12
In a nontraffic installation, ensure that the areas above the
tanks are not subjected to traffic or other types of loads,
which could cause tank damage and result in death or
serious injury.
5.1.5.3. The maximum burial depth is 7 feet of cover over the
top of the tank. Deviation from this may be permissible with prior
written authorization from Xerxes. Call your Xerxes representa-
tive for a special quotation prior to tank purchase if the burial
depth is to be greater than 7 feet.
5.1.5.4. Asphalt and concrete pads must extend a minimum of
12 inches beyond the tank in all directions.
5.1.5.5. An unattached manway riser (if present) must not
transmit load from the concrete slab to the tank. A minimum
space of 6 inches must exist between the bottom of the riser
and the top of the tank.
5.1.5.6. Traffic loads from the top slab must not be transmitted
to an attached sump or riser. A minimum space of 3 inches must
exist between the riser or sump and the slab.
5.2. TANK SPACING
5.2.1. GENERAL
5.2.1.1. The following are minimum spacings and must be
increased as needed to accommodate deadmen or anchor
slabs.
(See SECTION 6.)
5.2.1.2. Always provide sufficient clearance to allow the deadmen
to be set outside of the tank “shadow.”
(See FIGURE 5-3.)
FIGURE 5-3
5.2.2. STABLE IN SITU (NATIVE) SOIL CONDITIONS
5.2.2.1. Where shoring is not required to maintain a vertical wall
from top to bottom of the excavation, and where the soil is
stable, the minimum spacing between the sidewall or endcap
of the tank and the side of the excavation must be 18 inches
[24 inches for 12-foot-diameter tanks].
Tank Shadow
Width
(See TABLE 6-1.)
2 x Width
12-foot-diameter tanks] plus 6 inches of reinforced concrete or
9 inches of asphalt.
(See FIGURE 5-1.)
In a wet condition,
sufficient overburden and/or an appropriate anchoring
system must be present to offset buoyancy of the tank.
FIGURE 5-1
5.1.5.2. Tanks not subjected to traffic loads must have a cover
depth of at least 24 inches of backfill [48 inches for 12-foot-
diameter tanks], or 12 inches of backfill [36 inches for 12-foot-
diameter tanks] plus 4 inches of reinforced concrete or 6 inches of
asphalt.
(See FIGURE 5-2.)
In a wet condition, sufficient
overburden and/or an appropriate anchoring system must
be present to offset buoyancy of the tank.
FIGURE 5-2
No
Traffic
24”
[48”]
12”
[36”]
12”
4”
Concrete
6”
Asphalt
Note: Number in brackets refers to 12-foot-diameter tanks.
36”
[48”]
18”
[36”]
9”
Asphalt
6”
Concrete
12”
Traffic
Note: Number in brackets refers to 12-foot-diameter tanks.
