IGNITION-RESISTANT CONSTRUCTION: THE WHY BEHIND THE WHAT

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1 IGNITION-RESISTANT CONSTRUCTION: THE WHY BEHIND THE WHAT

2 WHAT IS THE RATIONALE BEHIND THE REQUIREMENTS FOR IGNITION RESISTANT CONSTRUCTION? The wildfires of 2003 and 2007 were the largest in California history, and had a huge impact on lives in San Diego County. The fires demonstrated, again, how vulnerable and powerless we are in the face of wildfire. Some examples of the problems that have been identified from prior fires are: vulnerable building construction, structures ignited by native and landscape vegetation, poor access and escape routes, inadequate water supplies and limited fire fighting resources. For decades, the County has worked with fire agencies, planners, environmental experts and the building industry to craft codes that are responsive to the wildfire challenge. Since the 1980's, the County's fire codes have been strengthened in successive code adoption cycles with the primary goal of protecting the safety of our citizens and enhancing your home s ability to survive wildfire.

3 WHAT IS THE OBJECTIVE OF THESE REQUIREMENTS? For most residents of San Diego County, it is not a matter of IF but WHEN their communities will be impacted by a wildfire. Every fire, no matter how small when it starts, has the potential to grow and spread under the right conditions; especially during those times when our weather is characterized by the high temperatures, low humidities and increased wind speeds unique to the off-shore event known as Santa Ana. In regards to the use of the term Santa Ana ; The most well-accepted explanation for the name Santa Ana winds is that it is derived from the Santa Ana Canyon in Orange County, one of the many locations the winds blow intensely. Newspaper references to the name Santa Ana winds date as far back as (

4 In light of this reality; the requirements for ignition resistant construction, in conjunction with the requirements for defensible space, are designed to better the survival rate of those structures that are found to be in the path of a wildfire. Structure hardening is one term that is used to describe those measures that serve to harden, or protect, a particular building from an advancing fire by minimizing the opportunity for embers to enter confined spaces, flames to readily ignite building materials, and heat to compromise windows and skylights.

5 WHAT EXACTLY ARE THE REQUIREMENTS? LET S TAKE A LOOK, STARTING FROM THE TOP

6 DID YOU KNOW ROOF MATERIALS WITH A CLASS A FIRE RATING (TESTED IN ACCORDANCE WITH UL 790 STANDARD) AFFORD A HIGH DEGREE OF FIRE PROTECTION. All roof material; whether concrete tile, composition shingles, metal or built up, shall have a Class A Fire Rating. For roof coverings where the profile allows a space between the roof covering and roof decking, the space at the eave ends shall be fire stopped to preclude entry of flames or embers.

7 DID YOU KNOW GAPS AND OPENINGS IN UN-PROTECTED EAVES ARE PARTICULARILY VULNERABLE TO EMBER INTRUSION. Eaves must be either enclosed ( boxed ) or constructed of, or finished with, materials that are non-combustible, fire-retardant or otherwise code compliant. In addition, openings for attic ventilation purposes are not allowed in overhang areas.

8 DID YOU KNOW KEEPING YOUR ROOF AND GUTTERS CLEAR OF DEBRIS HELPS TO PREVENT POINTS OF IGNITION RESULTING FROM AIR BORNE EMBERS. Roof gutters shall be provided with the means (such as gutter screens) to prevent the accumulation of leaves and debris in the gutter.

9 DID YOU KNOW ATTIC VENTILATION IS A CODE REQUIREMENT, BUT IF THE OPENINGS ARE NOT PROPERLY PROTECTED THEY CAN BE A POINT OF ENTRY INTO THE ATTIC FOR EMBERS THAT CAN LAND AND IGNITE. Vents shall resist the intrusion of flames and embers or shall be protected by louvers and 1/8-inch non-combustible, corrosion-resistant metal mesh. Gable end vents (pictured) are allowed if located a minimum of 12 inches below the lowest eave/rake projection.

