CRSC · California Referenced Standards Code

Required air velocity, burner placement and flame conditions for the test

For homeowners: the CRSC test for furnace/air filters requires a specific duct and burner setup and that the filter be exposed to yellow, wavering flames while air is drawn at about 200 feet per minute; the resulting smoke and flame behavior determine if a clean filter meets Class 1 or Class 2 per § 12-71-100 .

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Last reviewed: July 6, 2026

What the code requires — plain English

The test for air filters must be run in a 21-inch-square, 13.5-foot-long test duct with a nominal 20 × 20‑inch filter unit in the middle. The apparatus uses two burner outlets positioned about 18 inches from the base of the filter that produce yellow, wavering flames and the air velocity with the filter installed must be adjusted to approximately 200 linear feet per minute measured at the duct discharge. These requirements are specified in § 12-71-100 .

The single most important rule: set up the duct and burners exactly as described and adjust airflow so the filter sees about 200 ft/min at the discharge — measurement location and flame character are prescribed by § 12-71-100 .

Requirements in detail

Test apparatus (key dimensions)

  • The test duct is 21 inches square and 13.5 feet (4,114 mm) long. A metal filter frame is centered to hold one 20 × 20‑inch (nominal) filter. Observation windows are provided in the doors. See § 12-71-100 .

Burner placement & flame conditions

  • Two burner outlets are formed from 1‑inch (25 mm) pipe elbows located about 18 inches (457 mm) from the base of the test filter.
  • The burners are adjusted to provide yellow, wavering flames and consume approximately 4 cubic feet of gas per minute (text gives gas consumption context). See § 12-71-100 .

Required air velocity and measurement

  • With the filter in place, the air velocity is adjusted to approximately 200 linear feet per minute and that velocity is measured at the discharge end of the duct using an Alnor Velometer Anemometer. See § 12-71-100 .

Test exposure & observations

  • The flames are applied for 3 minutes while observations are made of flame or spark travel downstream and the density, duration and character of products of combustion. Smoke density is quantified as area under the smoke density vs. time curve per the method in § 12-71-100 .

Classification thresholds (decision‑relevant values)

Parameter / item Required value / threshold Code Reference
Test duct cross‑section 21 in × 21 in § 12-71-100
Test duct length 13.5 ft (4114 mm) § 12-71-100
Filter nominal size 20 in × 20 in § 12-71-100
Burner outlet pipe 1 in (25 mm) § 12-71-100
Burner distance from filter base ~18 in (457 mm) § 12-71-100
Burner flame character Yellow, wavering flames § 12-71-100
Burner gas consumption ≈ 4 cubic ft gas/min § 12-71-100
Air velocity (with filter installed) ≈ 200 ft/min at duct discharge § 12-71-100 cite
Flame application duration 3 minutes § 12-71-100
Class 1 smoke area (area under curve) < 1.5 sq in § 12-71-100
Class 2 smoke area ≤ 6.0 sq in § 12-71-100

(Entries paraphrase and synthesize the measurements and thresholds required by § 12-71-100 .)

Exceptions & special cases

  • § 12-71-100 does not list alternate burner locations, alternate air-velocity setpoints, nor explicit exceptions for used/loaded filters — it specifies the apparatus and procedure as the standard test setup. If you need to deviate or use alternate apparatus, the code text for § 12-71-100 does not provide allowance language; consult the Authority Having Jurisdiction or the State Fire Marshal procedures for any permitted alternate methods .
  • The standard requires filters to be tested clean (unused) — testing loaded or in-service filters is not the method described in § 12-71-100 .

Common mistakes

  • Measuring air velocity at the wrong location. The code requires velocity to be measured at the discharge end of the duct with an Alnor Velometer Anemometer; measuring mid‑duct or upstream will not satisfy § 12-71-100 .
  • Incorrect burner placement. The burners must be formed by two 1‑inch elbows about 18 inches from the base of the filter. Moving burners closer/farther or changing orientation changes exposure and invalidates the test setup per § 12-71-100 .
  • Using a non‑yellow or steady blue flame. The code specifies yellow, wavering flames; over‑airing the burner to get a blue, non‑sooty flame changes the exposure condition § 12-71-100 .
  • Testing used filters or failing to start with clean specimens. The test method explicitly states filters are tested clean .
  • Miscomputing classification: be sure to use the smoke‑density area under the curve method described in the section — the Class 1 / Class 2 thresholds in § 12-71-100 are based on that calculated area .

Worked example — step by step with numbers

Scenario: Lab has the prescribed duct and a new pleated filter (nominal 20 × 20 in). You will perform one test.

