VCAP Frequently Asked Questions

The Verified Conformity Assessment Program, or VCAP, is a program implemented by the National Conference on Weights and Measures to ensure continued compliance of certain device types with environmental requirements. These device types are ones for which performance can be affected by changes in their physical environment. The intent of the VCAP is to provide assurance that these devices perform at a level equal to or better than the device that was evaluated by NTEP.

Any device listed on a NTEP Certificate of Conformance whose performance can be affected by changes in its operating environment. Generally, these include load cells, digital weight indicators, weighing and load-receiving elements using load cells that do not have a NTEP certificate, complete scales, automatic weighing systems, belt-conveyor scales and automatic bulk weighing systems.

A device typThe National Conference on Weights and Measures (NCWM) and National Type Evaluation Program (NTEP) have been concerned about production meeting type, and protecting the integrity of the NTEP Certificate of Conformance since the inception of NTEP. The NCWM Board of Directors believes that the Verified Conformity Assessment Program addresses their concerns.e is a model(s) of a particular measuring system, instrument, element or field standard that positively identifies the design. A specific type may vary in its measurement range, size, performance and operating characteristics as specified in the NTEP Certificate of Conformance.

Any holder of an NTEP Certificate of Conformance for a device type listed above must comply with the program.

No, while the ISO 9000 series quality standards and VCAP share a number of common features, ISO certification is not required.

No. Although there are some similarities, VCAP extends into device compliance testing. Therefore, ISO certification alone is not an acceptable substitute.

The CC holder is responsible for providing proof of VCAP certification, by a certification body or NTEP auditor, to NTEP. NTEP will not pay any costs associated with accreditation, audits, testing or certification.

In the eyes of NTEP, the CC holder is responsible for the product, including taking responsibility for assuring that production devices meet type.  NTEP expects the CC holder to take responsibility for the integrity of the certificate and product (device, instrument, main element, component, etc.).  NTEP is expecting private label certificate holders to verify with the manufacturer under contract that VCAP requirements are being met.  It is expected CC holders will have QA procedures in place, including controls over the supplier, purchase and compliance of the product covered under the private label agreement.

If you are the manufacturer of the device, there are a number of requirements. They include:

  1. A Quality Management System that governs the design and manufacture of the device.  This Quality Management System must be documented in your Quality Manual.
  2. Facilities and equipment necessary for the production and subsequent testing of the device.
  3. You must identify those metrologically significant components (MSC) used in the device.  These are the components, materials, processes, and software that have an effect on the performance of the device when subjected to defined influence factors.  It is up to you as a manufacturer to identify these items.  To determine whether an item is metrologically significant or not you must ask whether a change in the characteristics of that item will affect the performance of the device.  If the answer is yes, then the item is metrologically significant.
  4. You must possess and use appropriate statistical tools or methods to ensure that the processes used to manufacture the device are in control.  This is commonly referred to as statistical process control and is a means to determine whether your processes are consistent and repeatable.
  5. An appropriate sampling plan along with the required acceptance criteria for testing of the device.  The sampling plan that you choose must be traceable to a nationally recognized quality standard.  Optionally, you may use the sampling plan that is presented in the VCAP program description found in the most recent edition of the NCWM, Publication 14, Administrative Policy.
  6. Possess the required operators’ manuals and calibration procedures for all appropriate production and testing equipment.  Of course, you must not only possess these manuals, you must also ensure that your operators are familiar with them and follow the procedures contained within them.
  7. A system to deal with nonconforming material and components, whether you purchase them or build them yourself.  This system must deal with the identification, control, and disposition of these items.
  8. Adequate controls over suppliers to ensure the material or components they supply meet the necessary requirements.
  9. A corrective action system designed and implemented to handle noncompliant or nonconforming material and components.
  10. An engineering change system to control engineering design changes that affect metrologically significant components.
  11. A document and data control system to document, record, and distribute to affected parties changes affecting metrologically significant components.
  12. A production control system that manages changes that affect metrologically significant components.
  13. A system that identifies and traces metrologically significant components.
  14. A training system for personnel with documentation to verify that the appropriate training has taken place.

