Each toughness test must be conducted at temperatures not warmer than -20 [deg]F or 10 [deg]F below the minimum service temperature, whichever is lower, except that for service at or below -320 [deg]F, the tests may be conducted at the service temperature in accordance with Sec. 54.25-10(a)(2). [CGD 85-061, 54 FR 50964, Dec. 11, 1989]