backup. This provides a spare detector in the event of failure of one of the primary detectors
and also allows verification if the two primary detectors provide different readings. A.12.9 Where gas must be released intermittently or in an emergency, a discharge directed
upward at high velocity will safely dissipate the gas. Leveroperated relief valves often can
be used for this purpose. An ignited flare is permitted in LNG facilities if local conditions
warrant. A.13.6.6 For information on corrosion protection, see NACE RP 0169, Control of External
Corrosion on Underground or Submerged Metallic Piping Systems. A.13.18.3.2 Extinguishment of gaseous fires can cause a buildup of flammable vapors that
can result in an explosion causing damage beyond that resulting from the fire itself. Normally
the best method for suppression of a gaseous fuel fire is shutoff of the fuel supply, which
results in extinguishment of the fire by fuel starvation. In cases where the control equipment
is involved in the fire or where damage to equipment or structures will result in loss of
control or loss of life, the fire may need to be extinguished. In those cases, vapor control
must be implemented immediately to prevent an accumulation of vapors that could result in
an explosion. A.14.1 Because of many variables, it is not possible to describe in a national standard a set
of operating and maintenance procedures that will be adequate from the standpoint of safety
in all cases without being burdensome or, in some cases, impractical. A.14.2.2(6) Definitions of safetyrelated malfunctions are given in 49 CFR 191 for LNG
plants under the jurisdiction of the U.S. Department of Transportation under 49 CFR 193.
A.14.4.6.1 If an LNG facility is designed to operate unattended, it is recommended that
alarm circuits that can transmit an alarm to the nearest attended company facility be provided
to indicate abnormal pressure, temperature, or other symptoms of trouble. A.14.6.1 For information on operation of piers, docks, and wharves, see NFPA 30, Flammable and Combustible Liquids Code. A.14.8.1.1 Where gas must be released intermittently or in an emergency, a discharge
directed upward at high velocity will safely dissipate the gas. Leveroperated relief valves
often can be used for this purpose. An ignited flare is permitted in LNG facilities if local
conditions warrant. A.14.12.4 API RP 651, Cathode Protection of Aboveground Petroleum Storage Tanks, provides guidance in the use of cathodic protection