Compliance with the VCAP can be verified by submitting to a VCAP audit of your manufacturing / testing facility by a VCAP auditor. The auditor will verify that the previously mentioned quality and control elements exist, are documented, and that the appropriate procedures are being followed. The auditor also verifies that the proper equipment needed to test and calibrate the devices you manufacture is present, sufficient for the task, and that they are being properly calibrated and operated. The audit will also include partial or complete testing of a randomly selected device. For that reason, it is best to schedule the audit at a time when devices are available for testing.

For manufacturers receiving their first NTEP Certificate of Conformance, NCWM has the responsibility to ensure that the manufacturers' VCAP certification has been completed, within a one year cycle of the first maintenance fee, but not to exceed 18 months, from the date the certificate was issued. (Example: if NTEP issued the certificate in July 2019, VCAP certification would be required by November 2020).

To perform a VCAP audit, the auditor must meet certain requirements.

  • The auditor must be part of a certification body that is accredited by ANSI-ASQ National Accreditation Board (ANAB) or an authorized representative of the NCWM/NTEP.
  • The certification body must have accreditation to Standard Industry Classification (SIC) codes 3596 and 3821 or Sequence Number 847 NAICS, US Code 333997, Scale and Balance Manufacturing defined in the 2007 North American Industry Classification System or equivalent accreditation. There are several certification bodies that have auditors qualified to perform VCAP audits. We cannot make any specific recommendations.

The NCWM Board has decided not to publish a list of certification bodies and/or auditors as it could appear the NCWM is recommending the companies or individuals.

It has been reported that the SIC codes and NAICS codes used are outdated.  Manufacturers are working to identify the correct codes.  This issue should not be a show stopper because the VCAP document already has the words “or equivalent”, recognizing other documents.

You are responsible for making certain that your supplier complies with the VCAP program. If your supplier fails to conform, their NTEP CC will ultimately become inactive as well as your private label certificate. One way to make sure your supplier complies is to ask that you receive a copy of the VCAP auditor’s report or certificate.

Yes, the CC holder is responsible for assuring that a documented quality management system, meeting VCAP requirements is in place, scheduling the VCAP audit, and providing NTEP with a certification body audit report containing a clear statement of compliance with VCAP.

The certification body is the organization that provides the auditor that performs the VCAP audit. It is the certification body that sends the auditor’s report to NTEP to show compliance with VCAP. The requirements for this report are listed in the VCAP Program Procedures of the Administrative Policy as shown in NCWM, Publication 14.

The VCAP audit is site specific. If there is more than one site where the testing of the device takes place, then each site must be audited. If the site does not perform any activities that affect the performance of the device and does not perform any device testing, it does not need to be subjected to a VCAP audit.

To ensure compliance with VCAP, the auditor may need to audit more than one site (for example: testing, control, manufacturing) if they are at different locations.

In this case, the factory has been identified as the control facility.  VCAP also requires that the CC holder have a documented quality management system governing the design and manufacture of the device.  The management system you describe may work and meet the requirements if adequate control can be verified.  Documentation of the quality management system and the decision of your auditor based upon the documentation and verification that the plan is working is critical, as an auditor may choose to conduct an audit at one or more sites to verify compliance.  It is important to recognize that VCAP Program Procedures address the sampling plan and testing of the finished device covered by the NTEP certificate.  The sampling plan applies to the device covered by the NTEP certificate, not the metrologically significant components.

No.  For example, if your company manufactures five different families of load cells each with its own NTEP Certificate of Conformance you must only submit to one VCAP audit.  Successful completion of the VCAP audit will apply to all five NTEP Certificates of Conformance.  During the audit, the auditor will know what NTEP Certificates of Conformance you are being audited for and will take the necessary steps to ensure that all are covered.  If, for example, you make load cells of different capacities, the auditor will ensure that you have testing equipment sufficient to apply the appropriate test loads to each model of load cell that you manufacture.

The basic concept of NTEP is that by accepting an NTEP Certificate of Conformance (CC), each NTEP CC holder agrees to continue to manufacture and sell devices that meet the current requirements of NIST Handbook 44 and the requirements described in the NTEP CC. Devices must show, by their markings, that they have an NTEP CC, and what tolerance values, class etc. the device meets. The NTEP CC holder has submitted a device which is typical of the production devices that will be manufactured and sold subsequent to the issuance of the NTEP CC. The intent of VCAP is to ensure that the NTEP CC holder has an acceptable Quality Management System in place for the requirements that must meet Influence Factors. For example: In the case of load cells this is mainly temperature effects on linearity, hysteresis, span, repeatability, zero (vmin or MDLO), and creep. This can also include effects of barometric pressure and in the case of digital load cells, effects of variation in power supply parameters.