10 EMBER STORM DEMONSTRATION

11 Exterior wall surfaces shall be noncombustible/ignition resistant materials such as cement fiber board siding, stucco and masonry/stone, or heavy timber or log wall construction. DID YOU KNOW EXTERIOR FINISH MATERIALS THAT RESIST IGNITION RESULTING FROM DIRECT FLAME IMPINGEMENT AND/OR RADIANT HEAT EXPOSURE SUBSTANTIALLY REDUCE THE POTENTIAL FOR DAMAGE OR DESTRUCTION.

12 Exterior windows and all other exterior glazed openings shall be dual-paned units with a minimum of one-tempered pane. Glazing frames made of vinyl shall have welded corners and metal reinforcement in the interlock area. Skylights shall be tempered glass.

13 WINDOW & SKYLIGHT REQUIREMENTS DID YOU KNOW Research has shown that glass is the most vulnerable part of a window. A window with a single pane of tempered glass breaks at a radiant exposure that is approximately two times as great as a window constructed of two panes of annealed (non-tempered glass) in a dual pane insulated glass unit, and more than four times as great as a window with a single pane of annealed (non-tempered) glass. The greater resistance to radiant exposure translates into valuable time that can potentially save lives and property.

14 GRAPHIC REPRESENTATION OF WINDOW BREAKAGE

15 WINDOW FRAME REQUIREMENTS DID YOU KNOW A research project by the National Institute of Standards and Technology published in June 1998 entitled Window Breakage Induced by Exterior Fires investigated the effect of radiant heat on the glass itself as well as on the window frames. The research concluded that: Vinyl-frame windows did not perform well under the exposure of imposed heat fluxes. The vinyl frames and sashes of these windows lost strength, distorted and sagged, permitting openings to develop. Consequently, vinyl-frame windows would not be suitable for use with fire resistant glazing materials. As a result, vinyl window frames are now required to have welded corners and metal reinforcement in the interlock area with the frame certified and labeled to ANSI/AAMA/NWWDA 101/I.S. 2-97; which is the voluntary performance specification for aluminum, vinyl and wood-framed windows and glass doors. It provides standards for air leakage, water penetration, structural strength and forced-entry resistance.

16 Exterior doors shall be approved ignitionresistant construction (metal), solid-core wood not less than 1-3/8 thick, or have a fire protection rating of not less than 20 minutes. DID YOU KNOW DOORS THAT ARE OF SUBSTANTIAL CONSTRUCTION AND THAT RESIST IGNITION RESULTING FROM DIRECT FLAME IMPINGEMENT AND/OR RADIANT HEAT EXPOSURE PROVIDE A SIGNIFICANT LEVEL OF PROTECTION AT DOOR OPENINGS.

17 Decks, patios, carports, etc. shall be constructed of non-combustible materials, fire-retardant treated wood, heavy timber construction or one-hour fire-resistive construction. DID YOU KNOW For a product to be approved by the County of San Diego Planning Development Services Building Division for construction in a fire hazard severity zone, the manufacturer must submit test reports for review to determine compliance with County Building Code Section A Testing of Alternative Decking Materials. The County Building Code requires that all decking materials passing the performance requirement of the code be identified with a grading stamp or label at a minimum of six feet along the length of the decking board.

18 DID YOU KNOW The threat of wildfires is something we live with here in San Diego; it is not something we have control over. The reasons for property loss as a result of wildfire activity are numerous; vulnerable building construction, structures ignited by native and landscape vegetation, poor access and escape routes, inadequate water supplies and limited fire fighting resources - some of which we have no control over. What we do have control over is what we do to prepare our properties and homes to give them the best chance of survival in a wildfire event. By taking the measures highlighted in this presentation to harden our homes, in conjunction with creating and maintaining an area of defensible space around our homes through effective fuel modification, our homes can survive the threat.

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