Section 1615.4 - Test procedure(a)Apparatus -(1)Test chamber. The test chamber shall be a steel cabinet with inside dimensions of 32.9 cm. (1215/16 in.) wide, 32.9 cm. (1215/16 in.) deep, and 76.2 cm. (30 in.) high. It shall have a frame which permits the suspension of the specimen holder over the center of the base of the cabinet at such a height that the bottom of the specimen holder is 1.7 cm. (3/4 in.) above the highest point of the barrel of the gas burner specified in paragraph (c) of this section and perpendicular to the front of the cabinet. The front of the cabinet shall be a close fitting door with a glass insert to permit observation of the entire test. The cabinet floor may be covered with a piece of asbestos paper, whose length and width are approximately 2.5 cm. (1 in.) less than the cabinet floor dimensions. The cabinet to be used in this test method is illustrated in Figure 1 and detailed in Engineering Drawings, Nos. 1 to 7.(2)Specimen holder. The specimen holder is designed to permit suspension of the specimen in a fixed vertical position and to prevent curling of the specimen when the flame is applied. It shall consist of two U-shaped 0.20 cm. (14 ga. USS) thick steel plates, 42.2 cm. (165/8 in.) long, and 8.9 cm. (3.5 in.) wide, with aligning pins. The openings in the plates shall be 35.6 cm. (14 in.) long and 5.1 cm. (2 in.) wide. The specimen shall be fixed between the plates, which shall be held together with side clamps. The holder to be used in this test method is illustrated in Figure 2 and detailed in Engineering Drawing No. 7.(3)Burner. The burner shall be substantially the same as that illustrated in Figure 1 and detailed in Engineering Drawing No. 6. It shall have a tube of 1.1 cm. (0.43 in.) inside diameter. The input line to the burner shall be equipped with a needle valve. It shall have a variable orifice to adjust the height of the flame. The barrel of the burner shall be at an angle of 25° from the vertical. The burner shall be equipped with an adjustable stop collar so that it may be positioned quickly under the test specimen. The burner shall be connected to the gas source by rubber or other flexible tubing.(4)Gas supply system. There shall be a pressure regulator to furnish gas to the burner under a pressure of 129±13mm. Hg (21/2±1/4 lbs. per sq. in.) at the burner inlet.(5)Gas. The gas shall be at least 97 percent pure methane.(6)Hooks and weights. Metal hooks and weights shall be used to produce a series of loads for char length determinations. Suitable metal hooks consist of No. 19 gauge steel wire, or equivalent, made from 7.6 cm. (3 in.) lengths of the wire, bent 1.3 cm. (0.5 in.) from one end to a 45° angle hook. The longer end of the wire is fastened around the neck of the weight to be used and the other in the lower end of each burned specimen to one side of the burned area. The requisite loads are given in table 1. View Image
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Table 1-Original Fabric Weight1
| Grams per square meter | Ounces per square yard | Loads |
| Grams | Pounds |
| Less than 101 | Less than 3 | 54.4 | 0.12 |
| 101 to 207 | 3 to 6 | 113.4 | .25 |
| 207 to 338 | 6 to 10 | 226.8 | .50 |
| Greater than 338 | Greater than 10 | 340.2 | .75 |
1 Weight of the original fabric, containing no seams or trim, is calculated from the weight of a specimen which has been conditioned for at least 8 h at 21±1.1 °C (70±2 °F) and 65±2 pct relative humidity. Shorter conditioning times may be used if the change in weight of a specimen in successive weighings made at intervals of not less than 2 h does not exceed 0.2 pct of the weight of the specimen.