  1. Install the filter in the metal frame centered in the duct (21 in square, 13.5 ft long) per § 12-71-100 .
  2. Place the two burner outlets (1‑inch pipe elbows) so they are about 18 inches from the base of the filter and aligned as used in your lab’s fixture. Adjust the burners to produce yellow, wavering flames and confirm gas flow is about 4 cubic ft/min as noted in the section .
  3. With the filter installed, measure air velocity at the discharge end of the duct using an Alnor Velometer Anemometer. Suppose your initial reading is 150 ft/min. Increase blower speed and re‑measure until the reading is ≈ 200 ft/min (target per § 12-71-100). Record the final reading and the instrument used .
  4. Ignite burners and apply flames to the filter for 3 minutes. Observe both faces and record downstream travel of flame/sparks and smoke appearance. Use the photoelectric cell/microammeter arrangement described to collect light‑intensity drop readings and compute the area under the smoke density‑vs‑time curve per the method in § 12-71-100 .
  5. Suppose the computed area under the curve is 1.2 sq in. That result is less than 1.5 sq in, so the unit classifies as Class 1 per § 12-71-100 .

Related provisions (see these CRSC sections)

  • § 12-71-100 — Air filter test apparatus, burner placement, air velocity and classification (primary reference) .
  • § 12-8-113 — Calibration and documentation of ignition source and test equipment (useful when verifying burner output and instruments) .
  • § 12-7A-1.6 — Burner details and heat‑output control for wall exposure tests (related burner‑output and burner‑positioning guidance in other SFM standards) .
  • § 12-7A-1.9 — Conduct of tests and ambient airflow limits for wall/fire tests (context on airflows and draft protection used elsewhere in SFM standards) .

(If you need copies of the exact text for lab SOPs or calibration records, consult the full § 12-71-100 text in the CRSC and the calibration guidance in § 12-8-113 .)

Code references

Grounded in the retrieved California Referenced Standards Code — click a citation to read the verbatim passage:

  • CRSC § 12-71 High relevance — show source text

    STATE FIRE MARSHAL

    DESCRIPTION OF TEST APPARATUS, METHOD AND CLASSIFICATION REQUIREMENTS FOR AIR FILTERS

    Sec. 12-71-100.

    (a) Test apparatus.

    1. The test duct, made of M.S. gage galvanized sheet metal reinforced with angle irons, is 21 inches square (13 548 mm [2] ) and 13 [1] / 2 feet (4114 mm) long.
    2. One end of the duct is tapered to the discharge of a variable-speed blower and the other end is open to discharge. A metal filter frame is provided near the middle of the length of the duct to receive one 20 by 20 inches (508 mm by 508 mm) (nominal) filter unit. Two tightfitting doors, located to permit access to the filter frame, are each provided with a mica window to permit observation of both faces of the filter and conditions in the duct downstream from the filter.
    3. Two 1-inch (25 mm) pipe elbows, about 18 inches (457 mm) from the base of the test filter, form gas burner outlets adjusted to provide yellow, wavering flames. The burners consume approximately 4 cubic feet (approximately 1,000 Btu/cubic feet) of gas per minute.
    4. With the filter in place the air velocity is adjusted to approximately 200 linear feet per minute as measured at the discharge end of the duct by an Alnor Velometer Anemometer.

    (b) Test method.

    1. Filters are tested clean, that is, unused. The flames are applied for 3 minutes during which time observations are made of both faces of the filter as to the downstream travel of flame or sparks and the density, duration and character of the products of combustion.

    2. Smoke density is measured as the drop in light intensity on a microammeter by means of photoelectric cell mounted a few inches below and about 12 inches (305 mm) inside the discharge end of the duct. The light source, stabilized for light intensity, is mounted 1 inch (25 mm) above the duct directly above the photoelectric cell. The microammeter readings are recorded every 5 seconds for the first minute and every 10 seconds for the next 2 minutes.

    3. The differences between these readings and the readings taken before the test are plotted against time (the scale being 40 μA and 40 seconds to the inch) with the resulting area under the curve being measured by use of a planimeter or calculated mathematically. This area is a measure of the smoke density produced during the test.

    (c) Classification. As a result of the tests, air filter units are classified as Class 1 or 2 as indicated below:

    1. Class 1 air filter units are those which, when clean, do not produce flames or sparks when attacked by flame and which develop areas under the smoke density curves that are less than 1.5 square inches (967 mm [2] ).
    2. Class 2 air filter units are those which, when clean, burn moderately when attacked by flame or emit moderate amounts of smoke or both. These units, although they may be consumed to some extent, do not project flames or extensive sparks that would ignite adjacent combustible materials beyond the discharge end of the duct during the test and do not develop areas under the smoke density curves that are more than 6.0 square inches (3871 mm [2] ).

    (d) Adhesive coatings. Liquid-adhesive coatings used on filters shall have a flash point of 325°F (163°C) Cleveland open cup tester, or higher.

  • CRSC § 0.5 High relevance — show source text

    ** The horizontal airflow, measured at a horizontal distance of 20 inches (0.5 m) from the edge of the wall assembly, shall not exceed 1.64 ft/s (0.5 m/s). 3. Placement of test frame. Prior to testing, and without the test specimen in place, position the frame assembly under the exhaust hood and set the gas burner for the prescribed level of output. 4. Placement of specimen. Once the burner output is verified, position the specimen holder assembly at the desired test location under the collection hood.

