Asphalt Shingle & Other Roofing Materials Fire Rating Tests & Standards
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Roofing standards
Specifications for the manufacture and testing of asphalt roof shingles
Directory of Roof Shingle Testing Laboratories
This article describes testing and standards for fire ratings and fire resistance of asphalt shingles and other roofing materials.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.
Readers should see our complete list of standards for roofing and roofing products. We include a list of roof testing services and laboratories. Our page top photo shows remains of roofing materials found on a buildings following a roof fire ignited by a chimney fire that spread out of the chimney and into the roof structure.
Keep in mind that the purposes of roof covering fire ratings (to desribe the fire resistance of a roofing material), and the intent of roof fire resistance in general are to allow building occupants more time to escape in event of a fire, not to guarantee that the building nor its ocupants will be unharmed in the event of a fire. A table of roof fire ratings and details about the applicable standards is at FIRE RATINGS for ROOF SURFACES.
All roofing materials that carry any fire rating (A, B, or C - see "Table of Roof Covering Fire Ratings & Standards" below) must:
Apply to fires originating from outside the building.
During or after a fire the roof materials will not:
Blow off or fall off of the roof deck as flaming or glowing brands (burning embers that might further spread fire)
Break, slide, crack, or warp to expose the underlying roof deck
Allow the roof deck to fall away as glowing particles
Allow sustained flaming of the underside of the roof deck
Watch out: if a roofing shingle or other roof covering material is not installed exactly according to the manufacturer's recommendations its fire rating may be compromised and reduced, as may the roof warranty too. Also, a roof that has resisted a fire successfully, and thus helped protect the building from a fire, is likely to need to be replaced after a fire or after exposure to high heat from a nearby fire. Also watch for discount-grade roof shingles that may carry no fire rating whatsoever.
Also see these roofing material articles where we describe fire ratings:
Both UL 790 and ASTM E 108 fire classification tests discussed below use the same test methods. These standards include
An intermittent-flame exposure fire resistance test
A burning-brand fire resistance test - does the roof resist catching fire from flying brands landing on it from another fire
A flying brand fire resistance test - does the roof release flying brands in a fire, pieces of roofing product that could fall into the structure, adding to the spread of fire to floors below if the roof is subjected to fire.
Rain tests - apply if the roof product or assembly can be adversely affected by water (such as a coated or smooth-surfaced roof system)
How these standard fire rating tests are applied will vary, however, for each type of roof covering product and roof assembly or structure. For example as NRCA (Kirby) points out, a roof system whose application is restricted to use on noncombustible decks (such as a steel or concrete or gypsum surface), only the spread-of-flame test will be required, while a roof system that is applied over a combustible roof deck (a wood-framed building with plywood roof sheathing for example), the tests for fire resistance of that product will include spread-of flame as well as intermittent flame and burning brand tests.
Keep in mind that the purposes of roof covering fire ratings (to describe the fire resistance of a roofing material), and the intent of roof fire resistance in general are to allow building occupants more time to escape in event of a fire, not to guarantee that the building nor its occupants will be unharmed in the event of a fire. Our table of roof fire ratings is given below.
Table of Roof Covering Fire Ratings & Standards: UL 790 & ASTM E-108
Roof Fire Rating
Fire Rating Properties
Roof coverings with Class A, B, or C fire ratings must all have these properties
Apply to fires originating from outside the building.
During or after a fire the roof materials will not:
Blow off or fall off of the roof deck as flaming or glowing brands (burning embers that might further spread fire)
Break, slide, crack, or warp to expose the underlying roof deck
Allow the roof deck to fall away as glowing particles
Allow sustained flaming of the underside of the roof deck
Class A Fire Protection
Highest fire resistance: the roof can withstand severe exposure to fire
See ASTM E-108
According to the NRCA (Kirby) who referred to ASTM E 108 and ANSI/UL 790, "Class A roof coverings are not readily flammable, are effective against moderate fire exposures, and do not carry or communicate (i.e. spread) the fire. "
Example test process for Class A Fire Protection Rating: A 12" x 12" x 2-1/4" gridded configuration of 3 tiers of 12 12-inch wood strips are placed on a test sample while air is forced over the brand and the brand is allowed to burn up to 1 1/2 hours until it extinguishes itself or the roof assembly fails.
Class B Fire Protection
Moderate fire resistance
NRCA (Kirby): "Class B roof coverings are not readily flammable, are effective against moderate fire exposures, and do not readily cary or communicate fire."
Example test process for Class B Fire Protection Rating: similar to Class A above, but the fire test configuration is smaller: 6" x 6" x 2 1/4-" grid using 3 tiers of six six-inch long wood strips is used.
Class C Fire Protection
Light fire resistance
NRCA (Kirby): "Class C roof coverings are not readily flammable, are effective against light fire exposures, and do not readily carry or communicate fire."
