KTA-TATOR,
INC.
Corporate Headquarters
115 Technology Drive
Pittsburgh, PA 15275
Phone: 412.788.1300
Fax: 412.788.1306
E-mail:
info@kta.com
Instrument
Sales
1-800-KTA-GAGE
Lead
Hotline
1-800-LEAD-OFF
News and Articles
KTA's 56 plus years in the corrosion industry has provided its clients with invaluable knowledge and experience. This knowledge and experience translates into value for today's customers.
With trained and experienced professionals, we can draw on a vast knowledge base to solve complex problems, recommend and implement solutions, and provide continued support and training.
CALIBRATION AND VERIFICATION OF ACCURACY
We hear, say, read, and write words like "calibration, verification, adjustment, and verification of accuracy, …;" But do we really know what the mean? This is further complicated because different organizations define them differently.
This article is an attempt to provide the current definitions related to control of instruments and an explanation of each.
Calibration
- Calibration (from SSPC-PA2) - The controlled and documented process of measuring traceable calibration standards and verifying that the results are within the stated accuracy of the gage. Calibrations are typically performed by the gage manufacturer or by a qualified laboratory in a controlled environment using a documented process. The standards used in the calibration are such that the combined uncertainties of the resultant measurement are less than the stated accuracy of the gage.
- Calibration (from ASTM D7091) - The high-level, controlled an documented process of obtaining measurements on traceable calibration standards over the full operating range of the gage, then making the necessary gage adjustments (as required) to correct any out-of-tolerance conditions.
- Calibration (from ISO 17025) - Performed under a set of specified and controlled measurement conditions, and with a specified and controlled measurement system.
Simply put, calibration is performed by the manufacturer or a certified
laboratory (typically ISO 17025 or A2LA, ISO 9001, NIST, etc.). A certificate
of calibration showing traceability to a national standard can typically
be issued. The frequency of calibration is typically established by the
manufacturer.
Verification of Accuracy
- Verification of Accuracy (from ASTM D 7091) - Obtaining measurements on a reference standard prior to using the gage for the purpose of determining the ability of the coating thickness gage to produce reliable values, compared to the combined gage manufacturer's stated accuracy and the state accuracy of the reference standard.
- Verification (from SSPC PA-2) - An accuracy check performed by the user using known reference standards.
- Verification (from ISO 17025) - Confirmation by examination and provision of objective evidence that specified requirements have been fulfilled.
Verification of Accuracy or verification can be performed in the field or in a facility (such as KTA). In the field, verifying the DFT gage on the NIST plates or shims is considered verification of accuracy. This can also occur in a facility on a periodic basis to determine if instruments are functioning properly or whether they need to be returned to the manufacturer for calibration.
For DFT gages both SSPC PA-2 and ASTM D 7091 require verification of accuracy before, during and after each use.
Typically if a gage or instrument cannot be verified as accurate in the facility or the field, it is removed from stock and repaired or replaced.
Accuracy
- Accuracy (from SSPC PA-2) - Consistency between a measured value and the true value of the thickness standard.
- Accuracy (from ISO 17025) - Is a qualitative indication of the ability of a measuring instrument to give responses close to the true value of the parameter being measured. Accuracy is a design specification and may be verified during calibration.
SSPC PA-2 requires that gages have a stated accuracy of at least +/- 5% in order to qualify for use. Note however that some Type 1 (magnetic pull-off) gages may not, and reference to this standard in a specification may preclude a contractor or other inspector from using certain gages. Pen type gages (a.k.a. pencil pull-off gages) have been eliminated from the standard, as they cannot be calibrated or adjusted, and do not meet the +/- 5% accuracy requirement.
Adjustment
- Adjustment (from SSPC PA-2) - The act of aligning the gage's thickness readings to match those of a known sample in order to improve the accuracy of the gage on a specific surface or in a specific portion of its measurement range. Most Type 2 gages can be adjusted on a coated part or on a shim, where the thickness of the coating or of the shim is known.
Calibration and verification of accuracy are performed on "smooth" plates or shims to confirm gage accuracy. Adjustment aligns the gage to the actual conditions (i.e., the profile of the roughened steel). Adjustment is an attempt to make the gage read more accurately over a roughened surface such as that created during blasting.
SSPC PA-2 Appendix 2 provides the user with expanded guidance on methods
to adjust electronic coating thickness gages, including a single point
adjustment procedure (i.e., using a single shim representative of the
anticipated coating thickness measurement) and a two-point adjustment
procedure (i.e., using two shims representative of the lower and upper
range of coating thickness measurement).
