[Code of Federal Regulations]
[Title 29, Volume 8]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1926.152]
[Page 189-204]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1926_SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION--Table of Contents
Subpart F_Fire Protection and Prevention
Sec. 1926.152 Flammable and combustible liquids.
(a) General requirements. (1) Only approved containers and portable
tanks shall be used for storage and handling of flammable and
combustible liquids. Approved safety cans or Department of
Transportation approved containers shall be used for the handling and
use of flammable liquids in quantities of 5 gallons or less, except that
this shall not apply to those flammable liquid materials which are
highly viscid (extremely hard to pour), which may be used and handled in
original shipping containers. For quantities of one gallon or less, the
original container may be used, for storage, use and handling of
flammable liquids.
(2) Flammable or combustible liquids shall not be stored in areas
used for exits, stairways, or normally used for the safe passage of
people.
(b) Indoor storage of flammable and combustible liquids. (1) No more
than 25 gallons of flammable or combustible liquids shall be stored in a
room outside of an approved storage cabinet. For storage of liquefied
petroleum gas, see Sec. 1926.153.
(2) Quantities of flammable and combustible liquid in excess of 25
gallons shall be stored in an acceptable or approved cabinet meeting the
following requirements:
[[Page 190]]
(i) Acceptable wooden storage cabinets shall be constructed in the
following manner, or equivalent: The bottom, sides, and top shall be
constructed of an exterior grade of plywood at least 1 inch in
thickness, which shall not break down or delaminate under standard fire
test conditions. All joints shall be rabbeted and shall be fastened in
two directions with flathead wood screws. When more than one door is
used, there shall be a rabbeted overlap of not less than 1 inch. Steel
hinges shall be mounted in such a manner as to not lose their holding
capacity due to loosening or burning out of the screws when subjected to
fire. Such cabinets shall be painted inside and out with fire retardant
paint.
(ii) Approved metal storage cabinets will be acceptable.
(iii) Cabinets shall be labeled in conspicuous lettering,
``Flammable--Keep Fire Away.''
(3) Not more than 60 gallons of flammable or 120 gallons of
combustible liquids shall be stored in any one storage cabinet. Not more
than three such cabinets may be located in a single storage area.
Quantities in excess of this shall be stored in an inside storage room.
(4)(i) Inside storage rooms shall be constructed to meet the
required fire-resistive rating for their use. Such construction shall
comply with the test specifications set forth in Standard Methods of
Fire Test of Building Construction and Material, NFPA 251-1969.
(ii) Where an automatic extinguishing system is provided, the system
shall be designed and installed in an approved manner. Openings to other
rooms or buildings shall be provided with noncombustible liquid-tight
raised sills or ramps at least 4 inches in height, or the floor in the
storage area shall be at least 4 inches below the surrounding floor.
Openings shall be provided with approved self-closing fire doors. The
room shall be liquid-tight where the walls join the floor. A permissible
alternate to the sill or ramp is an open-grated trench, inside of the
room, which drains to a safe location. Where other portions of the
building or other buildings are exposed, windows shall be protected as
set forth in the Standard for Fire Doors and Windows, NFPA No. 80-1970,
for Class E or F openings. Wood of at least 1-inch nominal thickness may
be used for shelving, racks, dunnage, scuffboards, floor overlay, and
similar installations.
(iii) Materials which will react with water and create a fire hazard
shall not be stored in the same room with flammable or combustible
liquids.
(iv) Storage in inside storage rooms shall comply with Table F-2
following:
Table F-2
----------------------------------------------------------------------------------------------------------------
Total
allowable
quantities
Fire protection provided Fire resistance Maximum size gals./sq.
ft./floor
area
----------------------------------------------------------------------------------------------------------------
Yes...................................... 2 hrs....................... 500 sq. ft................. 10
No....................................... 2 hrs....................... 500 sq. ft................. 4
Yes...................................... 1 hr........................ 150 sq. ft................. 5
No....................................... 1 hr........................ 150 sq. ft................. 2
----------------------------------------------------------------------------------------------------------------
Note: Fire protection system shall be sprinkler, water spray, carbon dioxide or other system approved by a
nationally recognized testing laboratory for this purpose.
(v) Electrical wiring and equipment located in inside storage rooms
shall be approved for Class I, Division 1, Hazardous Locations. For
definition of Class I, Division 1, Hazardous Locations, see Sec.
1926.449.
(vi) Every inside storage room shall be provided with either a
gravity or a mechanical exhausting system. Such system shall commence
not more than 12 inches above the floor and be designed to provide for a
complete change of air within the room at least 6 times per hour. If a
mechanical exhausting system is used, it shall be controlled by a switch
located outside of the door. The ventilating equipment and any lighting
fixtures shall be operated by the same switch. An electric pilot light
shall be installed adjacent to the switch if flammable liquids are
dispensed within the room. Where gravity ventilation is provided, the
fresh air intake, as well as the exhausting outlet from the room, shall
be on the exterior of the building in which the room is located.
(vii) In every inside storage room there shall be maintained one
clear aisle at least 3 feet wide. Containers over 30 gallons capacity
shall not be stacked one upon the other.
(viii) Flammable and combustible liquids in excess of that permitted
in inside storage rooms shall be stored
[[Page 191]]
outside of buildings in accordance with paragraph (c) of this section.
(5) Quantity. The quantity of flammable or combustible liquids kept
in the vicinity of spraying operations shall be the minimum required for
operations and should ordinarily not exceed a supply for 1 day or one
shift. Bulk storage of portable containers of flammable or combustible
liquids shall be in a separate, constructed building detached from other
important buildings or cut off in a standard manner.
(c) Storage outside buildings. (1) Storage of containers (not more
than 60 gallons each) shall not exceed 1,100 gallons in any one pile or
area. Piles or groups of containers shall be separated by a 5-foot
clearance. Piles or groups of containers shall not be nearer than 20
feet to a building.
(2) Within 200 feet of each pile of containers, there shall be a 12-
foot-wide access way to permit approach of fire control apparatus.
(3) The storage area shall be graded in a manner to divert possible
spills away from buildings or other exposures, or shall be surrounded by
a curb or earth dike at least 12 inches high. When curbs or dikes are
used, provisions shall be made for draining off accumulations of ground
or rain water, or spills of flammable or combustible liquids. Drains
shall terminate at a safe location and shall be accessible to operation
under fire conditions.
(4) Outdoor portable tank storage: (i) Portable tanks shall not be
nearer than 20 feet from any building. Two or more portable tanks,
grouped together, having a combined capacity in excess of 2,200 gallons,
shall be separated by a 5-foot-clear area. Individual portable tanks
exceeding 1,100 gallons shall be separated by a 5-foot-clear area.
(ii) Within 200 feet of each portable tank, there shall be a 12-
foot-wide access way to permit approach of fire control apparatus.
(5) Storage areas shall be kept free of weeds, debris, and other
combustible material not necessary to the storage.
(6) Portable tanks, not exceeding 660 gallons, shall be provided
with emergency venting and other devices, as required by chapters III
and IV of NFPA 30-1969, The Flammable and Combustible Liquids Code.
