ACCREDITATION ISO17025Calibration level

Quality in Calibration Mixtures

P.Boermans Maastricht February 2002

www.praxair.comPraxair and the Flowing Airstream design are trademarks or registered trademarks of Praxair Technology, Inc in the United States and/or other countries Other trademarks used herein are trademarks of their respective owners

Application of Calibration Mixtures

• Crucial role in the Calibration of Lab- and Proces analytical Equipment used in:

• Chemical - Petrochemical Industries

• Refineries

• Natural Gas Processors

• Environmental applications:

• Stack Emission

• Ambient Air control

• Personal protection

• Workplace and Safety Monitoring

Application of Calibration Mixtures

• High versatility of requirements in these applications:

• Multicomponents in different hydrocarbon matrices for QC of raw material (propylene,ethylene,…..)

• Process control of cracker fractions• LEL mixtures for explosimeters• Multi-emission (NO-CO-CO2-SO2 in N2)• Volatile Organics• Benzene, HCl, HF, HCN, NH3, ……..

Quality of Calibration Mixtures

• Enduser expects despite this versatility in components and concentrations:

• Reliable (low) uncertainty in certification• Consistent quality• (Long term) Stability• Traceability of the certification result

……for his specific application

Quality of Calibration Mixtures

• Quality fullfillment in function of this versatility in needs :

• Quality systems under ISO 9000 / QS 9000

• Specific acceptance protocols between producer <--> enduser

• ISO17025 accreditation at calibration level….. Driven by

Quality of Calibration Mixtures

• Legislation

• Capabilities of (inter)national Metrology Institutes or Labs (NMI, LNE, NPL, NIST,…)

• Quality Systems at endusers (ISO 9000, ISO17025 Testing level,…..)

Calibration Mixtures:Quality under ISO 9000

• Typical for the Chemical and Petrochemical Industries:

• Large variety in compositions

• Concentration ranges from low ppm to high %

• Critical Processes like f.e.:• Monitoring of Product Quality• Monitoring of Proces Safety• Explosion risk control

Preparation of Calibration Mixtures:Certified Standard

• Filling on basis of weight,volume(@21°C,1 atm) or partial pressure

• Specific filling manifolds for:- Hydrocarbons,CO,CO2,H2,...- Inerts- Nox, HCl, SO2, H2S, NH3, HF COCl2- Liquids

• Calibrated weights,volumes and manometers

• ISO 9002 follow up system of measuring tools - calibrationfrequency and uncertainty level

Certified Standard:Certification method

• Reference Standards• Volumetrical (ISO 6144)• Gravimetrical (ISO 6142 NBN T97-101 VDI 3490)• External Standards (NMI - NIST -, …….)

• Calibration method• Comparison method (ISO 6143)

• Certificate of Analysis• Conform ISO 6141

Certified Standard:Certification method

• ISO 6143

• dCx/Cx < (dCe/Ce)2+(dYe/Ye)2+(dYx/Yx)2

dCx/Cx rel.error on [Cx] in the sampledCe/Ce rel.error on [Ce] in reference material dYe(x)/Ye(x) rel.error outputsignal sample & reference

• dYe(x) = Sy x t / n Sy standard deviation analytical result

t Student-Fisher for 2σ probability n number of analytical results

External StandardMass

Primary Standard

Stock of PrimaryStandards

External Reference Standards

Other CertifiedReference Standards

Preparation ofCalibration Mixtures

(W V P)

Analytical validation

Certification

Traceability: Certified Standard

Internal ManagementReference Standards

ISO 6142

ISO 6143

ISO 6141ISO 6144ISO 6145

25/2/99/mb

Calibration Mixtures:Quality under Acceptance Protocol

• Example: Synthetic Natural Gas

• Low uncertainties required

• Determination of composition for Wobbe index calculation of the Natural gas stream

• Traceability to an accredited level (EN45000 / ISO 17025 calibration level)

• NMI• EffecTech

High Accuracy Gravimetric Standard:Gravimetrical Preparation

• Analytical balance (100 kg capacity - 10 mg sensitivity)

• Identification and follow up of all uncertainties in the filling process

• Uncertainty calculation accordong Guideline EAL-R2

• Filling Procedures according ISO 6142

• Operational– Weights OIML Class 2

– Resolution 105 - 107

– Checkups:• Linearity

• Reproductibility

• Sensitivity

• Quality– Components with

known impurities– Validation (analytical)