Eric Kline, Alison Kaelin, Bill Corbett, Ken Trimber
Ms. Alison B. Kaelin was named an ASQ - Certified Quality Auditor (CQA) on December 12, 2005, by the Certification Board of the American Society for Quality (ASQ). This certification is in recognition of Alison's expertise in quality audit tools and techniques. She has been serving as KTA's Quality Assurance Manager for the past three years and during this time has played a critical role in the development and implementation of KTA's QA/QC procedures and policies, and maintenance of KTA's SSPC QP-5 certification.
KTA Professionals Eric S. Kline, Alison B. Kaelin, William D. Corbett, and Kenneth A. Trimber were honored with awards at PACE 2006 (Paint and Coatings Expo) on Sunday, January 29, 2006. The awardees are discussed in the order pictured from left to right.
Eric Kline, Executive Vice President, was recognized for his contribution as the Chair of the Education Advisory Committee and to the success of PACE 2006. Eric has been chairing this Committee for the past 3 years.
Alison Kaelin was selected by the SSPC: Society for Protective Coatings as the 2005 recipient of the prestigious Technical Achievement Award. This award recognizes outstanding service, leadership and contribution to the SSPC technical committees and other technical functions. Given annually since 1985, Alison joins a short list of 20 industry professionals who have received this distinguished award.
Bill Corbett, Technical Service Manager, was the recipient of SSPC's Coatings Education Award. This honor recognizes the efforts of an individual who has advanced the industry through his/her educational activities. This recognition comes as a result of Mr. Corbett conducting numerous training sessions each year for various industry professionals as well as for his many technical papers and presentations.
Ken Trimber, President, was honored with one of the Journal of Protective Coatings & Linings (JPCL) Editors' Awards for the following article, "Streamlining the Specification Development Process for Bridge Painting." This article was published in JPCL in February 2005.
Congratulations to all!
On Wednesday,
Feb. 8, 2006, Bill Wallhausser was recognized with the Lifetime Achievement
Award by the 39th Annual Mid-Atlantic Region Quality Assurance Workshop
(QAW) at its meeting in Norfolk, Virginia. The QAW is sponsored by the
Federal Highway Administration and the State Department of Transportation
agencies in Delaware, District of Columbia, Maryland, New Jersey, Pennsylvania,
Virginia and West Virginia. The mission of the QAW is “to promote
and adopt beneficial and cost effective new transportation technologies
and to implement proactive policies, practices and procedures that contribute
to increased life of the transportation infrastructure at a minimum overall
cost.”
The Lifetime Achievement Award from the QAW acknowledged Bill’s efforts and contributions to the bridge industry. The award citation reads, “In grateful appreciation and admiration of your lifetime contribution to Steel Bridge Fabrication and Quality Assurance. Given by your friends and colleagues.”
Below are a few articles from KTA's eNews. Please visit eNews for the latest month's edition.
-
KTA Coating Consultant Jim Machen discusses a case involving a coating failure on the painted structural steel and steel roof joists of an outdoor parking facility.
- New Safety and Health Program
Requirement Being Implemented by Industrial Facilities
Many facility owners of Petrochemical Refineries are now requiring contractors to have and implement a safety and health program that meets the criteria of 29 CFR 1910, General Industry Standard. KTA's Environmental, Health & Safety Group will assist you in preparing for this new requirement.
- OSHA to Include Hearing Loss
Column on Recordkeeping Form in 2004
In conjunction with new recordkeeping standards currently in effect, the Occupational Safety and Health Administration (OSHA) will require employers to address hearing loss on its recordkeeping form beginning 2004.
To keep informed and to have industry news delivered directly to your IN box with more great articles and news from KTA and the industry, please sign up below to subscribe to future mailings.
Subscribe to KTA's Black & Gold Club
Be part of the KTA Black & Gold team.
- Be the first to know about new instruments offered at KTA and special sales events.
- Receive tips for using your inspection instruments.
- Find out what KTA's state-of-the art, fully equipped laboratory is up to in the R&D arena.
- Stay informed with training classes from KTA.
© 2004 KTA-Tator,
Inc. All Rights Reserved. Privacy
Statement
Site maintained by KTA. webmaster@kta.com
Best viewed with Microsoft Internet Explorer
