and hardened appropriately to limit fire pathways to a home or business, such as:

• Ember to mulch next to shed building
• Ember to mulch next to the house to the building
• Ember to gutter to roof and rest of building

Once home and business owners understand how much damage can be caused by embers from wildfires, they should be motivated to take steps to help reduce the risk.