Regl. 5293, art. 5-3.3.2
where flamany edge of such equipment,
Cite as Reglamento Núm. 5293, Art. 5-3.3.2
mable vapor-air mixtures may
extending in all directions. Also,
exist under normal operation.
space up to 3 feet above floor or
grade level within 5 feet to 25 feet
horizontally from any edge of such
equipment.*
Outdoor equipment of the type
1
Space within 3 feet of any edge of
covered in Flammable and
such equipment, extending in all
Combustible Liquids Code,
directions.
NFPA 30-1990 (ANSI), Section
2
Space between 3 feet and 8 feet of
5-3.3.2 where flammable vaporany edge of such equipment,
air mixtures may exist under
extending in all directions. Also,
normal operation.
space up to 3 feet above floor or
grade level within 3 feet to 10 feet
horizontally from any edge of such
equipment.
Tank - Aboveground**
1
Space inside dike where dike
height is greater than the distance
from the tank to the dike for more
than 50 percent of the tank circumference.
Shell, Ends, or Roof and Dike
2
Within 10 feet from shell, ends, or
Space
roof of tank. Space inside dikes to
level of top of dike.
Vent
1
Within 5 feet of open end of vent,
extending in all directions.
2
Space between 5 feet and 10 feet
from open end of vent, extending
in all directions.
Floating Roof
1
Space above the roof and within
the shell.
Underground Tank Fill Opening
1
Any pit, box, or space below
grade level, if any part is within a
Division 1 or 2 classified location.
2
Up to 18 inches above grade level
within a horizontal radius of 10
feet from a loose fill connection,
and within a horizontal radius of 5
feet from a tight fill connection.
Vent - Discharging Upward
1
Within 3 feet of open end of vent,
extending in all directions.
2
Space between 3 feet and 5 feet of
open end of vent, extending in all
directions.
*The release of Class I liquids may generate vapors to the extent that the entire building,
and possibly a zone surrounding it, should be considered a Class I, Division 2 location.
For Tanks - Underground, see Section 514-2.
ARTICLE 515 - BULK STORAGE PLANTS
70-517
Table 515-2. Class I Locations - Bulk Plants (cont.)
Class I,
Location
Division
Extent of Classified Location
Drum and Container Filling
Outdoors, or Indoors with
1
Within 3 feet of vent and fill open-
Adequate Ventilation
ings, extending in all directions.
2
Space between 3 feet and 5 feet
from vent or fill opening, extending in all directions. Also, up to 18
inches above floor or grade level
within a horizontal radius of 10
feet from vent or fill openings.
Pumps, Bleeders, Withdrawal
Fittings, Meters and Similar
Devices
Indoors
2
Within 5 feet of any edge of such
devices, extending in all directions. Also up to 3 feet above
floor or grade level within 25 feet
horizontally from any edge of
such devices.
Outdoors
2
Within 3 feet of any edge of such
devices, extending in all directions. Also up to 18 inches above
grade level within 10 feet horizontally from any edge of such
devices.
Pits
Without Mechanical
1
Entire space within pit if any part
Ventilation
is within a Division 1 or 2 classified location.
With Adequate Mechanical
2
Entire space within pit if any part
Ventilation
is within a Division 1 or 2 classified location.
Containing Valves, Fittings, or
2
Entire pit.
Piping, and not within a Division 1 or 2 Classified Location
Drainage Ditches, Separators,
Impounding Basins
Outdoor
2
Space up to 18 inches above
ditch, separator, or basin. Also up
to 18 inches above grade within 15
feet horizontally from any edge.
Indoor
Same as pits.
Tank Vehicle and Tank Car*
Loading Through Open Dome
1
Within 3 feet of edge of dome,
extending in all directions.
2
Space between 3 feet and 15 feet
from edge of dome, extending in
all directions.
*When classifying extent of space, consideration shall be given to fact that tank cars or
tank vehicles may be spotted at varying points. Therefore, the extremities of the loading or
unloading positions shall be used.
70-518
NATIONAL ELECTRICAL CODE
Table 515-2. Class I Locations - Bulk Plants (cont.)
Class I,
Location
Division
Extent of Classified Location
Loading through Bottom
1
Within 3 feet of point of venting to
Connections with
atmosphere, extending in all
Atmospheric Venting
directions.
2
Space between 3 feet and 15 feet
from point of venting to atmosphere, extending in all directions.
Also up to 18 inches above grade
within a horizontal radius of 10 feet
from point of loading connection.
Office and Rest Rooms
Ordinary
If there is any opening to these
rooms within the extent of an
indoor classified location, the
room shall be classified the same
as if the wall, curb, or partition
did not exist.
Loading through Closed
1
Within 3 feet of open end of vent,
Dome with Atmospheric
extending in all directions.
Venting
2
Space between 3 feet and 15 feet
from open end of vent, extending
in all directions. Also within 3 feet
of edge of dome, extending in all
directions.
Loading through Closed
2
Within 3 feet of point of connec-
Dome with Vapor Control
tion of both fill and vapor lines,
extending in all directions.
Bottom Loading with Vapor
2
Within 3 feet of point of connec-
Control
tions, extending in all directions.
Any Bottom Unloading
Also up to 18 inches above grade
within a horizontal radius of 10
feet from point of connections.
Storage and Repair Garage for
1
All pits or spaces below floor
Tank Vehicles
level.
2
Space up to 18 inches above floor
or grade level for entire storage or
repair garage.
Garages for other than Tank
Ordinary
If there is any opening to these
Vehicles
rooms within the extent of an outdoor classified location, the entire
room shall be classified the same
as the space classification at the
point of the opening.
Outdoor Drum Storage
Ordinary
Indoor Warehousing Where
Ordinary If there is any opening to these
There is No Flammable
rooms within the extent of an
Liquid Transfer
indoor classified location, the
room shall be classified the same
as if the wall, curb, or partition
did not exist.
Piers and Wharves
See Figure 1.
For SI units: one inch = 25.4 millimeters; one foot = 0.3048 meter.
ARTICLE 515 - BULK STORAGE PLANTS
70-519
50'
50'
25'
Deck
25'
25'
Open sump in deck for
Operating envelope
draining lines and hoses
and stored position
of loading arms or
hoses
1 Foot = 0.3 meters
50'
2'
25'
Approach
Pier
Shore
Water level
Division 1
Division 2
Nonclassified
Notes:
(1) The "source of vapor" shall be the operating envelope and stored position of the
outboard flange connection of the loading arm (or hose).
(2) The berth area adjacent to tanker and barge cargo tanks is to be Division 2 to the
following extent:
a. 25 ft (7.6 m) horizontally in all directions on the pier side from that
portion of the hull containing cargo tanks.
b. From the water level to 25 ft (7.6 m) above the cargo tanks at their
highest position.
(3) Additional locations may have to be classified as required by the presence of other
sources of flammable liquids on the berth, or by Coast Guard or other regulations.
Figure 1.x Marine Terminal Handling Flammable Liquids.
(c) Nonmetallic Wiring. Where rigid nonmetallic conduit or cable with a
nonmetallic sheath is used, an equipment grounding conductor shall be
included to provide for electrical continuity of the raceway system and for
grounding of noncurrent-carrying metal parts.
515-6. Sealing. Approved seals shall be provided in accordance with