(7)Stopwatch. A stopwatch or similar timing device shall be used to measure time to 0.1 second.(8)Scale. A linear scale graduated in millimeters or 0.1 inch divisions shall be used to measure char length.(9)Circulating Air Oven. A forced circulation drying oven capable of maintaining the specimens at 105±2.8 °C. (221±5 °F.), shall be used to dry the specimen while mounted in the specimen holders.(10)Desiccator. An air-tight and moisture-tight desiccating chamber shall be used for cooling mounted specimens after drying. Anhydrous silica gel shall be used as the desiccant in the desicating chamber.(11)Hood. A hood or other suitable enclosure shall be used to provide a draft-free environment surrounding the test chamber. This enclosure shall have a fan or other suitable means for exhausting smoke and/or toxic gases produced by testing.(b)Specimens and sampling-General.(1) The test criteria of § 1615.3(b) shall be used in conjunction with the following fabric and garment sampling plan, or any other approved by the Consumer Product Safety Commission that provides at least the equivalent level of fire safety to the consumer. Alternate sampling plans submitted for approval shall have operating characteristics such that the probability of Unit acceptance at any percentage defective does not exceed the corresponding probability of Unit acceptance of the following sampling plan in the region of the latter's operating characteristic curves that lies between 5 and 95 percent acceptance probability.(2) Different colors or different print patterns of the same fabric may be included in a single Fabric or Garment Production Unit, provided such colors or print patterns demonstrate char lengths that are not significantly different from each other as determined by previous testing of at least three samples from each color or print pattern to be included in the Unit.(3) Garments with different trim and findings may be included in a single Garment Production Unit providing the other garment characteristics are identical except for size, color, and print pattern.(4) For fabrics whose flammability characteristics are not dependent on chemical additives or chemical reactants to fiber, yarns, or fabrics, the laundering requirement of paragraph (g)(4) of this section is met on subsequent Fabric Production Units if results of testing an initial Fabric Production Unit demonstrate acceptability according to the requirements of paragraph (c) of this section, Normal Sampling, both before and after the appropriate laundering.(5) If the fabric has been shown to meet the laundering requirement, paragraph (g)(4) of this section, the garments produced from that fabric are not required to be laundered.(6) Each Sample (five specimens) for all Fabric Sampling shall be selected so that two specimens are in one fabric direction (machine or cross-machine) and three specimens are in the other fabric direction except for the additional Sample selected after a failure, in which case, all five specimens shall be selected in the same fabric direction in which the specimen failure occurred.(7) Fabric Samples may be selected from fabric as outlined in paragraph (c) of this section entitled Fabric Sampling, or, for verification purposes, from randomly selected garments.(8) Multilayer fabrics shall be tested with a hem of approximately 2.5 cm. (1 in.) sewn at the bottom edge of the specimen with a suitable thread and stitch. The specimen shall include each of the components over its entire length. Garments manufactured from multilayer fabrics shall be tested with the edge finish at the bottom edge of the specimen which is used in the garment.(c)Specimens and Sampling-Fabric Sampling. A Fabric Production Unit (Unit) is either accepted or rejected in accordance with the following plan: (1)Normal Sampling. Select one Sample from the beginning of the first Fabric Piece (Piece) in the Unit and one Sample from the end of the last Piece in the Unit, or select a sample from each end of the Piece if the Unit is made up of only one Piece. Test the two selected Samples. If both Samples meet all the Test Criteria of § 1615.3(b) , accept the unit. If either or both of the Samples fail the 17.8 cm. (7.0 in.) average char length criterion, § 1615.3(b)(1) , reject the Unit. If two or more of the individual specimens, from the 10 selected specimens fail, the 25.4 cm. (10 in.) char length, .3(b)(2), reject the Unit. If only one individual specimen, from the 10 selected specimens, fails the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , select five additional specimens from the same end of the Piece in which the failure occurred, all five to be taken in the fabric direction in which the specimen failure occurred. If this additional Sample passes all the test criteria, accept the Unit. If this additional Sample fails any part of the test criteria, reject the Unit.(2)Reduced Sampling.(i) The level of sampling required for fabric acceptance may be reduced provided the preceding 15 Units of the fabric have all been accepted using the Normal Sampling plan.