The simple answer is that the audit, by the certification body, which is based on the parameters described in the VCAP procedures, will be the basis of evidence that the NTEP CC holder is capable of meeting those requirements. The VCAP procedure is loosely based on ISO 9001:2000. The procedure describes an audit of the quality management system, with an addition of objective evidence, in the form of audits on devices that indicate the capability of the device to meet the influence factor requirements. The audits of devices are conducted by the NTEP CC holder. If the auditor is convinced that the VCAP requirements are being met then a report or certificate indicating compliance would be issued and submitted to NTEP for review.

Handbook 44, Appendix A - Fundamental Consideration, Paragraph 3 Test Apparatus describes the accuracy of testing equipment and standards necessary to confirm NTEP compliance.

If the product does not meet applicable NIST Handbook 44 requirements, including tolerances, it cannot be sold for use in a commercial (legal for trade) application. What you do with nonconforming product should be addressed by your Quality Management System. Non-conforming devices must be re-worked to achieve conformance, scrapped or identified in some manner as non-commercial.  Non-conforming devices must NOT be sold for commercial use.

VCAP does not cover every component of a device, only those that are metrologically significant and are susceptible to influence factors identified in the appropriate code in NIST Handbook 44. For example, software can be considered a metrologically significant component but it is not affected by environmental influence factors. A manufacturer can chose to consider the complete device or main element to be metrologically significant.

Yes, the device manufacturer has the option of declaring the entire load cell as a metrologically significant component. In this case the entire load cell is then required to meet the requirement of a MSC.

It is up to the manufacturer to declare a component a MSC.  That could be an individual component or the assembly in which the component is used or the complete device.

Yes, they are separate requirements. The verification of a metrologically significant component (MSC) requires a change to a component identified as a metrologically significant part of the device to be verified and recognizes that MSC verification can take place by testing the finished device. The "sampling plan" deals with the testing of the finished device covered by the NTEP certificate.  

The sample sizes are based on annual production per Certificate of Conformance (CC).  If the CC lists several models or versions in a family (capacity, size, enclosure style, etc.), you could combine the yearly forecast for all to determine the total production quantity and then test a mix of the versions based on the minimum sample size.  VCAP also allows other national recognized quality standard sampling plans, that are Acceptable Quality Level (AQL).  The idea behind the AQL information is based on performing sample inspections of a fixed lot size of a product or part.  Again, in the case of VCAP, the lot size is the annual product quantity per CC. After determining the number of samples to be tested, selection and testing must be conducted in accordance to NCWM Publication 14.

The interpretation of the timeline for new certificate holders, ensure that VCAP certification has been completed, is within a one year cycle of  the first maintenance fee, but not to exceed 18 months (example: if  NTEP certified in July 2011, VCAP certification would be required by November 2012). 

Any nonconformities, be it major or minor, indicate a non compliant condition and must have corrective action taken within 90 days.  The difference between the two is that a minor noncomformity can be verified by the auditor via paperwork and may not require a revisit by the auditor whereas a major nonconformity does require a return visit.  Each nonconformance is unique but this is a general understanding.  At the time of the audit, the auditor may advise you of whether a follow up audit is required or if only a review of objective evidence is required to show that the nonconformities have been addressed.

Compliance testing must represent the test requirements as shown in NCWM, Publication 14.

NCWM, Publication 14Administrative Policy states the certificate(s) will be declared inactive. NTEP anticipates a certificate could also be withdrawn.

No. For example, if the auditor finds that you have sufficient production equipment to produce your full line of load cells but have testing equipment that can only test up to 5000 pounds, then only those load cells that require performance testing to loads greater than 5000 pounds will not comply. Failure to obtain the required testing equipment could ultimately result in the loss of the NTEP Certificate that covers the cells with capacities greater than 5000 pounds.

In response to this concern, the NTEP Committee has implemented a “Systems Audit Checklist,” which the auditor is required to complete and submit to NCWM.