Hi, At the last two NEBS conferences Mike Bentley of USWest stated that all he was concerned about was the EUT performance at high temperature. What changes at altitude is the heat capacity of air. Thus it becomes more difficult to cool equipment because the air is "thin". USWest is the RBOC which is most concerned with this test as they are the only one to my knowledge with COs above 12,000 feet.
We run the altitude test at 50C for frames and 55C for shelves. We allow the EUT to stabilize within the chamber and we also determine the temperature at which equipment starts to fail in the event that the EUT has a problem at the extreme temperature. AT&T NEDS does have a non-operational test at 40,000 feet which we run at ambient temperature and humidity as an unpressurized airplane bay is unlikely to be very hot.. BTW, the next NEBS conference is in Baltimore next week. See www.800teachme.com for details. -Jon Curtis David Spencer wrote: > Hi Jeffrey, > Our friends at Telcordia do seem to enjoy listing requirements where we > would least expect them. GR63 is no exception. For altitude, the limits > called out in R4-8 [74] and O4-10[76] for Table 4-4 are the general > temperature/humidity limits for long and short term exposure. The > application of those criteria can be found in Table 4.5 in the 182 hour > profile. > > It is my belief that you test to at 4000m using the profile from table 4.5, > unless you wanted to make a profile of your own that covered the same ground > over a longer period of time, using Table 4-4 for the limits, rates of > change, and duration. If the EUT cannot tolerate the resulting temperature > rise from the 4000m altitude, it will be necessary to retest at 1800 to meet > R4-8. The failure is documented in the NEBS data submitted to the carrier > who decides if it is something he wants you to do something about before he > purchases you equipment. I do not think it is necessary to test 1800m if > you have passed the table 4-5 profile at 4000m. > > Don't forget: Objective requirements are not elective. The tests must be > performed and the results documented. It is by this means that decisions > are made about making the objective a mandatory requirement down the road. > > Good Luck! > Dave Spencer Compliance Engineer > Oresis Communications, Inc. > 14670 NW Greenbrier Parkway, Beaverton, OR 97006 > * [email protected] * http://www.oresis.com > * (503) 466-6289 * (503) 533-8233 > > -----Original Message----- > From: Collins, Jeffrey [mailto:[email protected]] > Sent: Monday, September 25, 2000 6:36 AM > To: '[email protected] ' > Subject: NEBS: GR-63 Altitude Test Profile > > Group, > > GR-63 sections 4.1.3 & 5.1 do not give a definitive testing profile for > Altitude testing. If you have completed this test what profile did you use? > Is there a customer specification from an RBOC or CLEC that you found to be > definitive. It appears that by only addressing these sections you could have > to retest down the road for a customer located in a high altitude > environment. Which Telco has the most stringent internal specifications for > this test? > > Points to be considered are: > > * Max Altitude > 4000m > > * Temperature at max Altitude > Profile in Table 4-5 > > * Relative Humidity > Profile in Table 4-5 > > * Length of time at Max Altitude > 182 hrs > > Thanks in advance, > > Jeffrey Collins > MTS, Principal Compliance Engineer > Ciena Core Switching Division > [email protected] > www.ciena.com > > ------------------------------------------- > 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] -- Jon D. Curtis, P.E. Director of Engineering Curtis-Straus LLC One Stop Laboratory for NEBS, EMC, Product Safety, and Telecom Testing. 527 Great Road Littleton, MA 01460 USA Voice 978-486-8880 Fax 978-486-8828 email: [email protected] WWW.CURTIS-STRAUS.COM ------------------------------------------- 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]