    1. Test specimen. Insert the test specimen into the frame assembly, sealing all edges with ceramic wool.
    2. Ignition. Simultaneously ignite the gas burner and start the timer marking the beginning of the test. Control the burner to a constant 150 ± 8 kW output. Control the hood duct flow to collect all products of combustion.
    3. Flame exposure. Continue the flame exposure until flame penetration of the test specimen and sustained flaming on the unexposed side occurs or for a period of 10 minutes, then extinguish the burner.
    4. Observation. If sustained flaming on the unexposed side of the test specimen has not occurred, observe the unexposed side of the test specimen for an additional 60 minutes for evidence of sustained flaming or glowing combustion on the unexposed side. Terminate the observation prior to the completion of the 60-minute observation period if all evidence of flame, glow and smoke has disappeared.

    Note: An infrared thermometer has been found to be useful to detect the increase of temperature on the unexposed side of the test assembly. 9. Documentation. Perform photographic and/or video documentation before, during and after each test.

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    MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE

    12-7A-1.10 Report. The report shall include the following:

    1. Name and address of the testing laboratory.

    2. Name and address of test sponsor.

    3. Description of the test specimen including construction details of the wall system, including details of individual components (such as type, thickness and installation method of any sheathing) and the manufacturer’s installation details and limitations as applicable.

    4. Number of specimens tested.

    5. Description of weathering, as applicable.

    6. Moisture content of hygroscopic elements of wall system construction at the time of testing.

    7. Details of the burner verification, including heat supply rate.

    8. Date of test, test identification number and date of report.

    9. The test results shall include:

    9.1. A notation of the time and location of sustained flaming on the unexposed side of the test specimen during the test, along with the sequence number of the test specimen. 9.2. A determination of the presence of glow on the unexposed side of the test specimen at the end of the 60-minute observation period. 9.3. Observations of the burning characteristics of the exposed surface of the test wall during and after the flame

    exposure.

    12-7A-1.11 Conditions of Acceptance. Should one of the three replicates fail to meet the Conditions of Acceptance, three additional tests may be run. All of the additional tests must meet the Conditions of Acceptance.

    1. Absence of flame penetration through the wall assembly at any time.
    2. Absence of evidence of glowing combustion on the interior surface of the assembly at the end of the 70-minute test.
  • CRSC § 0.02 High relevance — show source text

    Alternate systems can be used, but the color temperature of the light source must match that of the 1810 lamp under the specified operating conditions, and the light receiver, including the photo detector, must match the standard photopic curve of the eye. The optical density shall be continuously recorded over the duration of the test. After completion of the test, the optical density reading must be less than 0.02 (transmission higher than 95 percent).

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    FIRE-RESISTIVE STANDARDS FOR FIRE PROTECTION

    CALIBRATION AND DOCUMENTATION OF IGNITION SOURCE AND TEST EQUIPMENT

    Sec. 12-8-113. A calibration test shall be performed prior to and within 30 days of any fire test. The calibration test, to last for 15 minutes, shall use the standard ignition source with inert wall and ceiling materials (calcium silicate board of 46 pcf density and 0.5inch (13 mm) thickness. The following quantities shall be reported:

    1. Once the burner is activated, the output of all instruments normally used in the test is to be measured and data recorded as a function of time.

    2. The time history of the total heat flux at the wall location.

    3. The maximum extension of the burner flame as recorded by still color photographs of 0.1 second exposure time taken at a minimum of 30-second intervals, or more often if it is changing rapidly. These shall be taken with a camera operating in the “operative mode” with the camera set to the standard ASA ratings of the film.

    4. The temperature and velocity profiles across the duct cross-section at the location of the bidirectional probe if one is used. These profiles shall be used to determine the factor “k” in Equation 12, Appendix 12-8-1A.

    5. The total rate of heat production is determined both by the oxygen consumption calculation and by the metered gas input. These must agree within 5 percent. Note: The net heat of combustion is 2,283 Btu/ft [3] for propane at 68°F (20°C) and 14.7 psi. This value should be used in this calculation.

    TEST PROCEDURE

    Sec. 12-8-114. The following paragraphs describe the steps in the test procedure:

    1. Establish an initial volumetric flow rate of 1,000 cfm through the duct if a forced ventilation system is used. If a forced ventilation system is used, increase the volume flow rate through the duct to 5,000 cfm when the oxygen content falls below18 percent.
    2. Turn on all sampling and recording devices and establish steady state baseline readings for at least 1 minute.
    3. Ignite the gas burner and start the clock simultaneously. Increase gas flow rate in steps as indicated in Section 12-8-106 (c).
    4. Take 35 mm color slides at 15-second intervals during the first 3 minutes and at 30-second intervals thereafter to photographically document the growth of the fire.
    5. Provide a continuous voice or written record of the fire, which will give times of all significant events such as flame attachment to the wall, flames out of the doorway, flashover, etc.
    6. The ignition burner shall be shut off at 15 minutes after initiation of the test and the test terminated at that time unless safety considerations dictate an earlier termination.
    7. Photograph and verbally describe the damage after the test.

