Hello from San Diego:
Most IEC standards specify limits for the ambient temperature, relative humidity, and barometric pressure at the time of type testing. Pete Poulos asks about recording these parameters. His message implies some doubt as to the value of these parameters. I believe the IEC committees did not think through the environmental requirement. It is necessary to control the environment only when the parameter being measured could be influenced by the environmental parameter, be it ambient temperature, relative humidity, or barometric pressure. When making temperature tests of the equipment, it is essential to know the ambient temperature in order to standardize the test. When making temperature tests, barometric pressure COULD influence the temperature test results IF the pressure was very low. But, I suspect such pressure would be too low for effective human function. When making temperature tests, relative humidity is not likely to have any effect. Similarly, when making hi-pot tests, barometric pressure will influence the results, while temperature and humidity will have much less effects. Clearly, the mechanical impact and drop tests are not influenced by temperature, pressure, or humidity. In my opinion, it would be far better to specify the environmental requirements for each test rather than for all tests. Best regards, Rich ------------------------------------------------------------- Richard Nute Quality Department Hewlett-Packard Company Product Regulations Group San Diego Division (SDD) Tel : 619 655 3329 16399 West Bernardo Drive FAX : 619 655 4979 San Diego, California 92127 e-mail: [email protected] -------------------------------------------------------------