(ii) The Reduced Sampling plan shall be the same as for Normal Sampling except that the quantity of fabric in the Unit may be increased to 10,000 linear yards.(iii) Select and test two Samples in the same manner as in Normal Sampling. Accept or reject the Unit on the same basis as with Normal Sampling.(iv) Reduced Sampling shall be discontinued and Normal Sampling resumed if a Unit is rejected.(3)Tightened Sampling. The level of sampling required for acceptance shall be increased when a Unit is rejected under the Normal Sampling plan. The Tightened Sampling shall be the same as Normal Sampling except that one additional Sample shall be selected and cut from a middle Piece in the Unit. If the Unit is made up of less than two pieces, the Unit shall be divided into at least two Pieces. The division shall be such that the Pieces produced by the division shall not be smaller than 100 linear yards or greater than 2,500 linear yards. If the unit is made up of two Pieces, the additional Sample shall be selected from the interior end of one of the Pieces. Test the three selected Samples. If all three selected Samples meet all the test criteria of § 1615.3(b) , accept the unit. If one or more of the three selected Samples fail the 17.8 cm. (7.0 in.) average char length criterion, § 1615.3(b)(1) , reject the Unit. If two or more of the individual specimens from the 15 selected specimens fail the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , reject the unit. If only one individual specimen, of the 15 selected Specimens fails the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , select five additional specimens from the same end of the same piece in which the failure occurred, all five to be taken in the fabric direction in which the Specimen failure occurred. If this additional Sample passes all the test criteria, accept the Unit. If this additional Sample fails any part of the test criteria, reject the Unit. Tightened Sampling may be discontinued and Normal Sampling resumed after five consecutive Units have all been accepted using Tightened Sampling. If Tightened Sampling remains in effect for 15 consecutive units, production of the specific fabric in Tightened Sampling must be discontinued until that part of the process or component which is causing failure has been identified and the quality of the end product has been improved.(4)Disposition of rejected Units.(i) The Piece or Pieces which have failed and resulted in the initial rejection of the Unit may not be retested, used, or promoted for use in children's sleepwear as defined in § 1615.1(a) except after reworking to improve the flammability characteristics and subsequent retesting in accordance with the procedures in Tightened Sampling.(ii) The remainder of a rejected Unit, after removing the Piece or Pieces the failure of which resulted in Unit rejection, may be accepted if the following test plan is successfully concluded at all required locations. The required locations are those adjacent to each such failed Piece. (Required locations exist on both sides of the "Middle Piece" tested in Tightened Sampling if failure of that Piece resulted in Unit rejection.) Failure of a Piece shall be deemed to have resulted in Unit rejection if Unit rejection occurred and a Sample or specimen from the Piece failed any test criterion of § 1615.3(b) .(iii) The Unit should contain at least 15 Pieces for disposition testing after removing the failing Pieces. If necessary for this purpose, the Unit shall be demarcated into at least 15 approximately equal length Pieces unless such division results in Pieces shorter than 100 linear yards. In this latter case, the Unit shall be demarcated into roughly equal length Pieces of approximately 100 linear yards each. If such a division results in five Pieces or less in the Unit for each failing Piece after removing the failing Pieces, only the individual Piece retest procedure (described subsequently) may be used.(iv) Select and cut a Sample from each end of each adjoining Piece beginning adjacent to the Piece which failed. Test the two Samples from the Piece. If both Samples meet all the test criteria of § 1615.3(b) , the Piece is acceptable. If one or both of the two selected Samples fail the 17.8 cm. (7.0 in.) average char length criterion, § 1615.3(b)(1) , the Piece is unacceptable. If two or more of the individual Specimens, from the 10 selected specimens, fail the 25.4 cm. (10 in.) char length § 1615.3(b)(2) , the Piece is unacceptable. If only one individual specimen, from the 10 selected specimens, fails the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , select five additional specimens from the same end of the Piece in which the failure occurred, all five to be taken in the fabric direction in which the specimen failure occurred. If this additional Sample passes all the test criteria, the Piece is acceptable. If this additional Sample fails any part of the test criteria, the Piece is unacceptable.