SAP 3 Supplier Evaluation – 2023 Page 1 of 4

This publication is available free of charge from: Link to be provided when approved for publication.

SAP 3

OWM PT Standard Administrative Procedure 

for 

Supplier Evaluation for PT Supplies and Calibration Services 

1 Introduction

Purpose of the Procedure 

This is the OWM Laboratory Metrology Program procedure for purchase, storage, and 

evaluation of supplies, measurement standards, and calibration services related to the 

PT program and Training program where possible and applicable to ensure that the 

products and services are sufficient for their applications in the PT or Training 

programs. Obtaining calibration services from organizations accredited to ISO/IEC 

17025 is required where possible and shall be documented as a part of the purchasing 

statement of work or purchasing documents; however, this is no guarantee of 

acceptable quality. The Laboratory Metrology Program staff ensures applicable 

specifications and tolerances are including in purchasing specifications and inspects 

and evaluates all products or services and identifies any unique storage requirements 

when products are received or returned.

Scope

The Scope of this procedure covers writing all statements of work and purchasing 

specifications of measurement standards and calibration services purchased for use in 

the Laboratory Metrology Program within the Office of Weights and Measures to the 

extent purchases can be managed with local credit cards or through the NIST Office of 

Acquisition and Agreements Management (OAAM). Compliance with federal 

regulations governing purchase of supplies and services is overseen by the NIST 

OAAM which manages purchasing, contracts, and ensures compliance with the Federal 

Acquisition Regulations System (FARS). When applicable, in support with OAAM, 

Laboratory Metrology Program staff evaluate quotes to ensure compliance with 

purchasing requests prior to contracts or purchase orders being issued. 

The Scope of this procedure also covers the evaluation of all measurement standards 

owned by PT participants where the items are loaned to the program for a PT scheme. 

The OWM PT program does NOT purchase externally provided products or services 

for the following tasks:

• Design or planning of PT schemes;

• Evaluation of performance; or 

• Final authorization of PT reports.
SAP 3 Supplier Evaluation – 2023 Page 2 of 4

This publication is available free of charge from: Link to be provided when approved for publication.

Applicable Documentary References

• ISO/IEC 17025:2017 is used and referenced for accreditation requirements

when calibration or laboratory equipment maintenance services are obtained.

• ISO/IEC 17043:2023 (DIS 2022) is used and referenced for PT program 

compliance requirements when supplies or services can impact the quality of 

the PT program. 

• Additional documentary standards which contain specifications and tolerances 

for measurement standards are used whenever possible and applicable (see 

examples in section 2.2.2).

Responsibility and Authority 

Laboratory Metrology Program staff are all responsible for 

documenting purchasing requests to the extent required and allowed for 

credit card purchasing approvals, and contracts or purchases managed 

by OAAM, to ensure quality of measurement standards and quality and 

traceability of calibration services. The local staff authority is limited 

by Federal regulation. Purchasing requests include demonstration of 

compliance to meet requirements prior to signing off on payments as 

possible and prior to use in the PT or Training programs. 

OWM staff are responsible for the impact of purchased products and 

services on the PT program outputs and outcomes and have the authority 

to refuse the use of products or services where they could jeopardize the 

quality of the PT or training programs. 

OWM staff are responsible for evaluating loaned measurement 

standards for compliance to requirements in section 2.2 prior to use in a 

PT scheme.

Communications with Suppliers of Products or Services

To the extent possible, the Laboratory Metrology Program staff will communicate the 

requirements listed below to its suppliers. In the event that purchasing is completed 

through the OAAM, communication requirements are documented in federal 

regulations. 

• Products and services to be provided;

• Acceptance criteria;

• Competency (including compliance with specifications, accreditation); 

and

• Any activities that are provided at alternative locations.

2 Methodology

Workflow
SAP 3 Supplier Evaluation – 2023 Page 3 of 4

This publication is available free of charge from: Link to be provided when approved for publication.

Credit card purchases are restricted to amounts of less than $10,000 and 

handled locally through the Office of Weights and Measures and 

overseen by an Administrative Officer of the Physical Measurements 

Laboratory. Purchase requests are managed through internal OWM 

processes and approvals by the OWM Chief. 

Purchasing of contracts or services through OAAM are constrained by 

the forms and workflow of government procurement requirements. 

The following characteristics are considered when evaluating possible purchase 

of supplies and services, when documenting requests for purchase, or when 

considering the loan of a measurement standard for an individual PT scheme: 

Accreditation status to ISO/IEC 17025 with applicable Scope and 

Uncertainties.

Compliance with latest applicable editions of documentary standards 

that include specifications and tolerances such as:

2.2.2.1 Mass standards: OIML R111 or ASTM E 617;

2.2.2.2 Mass field standards: NIST Handbook 105-1, 105-8;

2.2.2.3 Volumetric field standards: NIST Handbook 105-2, 105-3, 105-

4, 105-7; 

2.2.2.4 Timing Devices: NIST Handbook 105-5; 

2.2.2.5 Thermometers: ASTM E 1 or NIST Handbook 105-6; and

2.2.2.6 Proving rings or Load Cells: ASTM E 74.

Familiarity with the product, word of mouth experience from other 

laboratories (quality factor) as possible within government purchasing 

constraints.

Prior relationship with supplier, supplier’s reputation, and commitment 

to customer satisfaction as possible within government constraints.

Cost and turn-around time and ability to meet OWM time requirements. 

Availability of product, parts, or services and willingness to quote on 

products or services.

Stability and history available for measurement standards loaned to a 

PT scheme by a participating laboratory. 

Compliance any other OWM PT or Training program requirements that 

arise. 
SAP 3 Supplier Evaluation – 2023 Page 4 of 4

This publication is available free of charge from: Link to be provided when approved for publication.

Acceptance and competency requirements are included in purchasing requests 

and statements of work whenever possible and incorporate demonstration of 

compliance with purchasing requests whenever allowed. 

Inspection and Validation Prior to Use

All products and services may require demonstration of compliance to purchasing 

requirements and are inspected or validated prior to use. Whenever possible, final 

payment is linked to approvals for program use. In the case of loaned measurement 

standards, the history and stability of the standards is verified prior to acceptance for 

use and PT participants are included in the discussion regarding measurement standards 

to be used during the PT planning process. 

Complaints or Failures to Comply with Purchase Requests

Any product or service that fails to comply with purchasing requirements will be 

documented. A complaint/resolution is implemented with the vendor and/or refusal of 

payment will be documented. Depending on purchasing methodology, complaints or 

failures may be direct communications with the vendor or may be required to go 

through the OAAM processes. Two examples follow. 

An accredited calibration is purchased through credit card processing, 

but the calibration certificate is not compliant with ISO/IEC 17025 or 

includes unrequested “due dates”, but upon complaint, is amended by 

the vendor. 

A new balance is purchased through OAAM federal purchasing 

processes and includes installation and demonstration of compliance 

before final payments. The balance does not meet the purchasing 

specifications. Laboratory Metrology Program staff indicate that the 

product does not comply with purchasing requirements, and payment is 

officially refused. An opportunity to replace equipment is usually 

included as part of resolution.

3 Records

Laboratory Metrology staff maintain copies of purchasing documents, 

evaluation and approval records, and any applicable complaints according to 

retention policies. Applicable communications and forms are retained where 

possible. The OAAM, OWM office staff, and the PML Administrative Officer 

also maintain primary copies of official purchases. 

Calibration certificates received for standard calibration services are maintained 

electronically in the applicable sections of the OWM network system. 

Lists of acceptable suppliers are not maintained or specified in the OWM PT 

program due to government purchasing limitations.