the meaning of § 191.1 (e) and (f) when used according to label directions to extinguish a fire, the containers for such substances shall bear the following labeling:

(a) When substances are produced which meet the definition of highly toxic within the meaning of § 191.1(e) the signal word "Danger" and the statement of hazard, "Poisonous gases formed when used to extinguish flame or on contact with heat" are specified.

(b) When substances are produced which meet the definition of toxic within the meaning of § 191.1(f), the signal word "Caution" or "Warning," and the statement of hazard, "Dangerous gas formed when used to extinguish flame or on contact with heat" are specified. These statements shall be in addition to any other that may be required under the act or this section. All containers shall also bear the additional statements: "Use in an enclosed place may be fatal," and "Do not enter area until well ventilated and all odor of chemical has disappeared."

(c) Regardless of whether paragraph (a) or (b) of this section applies, any substance or mixture of substances in a container labeled for use as a fire extinguisher, which, if applied to an electrical fire, would subject the user to the likelihood of electrical shock, shall be conspicuously labeled, "Caution: Do not use on electrical fires."

[27 F.R. 2457, Mar. 15, 1962, as amended at 27 F.R. 3255, Apr. 5, 1962]

§ 191.10 Method of testing toxic sub

stances.

The method of testing the toxic substances named in § 191.1 (e) (3) and (f) (3) is as follows:

(a) Acute dermal toxicity (single exposure). In the acute exposures the agent is held in contact with the skin by means of a sleeve for periods varying up to 24 hours. The sleeve, made of rubber dam or other impervious material, is so constructed that the ends are reinforced with additional strips and should fit snugly around the trunk of the animal. The ends of the sleeve are tucked, permitting the central portion to "balloon" and furnish a reservoir for the dose. The reservoir must have sufficient capacity to contain the dose without pressure. In the following table are given the dimensions of sleeves and the approximate body surface exposed to the test substance. The sleeves may vary in

size to accommodate smaller or larger subjects. In the testing of unctuous materials that adhere readily to the skin. mesh wire screen may be employed instead of the sleeve. The screen is padded and raised approximately 2 centimeters from the exposed skin. In the case of dry powder preparations, the skin and substance are moistened with physiologi cal saline prior to exposure. The sleeve or screen is then slipped over the gauze which holds the dose applied to the skin In the case of finely divided powders, the measured dose is evenly distributed on cotton gauze, which is then secured to the area of exposure.

DIMENSIONS OF SLEEVES FOR ACUTE DERMAL TCIT TEST

(b) Preparation of test animals. The animals are prepared by clipping the skir of the trunk free of hair. Approximately one-half of the animals are further prepared by making epidermal abrasions every 2 centimeters or 3 centimeters longitudinally over the area of exposure. The abrasions are sufficiently deep to penetrate the stratum corneum (horny layer of the epidermis), but not to disturb the derma-that is, not to obtain bleeding.

(c) Procedures for testing. The sleeve is slipped onto the animal, which is then placed in a comfortable but immobilized position in a multiple animal holder. Selected doses of liquids and solutions are introduced under the sleeve. If there is slight leakage from the sleeve, which may occur during the first few hours of exposure, it is collected and reapplied. Dosage levels are adjusted in subsequent exposures (if necessary) to enable a calculation of a dose that would be fatal to 50 percent of the animals. This can be determined from mortality ratios obtained at various doses employed. At the end of 24 hours the sleeves or screens are removed, the volume of unabsorbed material, if any, is measured, and the skin reactions are noted. The subjects are cleaned by thorough wiping, observed for gross symptoms of poisoning, and then observed for 2 weeks.

§ 191.11

Method of testing primary irritant substances.

Primary irritation to the skin is measured by a patch-test technique on the abraded and intact skin of the albino rabbit, clipped free of hair. A minimum of six subjects are used in abraded and intact skin tests. Introduce under a square patch such as surgical gauze measuring 1 inch x 1 inch, two single layers thick, 0.5 milliliter (in case of liquids) or 0.5 gram (in the case of solids and semisolids) of the test substance. Dissolve solids in an appropriate solvent and apply the solution as for liquids. The animals are immobilized with patches secured in place by adhesive tape. The entire trunk of the animal is then wrapped with an impervious material such as rubberized cloth for the 24-hour period of exposure. This material aids in maintaining the test patches in position and retards the evaporation After 24 hours of exposure, the patches are removed and the resulting reactions are evaluated on the basis of the designated values in the following table:

of volatile substances.

1 The "value" recorded for each reading is the average value of the six or more animals subject to the test.

Readings are again made at the end of a total of 72 hours (48 hours after the first reading). An equal number of exposures are made on areas of skin that have been previously abraded. The abrasions are minor incisions through the stratum corneum, but not sufficiently deep to disturb the derma or to produce bleeding. Evaluate the reactions of the abraded skin at 24 hours and 72 hours, as described in this paragraph. Add the values for erythema and Eschar forma

Six albino rabbits are used for each substance tested. One-tenth of a milliliter of the test substance is instilled in one eye of each rabbit; the other eye, remaining untreated, serves as a control. The treated eyes are not washed following instillation. Ocular reactions are read either with the unaided eye or with the aid of a hand slit lamp. Readings are made at 24 hours, 48 hours, and 72 hours after treatment.