    FLASHOVER AND SMOKE

  • CRSC § 1.18 High relevance — show source text

    Test chamber. The test chamber consists of a sheet- metal cell 2 feet by 1 foot by 1 foot (609 mm by 305 mm by 305 mm), open at the top and on one long side. The chamber shall be located so that an ample supply of air is provided, but the sample is not subjected to drafts. The chamber may be placed in a hood, provided that the fan is turned off during the test and is allowed to run only between tests to remove fumes. 2. A ring stand with a suitable clamp is used for supporting the specimens. 3. Burner and mounting block. The test flame is to be obtained by means of a Tirrill burner having a nominal bore of [3] / 8 inch (9 mm). The tube length above the primary air inlets is to be approximately 4 inches (101 mm). The burner is to be adjusted so that, while the burner is in a vertical position, the overall height of the flame is 5 inches (127 mm) and the height of the inner blue cone is 1 [1] / 2 inches (38 mm). A mounting block is to be provided so that the burner may be positioned at an angle of 20 degrees from the vertical. 4. A stopwatch or clock. 5. Circulating-air oven.

    (e) Conditioning and mounting. The test samples are to be conditioned by placing them in a circulating-air oven maintained at a uniform temperature not less than 10°C higher than the maximum temperature of the material measured under normal operating conditions but not less than 70°C in any case. The samples are to remain in the oven for 7 days. Prior to test the samples are to be returned to room temperature. The test sample is to be mounted as intended in service in the test chamber. The test flame is to be applied at an angle of 20 degrees from the vertical to any portion of the interior of the enclosure judged as liable to be ignited by proximity to live or arcing parts, coils, wiring, etc. The test flame shall be applied to a different location on each of the three samples tested. The test flame is to be applied for 5 seconds and removed for 5 seconds. The operation is to be repeated until the specimen has been subjected to a total of five applications of the test flame.

    (f) Impact test. An appliance employing a thermoplastic enclosure shall withstand three 5 foot-pound impacts without exposure of live parts, impairment of the operation of the appliance or result in a shock hazard.

    Each of two units is to be mounted securely in a position of normal use on a surface representative of a typical installation. Three 5 foot-pound impacts are to be applied to each sample, each trial on a different section of the enclosure, by means of a 1.18 pound, 2inch (51 mm) diameter steel sphere swung through a pendulum arc from a sufficient height to apply 5 foot-pounds of energy.

    Following the impacts, the unit is to be examined for damage and checked for normal operation by being energized from a source of rated voltage and frequency. Cracking of the enclosure is acceptable if it does not impair normal operation, but is not acceptable if a dust or moisture tight enclosure is required.

    (g) Infrared analysis of plastics. The basic composition of a plastic material employed for the sole support of current carrying parts or an enclosure is to be by infrared analysis.

  • CRSC § 12-7 High relevance — show source text

    Observations are made for the appearance of sustained flaming or glow on the unexposed side and/or sustained glowing on the unexposed side at the end of a 60-minute observation period.

    12-7A-1.6 Equipment. Unless otherwise noted, dimensions in the following descriptions shall be followed with a tolerance of ± 0.5 inch (13 mm).

    1. Wall assembly holding fixture. The test specimen support assembly shown in Figure 1 is designed to permit rapid installation and removal of wall assemblies, and to prevent edge penetration of fire at the margins of the wall assembly. It includes a sturdy frame assembly to hold the specimen and a simulated soffit that is noncombustible. The frame assembly permits a 4-foot by 8-foot (1220 mm by 2440 mm) prefabricated wall section to be inserted and to be sealed in such a way that protects the edges from fire. Side shields are situated near the vertical edges and to within 12 inches (304 mm) of the top of the test wall assembly as shown in Figure 1 to aid in minimizing extraneous drafts to the surface of the assembly.

    2. Burner.

    2.1. Burner details. The ignition source for the test shall be a gas diffusion burner with a nominal 4-inch-wide by 39-inchlong (100 mm wide by 1000 mm long) porous top surface of a refractory material, as shown in Figure 2. With the exception of top surface dimensions, the essential configuration of the burner is comparable to the burner design described in ASTM E2257. The burner enclosure shall be positioned so that it is centered relative to the width of the test wall. The distance from the bottom of the test specimen to the top surface of the burner shall be 12 inches ± 2 inches (300 mm ± 50 mm). The bottom of the test specimen shall be protected from burner fire exposure by the placement of a 4-foot-wide (1220-mm) thermal barrier consisting of nominal 0.75 inch (19 mm) cement board (or equivalent) between the burner enclosure and the test specimen. The burner enclosure shall be in contact with the protective barrier. The thermal barrier shall be positioned so that the top edge extends 3 inch ± 1 inch (76 mm ± 25 mm) above the top edge of the burner, and fastened to the base of the wall in such a manner to prevent obstruction of the burner flame caused by distortion away from the surface of the wall. Any gaps between the top edge of the thermal barrier and the test wall surface shall be filled with ceramic wool, or equivalent, prior to the test. Natural gas, methane or propane shall be supplied to the burner through a metered control system. The gas supply to the burner shall produce a net heat output of 8535 ± 454 Btu/min (150 ± 8 kW) throughout the flame

    exposure. The burner shall be ignited by a pilot burner or a remotely controlled spark igniter.