(7) Portable tanks, in excess of 660 gallons, shall have emergency
venting and other devices, as required by chapters II and III of The
Flammable and Combustible Liquids Code, NFPA 30-1969.
(d) Fire control for flammable or combustible liquid storage. (1) At
least one portable fire extinguisher, having a rating of not less than
20-B units, shall be located outside of, but not more than 10 feet from,
the door opening into any room used for storage of more than 60 gallons
of flammable or combustible liquids.
(2) At least one portable fire extinguisher having a rating of not
less than 20-B units shall be located not less than 25 feet, nor more
than 75 feet, from any flammable liquid storage area located outside.
(3) When sprinklers are provided, they shall be installed in
accordance with the Standard for the Installation of Sprinkler Systems,
NFPA 13-1969.
(4) At least one portable fire extinguisher having a rating of not
less than 20-B:C units shall be provided on all tank trucks or other
vehicles used for transporting and/or dispensing flammable or
combustible liquids.
(e) Dispensing liquids. (1) Areas in which flammable or combustible
liquids are transferred at one time, in quantities greater than 5
gallons from one tank or container to another tank or container, shall
be separated from other operations by 25-feet distance or by
construction having a fire resistance of at least 1 hour. Drainage or
other means shall be provided to control spills. Adequate natural or
mechanical ventilation shall be provided to maintain the concentration
of flammable vapor at or below 10 percent of the lower flammable limit.
(2) Transfer of flammable liquids from one container to another
shall be done only when containers are electrically interconnected
(bonded).
(3) Flammable or combustible liquids shall be drawn from or
transferred into vessels, containers, or tanks within a building or
outside only through a closed piping system, from safety cans, by means
of a device drawing through the top, or from a container, or portable
tanks, by gravity or pump, through an approved self-closing valve.
[[Page 192]]
Transferring by means of air pressure on the container or portable tanks
is prohibited.
(4) The dispensing units shall be protected against collision
damage.
(5) Dispensing devices and nozzles for flammable liquids shall be of
an approved type.
(f) Handling liquids at point of final use. (1) Flammable liquids
shall be kept in closed containers when not actually in use.
(2) Leakage or spillage of flammable or combustible liquids shall be
disposed of promptly and safely.
(3) Flammable liquids may be used only where there are no open
flames or other sources of ignition within 50 feet of the operation,
unless conditions warrant greater clearance.
(g) Service and refueling areas. (1) Flammable or combustible
liquids shall be stored in approved closed containers, in tanks located
underground, or in aboveground portable tanks.
(2) The tank trucks shall comply with the requirements covered in
the Standard for Tank Vehicles for Flammable and Combustible Liquids,
NFPA No. 385-1966.
(3) The dispensing hose shall be an approved type.
(4) The dispensing nozzle shall be an approved automatic-closing
type without a latch-open device.
(5) Underground tanks shall not be abandoned.
(6) Clearly identified and easily accessible switch(es) shall be
provided at a location remote from dispensing devices to shut off the
power to all dispensing devices in the event of an emergency.
(7)(i) Heating equipment of an approved type may be installed in the
lubrication or service area where there is no dispensing or transferring
of flammable liquids, provided the bottom of the heating unit is at
least 18 inches above the floor and is protected from physical damage.
(ii) Heating equipment installed in lubrication or service areas,
where flammable liquids are dispensed, shall be of an approved type for
garages, and shall be installed at least 8 feet above the floor.
(8) There shall be no smoking or open flames in the areas used for
fueling, servicing fuel systems for internal combustion engines,
receiving or dispensing of flammable or combustible liquids.
(9) Conspicuous and legible signs prohibiting smoking shall be
posted.
(10) The motors of all equipment being fueled shall be shut off
during the fueling operation.
(11) Each service or fueling area shall be provided with at least
one fire extinguisher having a rating of not less than 20-B:C located so
that an extinguisher will be within 75 feet of each pump, dispenser,
underground fill pipe opening, and lubrication or service area.
(h) Scope. This section applies to the handling, storage, and use of
flammable and combustible liquids with a flashpoint below 200 [deg]F
(93.33 [deg]C). This section does not apply to:
(1) Bulk transportation of flammable and combustible liquids; and
(2) Storage, handling, and use of fuel oil tanks and containers
connected with oil burning equipment.
(i) Tank storage--(1) Design and construction of tanks--(i)
Materials. (A) Tanks shall be built of steel except as provided in
paragraphs (i)(1)(i) (B) through (E) of this section.
(B) Tanks may be built of materials other than steel for
installation underground or if required by the properties of the liquid
stored. Tanks located above ground or inside buildings shall be of
noncombustible construction.
(C) Tanks built of materials other than steel shall be designed to
specifications embodying principles recognized as good engineering
design for the material used.
(D) Unlined concrete tanks may be used for storing flammable or
combustible liquids having a gravity of 40[deg] API or heavier. Concrete
tanks with special lining may be used for other services provided the
design is in accordance with sound engineering practice.
(E) [Reserved]
(F) Special engineering consideration shall be required if the
specific gravity of the liquid to be stored exceeds that of water or if
the tanks are designed to contain flammable or combustible liquids at a
liquid temperature below 0 [deg]F.
(ii) Fabrication. (A) [Reserved]
(B) Metal tanks shall be welded, riveted, and caulked, brazed, or
bolted, or
[[Page 193]]
constructed by use of a combination of these methods. Filler metal used
in brazing shall be nonferrous metal or an alloy having a melting point
above 1000 [deg]F. and below that of the metal joined.
(iii) Atmospheric tanks. (A) Atmospheric tanks shall be built in
accordance with acceptable good standards of design. Atmospheric tanks
may be built in accordance with:
(1) Underwriters' Laboratories, Inc., Subjects No. 142, Standard for
Steel Aboveground Tanks for Flammable and Combustible Liquids, 1968; No.
58, Standard for Steel Underground Tanks for Flammable and Combustible
Liquids, Fifth Edition, December 1961; or No. 80, Standard for Steel
Inside Tanks for Oil-Burner Fuel, September 1963.
(2) American Petroleum Institute Standards No. 12A, Specification
for Oil Storage Tanks with Riveted Shells, Seventh Edition, September
1951, or No. 650, Welded Steel Tanks for Oil Storage, Third Edition,
1966.
(3) American Petroleum Institute Standards No. 12B, Specification
for Bolted Production Tanks, Eleventh Edition, May 1958, and Supplement
1, March 1962; No. 12D, Specification for Large Welded Production Tanks,
Seventh Edition, August 1957; or No. 12F, Specification for Small Welded
Production Tanks, Fifth Edition, March 1961. Tanks built in accordance
with these standards shall be used only as production tanks for storage
of crude petroleum in oil-producing areas.
(B) Tanks designed for underground service not exceeding 2,500
gallons (9,462.5 L) capacity may be used aboveground.
(C) Low-pressure tanks and pressure vessels may be used as
atmospheric tanks.
(D) Atmospheric tanks shall not be used for the storage of a
flammable or combustible liquid at a temperature at or above its boiling
point.
(iv) Low pressure tanks. (A) The normal operating pressure of the
tank shall not exceed the design pressure of the tank.
