TITLE 15 - COMMERCE AND FOREIGN TRADE

SUBTITLE B - REGULATIONS RELATING TO COMMERCE AND FOREIGN TRADE

CHAPTER II - NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE

SUBCHAPTER B - STANDARD REFERENCE MATERIALS

PART 230 - STANDARD REFERENCE MATERIALS

subpart a - GENERAL INFORMATION

230.2 - Identification of Standard Reference Materials.

The SRM's are listed by category in SP 260 and by sequential number in the supplements. The number uniquely identifies a particular SRM.

Renewals are indicated by the addition of a letter to the original number. Thus, 11a is the first, 11b the second, and 11c the third renewal of SRM 11, Basic Open-Hearth Steel, 0.2 percent carbon. In this way, a particular number or number and letter always represent a material of fixed or approximately fixed composition.