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    2.2. Burner output verification. The gas supply to the burner shall be the same as used for testing.

    1. Without a test specimen in the apparatus, place the gas burner in the configuration to be used for testing and obtain a heat release rate value of 150 kW.
  • CRSC § 12-7 High relevance — show source text
    1. When tested as follows, flames shall not reach the top edge of the specimen. The test shall be conducted in a draft free area, on a specimen of the material 12 inches by 12 inches (305 mm by 305 mm) suspended at a 45-degree angle from the horizontal with the upper and lower edges in a horizontal plane. The test flame shall be 3 inches (76 mm) long from a Bunsen burner of approximately [1] / 2 -inch (13 mm) inside diameter with the air supply completely shut off. The burner shall be positioned so that its top is 1 inch (25 mm) vertically below a point on the lower surface of the test specimen, 1 inch (25 mm) up from its lower horizontal edge and midway between the inclined edges. The exposure to the test flame and the duration of test shall be for a period of 2 minutes.

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    12-7A MATERIALS AND CONSTRUCTION METHODS

    FOR EXTERIOR WILDFIRE EXPOSURE

    EXTERIOR WALL SIDING AND SHEATHING

    SFM STANDARD 12-7A-1

    12-7A-1.1 Application. The minimum design, construction and performance standards set forth herein for exterior wall siding and sheathing are those deemed necessary to establish conformance to the provisions of these regulations. Materials and assemblies that meet the performance criteria of this standard are acceptable for use as defined in California Building Standards Code.

    12-7A-1.2 Scope. This standard evaluates the performance of exterior walls of structures when exposed to direct flames.

    12-7A-1.3 Referenced documents.

    1. ASTM E2257, Test Method for Room Fire Test of Wall and Ceiling Materials and Assemblies.

    2. ASTM D4442, Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials.

    3. ASTM D4444, Test Methods for Use and Calibration of Hand-Held Moisture Meters.

    4. California Building Code, Chapter 7A.

    12-7A-1.4 Definitions.

    1. Siding (cladding). Any material that constitutes the exposed exterior covering of an exterior wall and is applied over sheathing or is directly attached to the wall structural system.
    2. Sheathing. The material placed on an exterior wall beneath cladding or siding and is directly attached to the wall structural system.

    12-7A-1.5 Summary of test method.

    1. Direct flame exposure. This test method provides for the direct flame exposure of a wall specimen to a flame source centered at the base of a 4-foot by 8-foot (1220 mm by 2440 mm) test assembly.
    2. Gas burner. The method employs a gas burner to produce a diffusion flame in contact with the test wall assembly.
    3. Heat output. The gas burner produces a prescribed net rate of heat output of 8535 Btu/min (150 kW) for a period of 10 minutes, after which the flame exposure is terminated.
    4. Resistance to fire penetration. The test method measures the ability of the wall system to resist fire penetration from the exterior to the unexposed side of the test assembly under the conditions of exposure.
  • CRSC § 12-7 High relevance — show source text
    1. Test Fixture. The test fixture shall be as described in SFM 12-7A-1, with the exception that the top soffit projection of the wall assembly fixture is modified to facilitate installation and removal of eave assemblies. Gypsum board (or equivalent) is used to create a noncombustible wall surface in the 4 x 8 ft. opening in the wall test fixture.
    2. Eaves assembly. Fit the eave assembly into the test module so that the horizontal surface of the assembly is 84 inches (2.1 m) from the top of the burner.
    3. Moisture content. Measure the moisture content of the wooden members of the assembly using a moisture meter (ASTM D4444), and for sheathing products, by methods outlined in ASTM D4442.
    4. Sealing. Seal the edges and ends with ceramic wool or comparable material to prevent flame penetration in these locations of the eave assembly.

    12-7A-3.8 Conduct of Tests.

    1. Airflow. The wall test shall be conducted under conditions of ambient airflow.

    2. Number of tests. Conduct the tests on three replicate eaves assemblies.

    3. Burner output verification. Without the eaves assembly in place, adjust the burner for 300 ± 15 kW output. Extinguish the burner.

    4. Burner positioning. Center the burner with respect to the width of the eaves wall assembly and 0.75 inch (20 mm) from the wall. The distance from the floor to the top of the burner shall be 12 inches (300 mm).

    5. Procedure.

    5.1. Ignition. Ignite the burner, controlling for a constant 300 ± 15 kW output. 5.2. Flame exposure. Continue the exposure until flame penetration of the eaves occurs or for a 10-minute period.

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    5.3. Continued combustion. If penetration does not occur, continue observation for an additional 30 minutes or until all combustion has ceased.

    Note: An infrared thermometer has been found to be useful to detect the increase of temperature on the back side of the eaves and as an aid to identify the areas of potential combustion. 6. Observations. Note the time, location and nature of flame penetration.