(B) Low-pressure tanks shall be built in accordance with acceptable
standards of design. Low-pressure tanks may be built in accordance with:
(1) American Petroleum Institute Standard No. 620. Recommended Rules
for the Design and Construction of Large, Welded, Low-Pressure Storage
Tanks, Third Edition, 1966.
(2) The principles of the Code for Unfired Pressure Vessels, Section
VIII of the ASME Boiler and Pressure Vessels Code, 1968.
(C) Atmospheric tanks built according to Underwriters' Laboratories,
Inc., requirements in paragraph (i)(1)(iii)(A) of this section and shall
be limited to 2.5 p.s.i.g. under emergency venting conditions.
This paragraph may be used for operating pressures not exceeding 1
p.s.i.g.
(D) Pressure vessels may be used as low-pressure tanks.
(v) Pressure vessels. (A) The normal operating pressure of the
vessel shall not exceed the design pressure of the vessel.
(B) Pressure vessels shall be built in accordance with the Code for
Unfired Pressure Vessels, Section VIII of the ASME Boiler and Pressure
Vessel Code 1968.
(vi) Provisions for internal corrosion. When tanks are not designed
in accordance with the American Petroleum Institute, American Society of
Mechanical Engineers, or the Underwriters' Laboratories, Inc.'s,
standards, or if corrosion is anticipated beyond that provided for in
the design formulas used, additional metal thickness or suitable
protective coatings or linings shall be provided to compensate for the
corrosion loss expected during the design life of the tank.
(2) Installation of outside aboveground tanks. (i) [Reserved]
(ii) Spacing (shell-to-shell) between aboveground tanks. (A) The
distance between any two flammable or combustible liquid storage tanks
shall not be less than 3 feet (0.912 m).
(B) Except as provided in paragraph (i)(2)(ii)(C) of this section,
the distance between any two adjacent tanks shall not be less than one-
sixth the sum of their diameters. When the diameter of one tank is less
than one-half the diameter of the adjacent tank, the distance between
the two tanks shall not be less than one-half the diameter of the
smaller tank.
(C) Where crude petroleum in conjunction with production facilities
are located in noncongested areas and have
[[Page 194]]
capacities not exceeding 126,000 gallons (3,000 barrels), the distance
between such tanks shall not be less than 3 feet (0.912 m).
(D) Where unstable flammable or combustible liquids are stored, the
distance between such tanks shall not be less than one-half the sum of
their diameters.
(E) When tanks are compacted in three or more rows or in an
irregular pattern, greater spacing or other means shall be provided so
that inside tanks are accessible for firefighting purposes.
(F) The minimum separation between a liquefied petroleum gas
container and a flammable or combustible liquid storage tank shall be 20
feet (6.08 m), except in the case of flammable or combustible liquid
tanks operating at pressures exceeding 2.5 p.s.i.g. or equipped with
emergency venting which will permit pressures to exceed 2.5 p.s.i.g. in
which case the provisions of paragraphs (i)(2)(ii) (A) and (B) of this
section shall apply. Suitable means shall be taken to prevent the
accumulation of flammable or combustible liquids under adjacent
liquefied petroleum gas containers such as by diversion curbs or
grading. When flammable or combustible liquid storage tanks are within a
diked area, the liquefied petroleum gas containers shall be outside the
diked area and at least 10 feet (3.04 m) away from the centerline of the
wall of the diked area. The foregoing provisions shall not apply when
liquefied petroleum gas containers of 125 gallons (473.125 L) or less
capacity are installed adjacent to fuel oil supply tanks of 550 gallons
(2,081.75 L) or less capacity.
(iii) [Reserved]
(iv) Normal venting for aboveground tanks. (A) Atmospheric storage
tanks shall be adequately vented to prevent the development of vacuum or
pressure sufficient to distort the roof of a cone roof tank or exceeding
the design pressure in the case of other atmospheric tanks, as a result
of filling or emptying, and atmospheric temperature changes.
(B) Normal vents shall be sized either in accordance with: (1) The
American Petroleum Institute Standard 2000 (1968), Venting Atmospheric
and Low-Pressure Storage Tanks; or (2) other accepted standard; or (3)
shall be at least as large as the filling or withdrawal connection,
whichever is larger but in no case less than 1\1/4\ inch (3.175 cm)
nominal inside diameter.
(C) Low-pressure tanks and pressure vessels shall be adequately
vented to prevent development of pressure or vacuum, as a result of
filling or emptying and atmospheric temperature changes, from exceeding
the design pressure of the tank or vessel. Protection shall also be
provided to prevent overpressure from any pump discharging into the tank
or vessel when the pump discharge pressure can exceed the design
pressure of the tank or vessel.
(D) If any tank or pressure vessel has more than one fill or
withdrawal connection and simultaneous filling or withdrawal can be
made, the vent size shall be based on the maximum anticipated
simultaneous flow.
(E) Unless the vent is designed to limit the internal pressure 2.5
p.s.i. or less, the outlet of vents and vent drains shall be arranged to
discharge in such a manner as to prevent localized overheating of any
part of the tank in the event vapors from such vents are ignited.
(F) Tanks and pressure vessels storing Class IA liquids shall be
equipped with venting devices which shall be normally closed except when
venting to pressure or vacuum conditions. Tanks and pressure vessels
storing Class IB and IC liquids shall be equipped with venting devices
which shall be normally closed except when venting under pressure or
vacuum conditions, or with approved flame arresters.
Exemption: Tanks of 3,000 bbls. (84 m\3\) capacity or less
containing crude petroleum in crude-producing areas; and, outside
aboveground atmospheric tanks under 1,000 gallons (3,785 L) capacity
containing other than Class IA flammable liquids may have open vents.
(See paragraph (i)(2)(vi)(B) of this section.)
(G) Flame arresters or venting devices required in paragraph
(i)(2)(iv)(F) of this section may be omitted for Class IB and IC liquids
where conditions are such that their use may, in
[[Page 195]]
case of obstruction, result in tank damage.
(v) Emergency relief venting for fire exposure for aboveground
tanks. (A) Every aboveground storage tank shall have some form of
construction or device that will relieve excessive internal pressure
caused by exposure fires.
(B) In a vertical tank the construction referred to in paragraph
(i)(2)(v)(A) of this section may take the form of a floating roof,
lifter roof, a weak roof-to-shell seam, or other approved pressure
relieving construction. The weak roof-to-shell seam shall be constructed
to fail preferential to any other seam.
(C) Where entire dependence for emergency relief is placed upon
pressure relieving devices, the total venting capacity of both normal
and emergency vents shall be enough to prevent rupture of the shell or
bottom of the tank if vertical, or of the shell or heads if horizontal.
If unstable liquids are stored, the effects of heat or gas resulting
from polymerization, decomposition, condensation, or self-reactivity
shall be taken into account. The total capacity of both normal and
emergency venting devices shall be not less than that derived from Table
F-10 except as provided in paragraph (i)(2)(v) (E) or (F) of this
section. Such device may be a self-closing manhole cover, or one using
long bolts that permit the cover to lift under internal pressure, or an
additional or larger relief valve or valves. The wetted area of the tank
shall be calculated on the basis of 55 percent of the total exposed area
of a sphere or spheroid, 75 percent of the total exposed area of a
horizontal tank and the first 30 feet (9.12 m) above grade of the
exposed shell area of a vertical tank.
