If A2LA wants something they should be able to define it and tell their customer (you laboratory) what it is they want. Some things are not definable. How do you put an uncertainty on insulation thickness measurements when the value is given by a vendor to your specifications? Put the shoe on A2LA's foot. Did they walk the walk or are they just asking with the hope you will solve it for them? How does one know what is acceptable if it is not defined? Unless they define what is acceptable up front you could make a lifetime carrier of mathematical assumptions and computations. Sometimes a little push back on unreasonable requests is in order.
Best treatment of the subject is given by EA-4/02 written first by ECMA then improved by EA (The European Co-operation for Accreditation) but it doesn't really solve your problem since uncertainty of most safety requirements are either unsolvable or so many assumptions are required the results of the computations are meaningless. Se if A2LA knows how to do it first before they require their customer to try to explain the uncertainty of a product safety test. Dave George Unisys -----Original Message----- From: Ned Devine [mailto:[email protected]] Sent: Friday, April 28, 2000 2:38 PM To: IEEE EMC/Product Safety (E-mail) Subject: Measurement Uncertainty for product safety tests Hi, One of the accreditations our lab has, is from the American Association for Laboratory Accreditation (A2LA). A2LA has recently mandated that we determine the measurement uncertainty for all of the tests we do. I have been assigned the task of determining the measurement uncertainty for the "normal" product safety tests. I have talked to a number of people, but all I get are different answers. Some say to just pick an uncertainty based on your judgment. Others say it is a mathematical derived number based on the accuracy of the equipment used. Still others say it is a combination of the first two. Has any one done this or knows how to do it? Thanks Ned Devine Entela, Inc. Program Manager III Phone 616 248 9671 Fax 616 574 9752 e-mail [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