    12-7A-3.9 Report. The report shall include a description of the eaves material, details of the construction of the eaves, moisture content of the framing and wood-based soffit elements as applicable, and point of flame penetration. Provide details on the time and reasons for early termination of the test.

    12-7A-3.10 Conditions of Acceptance. Should one of the three replicates fail to meet the Conditions of Acceptance, three additional tests may be run. All of the additional tests must meet the Conditions of Acceptance.

    1. Absence of flame penetration of the eaves or horizontal projection assembly at any time.
    2. Absence of structural failure of the eaves or horizontal projection subassembly at any time.
    3. Absence of sustained combustion of any kind at the conclusion of the 40-minute test.

    FIGURE 1 — EAVES TEST ASSEMBLY

  • CRSC § 436.5. High relevance — show source text

    DEPARTMENT OF HEALTH SERVICES

    Authority: Sections 102, 208 and 25811.

    Reference: Sections 102, 208 and 436.5.

    ALL HEALING ARTS X-RAY INSTALLATIONS

    Sec. 12-31C-101. All radiation shielding barriers in rooms and enclosures housing radiation machines shall comply with the mandatory standards and appendices in Report No. 35, “Dental X-RAY Protection”; Report 49, “Structural Shielding Design and Evaluation for Medical use of X-rays and Gamma Rays of Energies up to 10 MeV”; and Report No. 51, “Radiation Protection Design Guidelines for 0.1-100 MeV Particle Accelerator Facilities.” Published by the National Council on Radiation Protection and Measurements, 7910 Woodmont Avenue, Bethesda, Maryland 20814.

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    12-71 AIR FILTERS

    STANDARD 12-71-1

    STATE FIRE MARSHAL

    DESCRIPTION OF TEST APPARATUS, METHOD AND CLASSIFICATION REQUIREMENTS FOR AIR FILTERS

    Sec. 12-71-100.

    (a) Test apparatus.

    1. The test duct, made of M.S. gage galvanized sheet metal reinforced with angle irons, is 21 inches square (13 548 mm [2] ) and 13 [1] / 2 feet (4114 mm) long.
    2. One end of the duct is tapered to the discharge of a variable-speed blower and the other end is open to discharge. A metal filter frame is provided near the middle of the length of the duct to receive one 20 by 20 inches (508 mm by 508 mm) (nominal) filter unit. Two tightfitting doors, located to permit access to the filter frame, are each provided with a mica window to permit observation of both faces of the filter and conditions in the duct downstream from the filter.
    3. Two 1-inch (25 mm) pipe elbows, about 18 inches (457 mm) from the base of the test filter, form gas burner outlets adjusted to provide yellow, wavering flames. The burners consume approximately 4 cubic feet (approximately 1,000 Btu/cubic feet) of gas per minute.
    4. With the filter in place the air velocity is adjusted to approximately 200 linear feet per minute as measured at the discharge end of the duct by an Alnor Velometer Anemometer.

    (b) Test method.

    1. Filters are tested clean, that is, unused. The flames are applied for 3 minutes during which time observations are made of both faces of the filter as to the downstream travel of flame or sparks and the density, duration and character of the products of combustion.
  • CRSC § 9.5 High relevance — show source text

    1. The specimen shall be suspended vertically with its lower edge 2 inches (51 mm) above the top of a [3] / 8 inch (9.5 mm) diameter Bunsen Burner. The test shall be performed in a draft-free area.

    2. The flames from the burner shall be 4 inches (101 mm) long and shall be adjusted with sufficient air supply to eliminate any yellow flame tips but without any distinct inner blue cone.

    3. The specimen shall be exposed to the flame at each corner and at not less than one other point along the lower edge. Each exposure shall be of sufficient duration to determine if the material will ignite and continue to burn, but shall be not less than 20 seconds.

    4. The criteria for acceptance shall be as follows: (A) There shall be not more than intermittent flaming appreciably beyond the area exposed to the test flame. (B) Flame shall not reach the top of the specimen. (C) On removing the test flame there shall be not more than 1 second of after flaming except there may be nonprogressive flaming of short duration in areas of accumulated char which were directly exposed to the test flame.

    Section 12-7-502

    (a) Framed rigid combustible decorative material. Rigid combustible decorative material and assemblies of materials not more than [1] / 4 inch (6 mm) in thickness used for folding doors, room dividers, decorative screens and similar applications, and which are installed with all edges protected, shall conform to the following:

    1. All exposed edges shall be protected with frames of metal or other noncombustible material, or solid wood of minimum [1] / 4 inch (6 mm) dimension.

    2. The total square foot area of the material shall not exceed ten percent of that of the floor area of the room in which the material is installed.

    3. When tested as follows, flames shall not reach the top edge of the specimen. The test shall be conducted in a draft free area, on a specimen of the material 12 inches by 12 inches (305 mm by 305 mm) suspended at a 45-degree angle from the horizontal with the upper and lower edges in a horizontal plane. The test flame shall be 3 inches (76 mm) long from a Bunsen burner of approximately [1] / 2 -inch (13 mm) inside diameter with the air supply completely shut off. The burner shall be positioned so that its top is 1 inch (25 mm) vertically below a point on the lower surface of the test specimen, 1 inch (25 mm) up from its lower horizontal edge and midway between the inclined edges. The exposure to the test flame and the duration of test shall be for a period of 2 minutes.

