CRSC · California Referenced Standards Code

What are the temperature classifications and oven/fire-test methods for mechanical devices?

Q: What oven air speed and starting temperature must the lab use?

Air speed must be 230–245 ft/min and normal oven start temperatures 85–90°F as specified in § 12-72-206 and oven test method details.

Q: Are environmental exposure tests (humidity, corrosion, low temp) required for all ratings?

These tests are generally conducted on Ordinary ratings only unless there is reason to anticipate different behavior for other ratings — see the specific subsections in § 12-72-202 .

Mechanical fire‑alarm devices are assigned **Ordinary** or **Intermediate** temperature classifications and must pass standardized oven and fire tests (oven time–temperature curve, air velocity, uniformity, and a fire test that compares device actuation to a 160°F sprinkler) to establish spacing and performance; the detailed requirements and test procedures are in **§ 12‑72‑202**, **§ 12‑72‑203**, and **§ 12‑72‑206**.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The California Referenced Standards Code requires mechanically operated single‑ and multiple‑station fire alarm devices to be assigned a temperature classification (e.g., Ordinary or Intermediate) and to pass standardized oven and fire tests that demonstrate sensitivity, uniformity and survivability under high/low temperature and environmental exposures — see § 12-72-202, § 12-72-203 and § 12-72-206.

The single most important requirement: devices must be classified as Ordinary or Intermediate, and ordinary-rated devices must operate within 2 minutes in the specified oven time–temperature test to qualify for a 15‑foot spacing — see § 12-72-203.

Requirements in detail

Defined terms & classifications (first mentions bolded)

Fire alarm device (mechanically operated single- or multiple‑station) — defined in § 12-72-202.
Temperature classification — each device’s temperature-sensitive element must be identified as Ordinary or Intermediate and marked accordingly; maximum rating shall not exceed 225°F (107°C). § 12-72-202 and related tables.

Decision‑relevant values (quick reference table)

Decision dimension	Value(s)	Code Reference
Temperature classifications (rating ranges)	Ordinary: 135–174°F (57–79°C); Intermediate: 175–225°F (79–107°C)	§ 12-72-202
Oven test “test temperature” (high‑temp exposure)	Ordinary test temp: 125°F (52°C); Intermediate test temp: 150°F (66°C)	Table 12‑72‑2A, § 12-72-202
Operating temperature limits (for recording operating temp)	Ordinary: 128–165°F, Tolerance 10°F; Intermediate: 166–225°F, Tolerance 15°F	Table 12‑72‑2B, § 12-72-202
Oven air velocity (during oven test)	230–245 ft/min	§ 12-72-206 (testing oven)
Oven start temperature (normal)	85–90°F (29.4–32.2°C)	Oven test procedure, § 12-72-206
Uniformity tolerance (operation in oven)	Ordinary: ±15°F (8.3°C); Intermediate: ±20°F (11°C)	Oven test uniformity, § 12-72-203(c)
Time-to-actuation criterion for 15‑ft spacing	≤ 2 minutes (device operating within 2 minutes in oven => qualifies for 15‑ft spacing)	§ 12-72-203(b)(4) & (c)(1)
Fire test comparison criterion (sprinkler)	Device must operate prior to a 160°F (71.1°C) rated sprinkler installed on a 10‑ft spacing schedule under control fire conditions	Fire test, § 12-72-203(d)
Fire test fuel & timing	Denatured alcohol (190 proof ethanol + 5% methanol) in pans sized so sprinkler operates in 2 min ± 10 sec — reproduces time‑temperature curve	Fire test, § 12-72-203(d)
Number of samples for oven uniformity	Five samples (same position) to determine uniform operation	Oven test sampling, § 12-72-203(c)
High‑temperature exposure duration	30 days at table test ambient, then oven test after 24‑hr return to room temp	High‑temp exposure, § 12-72-202(e)

(See the cited sections for figures: Figure 12‑72‑2‑1 time–temperature curve, Figure 12‑72‑2‑2 fire‑test layout, Figure 12‑72‑2‑3 test oven.)

Oven test method — key steps (summary)

Mount device so the temperature‑sensing element is in the moving air stream and unobstructed; pre‑condition in oven ≥ 5 minutes. § 12-72-206(b).
Use a full‑draft circulating‑air oven run to the time–temperature curve (Figure 12‑72‑2‑1) and maintain air velocity 230–245 fpm. Record time of actuation. § 12-72-203(c) and § 12-72-206.
Uniformity: test five samples; operation is “uniform” if actuation temperatures are within the tolerances listed above. § 12-72-203(c).

