Page 461 - 2018_IFC

FLAMMABLE AND COMBUSTIBLE LIQUIDS

within a diked area or drainage path for a tank or 5704.2.9.7 Additional requirements for protected
tanks storing Class I or II liquids. Where a Class above-ground tanks. In addition to the requirements
IIIB liquid storage tank is within the diked area of this chapter for above-ground tanks, the installation
or drainage path for a Class I or II liquid, dis- of protected above-ground tanks shall be in accordance
tances required by Section 5704.2.9.6.1.1 shall with Sections 5704.2.9.7.1 through 5704.2.9.7.9.
apply.
5704.2.9.7.1 Tank construction. The construction
5704.2.9.6.1.6 Reduction of separation dis- of a protected above-ground tank and its primary
tances to adjacent property. Where two tank tank shall be in accordance with Section 5704.2.7.
properties of diverse ownership have a common
boundary, the fire code official is authorized to, 5704.2.9.7.2 Normal and emergency venting. Nor-
with the written consent of the owners of the two mal and emergency venting for protected above-
properties, apply the distances in Sections ground tanks shall be provided in accordance with
5704.2.9.6.1.2 through 5704.2.9.6.1.5 assuming a Sections 5704.2.7.3 and 5704.2.7.4. The vent capac-
single property. ity reduction factor shall not be allowed.
5704.2.9.6.2 Separation between adjacent stable 5704.2.9.7.3 Secondary containment. Protected
or unstable liquid tanks. The separation between above-ground tanks shall be provided with second-
tanks containing stable liquids shall be in accor- ary containment, drainage control or diking in accor-
dance with Table 22.4.2.1 of NFPA 30. Where tanks dance with Section 5004.2. A means shall be
are in a diked area containing Class I or II liquids, or provided to establish the integrity of the secondary
in the drainage path of Class I or II liquids, and are containment in accordance with NFPA 30.
compacted in three or more rows or in an irregular 5704.2.9.7.4 Vehicle impact protection. Where
pattern, the fire code official is authorized to require protected above-ground tanks, piping, electrical con-
greater separation than specified in Table 22.4.2.1 of duit or dispensers are subject to vehicular impact,
NFPA 30 or other means to make tanks in the inte-
rior of the pattern open for fire-fighting purposes. they shall be protected therefrom, either by having
the impact protection incorporated into the system
The separation between tanks containing unsta- design in compliance with the impact test protocol
ble liquids shall be not less than one-half the sum of of UL 2085, or by meeting the provisions of Section
their diameters.
312, or where necessary, a combination of both.
Exception: Tanks used for storing Class IIIB liq- Where guard posts or other approved barriers are
uids are allowed to be spaced 3 feet (914 mm) provided, they shall be independent of each above-
apart unless within a diked area or drainage path ground tank.
for a tank storing Class I or II liquids.
5704.2.9.7.5 Overfill prevention. Protected above-
5704.2.9.6.3 Separation between adjacent tanks ground tanks shall not be filled in excess of 95 per-
containing flammable or combustible liquids and cent of their capacity. An overfill prevention system
LP-gas. The minimum horizontal separation shall be provided for each tank. During tank-filling
between an LP-gas container and a Class I, II or IIIA
liquid storage tank shall be 20 feet (6096 mm) operations, the system shall comply with one of the
except in the case of Class I, II or IIIA liquid tanks following:
operating at pressures exceeding 2.5 psig (17.2 kPa) 1. The overfill prevention system shall include
or equipped with emergency venting allowing pres- the following:
sures to exceed 2.5 psig (17.2 kPa), in which case 1.1. An independent means of notifying the
the provisions of Section 5704.2.9.6.2 shall apply.
person filling the tank that the fluid
An approved means shall be provided to prevent level has reached 90 percent of tank
the accumulation of Class I, II or IIIA liquids under capacity by providing an audible or
adjacent LP-gas containers such as by dikes, diver- visual alarm signal, providing a tank
sion curbs or grading. Where flammable or combus- level gauge marked at 90 percent of
tible liquid storage tanks are within a diked area, the tank capacity, or other approved
LP-gas containers shall be outside the diked area means.
and not less than 10 feet (3048 mm) away from the
centerline of the wall of the diked area. 1.2. Automatic shut off of the flow of fuel
to the tank when the quantity of liquid
Exceptions:
in the tank reaches 95 percent of tank
1. Liquefied petroleum gas containers of 125 capacity. For rigid hose fuel-delivery
gallons (473 L) or less in capacity installed systems, an approved means shall be
adjacent to fuel-oil supply tanks of 660 gal- provided to empty the fill hose into the
lons (2498 L) or less in capacity.
tank after the automatic shutoff device
2. Horizontal separation is not required is activated.
between above-ground LP-gas containers 2. The system shall reduce the flow rate to not
and underground flammable and combusti- more than 15 gallons per minute (0.95 L/s) so
ble liquid tanks.
that at the reduced flow rate, the tank will not
overfill for 30 minutes, and automatically shut

428 2018 INTERNATIONAL FIRE CODE ®
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