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    12-7A MATERIALS AND CONSTRUCTION METHODS

    FOR EXTERIOR WILDFIRE EXPOSURE

    EXTERIOR WALL SIDING AND SHEATHING

    SFM STANDARD 12-7A-1

    12-7A-1.1 Application. The minimum design, construction and performance standards set forth herein for exterior wall siding and sheathing are those deemed necessary to establish conformance to the provisions of these regulations. Materials and assemblies that meet the performance criteria of this standard are acceptable for use as defined in California Building Standards Code.

  • CRSC § 8.1. High relevance — show source text

    Pieces of any hygroscopic materials from the same stock from which the test specimen was constructed shall be tacked to the specimen during construction in such a manner that they are easily removed. These pieces shall be conditioned with the completed specimens. Prior to testing, the pieces of hygroscopic materials shall be tested for moisture content. 8.1. Make the moisture determination on two samples from each piece and report the average. For lumber and other wood-based materials, use Test Methods D 4442. Use of an appropriately calibrated moisture meter, as described in Test Methods D 4444, to determine the moisture content of wood or wood products is also permitted. For other hygroscopic materials, use test methods appropriate for those materials. 8.2. For lumber used in the construction of the supporting wall structure, the moisture content shall not be more than 12 percent. For wood sheathing, the moisture content shall not exceed 8 percent. For other hygroscopic materials, the moisture shall be within ranges specified by the manufacturer before the assembly is constructed. These specified ranges shall be typical for exposure at 77 ± 9°F [25 ± 5°C] and 55 ± 10% relative humidity.

    12-7A-1.8 Weathering. Weathering of materials shall be in accordance with California Building Code Section 703A Standards of Quality.

    12-7A-1.9 Conduct of tests.

    1. Test room environment. The ambient temperature in the test room shall be above 60°F (15°C) and the relative humidity shall be less than 75 percent. The test room shall be draft-protected and equipped with an exhaust hood system for removal of products of combustion during testing.

    2. Airflow. The horizontal airflow, measured at a horizontal distance of 20 inches (0.5 m) from the edge of the wall assembly, shall not exceed 1.64 ft/s (0.5 m/s).

    3. Placement of test frame. Prior to testing, and without the test specimen in place, position the frame assembly under the exhaust hood and set the gas burner for the prescribed level of output.

    4. Placement of specimen. Once the burner output is verified, position the specimen holder assembly at the desired test location under the collection hood.

    5. Test specimen. Insert the test specimen into the frame assembly, sealing all edges with ceramic wool.

    6. Ignition. Simultaneously ignite the gas burner and start the timer marking the beginning of the test. Control the burner to a constant 150 ± 8 kW output. Control the hood duct flow to collect all products of combustion.

    7. Flame exposure. Continue the flame exposure until flame penetration of the test specimen and sustained flaming on the unexposed side occurs or for a period of 10 minutes, then extinguish the burner.

    8. Observation. If sustained flaming on the unexposed side of the test specimen has not occurred, observe the unexposed side of the test specimen for an additional 60 minutes for evidence of sustained flaming or glowing combustion on the unexposed side. Terminate the observation prior to the completion of the 60-minute observation period if all evidence of flame, glow and smoke has disappeared.

    Note: An infrared thermometer has been found to be useful to detect the increase of temperature on the unexposed side of the test assembly. 9. Documentation. Perform photographic and/or video documentation before, during and after each test.

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  • CRSC § 12-7 High relevance — show source text

    12-7A-1.2 Scope. This standard evaluates the performance of exterior walls of structures when exposed to direct flames.

    12-7A-1.3 Referenced documents.

    1. ASTM E2257, Test Method for Room Fire Test of Wall and Ceiling Materials and Assemblies.

    2. ASTM D4442, Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials.

    3. ASTM D4444, Test Methods for Use and Calibration of Hand-Held Moisture Meters.

    4. California Building Code, Chapter 7A.

    12-7A-1.4 Definitions.

    1. Siding (cladding). Any material that constitutes the exposed exterior covering of an exterior wall and is applied over sheathing or is directly attached to the wall structural system.
    2. Sheathing. The material placed on an exterior wall beneath cladding or siding and is directly attached to the wall structural system.

    12-7A-1.5 Summary of test method.

    1. Direct flame exposure. This test method provides for the direct flame exposure of a wall specimen to a flame source centered at the base of a 4-foot by 8-foot (1220 mm by 2440 mm) test assembly.
    2. Gas burner. The method employs a gas burner to produce a diffusion flame in contact with the test wall assembly.
    3. Heat output. The gas burner produces a prescribed net rate of heat output of 8535 Btu/min (150 kW) for a period of 10 minutes, after which the flame exposure is terminated.
    4. Resistance to fire penetration. The test method measures the ability of the wall system to resist fire penetration from the exterior to the unexposed side of the test assembly under the conditions of exposure. Observations are made for the appearance of sustained flaming or glow on the unexposed side and/or sustained glowing on the unexposed side at the end of a 60-minute observation period.