§ 191.13 Tentative method of test for flashpoint of volatile flammable materials by Tagliabue open-cup apparatus.1 2

SCOPE

1. (a) This method describes a test procedure for the determination of open-cup

1 The Food and Drug Administration has obtained permission from the American Society for Testing Materials, Philadelphia, Pa., to reprint this method in these regulations. The text has been slightly modified, for practical reasons.

2 ASTM Designation: D 1310-59T, issued 1954; revised 1955, 1956, 1959. This tentative method has been approved by the sponsoring committee and accepted by the American Society for Testing Materials in accordance with established procedures, for use pending adoption as standard. Suggestions for revisions should be addressed to the Society at 1916 Race St., Philadelphia, Pa.

flashpoints of volatile flammable materials having flashpoints below 175° F.

(b) This method, when applied to paints and resin solutions which tend to skin over or which are very viscous, gives less reproducible results than when applied to solvents.

OUTLINE OF METHOD

2. The sample is placed in the cup of a Tag Open Tester, and heated at a slow but constant rate. A small test flame is passed at a uniform rate across the cup at specified intervals. The flashpoint is taken as the lowest temperature at which application of the test flame causes the vapor at the surface of the liquid to flash, that is, ignite but not continue to burn.

APPARATUS

3. The Tag open-cup tester is illustrated in Fig. 1. It consists of the following parts, which must conform to the dimensions shown, and have the additional characteristics as noted:

(a) Copper bath, preferably equipped with a constant level overflow so placed as to maintain the bath liquid level 1⁄2 inch below the rim of the glass cup.

(b) Thermometer holder. Support firmly with ringstand and clamp.

(c) Thermometer. For flashpoints above 40° F., use the ASTM Tag Closed Tester Thermometer, range of +20 to +230° F., in 1° F. divisions, and conforming to thermometer 9F. of ASTM Standard E 1. For flashpoints from 20° F. to 40° F., use ASTM Tag Closed Tester, Low Range, Thermometer 57F. For flashpoints below 20° F., use ASTM Thermometer 33F. The original Tag Open-Cup (Paper Scale) Thermometer will be a permissible alternate until January 1, 1962. It is calibrated to -20° F.

(d) Glass test cup. Glass test cup (Fig. 2), of molded clear glass, annealed, heat-resistant, and free from surface defects.

(e) Leveling device. Leveling device or guide, for proper adjustment of the liquid level in the cup (Fig. 3). This shall be made of No. 18-gage polished aluminum, with a projection for adjusting the liquid level when the sample is added to exactly -inch below the level of the edge or rim of the cup. (f) "Micro," or small gas burner of suitable dimensions for heating the bath. screw clamp may be used to help regulate the gas. A small electric heater may be used.

A

(g) Ignition taper, which is a small straight, blow-pipe type gas burner. The test flame torch prescribed in the method of test for flash and fire points by Cleveland Open Cup (ASTM designation: D 92) is satisfactory.

(h) Alternative methods for maintaining the ignition taper in a fixed horizontal plane above the liquid may be used, as follows:

(1) Guide wire, 2-inch in diameter and 31⁄2 inches in length, with a right-angle bend 1⁄2-inch from each end. This wire is placed snugly in holes drilled in the rim of the bath, so that the guide wire is %-inch from the center of the cup and resting on the rim of the cup.

(2) Swivel-type taper holder, such as is used in ASTM METHOD D 92. The height and position of the taper are fixed by adjusting the holder on a suitable ringstand support adjacent to the flash cup.

(1) Draft shield, consisting of two rectangular sheets of noncombustible material, 24 inches x 28 inches, are fastened together along the 28-inch side, preferably by hinges. A triangular sheet, 24 inches x 24 inches x 34 inches is fastened by hinges to one of the lateral sheets (to form a top when shield is open). The interior of the draft shield shall be painted a flat black.

PROCEDURE

4. (a) Place the tester on a solid table free of vibration, in a location free of perceptible draft, and in a dim light.

(b) Run water, brine, or water-glycol solution into the bath to a predetermined level. which will fill the bath to -inch below the top when the cup is in place. An overflow is permissible for water-level control.

(c) Firmly support the thermometer vertically halfway between the center and edge of the cup on a diameter at right angles to the guide wire, or on a diameter passing through the center of the cup and the pivot of the taper. Place so that the bottom of the bulb is 4-inch from the inner bottom surface of the cup. If the old Tagliabue thermometer is used, immerse to well cover the mercury bulb, but not the wide body of the thermometer.

(d) Fill the glass cup with the sample liquid to a depth just 1⁄2-inch below the edge, as determined by the leveling device. (e) Place the guide wire or swivel device in position, and set the draft shield around