Fire test method — key steps (summary)

Install devices at intended spacing (minimum 15 ft when comparing to oven results); arrange sprinkler system on standard 10‑by‑10 ft schedule with 160°F rated sprinklers. § 12-72-203(d).
Produce the control fire using denatured alcohol pans sized so sprinklers open in 2 min ± 10 sec; devices must operate prior to sprinkler activation to qualify for that spacing. § 12-72-203(d).
Four units are subjected simultaneously and all must respond prior to the sprinkler. Mounting position instructions are specified (ceiling vs side wall). § 12-72-203(d).

Environmental & durability exposures

High‑temperature exposure: 30‑day exposure at the Table 12‑72‑2A test ambient; no operation during exposure; after exposure response must be within 10% of oven test on as‑received samples. § 12-72-202(e).
Humidity, low temperature, corrosion, vibration, endurance tests: specific procedures and sample counts are prescribed and often limited to ordinary ratings unless other behavior is expected. See § 12-72-202(f)–(l) and § 12-72-203.

Exceptions & special cases

Devices not capable of repeated operation: when a device cannot be cycled, the post‑exposure response is compared to identical as‑received samples rather than to the same unit cycled before/after the exposure. § 12-72-202(e)(2), (f)(2).
Many environmental tests (humidity, low‑temp, vibration, corrosion) are typically conducted only on ordinary degree ratings, unless there is reason to expect different behavior in other ratings. § 12-72-202(i), (j), (h), (f).
Marking/labeling: if the thermally sensitive element is renewable, it must be identified with the manufacturer and temperature rating; all units must carry required markings and instructions. § 12-72-201(a)(3–7).

Common mistakes

Treating the oven test as a general sensitivity test for all spacings — the oven test is specifically tied to the 15‑foot spacing criterion; failure to operate in ≤ 2 minutes in the oven requires the device to be subjected to the full fire test. § 12-72-203(b)(4), (c)(1).
Confusing the table entries: know the difference between the rating range (where the marked rating falls) and the test ambient/test temperature used for long‑term exposures and oven tests. See Tables 12‑72‑2A and 12‑72‑2B. § 12-72-202.
Ignoring oven test setup details — air velocity (230–245 fpm), sample mounting and preconditioning (≥ 5 minutes), oven start temperature (85–90°F) and correct thermocouple placement are required for valid results. § 12-72-206(b).
Failing to test the number of samples or position uniformly — five samples, same position for uniformity determination. § 12-72-203(c).

Worked example — concrete scenario

You have a gas‑operated single‑station device whose marked rating is 150°F. Determine classification and whether it qualifies for a 15‑ft spacing by oven test.

Classification: 150°F falls inside Ordinary (135–174°F). Marking and maximum rating rules apply; device max rating must be ≤ 225°F. § 12-72-202.
Oven test setup: mount the unit with the sensing element in the oven air stream, preheat oven and let sample sit ≥ 5 minutes; oven start temp 85–90°F; air velocity 230–245 fpm; follow the time–temperature curve (Figure 12‑72‑2‑1). § 12-72-206(b) and § 12-72-203(c).
Actuation criterion: if this ordinary‑rated device goes into alarm within 2 minutes it qualifies for the 15‑ft spacing allocation. If it does not operate within 2 minutes, it must be subjected to the full fire test. § 12-72-203(b)(4) & (c)(1).
Uniformity: five samples tested in the same position must operate within ±15°F of one another for the unit to be judged uniform. § 12-72-203(c)(1).

Related provisions

§ 12-72-202 — General construction, calibration, materials, definitions, and temperature classification.
§ 12-72-203 — Performance: determination of spacing, oven test, fire test, environmental tests (humidity, low temp, vibration, endurance).
§ 12-72-206 — Testing oven construction and detailed oven test method.
§ 12-72-201 — Test reports, instructions, marking and labeling requirements for submitted samples.
Figures and tables: Figure 12‑72‑2‑1 (time–temperature curve), Figure 12‑72‑2‑2 (fire test layout), Figure 12‑72‑2‑3 (test oven), Tables 12‑72‑2A/2B for rating/test temperatures and operating limits.

Code references

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

CRSC § 12-72 High relevance — show source text
There shall be no change in the sound intensity when tested following the exposure. There shall be no evidence of eutectic flow as a result of this test. 2. Devices capable of repeated operation are to be subjected to the Oven Test before and after exposure to the test temperature ambient. Where devices are not capable of repeated operation the response data after exposure is to be compared to the response of identical as-received samples. 3. A fire alarm device shall withstand the high-temperature exposure without false operation and there shall be no visible deformation or change in the temperature sensitive element or any other part of the unit as a result of the test. 4. Five samples of each temperature rating are to be tested for their normal operating temperature after which they are to be placed in a circulating air oven maintained at the test temperature. 5. The units are to be removed from the oven after the 30-day period, allowed to remain at room temperature for at least 24 hours and then subjected to the oven test.