Example test process for Class C Fire Protection Rating: similar to Class A and B above, but a still smaller fire test configuration is used: 1 1/2" c 1 1/2" x 25/32" block of wood with one saw kerf on the wood block's top and bottom faces is used to conduct the fire resistance test.
Note1: External Building Fire Resistance vs. Internal Building Fire Resistance
External fires refers to fires that originate outside of the building rather than within the structure. Examples are nearby forest or brush fires, or other nearby building fires.
As Kirby points out, because these fire ratings evaluate the resistance to external fires, they do not bear on building hourly fire ratings for roofs or ceilings. Building hourly fire resistance ratings pertain to fires that originate inside the building.
Our house fire photo (left) shows the attic view of a section of plywood-sheathed asphalt-shingled roof that burned through when a 2004 chimney fire spread to the building structure in this New York Home.
Here is an outdoor view of the building exterior wall where the fire occurred, starting in a first-floor family room woodstove. This fire originated in the woodstove or metal chimney flue and spread from this "external" chimney to the roof and roof structure at the lower edge of the hipped roof visible in the outdoor photo. There were no injuries.
Roof Fire Rating Standards & Requirements
The U.S. Federal Housing Administration (FHA) and other lenders require that building roofing materials conform to these standards. Various U.S. national or model building codes & state & Canadian Provincial building codes or fire codes require that roofs must carry at least a Class C fire rating or better.
The tests described by ANSI/UL 790 and ASTM E 108 fire resistance evaluation for roofs are used by model building codes such as the Uniform Building Code (Table 15-A "Minimum Roof Classes"). Roof classifications with respect to fire resistance are A, B, C, and "non-rated".
The BOCA (Building Code Officials and Code Administrators International, Inc.) National Building Code [using 1999 as an example] describes roof classifications in BOCA section 1505, "Fire Classification" and uses Class A, B, and C roofs tested according to the two fire resistance test standards we discuss here.
UL 790 - Underwriters Laboratories Roof Fire Ratings A B C Tests
ASTM/UL 790 "Tests for Fire Resistance of Roof Covering Materials"
Underwriters Laboratories has defined the UL 790 Standard Tests of roofing material fire resistance to external fire sources: fires that originate outside of the structure itself. Roof covering packaging that encloses shingles or other roofing that have a fire rating will display the level of fire or wind resistance rating of the materials. UL 790 is a quality assurance service listing.
The UL tests under UL 790 evaluate the behavior of a roof covering under three fire hazards
Exposure of the roof to intermittent flame
Flame spread in the roofing material
Ignition of the roof covering from burning brands (say an ember or burning branch from a nearby brush fire)
ASTM E-108 - Standard Test Methods for Fire Tests of Roof Coverings
ASTM E 108 "Standard Test Methods for Fire Tests of Roof COverings" is the second widely-accepted fire-resistance capacity test used to determine a product or in this case a roof assembly's fire classification.
ABSTRACT: This specification covers mineral granule-surfaced asphalt roofing shingles. Covered here are the self-sealing (Type I) and non-self-sealing (Type II) types of shingles. The shingles shall consist of organic felt or glass mat(s) saturated or impregnated, and coated on both sides with a hot asphaltic material and completely surfaced on the weather side with mineral granules embedded in the coating.
The reverse side of the shingles shall be covered with a suitable material to prevent the shingles from sticking together in the package, causing possible damage upon being unpacked at ambient temperatures. Type I shingles shall have a factory-applied adhesive that will seal the shingles together after application. Both types shall meet the conditions for Class A fire exposure, and loss and behaviour on heating tests. Type I shingles shall pass an additional wind resistance test.
Watch out: if a roofing shingle or other roof covering material is not installed exactly according to the manufacturer's recommendations its fire rating may be compromised and reduced, as may the roof warranty too. Also, a roof that has resisted a fire successfully, and thus helped protect the building from a fire, is likely to need to be replaced after a fire or after exposure to high heat from a nearby fire. Also watch for discount-grade roof shingles that may carry no fire rating whatsoever.
Also see these roofing material articles where we describe fire ratings:
UL Underwriters Laboratories: Standards Pertaining to Roofing Systems
UL(R) 790 - Class A Fire Resistance [DF: a quality assurance listing service from Underwriters Laboratories]
UL(R) 997 - Wind Resistance [DF: a quality assurance listing service from Underwriters Laboratories]
Directory of Roofing Shingle Testing Laboratories
See TEST LABS - ROOF SHINGLE for our complete directory of companies offering various types of testing for roofing materials, including roof shingles and other roof surfaces.