(v) Continue testing adjoining Pieces until a Piece has been found acceptable. Then continue testing adjoining Pieces until three successive adjoining Pieces, not including the first acceptable Piece, have been found acceptable or until five such Pieces not including the first acceptable Piece, have been tested, whichever occurs sooner. Unless three successive adjoining Pieces have been found acceptable among five such Pieces, testing shall be stopped and the entire Unit rejected without further testing. If three successive Pieces have been found acceptable among five such Pieces, accept the three successive acceptable Pieces and the remaining Pieces in the Unit.(vi) Alternatively, individual Pieces from a rejected Unit containing three or more Pieces may be tested and accepted or rejected on a Piece-by-Piece basis according to the following plan, after removing the Piece or Pieces, the failure of which resulted in Unit rejection. Select four Samples (two from each end) from the Piece. Test the four selected Samples. If all four Samples meet all the Test Criteria of § 1615.3(b) , accept the Piece. If one or more of the Samples fail the 17.8 cm. (7 in.) average char length criterion, § 1615.3(b)(1) , reject the Piece. If two or more of the individual Specimens from the 20 selected specimens, fail the 25.4 cm. (10 in.) char length, § 1615.3(b)(1) , reject the Piece. If only one individual specimen, from the 20 selected specimens, fails the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , select two additional Samples from the same end of the Piece in which the failure occurred. If these additional two Samples meet all the Test Criteria of § 1615.3(b) , accept the Piece. If one or both of the two additional Samples fail any part of the Test Criteria, reject the Piece.(vii) The Pieces of a Unit rejected after retesting may not be retested, used, or promoted for use in children's sleepwear as defined in § 1615.1(a) except after reworking to improve the flammability characteristics, and subsequent retesting in accordance with the procedures set forth in Tightened Sampling.(5)Records. Records of all Unit sizes, test results, and the disposition of rejected Pieces and Units must be maintained by the manufacturer upon the effective date of this Standard. Rules and regulations may be established by the Consumer Product Safety Commission.(d)Specimens and Sampling-Garment Sampling.(1)(i) The garment sampling plan is made up of two parts: (A) Prototype Testing and(B) Production Testing. Prior to production, prototypes must be tested to assure that the design characteristics of the garments are acceptable. Garment Production Units (Units) are then accepted or rejected on an individual Unit basis.(ii) Edge finishes such as hems and binding are excluded from testing except that when trim is used on an edge the trim must be subjected to prototype testing. Seams attaching findings are excluded from testing.(2)Prototype Testing. Preproduction prototypes of a garment style or type shall be tested to assure that satisfactory garment specifications in terms of flammability are set up prior to production. (i)Seams. Make three Samples (15 specimens) using the longest seam type and three Samples using each other seam type 10 inches or longer that is to be included in the garment. Prior to testing, assign each specimen to one of the three Samples. Test each set of three Samples and accept or reject each seam design in accordance with the following plan:(A) If all three Samples meet all the test criteria of § 1615.3(b) , accept the seam design. If one or more of the three Samples fail the 17.8 cm. (7 in.) average char length criterion, § 1615.3(b)(1) , reject the seam design. If three or more of the individual Specimens from the 15 selected specimens fail the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , reject the seam design. If only one of the individual specimens from the 15 selected specimens fails the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , accept the seam design.(B) If two of the individual specimens from the 15 selected specimens, fail the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , select three more Samples (15 specimens) and retest. If all three additional Samples meet all the test criteria of § 1615.3(b) accept the seam design. If one or more of the three additional Samples fail the 17.8 cm. (7 in.) average char length criterion, § 1615.3(b)(1) , reject the seam design. If two or more of the individual specimens from the 15 selected specimens, fail the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) reject the seam design. If only one of the individual specimens from the 15 selected specimens, fails the 25.4 cm. (10 in.) char length § 1615.3(b)(2) accept the seam design.(ii)Trim.(A)(1) Make three samples (15 specimens) from each type of trim to be included in the garment. For trim used only in a horizontal configuration on the garment, specimens shall be prepared by sewing or attaching the trim horizontally to the bottom edge of an appropriate section of untrimmed fabric. Sleeve and neckline trim may not be tested in this manner. Where more than one row of trim is used on the garment, specimens shall be prepared with the same configuration (same number of rows and spacing between rows up to the limit of the specimen size) as the garment.