May 13, 2003

REPORT IN BRIEF

This Study Issue originated when a citizen expressed concern at the City Council meeting on August 27, 2002, about the potential spread of a fire from one building to another through flying embers. Mayor Miller and Vice Mayor Risch jointly sponsored the item and placed it as a potential study issue. At the Study Issues Workshop in December 2002, the Council ranked this issue number 2 for study in 2003 by the Community Development Department.

Roof material can have a fire rating of Class A, B, C or be non-rated. The minimum current requirement under State law for roof material is Class C.

As part of the research for this study issue, staff has reviewed standardized test findings to explain what the different fire ratings actually mean, provided costs estimates, and researched the requirements in other local jurisdictions. Based on these findings, staff is recommending that an ordinance be adopted to require a minimum of a Class B fire rating in the City of Sunnyvale.

BACKGROUND

This issue was raised at a City Council public hearing on August 27, 2002 by a concerned citizen. The purpose of the public hearing was to adopt the 2001 California Building Codes. The citizen suggested that Council consider requiring a higher fire rating for roof material than the Code required. This issue was of particular concern at that time because of the consequences of the Santana Row fire that had recently occurred in San Jose. Embers from the Santana Row fire spread to other buildings, causing them to also catch on fire.

At that meeting Mayor Miller and Vice Mayor Risch jointly sponsored this item to be placed as a study issue for consideration for 2003 (Attachment A). At the Council Study Issue Workshop in December 2002, this item was ranked number 2 for the Community Development Department.

EXISTING POLICY

The Uniform Building Code still allows non-rated roof material for certain types of buildings, including single family homes. However, since 1995 the State of California has amended the Uniform Building Code to require a minimum of a Class C roof material for all structures. This is the minimum requirement; depending on the use and type of construction, a building may be required to install a higher rated roof material such as a Class A or B.

Older buildings that still have the original roof material are not required to meet the current code requirements for the fire rating. The current code requires that when 50% or more of the roof material is replaced, the entire roof material must meet the current standards for fire rating.

DISCUSSION

There are four fire rating categories that roof material can be assigned: Class A, Class B, Class C, or non-rated. The Class A, B, and C have all been tested and proven to provide various degrees of fire safety. The non-rated classification has been tested and determined to provide no protection against fire exposure. As mentioned above, the current requirement in Sunnyvale, in accordance with State requirements, is a minimum of a Class C rating.

The fire rating assigned is based on the entire roof assembly including the material as well as the underlayment. Roofing material alone has a fire rating and, depending on the underlayment materials, the fire rating of the entire assembly could be increased. For example, in lieu of plywood, certain manufactured material can be used (which is designed to provide increased fire resistance) as the underlayment material.

The Building Code Standards set the testing requirements used to determine the fire rating for roof materials and assemblies. Various tests are conducted including intermittent flame test, burning brand test, and flying brand test. The material is tested when it is first installed and after simulated weathering of the material. Following is a summary of test results for each type of roof material:

Class A Rating

This is the highest fire rating for roof material. Class A roofing material has been proven to be effective against severe fire test exposures. Based on the test findings, the Class A rated assembly is not readily flammable, affords a fairly high degree of fire protection, and is not expected to produce flying embers. Overall, the Class A material provides over seven times the protection of Class C material.

Class B Rating

This rating has been proven to be effective against moderate fire test exposures. The Class B rated assembly is not readily flammable, affords a moderate degree of fire protection, and is not expected to produce flying embers. Overall, the Class B material provides almost 4.5 times the protection of Class C material.

Class C Rating

This rating has been proven to be effective against moderate fire test exposures. The Class C rated assembly is not readily flammable, affords a measurable degree of fire protection, and is not expected to produce flying embers.

Non-Rated Material

Non-rated roof coverings provide no protection against fire exposure. The most common type of material in this category is non-treated wood shake. As of 1995, non-rated roof material is not allowed on any type of structure in the State of California.