Testing Laboratory Serving a Wider Audience than Roofing Products & Roofing Industry Manufacturers
Applied Technical Services
http://www.atslab1.com/
Chemir Analytical Services
http://www.chemir.com/
EMS Lab, the megalith of testing in the U.S.: materialstestinglaboratory.com/
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ARMA - Asphalt Roofing Manufacturer's Association - http://www.asphaltroofing.org/
750 National Press Building, 529 14th Street, NW, Washington, DC 20045, Tel: 202 / 207-0917
ASTM - ASTM International, American Society for Testing and Materials, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA, 19428-2959 USA The ASTM standards listed below can be purchased in fulltext directly from http://www.astm.org/
NRCA - National Roofing Contractors Association - http://www.nrca.net/, 10255 W. Higgins Road, Suite 600,
Rosemont, IL 60018-5607, Tel: (847) 299-9070 Fax: (847) 299-1183
"Fire-resistance classifications", James R. Kirby, AIA, Professional Roofing, [NRCA] p. 52 Q&A, November 1999. Quoting: "What do the fire-resistance classifications A, B, and C mean in reference to roofing materials?"
UL - Underwriters Laboratories - http://www.ul.com/
2600 N.W. Lake Rd.
Camas, WA 98607-8542
Tel: 1.877.854.3577 / Fax: 1.360.817.6278
E-mail: cec.us@us.ul.com
Texas Department of Insurance, lists companies approved for testing the impact resistance of roofing - see http://tdi.state.tx.us/home/roofingx.html
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
Architectural elements: the technological revolution: Galvanized iron roof plates and corrugated sheets; cast iron facades, columns, door and window caps, ... (American historical catalog collection), Diana S Waite, available used out of Amazon.
Green Roof Plants: A Resource and Planting Guide, Edmund C. Snodgrass, Lucie L. Snodgrass, Timber Press, Incorporated, 2006, ISBN-10: 0881927872, ISBN-13: 978-0881927870. The text covers moisture needs, heat tolerance, hardiness, bloom color, foliage characteristics, and height of 350 species and cultivars.
Green Roof Construction and Maintenance, Kelley Luckett, McGraw-Hill Professional, 2009, ISBN-10: 007160880X, ISBN-13: 978-0071608800, quoting: Key questions to ask at each stage of the green building process Tested tips and techniques for successful structural design
Construction methods for new and existing buildings
Information on insulation, drainage, detailing, irrigation, and plant selection
Details on optimal soil formulation
Illustrations featuring various stages of construction
Best practices for green roof maintenance
A survey of environmental benefits, including evapo-transpiration, storm-water management, habitat restoration, and improvement of air quality
Tips on the LEED design and certification process
Considerations for assessing return on investment
Color photographs of successfully installed green roofs
Useful checklists, tables, and charts
Problems in Roofing Design, B. Harrison McCampbell, Butterworth Heineman, 1991 ISBN 0-7506-9162-X (available used)
Roofing The Right Way, Steven Bolt, McGraw-Hill Professional; 3rd Ed (1996), ISBN-10: 0070066507, ISBN-13: 978-0070066502
Slate Roofs, National Slate Association, 1926, reprinted 1977
by Vermont Structural Slate Co., Inc., Fair Haven, VT 05743, 802-265-4933/34. (We recommend this book if you can find it. It
has gone in and out of print on occasion.)
Roof Tiling & Slating, a Practical Guide, Kevin Taylor, Crowood Press (2008), ISBN 978-1847970237, If you have never fixed a roof tile or slate before but have wondered how to go about repairing or replacing them, then this is the book for you. Many of the technical books about roof tiling and slating are rather vague and conveniently ignore some of the trickier problems and how they can be resolved. In Roof Tiling and Slating, the author rejects this cautious approach. Kevin Taylor uses both his extensive knowledge of the trade and his ability to explain the subject in easily understandable terms, to demonstrate how to carry out the work safely to a high standard, using tried and tested methods.
This clay roof tile guide considers the various types of tiles, slates, and roofing materials on the market as well as their uses, how to estimate the required quantities, and where to buy them. It also discusses how to check and assess a roof and how to identify and rectify problems; describes how to efficiently "set out" roofs from small, simple jobs to larger and more complicated projects, thus making the work quicker, simpler, and neater; examines the correct and the incorrect ways of installing background materials such as underlay, battens, and valley liners; explains how to install interlocking tiles, plain tiles, and artificial and natural slates; covers both modern and traditional methods and skills, including cutting materials by hand without the assistance of power tools; and provides invaluable guidance on repairs and maintenance issues, and highlights common mistakes and how they can be avoided.
The author, Kevin Taylor, works for the National Federation of Roofing Contractors as a technical manager presenting technical advice and providing education and training for young roofers.
The Slate Roof Bible, Joseph Jenkins, www.jenkinsslate.com,
143 Forest Lane, PO Box 607, Grove City, PA 16127 - 866-641-7141 (We recommend this book).
Solar heating, radiative cooling and thermal movement: Their effects on built-up roofing (United States. National Bureau of Standards. Technical note), William C Cullen, Superintendent of Documents, U.S. Govt. Print. Off (1963), ASIN: B0007FTV2Q
"Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
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