Table F-10--Wetted Area Versus Cubic Feet (Meters) Free Air Per Hour
[14.7 psia and 60 [deg]F. (15.55 [deg]C)]
------------------------------------------------------------------------
Square Square
Square feet CFH (m\3\H) feet CFH feet CFH
(m\2\) (m\2\) (m\3\H) (m\2\) (m\3\H)
------------------------------------------------------------------------
20 (1.84) 21,100 200 (18.4) 211,000 1,000 524,000
(590.8) (5,908) (90.2) (14,672)
30 (2.76) 31,600 250 (23) 239,000 1,200 557,000
(884.8) (6,692) (110.4) (15,596)
40 (3.68) 42,100 300 (27.6) 265,000 1,400 587,000
(1,178.8) (7,420) (128.8) (16,436)
50 (4.6) 52,700 350 (32.2) 288,000 1,600 614,000
(1,475.6) (8,064) (147.2) (17,192)
60 (5.52) 63,200 400 (36.8) 312,000 1,800 639,000
(1,769.6) (8,736) (165.6) (17,892)
70 (6.44) 73,700 500 (46) 354,000 2,000 662,000
(2,063.6) (9,912) (180.4) (18,536)
80 (7.36) 84,200 600 (55.2) 392,000 2,400 704,000
(2,357.6) (10,976) (220.8) (19,712)
90 (8.28) 94,800 700 (64.4) 428,000 2,800 742,000
(2,654.4) (11,984) (257.6) (20,776)
100 (9.2) 105,000 800 (73.6) 462,000 and
(2,940) (12,936)
120 (11.04) 126,000 900 (82.8) 493,000 over
(3,528) (13,804)
140 (12.88) 147,000 1,000 524,000
(4,116) (90.2) (14,672)
160 (14.72) 168,000
(4,704)
180 (16.56) 190,000
(5,320)
200 (18.4) 211,000
(5,908)
------------------------------------------------------------------------
(D) For tanks and storage vessels designed for pressure over 1
p.s.i.g., the total rate of venting shall be determined in accordance
with Table F-10, except that when the exposed wetted area of the surface
is greater than 2,800 square feet (257.6 m\2\), the total rate of
venting shall be calculated by the following formula:
CFH = 1,107A\0.82\
Where:
CFH = Venting requirement, in cubic feet (meters) of free air per hour.
A = Exposed wetted surface, in square feet (m\2\).
Note: The foregoing formula is based on Q=21,000A\0.82\.
(E) The total emergency relief venting capacity for any specific
stable liquid may be determined by the following formula:
V = 1337/L<SUP>[radic]</SUP> M
V = Cubic feet (meters) of free air per hour from Table F-10.
L = Latent heat of vaporization of specific liquid in B.t.u. per pound.
M = Molecular weight of specific liquids.
(F) The required airflow rate of paragraph (i)(2)(v) (C) or (E) of
this section may be multiplied by the appropriate factor listed in the
following schedule when protection is provided as indicated. Only one
factor may be used for any one tank.
[[Page 196]]
0.5 for drainage in accordance with paragraph (i)(2)(vii)(B) of this
section for tanks over 200 square feet (18.4 m\2\) of wetted area.
0.3 for approved water spray.
0.3 for approved insulation.
0.15 for approved water spray with approved insulation.
(G) The outlet of all vents and vent drains on tanks equipped with
emergency venting to permit pressures exceeding 2.5 p.s.i.g. shall be
arranged to discharge in such a way as to prevent localized overheating
of any part of the tank, in the event vapors from such vents are
ignited.
(H) Each commercial tank venting device shall have stamped on it the
opening pressure, the pressure at which the valve reaches the full open
position, and the flow capacity at the latter pressure, expressed in
cubic feet (meters) per hour of air at 60 [deg]F. (15.55 [deg]C) and at
a pressure of 14.7 p.s.i.a.
(I) The flow capacity of tank venting devices 12 inches (30.48 cm)
and smaller in nominal pipe size shall be determined by actual test of
each type and size of vent. These flow tests may be conducted by the
manufacturer if certified by a qualified impartial observer, or may be
conducted by an outside agency. The flow capacity of tank venting
devices larger than 12 inches (30.48 cm) nominal pipe size, including
manhole covers with long bolts or equivalent, may be calculated provided
that the opening pressure is actually measured, the rating pressure and
corresponding free orifice area are stated, the word ``calculated''
appears on the nameplate, and the computation is based on a flow
coefficient of 0.5 applied to the rated orifice area.
(vi) Vent piping for aboveground tanks. (A) Vent piping shall be
constructed in accordance with paragraph (c) of this section.
(B) Where vent pipe outlets for tanks storing Class I liquids are
adjacent to buildings or public ways, they shall be located so that the
vapors are released at a safe point outside of buildings and not less
than 12 feet (3.648 m) above the adjacent ground level. In order to aid
their dispersion, vapors shall be discharged upward or horizontally away
from closely adjacent walls. Vent outlets shall be located so that
flammable vapors will not be trapped by eaves or other obstructions and
shall be at least 5 feet (1.52 m) from building openings.
(C) When tank vent piping is manifolded, pipe sizes shall be such as
to discharge, within the pressure limitations of the system, the vapors
they may be required to handle when manifolded tanks are subject to the
same fire exposure.
(vii) Drainage, dikes, and walls for aboveground tanks--(A) Drainage
and diked areas. The area surrounding a tank or a group of tanks shall
be provided with drainage as in paragraph (i)(2)(vii)(B) of this
section, or shall be diked as provided in (i)(2)(vii)(C) of this
section, to prevent accidental discharge of liquid from endangering
adjoining property or reaching waterways.
(B) Drainage. Where protection of adjoining property or waterways is
by means of a natural or manmade drainage system, such systems shall
comply with the following:
(1) [Reserved]
(2) The drainage system shall terminate in vacant land or other area
or in an impounding basin having a capacity not smaller than that of the
largest tank served. This termination area and the route of the drainage
system shall be so located that, if the flammable or combustible liquids
in the drainage system are ignited, the fire will not seriously expose
tanks or adjoining property.
(C) Diked areas. Where protection of adjoining property or waterways
is accomplished by retaining the liquid around the tank by means of a
dike, the volume of the diked area shall comply with the following
requirements:
(1) Except as provided in paragraph (i)(2)(vii)(C)(2) of this
section, the volumetric capacity of the diked area shall not be less
than the greatest amount of liquid that can be released from the largest
tank within the diked area, assuming a full tank. The capacity of the
diked area enclosing more than one tank shall be calculated by deducting
the volume of the tanks other than the largest tank below the height of
the dike.
(2) For a tank or group of tanks with fixed roofs containing crude
petroleum
[[Page 197]]
with boilover characteristics, the volumetric capacity of the diked area
shall be not less than the capacity of the largest tank served by the
enclosure, assuming a full tank. The capacity of the diked enclosure
shall be calculated by deducting the volume below the height of the dike
of all tanks within the enclosure.