 As explained above, the entire roof assembly (material and underlayment) determines the fire rating. Therefore, one type of roof material may have different ratings depending on the installation. Of the most common types of roof materials used in Sunnyvale, wood shake is the only material that is listed at a Class C; all other common roof materials are rated as Class A or B. At an increased cost, wood shakes can be fire treated and installed to meet a Class A or B rating. In order to provide an estimate of the cost difference, staff has contacted several roofing contractors that do business in Sunnyvale and received the following average estimates for wood shake material:

The roofing contractors also believe that, due to the chemical treatment, Class A and B rated wood shake roofs do not last as long as the Class C shakes. Class C rated shake roof generally lasts approximately 25 years. Class A or B rated shakes would need to be replaced after about 20 years.

Requirements of Other Local Jurisdictions

Several other local jurisdictions have adopted ordinances to require a higher fire rating than Class C. The majority of jurisdictions that have adopted higher standards are those that are located in high fire hazard areas such as heavily wooded and hillside communities. Additionally, the Santa Clara County Planning Office has developed a map of the county that shows areas of high and low fire hazards. According to this map, Sunnyvale is in a low hazard area.

The listing of local jurisdiction requirements and the Santa Clara County map are in Attachment B to this report.

Public Comments

Staff notified the community of this study through several methods as outlined in the Public Contact section of this report. Staff received a few comments from the community. The comments received from the roofing contractors supported the existing Class C fire rating as being adequate. Staff also received two comments from residents who were in support of increasing the fire rating.

Staff Recommendation

The main concern that initiated this study was the risk of fire spreading through flying embers landing on the roofs of other buildings. Requiring a higher rated roof material would decrease this potential. Increasing the minimum fire rating would mainly affect wood shake roof material as other common materials are already rated at Class A or B. Additionally, wood shake represents a small portion of re-roofs. Only about 5% of all re-roof permits are for wood shake. If a higher fire rating were adopted, property owners would still have the option to install wood shake; however, the costs would be increased (approximately 6%).

Based on the requirements of other local jurisdictions and the fact that Sunnyvale is not in a high fire hazard area, the existing State requirement for a minimum of a Class C fire rating is sufficient. However, based on the minimal additional costs and a small percentage of property owners being affected, staff recommends that Council adopt an ordinance (Attachment C) to require a minimum of a Class B fire rating for all roof material. Staff does not recommend that Council require a Class A. The additional cost for Class A rated wood shake is significant (over 21%). Additionally, other common roof materials that are rated as Class B (such as tar and gravel which is common on flat roofs) would be prohibited.

The recommended ordinance also requires compliance with the current requirements for the entire roof when over 50% of an existing roof material is replaced.

FISCAL IMPACT

No fiscal impact to the City is expected. Additional costs may be incurred by property owners when re-roofing a structure depending on the roof material chosen.

PUBLIC CONTACT

Staff notified the community of this study issue in the following ways:

• Mailed letters to roofing contractors that have done business in Sunnyvale (approximately 450 letters)

• Mailed letters to all neighborhood association presidents

• Notification was placed on the Building Division web site

• Placed an advertisement on KSUN

• Advertisement was published in the winter issue of the Quarterly Report

• Display advertisement was published in the April 30 and May 7 issues of The Sun

• A legal advertisement was published in The Sun on April 30

• The agenda of this meeting and the staff report were posted at the Library and on the City of Sunnyvale web site.

ALTERNATIVES

1. Introduce the ordinance to the Municipal Code (Attachment C) to require a minimum of Class B roof material for all structures in Sunnyvale.

2. Introduce the ordinance to the Municipal Code with modifications.

3. Do not modify the Municipal Code and retain the requirements of the Class C roof material.

RECOMMENDATION

Staff recommends Alternative #1.

Prepared by:
Frank Rainone
Plan Check Coordinator

Diana Perkins
Plan Checker I

Reviewed by:
Ali Fatapour
Chief Building Official

Randy Edwards
Fire Marshal

Robert Paternoster
Director, Community Development

Approved by:
Robert S. LaSala
City Manager

Attachments

1. Study Issue Paper

2. Roof Material Fire Rating for Bay Area Cities

3. Draft Ordinance