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Rocky Mountain Cooperative Program - Program Protocol

Scope

The purpose and scope of this document is to define certain terminology, procedural techniques, criteria and protocol to be utilized by members of the ongoing "Rocky Mountain Cooperative Program" (RMCP) conducted by Rocky Mountain Reference Materials International as it applies to the development, certification and production of certified reference materials.

Definitions

The International Standards Organization (ISO) definitions, expressed in ISO Guide 30 lists the following:

• Certifying Body - A technically competent body (organization or firm, public or private) that issues a Reference Material Certificate which provides the information detailed in ISO 17034:2016.
• Reference Material (RM) - Material or substance with one or more properties of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials.
• Certified Reference Material (CRM) - Reference material, accompanied by a certificate, one or more of whose property’s values are certified by a procedure which establishes its traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an expanded uncertainty.

Rocky Mountain Cooperative Program Design

ASTM Standard E691 applies to Inter-laboratory studies to "Determine the Precision of a Single Test Method".  This standard is also a well thought out and logical plan for conducting an Inter-laboratory program involving multiple techniques.  Therefore, the planning, conducting, analyzing, protocol and treatment of data resulting from the RMRMs-RMCP is performed utilizing the guidelines established in ASTM E691 where applicable.

Selection of Participating Laboratories

RMCP membership is totally voluntary and consists of approximately 50% actual producers of the materials being analyzed, 40% technically qualified commercial laboratories and 10% representing general industry and academia.  All volunteer cooperative labs are invited to participate on each and every candidate material they are deemed competent to analyze.  All cooperative labs evaluate only the materials they agree to.

Source Materials

Materials are typically selected from standard industry stocks so as to emulate material types found in the real-life circumstances dealt with by users in their daily Rocky Mountain endeavors.  Whenever possible, program materials are secured in a wrought condition.  Other methods of manufacture such as continuous cast, sand or static castings are utilized as a last resort and only in the case of those materials being unavailable in wrought condition.

Batch Determination

Since most metals are available in bar stock or rod form, a typical "batch" or "series" is defined as a single length of material or a single bar of one continuous length.

Sampling Procedure

The "batch" samples are taken by dividing the bar into a minimum of twelve sub-sections.  A 1¼ inch solid test sample is removed from each sub-section.  Each 1¼ inch test sample is further subdivided as follows: The "batch" samples are taken by dividing the bar into a minimum of twelve sub-sections.  A 1¼ inch solid test sample is removed from each sub-section.  Each 1¼ inch test sample is further subdivided as follows:

1. Approximately ~10 % (~⅛ in.) of the total sample is converted to chip form (~25 g) for analysis by classical wet chemistry, ICP, AA, and combustion procedures.
2. An additional ~10 % (~⅛ in.) is converted to the form of a solid pin disk for determination of C, S, N2 and O2 by combustion or inert gas fusion procedures.
3. The remaining 80 % (~1 in.) of each sample remains in a solid disk form for Optical Emission and X-Ray analysis where applicable.

Each member of the "Rocky Mountain Cooperative Program" receives the three sample types and is therefore responsible for a specific sub-section of the batch bar.  All sub-sections and corresponding test samples are sequentially marked with matching and unique internal identification numbers so that if abnormalities occur during the RMCP process, each test sample can be traced to the original sub-section.  Due to this extensive sampling procedure, homogeneity of the total batch is therefore reflected as a product of the overall statistics and the resulting certified data.

Specific Within Sample Determination of Homogeneity

All materials are assessed for homogeneity.  Specific homogeneity testing is determined by the RMCP program management, and incorporates homogeneity test procedures as outlined in ASTM E826, NBS Handbook 91, "Experimental Statistics", as well as other established practices for determination of practical homogeneity.

Methods of Analysis

The RMCP "Rocky Mountain Cooperative Program" encompasses an extremely wide variety of materials.  No single method would provide optimum data results.  Therefore, the methods utilized are a combination of methods for classical wet chemistry, ICP, AA, Optical Emission and X-Ray spectrometric methods in addition to combustion/inert gas fusion procedures for the determinations of Carbon, Sulfur, Nitrogen and Oxygen.

Extent of Data Reported

It is the policy of RMCP to report data submitted by two or more labs.  However, in accordance with the guidelines established by the RMCP membership protocol, final certification occurs only for those elements in which a minimum of six data points remain after final critique.  Therefore, data in parentheses ( ) is not certified but provided for information only. Certified Data that was selected by the RMCP membership for additional testing is indicated by brackets [ ].

Traceability

Traceability to the SI through an NMI is approached in two distinct ways within the RMRMs\RMCP.

1. In the case of some matrix groups, specific SRMs are not always available. In this case, the RMCP program members voluntarily make available to the RMCP a variety of SRMs produced by (NBS\NIST), some of which have been collected over almost two decades.  In addition to validating test methods and instrument performance, where possible, these resident SRMs are also used in the instrumental calibration curves for that portion of the RMCP which requires instrumental analysis.  Affidavits of the RMCP member labs' SRM inventory and their applications are on file and archived in the RMRMs historical database.

The Rocky Mountain data results for the RMCP developed under this program are therefore "Traceable" to the U.S. Department of Commerce, National Institute of Standards & Technology, (NIST).  The specific SRMs applicable to a certification are referenced on the face of the "Certificate of Analyses" for all RMCP certified materials.