(3) Walls of the diked area shall be of earth, steel, concrete or
solid masonry designed to be liquidtight and to withstand a full
hydrostatic head. Earthen walls 3 feet (0.912 m) or more in height shall
have a flat section at the top not less than 2 feet (0.608 m) wide. The
slope of an earthen wall shall be consistent with the angle of repose of
the material of which the wall is constructed.
(4) The walls of the diked area shall be restricted to an average
height of 6 feet (1.824 m) above interior grade.
(5) [Reserved]
(6) No loose combustible material, empty or full drum or barrel,
shall be permitted within the diked area.
(viii) Tank openings other than vents for aboveground tanks.
(A)-(C) [Reserved]
(D) Openings for gaging shall be provided with a vaportight cap or
cover.
(E) For Class IB and Class IC liquids other than crude oils,
gasolines, and asphalts, the fill pipe shall be so designed and
installed as to minimize the possibility of generating static
electricity. A fill pipe entering the top of a tank shall terminate
within 6 inches (15.24 cm) of the bottom of the tank and shall be
installed to avoid excessive vibration.
(F) Filling and emptying connections which are made and broken shall
be located outside of buildings at a location free from any source of
ignition and not less than 5 feet (1.52 m) away from any building
opening. Such connection shall be closed and liquidtight when not in
use. The connection shall be properly identified.
(3) Installation of underground tanks--(i) Location. Excavation for
underground storage tanks shall be made with due care to avoid
undermining of foundations of existing structures. Underground tanks or
tanks under buildings shall be so located with respect to existing
building foundations and supports that the loads carried by the latter
cannot be transmitted to the tank. The distance from any part of a tank
storing Class I liquids to the nearest wall of any basement or pit shall
be not less than 1 foot (0.304 m), and to any property line that may be
built upon, not less than 3 feet (0.912 m). The distance from any part
of a tank storing Class II or Class III liquids to the nearest wall of
any basement, pit or property line shall be not less than 1 foot (0.304
m).
(ii) Depth and cover. Underground tanks shall be set on firm
foundations and surrounded with at least 6 inches (15.24 cm) of
noncorrosive, inert materials such as clean sand, earth, or gravel well
tamped in place. The tank shall be placed in the hole with care since
dropping or rolling the tank into the hole can break a weld, puncture or
damage the tank, or scrape off the protective coating of coated tanks.
Tanks shall be covered with a minimum of 2 feet (0.608 m) of earth, or
shall be covered with not less than 1 foot (0.304 m) of earth, on top of
which shall be placed a slab of reinforced concrete not less than 4
inches (10.16 cm) thick. When underground tanks are, or are likely to
be, subject to traffic, they shall be protected against damage from
vehicles passing over them by at least 3 feet (0.912 m) of earth cover,
or 18 inches (45.72 cm) of well-tamped earth, plus 6 inches (15.24 cm)
of reinforced concrete or 8 inches (20.32 cm) of asphaltic concrete.
When asphaltic or reinforced concrete paving is used as part of the
protection, it shall extend at least 1 foot (0.304 m) horizontally
beyond the outline of the tank in all directions.
(iii) Corrosion protection. Corrosion protection for the tank and
its piping shall be provided by one or more of the following methods:
(A) Use of protective coatings or wrappings;
(B) Cathodic protection; or,
(C) Corrosion resistant materials of construction.
(iv) Vents. (A) Location and arrangement of vents for Class I
liquids. Vent pipes from tanks storing Class I liquids shall be so
located that the discharge point is outside of buildings, higher than
the fill pipe opening, and not less
[[Page 198]]
than 12 feet (3.648 m) above the adjacent ground level. Vent pipes shall
discharge only upward in order to disperse vapors. Vent pipes 2 inches
(5.08 cm) or less in nominal inside diameter shall not be obstructed by
devices that will cause excessive back pressure. Vent pipe outlets shall
be so located that flammable vapors will not enter building openings, or
be trapped under eaves or other obstructions. If the vent pipe is less
than 10 feet (3.04 m) in length, or greater than 2 inches (5.08 cm) in
nominal inside diameter, the outlet shall be provided with a vacuum and
pressure relief device or there shall be an approved flame arrester
located in the vent line at the outlet or within the approved distance
from the outlet.
(B) Size of vents. Each tank shall be vented through piping adequate
in size to prevent blow-back of vapor or liquid at the fill opening
while the tank is being filled. Vent pipes shall be not less than 1\1/4\
inch (3.175 cm) nominal inside diameter.
Table F-11--Vent Line Diameters
----------------------------------------------------------------------------------------------------------------
Pipe length \1\
Maximum flow GPM (L) --------------------------------------------------------
50 feet (15.2 m) 100 feet (30.4 m) 200 feet (60.8 m)
----------------------------------------------------------------------------------------------------------------
Inches (cm) Inches (cm) Inches (cm)
100 (378.5)............................................ 1\1/4\ (3.175) 1\1/4\ (3.175) 1\1/4\ (3.175)
200 (757).............................................. 1\1/4\ (3.175) 1\1/4\ (3.175) 1\1/4\ (3.175)
300 (1,135.5).......................................... 1\1/4\ (3.175) 1\1/4\ (3.175) 1\1/2\ (3.81)
400 (1,514)............................................ 1\1/4\ (3.175) 1\1/2\ (3.81) 2 (5.08)
500 (1,892.5).......................................... 1\1/2\ (3.81) 1\1/2\ (3.81) 2 (5.08)
600 (2,271)............................................ 1\1/2\ (3.81) 2 (5.08) 2 (5.08)
700 (2,649.5).......................................... 2 (5.08) 2 (5.08) 2 (5.08)
800 (3,028)............................................ 2 (5.08) 2 (5.08) 3 (7.62)
900 (3,406.5).......................................... 2 (5.08) 2 (5.08) 3 (7.62)
1,000 (3,785).......................................... 2 (5.08) 2 (5.08) 3 (7.62)
----------------------------------------------------------------------------------------------------------------
\1\ Vent lines of 50 ft. (15.2 m), 100 ft. (30.4 m), and 200 ft. (60.8 m) of pipe plus 7 ells.
(C) Location and arrangement of vents for Class II or Class III
liquids. Vent pipes from tanks storing Class II or Class III flammable
liquids shall terminate outside of the building and higher than the fill
pipe opening. Vent outlets shall be above normal snow level. They may be
fitted with return bends, coarse screens or other devices to minimize
ingress of foreign material.
(D) Vent piping shall be constructed in accordance with paragraph
(3)(iv)(C) of this section. Vent pipes shall be so laid as to drain
toward the tank without sags or traps in which liquid can collect. They
shall be located so that they will not be subjected to physical damage.
The tank end of the vent pipe shall enter the tank through the top.
(E) When tank vent piping is manifolded, pipe sizes shall be such as
to discharge, within the pressure limitations of the system, the vapors
they may be required to handle when manifolded tanks are filled
simultaneously.
(v) Tank openings other than vents. (A) Connections for all tank
openings shall be vapor or liquid tight.
(B) Openings for manual gaging, if independent of the fill pipe,
shall be provided with a liquid-tight cap or cover. If inside a
building, each such opening shall be protected against liquid overflow
and possible vapor release by means of a spring loaded check valve or
other approved device.
