Meridian America 61 Benutzerhandbuch

Failure  rate-Failure rate equals the estimated number of failures for that
item during one million 

 hours of operation. The only exception is to

measurements for cabling or other items with low failure rates. Rates are

also measured in Failures in Time (FIT) measurements. One FIT equals one

billion 

 hours of operation.

. .

Sparing interval-The  sparing interval is the period of time that stocks of

replaceable items should last without being replenished. This period is

assumed to be one year following the installation of the system.

Stock confidence  level-The stock confidence level is the allowed

probability of not being out of stock when the sparing interval of one year is

greater than 99.9 percent.

Pack ambient temperature-The  pack ambient temperature is the average
temperature of the air immediately surrounding the circuit pack (usually
higher than the ambient room temperature). Pack failure rates in this
document are based on a pack ambient temperature of 

 C.

Spares planning 553-3001-153