(a) Replacement process. Retroreflective sheeting required by this part shall comply with the replacement process in either paragraph (b) or (c) of this section.

(b) 10-year replacement cycle. Regardless of condition, retroreflective sheeting required by this part shall be replaced with new, undegraded, sheeting no later than 10 years after the initial installation date. At the time of replacement, it is not necessary to remove the previously installed sheeting unless it interferes with the placement of the replacement sheeting, as required by § 224.106, but the previously installed sheeting shall not be considered in calculating the required minimum area of retroreflective material required as shown in table 2 to this subpart.

(c) Replacement based on retroreflective comparator panel. Except as provided in paragraphs (c)(2)(ii) and (c)(3) of this section, retroreflective sheeting shall be evaluated using a properly calibrated comparator panel, manufactured to the specifications outlined under paragraph (c)(1) of this section, whenever a car undergoes a single car air brake test required by 49 CFR 232.305, or a locomotive receives an annual inspection required by 49 CFR 229.27.

(1) Retroreflective comparator panel specifications—(i) Retroreflectivity. Retroreflective comparator panels shall have the minimum (and maximum, if applicable) retroreflectivity values as outlined in Table 1 to paragraph (c)(1)(iv) of this section.

(ii) Color. Retroreflective comparator panels shall be yellow or white as outlined in § 224.103(b).

(iii) Construction. Retroreflective comparator panels shall be 4 inches wide by 4 inches high, be constructed with glass-beaded material or other material that displays uniform appearance when rotated and viewed with a light source, and have a magnetic backing so that the panel can be attached to rail freight rolling stock.

(iv) Labeling. Retroreflective comparator panels shall have a waterproof and dust-proof label affixed to the backing. The label shall contain: the phrase “Retroreflective Comparator Panel—Yellow” or “Retroreflective Comparator Panel—White;” and the name of the manufacturer, the part, model, or serial number, the date the panel was manufactured, the target retroreflectivity level to which the panel was manufactured (measured in cd/lx/m 2), and a space provided for the certified recalibration date. Retroreflective comparator panels shall be recalibrated at least every two years and the date of a panel's most recent recalibration must appear in the space provided on the label.

(2) Retroreflective comparator panel evaluation process and criteria. Each retroreflective sheeting on rail freight rolling stock shall be evaluated on its performance. The evaluation procedure shall consist of the following:

(i) Retroreflective sheeting shall be visually evaluated with the use of a light source. The light source must be of sufficient intensity to illuminate and overcome ambient lighting conditions. A brighter light source (LED) is recommended in daylight conditions.

(ii) Properly trained and experienced persons may pass sheeting that they determine to be obviously compliant and fail sheeting they determine to be obviously noncompliant (including obscured) based on their initial visual inspection. Any sheeting that they do not determine to be obviously compliant or noncompliant, shall be evaluated using a retroreflective comparator panel comparison.

(iii) Retroreflective comparator panels shall conform to the requirements outlined in paragraph (c)(1) of this section, and the panel's color shall match the color of the installed sheeting being evaluated.

(iv) The comparator panel shall be placed directly adjacent to, or overlapping, the retroreflective sheeting being evaluated. The retroreflective sheeting shall also be cleaned, as necessary, before the evaluation begins.

(v) Retroreflective sheeting and the comparator panel shall be evaluated from a position perpendicular to the installed sheeting, preferably from a distance of 15 feet from the installed sheeting and the comparator panel. In the event conducting the evaluation from 15 feet away is not practicable, the evaluation may be conducted from the next closest alternative distance that still permits effective evaluation.

(vi) The light source shall be positioned adjacent to the inspector's eye (left or right) and directed at the sheeting and comparator panel, and a comparison of the reflected light intensity of the entire installed sheeting to that of the comparator panel shall be made. The installed sheeting shall pass or fail based on the following criteria:

(A) If the perceived reflected light intensity of the entire installed sheeting appears brighter than that of the comparator panel, the installed sheeting passes the evaluation.

(B) If the perceived reflected light intensity of the entire installed sheeting does not appear brighter than that of the comparator panel, or if it cannot be discerned if one is brighter than the other, the sheeting fails the evaluation and shall be replaced prior to the equipment returning to service.

(C) Installed sheeting that is damaged, obscured, or missing, cannot be evaluated with the comparator panel and shall be replaced prior to the equipment returning to service.

(3) Handheld retroreflectometers. A properly calibrated handheld retroreflectometer may be used in lieu of a comparator panel, subject to the following conditions:

(i) The handheld retroreflectometer shall be an annular device. A single measurement on a strip of sheeting shall suffice with an annular device, provided that the sheeting is not damaged, obscured, or missing.

(ii) The handheld device shall be placed directly against the reflective sheeting, and the measurement shall be made based on the device manufacturer's recommendation.

(iii) The minimum allowable retroreflective value is 150 cd/lx/m 2 for yellow sheeting and 250 cd/lx/m 2 for white sheeting, when measured at the −4° entrance angle and 0.2° observation angle configuration. Sheeting that does not meet these minimum allowable retroreflectivity values shall be replaced prior to the equipment returning to service.