(C) Fill and discharge lines shall enter tanks only through the top.
Fill lines shall be sloped toward the tank.
(D) For Class IB and Class IC liquids other than crude oils,
gasolines, and asphalts, the fill pipe shall be so designed and
installed as to minimize the possibility of generating static
electricity by terminating within 6 inches (15.24 cm) of the bottom of
the tank.
(E) Filling and emptying connections which are made and broken shall
be located outside of buildings at a location free from any source of
ignition and not less than 5 feet (1.52 m) away from any building
opening. Such connection shall be closed and liquidtight when
[[Page 199]]
not in use. The connection shall be properly identified.
(4) Installation of tanks inside of buildings--(i) Location. Tanks
shall not be permitted inside of buildings except as provided in
paragraphs (e), (g), (h), or (i) of this section.
(ii) Vents. Vents for tanks inside of buildings shall be as provided
in paragraphs (i)(2) (iv), (v), (vi)(B), and (3)(iv) of this section,
except that emergency venting by the use of weak roof seams on tanks
shall not be permitted. Vents shall discharge vapors outside the
buildings.
(iii) Vent piping. Vent piping shall be constructed in accordance
with paragraph (c) of this section.
(iv) Tank openings other than vents. (A) Connections for all tank
openings shall be vapor or liquidtight. Vents are covered in paragraph
(i)(4)(ii) of this section.
(B) Each connection to a tank inside of buildings through which
liquid can normally flow shall be provided with an internal or an
external valve located as close as practical to the shell of the tank.
Such valves, when external, and their connections to the tank shall be
of steel except when the chemical characteristics of the liquid stored
are incompatible with steel. When materials other than steel are
necessary, they shall be suitable for the pressures, structural
stresses, and temperatures involved, including fire exposures.
(C) Flammable or combustible liquid tanks located inside of
buildings, except in one-story buildings designed and protected for
flammable or combustible liquid storage, shall be provided with an
automatic-closing heat-actuated valve on each withdrawal connection
below the liquid level, except for connections used for emergency
disposal, to prevent continued flow in the event of fire in the vicinity
of the tank. This function may be incorporated in the valve required in
paragraph (i)(4)(iv)(B) of this section, and if a separate valve, shall
be located adjacent to the valve required in paragraph (i)(4)(iv)(B) of
this section.
(D) Openings for manual gaging, if independent of the fill pipe (see
paragraph (i)(4)(iv)(F) of this section), shall be provided with a
vaportight cap or cover. Each such opening shall be protected against
liquid overflow and possible vapor release by means of a spring loaded
check valve or other approved device.
(E) For Class IB and Class IC liquids other than crude oils,
gasolines, and asphalts, the fill pipe shall be so designed and
installed as to minimize the possibility of generating static
electricity by terminating within 6 inches (15.24 cm) of the bottom of
the tank.
(F) The fill pipe inside of the tank shall be installed to avoid
excessive vibration of the pipe.
(G) The inlet of the fill pipe shall be located outside of buildings
at a location free from any source of ignition and not less than 5 feet
(1.52 m) away from any building opening. The inlet of the fill pipe
shall be closed and liquidtight when not in use. The fill connection
shall be properly identified.
(H) Tanks inside buildings shall be equipped with a device, or other
means shall be provided, to prevent overflow into the building.
(5) Supports, foundations, and anchorage for all tank locations--(i)
General. Tank supports shall be installed on firm foundations. Tank
supports shall be of concrete, masonry, or protected steel. Single wood
timber supports (not cribbing) laid horizontally may be used for outside
aboveground tanks if not more than 12 inches (30.48 cm) high at their
lowest point.
(ii) Fire resistance. Steel supports or exposed piling shall be
protected by materials having a fire resistance rating of not less than
2 hours, except that steel saddles need not be protected if less than 12
inches (30.48 cm) high at their lowest point. Water spray protection or
its equivalent may be used in lieu of fire-resistive materials to
protect supports.
(iii) Spheres. The design of the supporting structure for tanks such
as spheres shall receive special engineering consideration.
(iv) Load distribution. Every tank shall be so supported as to
prevent the excessive concentration of loads on the supporting portion
of the shell.
(v) Foundations. Tanks shall rest on the ground or on foundations
made of concrete, masonry, piling, or steel. Tank foundations shall be
designed to
[[Page 200]]
minimize the possibility of uneven settling of the tank and to minimize
corrosion in any part of the tank resting on the foundation.
(vi) Flood areas. Where a tank is located in an area that may be
subjected to flooding, the applicable precautions outlined in this
subdivision shall be observed.
(A) No aboveground vertical storage tank containing a flammable or
combustible liquid shall be located so that the allowable liquid level
within the tank is below the established maximum flood stage, unless the
tank is provided with a guiding structure such as described in
paragraphs (i)(5)(vi) (M), (N), and (O) of this section.
(B) Independent water supply facilities shall be provided at
locations where there is no ample and dependable public water supply
available for loading partially empty tanks with water.
(C) In addition to the preceding requirements, each tank so located
that more than 70 percent, but less than 100 percent, of its allowable
liquid storage capacity will be submerged at the established maximum
flood stage, shall be safeguarded by one of the following methods: Tank
shall be raised, or its height shall be increased, until its top extends
above the maximum flood stage a distance equivalent to 30 percent or
more of its allowable liquid storage capacity: Provided, however, That
the submerged part of the tank shall not exceed two and one-half times
the diameter. Or, as an alternative to the foregoing, adequate
noncombustible structural guides, designed to permit the tank to float
vertically without loss of product, shall be provided.
(D) Each horizontal tank so located that more than 70 percent of its
storage capacity will be submerged at the established flood stage, shall
be anchored, attached to a foundation of concrete or of steel and
concrete, of sufficient weight to provide adequate load for the tank
when filled with flammable or combustible liquid and submerged by flood
waters to the established flood stage, or adequately secured by other
means.
(E) [Reserved]
(F) At locations where there is no ample and dependable water
supply, or where filling of underground tanks with liquids is
impracticable because of the character of their contents, their use, or
for other reasons, each tank shall be safeguarded against movement when
empty and submerged by high ground water or flood waters by anchoring,
weighting with concrete or other approved solid loading material, or
securing by other means. Each such tank shall be so constructed and
installed that it will safely resist external pressures due to high
ground water or flood waters.
(G) At locations where there is an ample and dependable water supply
available, underground tanks containing flammable or combustible
liquids, so installed that more than 70 percent of their storage
capacity will be submerged at the maximum flood stage, shall be so
anchored, weighted, or secured by other means, as to prevent movement of
such tanks when filled with flammable or combustible liquids, and
submerged by flood waters to the established flood stage.
(H) Pipe connections below the allowable liquid level in a tank
shall be provided with valves or cocks located as closely as practicable
to the tank shell. Such valves and their connections to tanks shall be
of steel or other material suitable for use with the liquid being
stored. Cast iron shall not be permitted.
(I) At locations where an independent water supply is required, it
shall be entirely independent of public power and water supply.
Independent source of water shall be available when flood waters reach a
level not less than 10 feet (3.04 m) below the bottom of the lowest tank
on a property.