(f) Corrosion tests.
1. The response of a fire alarm device, after being subjected to corrosive atmospheres, shall not show a variation of more than 50 percent from the value obtained in the oven test on as-received samples. No false alarms shall occur during the exposure and there shall be no change in the sound intensity when the units are subjected to the oven test.
2. Devices capable of repeated operations are to be subjected to the oven test before and after exposure to the corrosive atmospheres. Where devices are not capable of repeated operation, the response data obtained from the oven test is to be compared to the response of identical as-received samples.
3. Two samples are to be exposed for 10 days to an atmosphere containing approximately 1 percent hydrogen sulfide by volume in air saturated with water vapor at room temperature.
4. Two samples are to be exposed for 10 days to an atmosphere containing approximately 1 percent sulfur dioxide in 1 percent carbon dioxide by volume in air saturated with water vapor at room temperature.
5. After exposure to the corrosive atmospheres, the samples are to be removed from the test chamber, allowed to remain in a normal atmosphere at room temperature for at least 24 hours and then subjected to the oven test.
6. This test is to be conducted only on devices of the ordinary degree rating unless there is reason to anticipate different behavior of other ratings.
(g) Operating temperature test.
1. A fire alarm device shall operate in a normal manner and within the operating temperature limits and tolerances included in Table 12-72-2B, when subjected to an operating temperature test in heated water, oil or air bath.
2. Five samples of each temperature rating are to be subjected to this test. Depending on their particular design, the devices are to be suspended in a circulating water, oil or air bath, and the temperature gradually increased at the rate of 1°F (0.6°C) per minute until operation takes place. The temperature of the bath at the instant of operation is to be recorded.
(h) Vibration test.
1. A fire alarm device shall be capable of withstanding vibration without false operation, without breakage or damage to parts or any leakage at fittings. Following the vibration test the response of a unit shall not show a variation of more than 50 percent from the value obtained in the oven test on as-received samples. There shall be no change in the sound intensity following the vibration.
2. Two samples are to be secured in the position of normal use on a mounting board and the board, in turn, securely fastened to a variable speed vibration machine having an amplitude of 0.01 inch (0.2 mm).

CRSC § 29.4 High relevance — show source text

In the event that the air flow tends to change during a test run, the speed of the fan is adjusted to keep the air velocity within the specified range.

(b) Test method.

The preparation for test consists of mounting the device on the small removable screen base of [1] / 4 -inch (6 mm) hardware cloth formed to a height where the temperature sensing element is midway between the top of the chamber and the guide vane. The sample under test is positioned in the air stream so that there is no obstruction between the guide vane and sensing element. A spring wound device is mounted with the sensing element in a horizontal position. The test sample shall remain in the oven at least 5 minutes prior to starting each test run.
The heating coils are permitted to preheat for 10 to 20 seconds prior to starting the test. The fan controlling the air flow is turned on and its speed adjusted to produce the required velocity. The temperatures are read every 10 seconds. The two autotransformers are adjusted as needed to obtain the desired rate of temperature rise. Normal oven temperatures at the start of the test are to be 85–90°F (29.4–32.2°C).
Upon operation of the device, the current applied to the bank of heaters is cut-off and the oven is cooled to normal room temperature by means of the cooling fan.

TABLE 12-72-2A—TEMPERATURE CLASSIFICATIONS	Col2	Col3
TEMPERATURE CLASSIFICATION	RATING RANGE °F (°C)	TEST TEMPERATURE °F (°C)
Ordinary	135-174 (57-74)	125 (51.7)
Intermediate	175-225 (79-107)	150 (66)

TABLE 12-72-2B—TEMPERATURE CLASSIFICATIONS	Col2	Col3	Col4
TEMPERATURE CLASSIFICATION	OPERATING TEMPERATURE LIMITS	OPERATION	OPERATION
TEMPERATURE CLASSIFICATION	Minimum °F (°C)	Maximum °F (°C)	Tolerance, °F (°C)
Ordinary	128 (53.3)	165 (73.9)	10 (5.6)
Intermediate	166 (74.4)	225 (107)	15 (8.3)

2025 CALIFORNIA REFERENCED STANDARDS CODE 129