• Error sources– Buoyancy– P,T,humidity– Molar mass– Cylinder expansion– Effects on fill lines

• Stability– Chemical stability of the

components– Cylinder choice

High Accuracy Gravimetric Standard: Preparation Method: ISO 6142

• Traceability (ISO,OIML,BIPM) is the characteristic of a measuring result to be related to an unbroken chain of national and international standards,each with their respective uncertainties

• Direct relation to mass

• Calibrated reference weights (BKO - NMI)

• Controlled conditions of P and T (climatisation)

• Operational procedures (ISO 9002) and follow up of measuring tools

• Filling- and control procedures according ISO 6142

• Error calculation (EAL-R2)

• Analytical Validation Protocol with traceability to recognised Metrological level (NMI, Effectech / NPL)

High Accuracy Gravimetric Standard: Traceability Aspects

High Accuracy Gravimetric Standard: Certification method

Considering all error sources , their uncertainties and the acceptance criteria of the Analytical Protocol

[MOL]A = MRA / A

N Mf

[MOL]A Molar fraction of component A

MRA Number of mol A (real purity)

A

N Mf Total number of mol of all

components incluve theirimpurities

Traceability: Gravimetric StandardQuality Controlpure products

Calculation and iterationof filling weights

Filling on Voland(ISO 6142)

Internal and/or externalReference Standard

AnalyticalQuality Control

(ISO 6143)

Validation Protocol

CertificationError calculation

(ISO 6141en ISO 6142)

External StandardMass

Certified StandardISO 6142

16/10/00 Rev 1

Example for Synthetic Natural Gas

Calibration Mixtures:Quality under EN 45000 (Calibration level)

• Accreditation: What is it ??• Protection of consumers by certification of products

and manufacturing under certified qualitysystems,checked and audited by accreditation bodies

• Accreditation bodies are under the umbrella of EA (European Accreditation) and can demonstrate that they operate an accreditation system compatible with EN 45003 or ISO/IEC Guide 58

• EA members signed multilateral agreements (see Publication reference EA-01/08)

Accreditation Equivalencies: Example for Benelux - France - Germany

Accreditation

European Accreditation

Mi.Ec.Za RVA COFRAC DAR

BKO

Beltest

Belcert

NKO

Sterlab

BKO Calibration

Certification

Environment

Test

Certification

Environment

MLA = Multi Lateral Agreement (EAL-S3) MRA = Multi Regional Agreement

Belcert,...EN 45011, ISO 9000

Environment,....EN 14000

DKD

PTBDAPDATech

DEKITZ

BKO,....EN 45001 --> calibration

Beltest,....EN 45001 --> testing

Calibration Mixtures:Quality under EN 45000 (Calibration level)

• Environmental Monitoring Applications

• Labs operating under EN 45000 Testing level• Basis for uniformity in analytical results• Highest quality and traceability level (“End product”)

EXTERNAL

AUDIT HIGH ACCURACYANALYTICAL GRAVIMETRIC VALIDATION PROCES PROCES

METROLOGICAL TRACEABILITY

Accreditation ISO17025 in Oevel by the BKO

• Project approved mid 1999• Dossier sent to BKO March 2000• Preaudit November 2000• Corrective measures + adaption dossier• Final audit July 2001• Final corrections• Approved September 2001• Official signature of Ministery end October 2001• Official Certificate end November 2001 • First scope extention in 2003• Major re-audit in Q4 2004• Second scope extention planned for Q4 2005

Accreditation ScopeAccreditation Scope

Analyte Balance Range(mol)

Uncertainty(% rel)

CO N2 or Air 5 ppm - 20% 1% - 0,2%

CO2 N2 or Air 100 ppm - 50% 0,5% - 0,2%

C3H8 N2 or Air 1 ppm - 10% 1% - 0,2%

NO N2 1 ppm - 1% 20% - 0,4%

O2 N2 or Air 0,1% - 25% 0,5% - 0,2%

CH4 N2 or Air 1 ppm - 0,1% 20% - 0,2%

SO2 N2 or Air 50 ppm - 200 ppm 2% - 1%

Thanks for your attention !

Questions ???