(J) The self-contained power and pumping unit shall be so located or
so designed that pumping into tanks may be carried on continuously
throughout the rise in flood waters from a level 10 feet (3.04 m) below
the lowest tank to the level of the potential flood stage.
(K) Capacity of the pumping unit shall be such that the rate of rise
of water in all tanks shall be equivalent to the established potential
average rate of rise of flood waters at any stage.
(L) Each independent pumping unit shall be tested periodically to
insure
[[Page 201]]
that it is in satisfactory operating condition.
(M) Structural guides for holding floating tanks above their
foundations shall be so designed that there will be no resistance to the
free rise of a tank, and shall be constructed of noncombustible
material.
(N) The strength of the structure shall be adequate to resist
lateral movement of a tank subject to a horizontal force in any
direction equivalent to not less than 25 pounds per square foot (1.05 kg
m\2\) acting on the projected vertical cross-sectional area of the tank.
(O) Where tanks are situated on exposed points or bends in a
shoreline where swift currents in flood waters will be present, the
structures shall be designed to withstand a unit force of not less than
50 pounds per square foot (2.1 kg m\2\).
(P) The filling of a tank to be protected by water loading shall be
started as soon as flood waters reach a dangerous flood stage. The rate
of filling shall be at least equal to the rate of rise of the
floodwaters (or the established average potential rate of rise).
(Q) Sufficient fuel to operate the water pumps shall be available at
all times to insure adequate power to fill all tankage with water.
(R) All valves on connecting pipelines shall be closed and locked in
closed position when water loading has been completed.
(S) Where structural guides are provided for the protection of
floating tanks, all rigid connections between tanks and pipelines shall
be disconnected and blanked off or blinded before the floodwaters reach
the bottom of the tank, unless control valves and their connections to
the tank are of a type designed to prevent breakage between the valve
and the tank shell.
(T) All valves attached to tanks other than those used in connection
with water loading operations shall be closed and locked.
(U) If a tank is equipped with a swing line, the swing pipe shall be
raised to and secured at its highest position.
(V) Inspections. The Assistant Secretary or his designated
representative shall make periodic inspections of all plants where the
storage of flammable or combustible liquids is such as to require
compliance with the foregoing requirements, in order to assure the
following:
(1) That all flammable or combustible liquid storage tanks are in
compliance with these requirements and so maintained.
(2) That detailed printed instructions of what to do in flood
emergencies are properly posted.
(3) That station operators and other employees depended upon to
carry out such instructions are thoroughly informed as to the location
and operation of such valves and other equipment necessary to effect
these requirements.
(vii) Earthquake areas. In areas subject to earthquakes, the tank
supports and connections shall be designed to resist damage as a result
of such shocks.
(6) Sources of ignition. In locations where flammable vapors may be
present, precautions shall be taken to prevent ignition by eliminating
or controlling sources of ignition. Sources of ignition may include open
flames, lightning, smoking, cutting and welding, hot surfaces,
frictional heat, sparks (static, electrical, and mechanical),
spontaneous ignition, chemical and physical-chemical reactions, and
radiant heat.
(7) Testing--(i) General. All tanks, whether shop built or field
erected, shall be strength tested before they are placed in service in
accordance with the applicable paragraphs of the code under which they
were built. The American Society of Mechanical Engineers (ASME) code
stamp, American Petroleum Institute (API) monogram, or the label of the
Underwriters' Laboratories, Inc., on a tank shall be evidence of
compliance with this strength test. Tanks not marked in accordance with
the above codes shall be strength tested before they are placed in
service in accordance with good engineering principles and reference
shall be made to the sections on testing in the codes listed in
paragraphs (i)(1) (iii)(A), (iv)(B), or (v)(B) of this section.
(ii) Strength. When the vertical length of the fill and vent pipes
is such that when filled with liquid the static head imposed upon the
bottom of the tank exceeds 10 pounds per square inch
[[Page 202]]
(68.94 kPa), the tank and related piping shall be tested hydrostatically
to a pressure equal to the static head thus imposed.
(iii) Tightness. In addition to the strength test called for in
paragraphs (i)(7) (i) and (ii) of this section, all tanks and
connections shall be tested for tightness. Except for underground tanks,
this tightness test shall be made at operating pressure with air, inert
gas, or water prior to placing the tank in service. In the case of
field-erected tanks the strength test may be considered to be the test
for tank tightness. Underground tanks and piping, before being covered,
enclosed, or placed in use, shall be tested for tightness
hydrostatically, or with air pressure at not less than 3 pounds per
square inch (20.68 kPa) and not more than 5 pounds per square inch
(34.47 kPa).
(iv) Repairs. All leaks or deformations shall be corrected in an
acceptable manner before the tank is placed in service. Mechanical
caulking is not permitted for correcting leaks in welded tanks except
pinhole leaks in the roof.
(v) Derated operations. Tanks to be operated at pressures below
their design pressure may be tested by the applicable provisions of
paragraphs (i)(7) (i) or (ii) of this section, based upon the pressure
developed under full emergency venting of the tank.
(j) Piping, valves, and fittings--(1) General--(i) Design. The
design (including selection of materials) fabrication, assembly, test,
and inspection of piping systems containing flammable or combustible
liquids shall be suitable for the expected working pressures and
structural stresses. Conformity with the applicable provisions of
Pressure Piping, ANSI B31 series and the provisions of this paragraph,
shall be considered prima facie evidence of compliance with the
foregoing provisions.
(ii) Exceptions. This paragraph does not apply to any of the
following:
(A) Tubing or casing on any oil or gas wells and any piping
connected directly thereto.
(B) Motor vehicle, aircraft, boat, or portable or stationary
engines.
(C) Piping within the scope of any applicable boiler and pressures
vessel code.
(iii) Definitions. As used in this paragraph, piping systems consist
of pipe, tubing, flanges, bolting, gaskets, valves, fittings, the
pressure containing parts of other components such as expansion joints
and strainers, and devices which serve such purposes as mixing,
separating, snubbing, distributing, metering, or controlling flow.
(2) Materials for piping, valves, and fittings--(i) Required
materials. Materials for piping, valves, or fittings shall be steel,
nodular iron, or malleable iron, except as provided in paragraphs (j)(2)
(ii), (iii) and (iv) of this section.
(ii) Exceptions. Materials other than steel, nodular iron, or
malleable iron may be used underground, or if required by the properties
of the flammable or combustible liquid handled. Material other than
steel, nodular iron, or malleable iron shall be designed to
specifications embodying principles recognized as good engineering
practices for the material used.
(iii) Linings. Piping, valves, and fittings may have combustible or
noncombustible linings.
(iv) Low-melting materials. When low-melting point materials such as
aluminum and brass or materials that soften on fire exposure such as
plastics, or non-ductile materials such as cast iron, are necessary,
special consideration shall be given to their behavior on fire exposure.
If such materials are used in above ground piping systems or inside
buildings, they shall be suitably protected against fire exposure or so
located that any spill resulting from the failure of these materials
could not unduly expose persons, important buildings or structures or
can be readily controlled by remote valves.
