MIL-HDBK-1022A
Table 2
APPURTENANCES
Item
Appurtenance
V-A
H-A
H-U
C-E
V-U
i
Ladders, railings, toeboards, a spiral
stairway, top platform, and handrail in
accordance with API Std 650 and OSHA
requirements. Provide stairways to access
high level shut-off and alarms.
Level Alarms
j
An individual automatic level alarm system,
*
*
independent of the gauging device or system
for each tank. Include high, high-high, and
low level alarms. On aboveground tanks: a
manual tester for all floats to ensure system
operability without a full tank; locate level
alarm equipment for ready access from
stairways and platforms; and high-level will
be 95 percent and high-high will be 98
percent. For underground tanks, high and
high-high will be 90 and 95 percent,
respectively. Provide both audible and
visible alarms. Set low level alarm such that
air is not allowed into the system. In
determining the low level, consider the time
it would take for the pump or system to shut
down. Review facility size and operating
method to determine the most audible and
visible location of alarms, usually in the
tank farm and in the operations building.
Connect to stop issue pump on low level alarm
and receipt pump (if in facility) on high
level alarm. Comply with most stringent of
local, state, or federal regulations.
Vents
LEGEND:
141
V-A
=
Vertical Aboveground Storage Tank
H-A
=
Horizontal Aboveground Storage Tank
H-U
=
Horizontal Underground Storage Tank
C-E
=
Aboveground Concrete-Encased Storage Tank
V-U
=
Vertical Underground Storage Tank
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