(2) For trim used in other than a horizontal configuration, specimens shall be prepared by sewing or attaching the trim to the center of the vertical axis of an appropriate section of untrimmed fabric, beginning the sewing or attachment at the lower edge of each specimen.(3) For either configuration, the sewing or attachment shall be made in the manner in which the trim is attached in the garment.(B)(1) Sewing or otherwise attaching the trim shall be done with thread or fastening material of the same composition and size to be used for this purpose in the garment and using the same stitching or seamtype. Trim used in the horizontal configuration shall be sewn or fastened the entire width (smaller dimension) of the specimen. Trim used in other than the horizontal configuration shall be sewn or fastened the entire length (longer dimension) of the specimen.(2) Prior to testing, assign each specimen to one of the three samples. Test the sets of three samples and accept or reject the type of trim and design on the same basis as seam design. A type of trim and design accepted when tested in a vertical configuration may be used in a horizontal configuration without further testing.(3)Production Testing. A Unit is either accepted or rejected according to the following plan: (i)(A) From each Unit select at random sufficient garments and cut three Samples (15 specimens) from the longest seam type. No more than five specimens may be cut from a single garment. Prior to testing, assign each specimen to one of the three Samples. All specimens cut from a single garment must be included in the same Sample. Test the three selected Samples. If all three Samples meet all the test criteria of § 1615.3(b) , accept the Unit. If one or more of the three Samples fail the 17.8 cm. (7 in.) average char length criterion, § 1615.3(b)(1) , reject the Unit. If four or more of the individual specimens, from the 15 selected specimens, fail the 25.4 cm (10 in.) char length, § 1615.3(b)(2) , reject the Unit. If three or less of the individual specimens, from the 15 selected specimens, fail the 25.4 cm. (10 in.) char length, § 1615.3(b)(2) , accept the Unit.(B)(1) If the garment under test does not have a 10-inch seam in the largest size in which it is produced, the following selection and testing procedure shall be followed.(2) Select and cut specimens 8.9 cm. (3.5 in.) wide by the maximum available seam length, with the seam in the center of the specimen and extending the entire specimen length. Cut three Samples (15 specimens). These specimens shall be placed in specimen holders so that the bottom edge is even with the bottom of the specimen holder and the seam begins in the center of the bottom edge. Prior to testing, assign each specimen to one of the three Samples. All specimens cut from a single garment must be included in the same Sample.(3) Test the three Samples. If all three Samples pass the 17.8 cm. (7 in.) average char length criterion, § 1615.3(b)(1) , and if three or less individual specimens fail by charring the entire specimen length, accept the Unit. If the Unit is not accepted in the above test, three Samples (15 specimens) of the longest seam type shall be made using fabric and thread from production inventory and sewn on production machines by production operators. The individual fabric sections prior to sewing must be no larger than 20.3 * 63.3 cm. (8 in. * 25 in.) and must be selected from more than one area of the base fabric. Test the three prepared Samples. Accept or reject the Unit as described previously in this subsection.(4)Disposition of Rejected Units. Rejected Units shall not be retested, used, or promoted for use in children's sleepwear as defined in § 1615.1(a) , except after reworking to improve the flammability characteristics and subsequent retesting in accordance with the procedures set forth in garment production testing.(5)Records. Records of all Unit sizes, test results, and the disposition of rejected Units must be maintained by the manufacturer upon the effective date of this standard. Rules and regulations may be established by the Consumer Product Safety Commission.(e)Specimens and Sampling-Compliance Market Sampling Plan. Sampling plans for use in market testing of items covered by this Standard may be issued by the Consumer Product Safety Commission. Such plans shall define noncompliance of a production Unit to exist only when it is shown, with a high level of statistical confidence, those production Units represented by tested items which fail such plans will, in fact, fail this standard. Production units found to be non-complying under the provisions of paragraph (e) of this section shall be deemed not to conform to this Standard. The Consumer Product Safety Commission may publish such plans in the FEDERAL REGISTER.(f)Mounting and conditioning of specimens.