    12-7A-1.6 Equipment. Unless otherwise noted, dimensions in the following descriptions shall be followed with a tolerance of ± 0.5 inch (13 mm).

    1. Wall assembly holding fixture. The test specimen support assembly shown in Figure 1 is designed to permit rapid installation and removal of wall assemblies, and to prevent edge penetration of fire at the margins of the wall assembly. It includes a sturdy frame assembly to hold the specimen and a simulated soffit that is noncombustible. The frame assembly permits a 4-foot by 8-foot (1220 mm by 2440 mm) prefabricated wall section to be inserted and to be sealed in such a way that protects the edges from fire. Side shields are situated near the vertical edges and to within 12 inches (304 mm) of the top of the test wall assembly as shown in Figure 1 to aid in minimizing extraneous drafts to the surface of the assembly.

    2. Burner.

    2.1. Burner details. The ignition source for the test shall be a gas diffusion burner with a nominal 4-inch-wide by 39-inchlong (100 mm wide by 1000 mm long) porous top surface of a refractory material, as shown in Figure 2. With the exception of top surface dimensions, the essential configuration of the burner is comparable to the burner design described in ASTM E2257. The burner enclosure shall be positioned so that it is centered relative to the width of the test wall.

  • CRSC § 12-7 High relevance — show source text

    12-7A-4.8 PART B. Burning brand exposure.

    12-7A-4.8.1 Equipment.

    1. Wind tunnel. The wind tunnel shall have the capability of providing 12 mph (5.4 m/s) airflow over the deck assembly.
    2. Anemometer. Device for measuring airflow across the deck.
    3. Burner. Gas-fueled burner for brand ignition.

    12-7A-4.8.2 Test system preparation. See Figure 2. The ASTM E108 “A” brand roof test apparatus is to be used, with the following modifications:

    1. Deck support. The deck shall be supported horizontally with the center 60 inches (150 mm) from the front opening of the wind tunnel and the joists parallel to the airflow and resting on two transverse metal supports. The top surfaces of these supports, no more than 3 inches (75 mm) wide, are at the same height as the floor of the wind tunnel.
    2. Fragments. Burning fragments shall be free to fall to the floor of the room.

    12-7A-4.8.3 Conduct of tests.

    1. Number of tests. Conduct the test on three replicate assemblies.
    2. Moisture content. Measure the moisture content of the wooden members of the assembly using a moisture meter (ASTM D4444).
    3. Procedure. Adhere to ASTM E108 “Standard Test Methods for Fire Tests of Roof Coverings” (burning brand test, “A” brand), with apparatus modified as described above in “Test system preparation” and the following procedure: 3.1. The air velocity shall be calibrated using the 60-inch (1.5 m) framework spacing, with a smooth noncombustible calibration deck at a 5-inch (127 mm) per 12-inch (305 mm) horizontal incline positioned 60 inches (1.5 m) from the front opening of the wind tunnel. All other measurement details shall be followed as specified in Sections 4.4.2, 4.4.3 and 4.4.4 of ASTM E108. Although ASTM E108 specifies calibration to be conducted with the 33-inch (840-mm) framework spacing used for the intermittent flame test set up, tests have shown that at the nominal 12 mph

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    MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE

    setting, there was not difference in measured velocity between the 33- and 60-inch (838 mm and 1524 mm) framework spacing. 3.2. Mount the test specimen at a zero horizontal incline positioned 60 inches (1.5 m) from the front opening of the wind tunnel.

    3.3. Ignite the “A” brands as specified in Section 9.4 of ASTM E108 as reprinted here:

    1. Each 12- x 12-inch (300 x 300 mm) face for 30 seconds.
    2. Each 2.25- x 12-inch (57 x 300 mm) edge for 45 seconds.
    3. Each 12- x 12-inch (300 x 300 mm) face again for 30 seconds. 3.4. Center the burning brand laterally on the deck with the front edge 2.5 inches (64 mm) from the entering air edge of the deck.

Frequently asked questions

What exactly must I measure to set the airflow?

Measure air velocity at the discharge end of the duct using an Alnor Velometer Anemometer and adjust the blower to approximately 200 ft/min as required by § 12-71-100 .

How long are the burners applied during the air‑filter test?

The flames are applied for 3 minutes while observations and smoke‑density recordings are made (see § 12-71-100) .

How must the burner flames look?

The burners must be adjusted to produce yellow, wavering flames (not a blue, non‑sooty diffusion flame) per § 12-71-100 .

Can I test a used (dirty) filter with this procedure?

No. § 12-71-100 specifies that filters are tested clean (unused); the method and classification thresholds are based on clean‑filter exposure .

What smoke‑area values correspond to Class 1 vs. Class 2?

Class 1: area under smoke curve < 1.5 sq in. Class 2: area under smoke curve ≤ 6.0 sq in (classification language and thresholds are in § 12-71-100) .

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