(3) Pipe joints. Joints shall be made liquid tight. Welded or
screwed joints or approved connectors shall be used. Threaded joints and
connections shall be made up tight with a suitable lubricant or piping
compound. Pipe joints dependent upon the friction characteristics of
combustible materials for mechanical continuity of piping shall not be
used inside buildings. They may be used outside of buildings above or
below ground. If used above ground, the piping shall either be secured
to prevent disengagement at the fitting or the piping system shall be so
designed
[[Page 203]]
that any spill resulting from such disengagement could not unduly expose
persons, important buildings or structures, and could be readily
controlled by remote valves.
(4) Supports. Piping systems shall be substantially supported and
protected against physical damage and excessive stresses arising from
settlement, vibration, expansion, or contraction.
(5) Protection against corrosion. All piping for flammable or
combustible liquids, both aboveground and underground, where subject to
external corrosion, shall be painted or otherwise protected.
(6) Valves. Piping systems shall contain a sufficient number of
valves to operate the system properly and to protect the plant. Piping
systems in connection with pumps shall contain a sufficient number of
valves to control properly the flow of liquid in normal operation and in
the event of physical damage. Each connection to pipelines, by which
equipments such as tankcars or tank vehicles discharge liquids by means
of pumps into storage tanks, shall be provided with a check valve for
automatic protection against backflow if the piping arrangement is such
that backflow from the system is possible.
(7) Testing. All piping before being covered, enclosed, or placed in
use shall be hydrostatically tested to 150 percent of the maximum
anticipated pressure of the system, or pneumatically tested to 110
percent of the maximum anticipated pressure of the system, but not less
than 5 pounds per square inch gage at the highest point of the system.
This test shall be maintained for a sufficient time to complete visual
inspection of all joints and connections, but for at least 10 minutes.
(k) Marine service stations--(1) Dispensing. (i) The dispensing area
shall be located away from other structures so as to provide room for
safe ingress and egress of craft to be fueled. Dispensing units shall in
all cases be at least 20 feet (6.08 m) from any activity involving fixed
sources of ignition.
(ii) Dispensing shall be by approved dispensing units with or
without integral pumps and may be located on open piers, wharves, or
floating docks or on shore or on piers of the solid fill type.
(iii) Dispensing nozzles shall be automatic-closing without a hold-
open latch.
(2) Tanks and pumps. (i) Tanks, and pumps not integral with the
dispensing unit, shall be on shore or on a pier of the solid fill type,
except as provided in paragraphs (k)(2) (ii) and (iii) of this section.
(ii) Where shore location would require excessively long supply
lines to dispensers, tanks may be installed on a pier provided that
applicable portions of paragraph (b) of this section relative to
spacing, diking, and piping are complied with and the quantity so stored
does not exceed 1,100 gallons (4,163.5 L) aggregate capacity.
(iii) Shore tanks supplying marine service stations may be located
above ground, where rock ledges or high water table make underground
tanks impractical.
(iv) Where tanks are at an elevation which would produce gravity
head on the dispensing unit, the tank outlet shall be equipped with a
pressure control valve positioned adjacent to and outside the tank block
valve specified in Sec. 1926.152(c)(8) of this section, so adjusted
that liquid cannot flow by gravity from the tank in case of piping or
hose failure.
(3) Piping. (i) Piping between shore tanks and dispensing units
shall be as described in paragraph (k)(2)(iii) of this section, except
that, where dispensing is from a floating structure, suitable lengths of
oil-resistant flexible hose may be employed between the shore piping and
the piping on the floating structure as made necessary by change in
water level or shoreline.
Table F-19--Electrical Equipment Hazardous Areas--Service Stations
------------------------------------------------------------------------
Class I
Location Group D Extent of classified area
division
------------------------------------------------------------------------
Underground tank:
Fill opening............... 1 Any pit, box or space below
grade level, any part of
which is within the Division
1 or 2 classified area.
[[Page 204]]
2 Up to 18 inches (45.72 cm)
above grade level within a
horizontal radius of 10 feet
(3.04 m) from a loose fill
connection and within a
horizontal radius of 5 feet
(1.52 m) from a tight fill
connection.
Vent--Discharging upward... 1 Within 3 feet (0.912 m) of
open end of vent, extending
in all directions.
2 Area between 3 feet (0.912 m)
and 5 feet (1.52 m) of open
end of vent, extending in
all directions.
Dispenser:
Pits....................... 1 Any pit, box or space below
grade level, any part of
which is within the Division
1 or 2 classified area.
Dispenser enclosure........ 1 The area 4 feet (1.216 m)
vertically above base within
the enclosure and 18 inches
(45.72 cm) horizontally in
all directions.
Outdoor.................... 2 Up to 18 inches (45.72 cm)
above grade level within 20
feet (6.08 m) horizontally
of any edge of enclosure.
Indoor:
With mechanical ventilation 2 Up to 18 inches (45.72 cm)
above grade or floor level
within 20 feet (6.08 m)
horizontally of any edge of
enclosure.
With gravity ventilation... 2 Up to 18 inches (45.72 cm)
above grade or floor level
within 25 feet (7.6 m)
horizontally of any edge of
enclosure.
Remote pump--Outdoor....... 1 Any pit, box or space below
grade level if any part is
within a horizontal distance
of 10 feet (3.04 m) from any
edge of pump.
2 Within 3 feet (0.912 m) of
any edge of pump, extending
in all directions. Also up
to 18 inches (45.72 cm)
above grade level within 10
feet (3.04 m) horizontally
from any edge of pump.
Remote pump--Indoor........ 1 Entire area within any pit.
2 Within 5 feet (1.52 m) of any
edge of pump, extending in
all directions. Also up to 3
feet (3.04 m) above floor or
grade level within 25 feet
(6.08 m) horizontally from
any edge of pump.
Lubrication or service room 1 Entire area within any pit.
2 Area up to 18 inches (45.72
cm) above floor or grade
level within entire
lubrication room.
Dispenser for Class I 2 Within 3 feet (0.912 m) of
liquids. any fill or dispensing
point, extending in all
directions.
Special enclosure inside 1 Entire enclosure.
building per Sec.
1910.106(f)(1)(ii).
Sales, storage and rest (\1\ ) If there is any opening to
rooms. these rooms within the
extent of a Division 1 area,
the entire room shall be
classified as Division 1.
------------------------------------------------------------------------
\1\ Ordinary.
(ii) A readily accessible valve to shut off the supply from shore
shall be provided in each pipeline at or near the approach to the pier
and at the shore end of each pipeline adjacent to the point where
flexible hose is attached.
(iii) Piping shall be located so as to be protected from physical
damage.
(iv) Piping handling Class I liquids shall be grounded to control
stray currents.
(4) Definition; as used in this section: Marine service station
shall mean that portion of a property where flammable or combustible
liquids used as fuels are stored and dispensed from fixed equipment on
shore, piers, wharves, or floating docks into the fuel tanks of self-
propelled craft, and shall include all facilities used in connection
therewith.
[44 FR 8577, Feb. 9, 1979; 44 FR 20940, Apr. 6, 1979, as amended at 51
FR 25318, July 11, 1986; 58 FR 35162, June 30, 1993; 63 FR 33469, June
18, 1998]