(1) The specimens shall be placed in specimen holders so that the bottom edge of each specimen is even with the bottom of the specimen holder. Mount the specimen in as close to a flat configuration as possible. The sides of the specimen holder shall cover 1.9 cm. (3/4 in.) of the specimen width along each long edge of the specimen, and thus shall expose 5.1 cm. (2 in.) of the specimen width. The sides of the specimen holder shall be clamped with a sufficient number of clamps or shall be taped to prevent the specimen from being displaced during handling and testing. The specimens may be taped in the holders if the clamps fail to hold them. Place the mounted specimens in the drying oven in a manner that will permit free circulation of air at 105 °C. (221 °F.) around them for 30 minutes.(2) Remove the mounted specimens from the oven and place them in the desiccator for 30 minutes to cool. No more than five specimens shall be placed in a desiccator at one time. Specimens shall remain in the desiccator no more than 60 minutes.(g)Testing - (1)Burner adjustment. With the hood fan turned off, use the needle valve to adjust the flame height of the burner to 3.8 cm. (11/2 in.) above the highest point of the barrel of the burner. A suitable height indicator is shown in Engineering Drawing No. 6 and Figure 1.(2) Specimen Burning and Evaluation. (i) One at a time, the mounted specimens shall be removed from the desiccator and suspended in the cabinet for testing. The cabinet door shall be closed and the burner flame impinged on the bottom edge of the specimen for 3.0±0.2 seconds. Flame impingement is accomplished by moving the burner under the specimen for this length of time, and then removing it.(ii) When afterglow has ceased, remove the specimen from the cabinet and holder, and place it on a clean flat surface. Fold the specimen lengthwise along a line through the highest peak of the charred or melted area; crease the specimen firmly by hand. Unfold the specimen and insert the hook with the correct weight as shown in table 1 in the specimen on one side of the charred area 6.4 mm. (1/4 in.) from the lower edge.(iii) Tear the specimen by grasping the other lower corner of the fabric and gently raising the specimen and weight clear of the supporting surface. Measure the char length as the distance from the end of the tear to the edge of the specimen exposed to the flame. After testing each specimen, vent the hood and cabinet to remove the smoke and/or toxic gases.(3)Report. Report the value of char length, in centimeters (inches), for each specimen, as well as the average char length for each set of five specimens.(4)Laundering.(i) The procedures described in sections 1615.4(b) through (g) shall be carried out on finished items (as produced or after one washing and drying) and after they have been washed and dried 50 times in accordance with sections 8.2.2 , 8.2.3 , and 8.3.1(A) of AATCC Test Method 124-1996 "Appearance of Fabrics after Repeated Home Laundering," Technical Manual of the American Association of Textile Chemists and Colorists, vol. 73, 1997, which is incorporated by reference. Copies of this document are available from the American Association of Textile Chemists and Colorists, P.O. Box 12215, Research Triangle Park, North Carolina 27709. This document is also available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 . Items which do not withstand 50 launderings shall be tested at the end of their useful service life.(ii) Washing shall be performed in accordance with sections 8.2.2 and 8.2.3 of AATCC Test Method 124-1996, using wash temperature V (60°±3 °C, 140°±5 °F) specified in Table II of that method, and the water level, agitator speed, washing time, spin speed and final spin cycle specified for "Normal/Cotton Sturdy" in Table III. A maximum washer load shall be 3.64 Kg (8 pounds) and may consist of any combination of test samples and dummy pieces. Drying shall be performed in accordance with section 8.3.1(A) of that test method, Tumble Dry, using the exhaust temperature (66°±5 °C, 150°±10 °F) and cool down time of 10 minutes specified in the "Durable Press" conditions of Table IV. Alternatively, a different number of times under another washing and drying procedure may be specified and used, if that procedure has previously been found to be equivalent by the Consumer Product Safety Commission. Such laundering is not required of items which are not intended to be laundered, as determined by the Consumer Product Safety Commission.(iii) Items which are not susceptible to being laundered and are labeled "dry-clean only" shall be drycleaned by a procedure which has previously been found to be acceptable by the Consumer Product Safety Commission.(iv) For the purpose of the issuance of a guarantee under section 8 of the act, finished sleepwear garments to be tested according to paragraphs (b) through (e) of this section need not be laundered or drycleaned provided all fabrics used in making the garments (except trim) have been guaranteed by the fabric producer to be acceptable when tested according to paragraphs (b) through (e) of this section.40 FR 59903, Dec. 30, 1975; 41 FR 1061, Jan. 6, 1976; 41 FR 8032, Feb. 24, 1976, as amended at 43 FR 4853, Feb. 6, 1978; 46 FR 63251, Dec. 31, 1981; 64 FR 24526, June 28, 1999; 65 FR 12927, Mar. 10, 2000; 72 FR 13689, Mar. 23, 2007