A control room received a tank lower flammability limit (LFL) analyzer low sample flow alarm. The control room operator initiated the appropriate alarm response procedure and the facility entered limiting conditions of operation. At the time of the alarm, the facility was experiencing severe weather and the field operator was unable to investigate the alarm in the field. After the severe weather cleared, the field operator investigated the alarm and found the sample flow to be low and out-of-limits.

At the given facility, composite lower flammability limit (CLFL) monitors are used to detect the presence of hydrogen and other flammable gases in waste tank vapor spaces. Maintaining the concentration of flammable vapors in tank vapor spaces below CLFL levels maintains tank view more