SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

RULE 4623 - STORAGE OF ORGANIC LIQUIDS

(Adopted April 11, 1991) (Amended September 19, 1991; December 17, 1992;

December 20, 2001; May 19, 2005)

1.0 Purpose

The purpose of this rule is to limit volatile organic compound (VOC) emissions from the

storage of organic liquids.

2.0 Applicability

This rule applies to any tank with a capacity of 1,100 gallons or greater in which any

organic liquid is placed, held, or stored.

3.0 Definitions

3.1 APCO-approved VOC Control System: either an external floating-roof tank

complying with Section 5.3 provisions, internal floating-roof tank complying with

Section 5.4 provisions, a vapor recovery system complying with Section 5.6

provisions, or pressure vessel as defined in Section 3.24.

3.2 Capacity: the volume of a tank, as shown in the Permit to Operate (PTO), or the

tank manufacturer’s specifications if a tank does not have a PTO, or as determined

by District measurements.

3.3 Clean Produced Water: as defined in Rule 1020 (Definitions).

3.4 Contact Floating Roof: a roof, located inside an internal floating roof tank, that

floats on the liquid surface.

3.5 Crude Oil: petroleum extracted from the earth and which has not been processed in

a refining operation.

3.6 Deck Fitting: a functional or operational device on a tank floating roof that

substantially closes or seals a penetration in the deck of a floating roof.

3.7 Degassing: the process of removing organic vapors from a storage tank.

3.8 Emergency Standby Tank: a tank that does not receive or store an organic liquid for

more than 60 cumulative days during any 12-month period.

3.9 External Floating Roof: a tank cover in an open top tank consisting of a pan type,

pontoon type, or double-deck type cover that rests upon and is supported by the
organic liquid being contained. An external floating roof is equipped with closure

seals to close the space between the roof edge and tank shell.

3.10 Fixed Roof Tank: a tank with a roof that is permanently affixed to the shell of the

tank.

3.11 Gas Leak: a reading in excess of 10,000 parts per million by volume (ppmv), as

methane, above background on a portable hydrocarbon detection instrument that is

calibrated with methane in accordance with the test method in Section 6.4.8.

3.12 Gasoline: any petroleum distillate, petroleum distillate/alcohol blend, or alcohol,

having a Reid vapor pressure of four (4) psia or greater which is used as motor fuel

which is commonly or commercially known or sold as gasoline.

3.13 Gauge Float: a device to indicate the level of the liquid within a tank. The float

rests on the liquid surface inside a gauge well in the tank.

3.14 Gauge Hatch/Sample Well (Ports): consists of a pipe sleeve equipped with a selfclosing gasketed cover (to reduce evaporative losses) and allows hand-gauging or

sampling of the stored liquid. The gauge hatch/sample port is usually located

beneath the gauger’s platform, which is mounted on top of the tank shell. A cord

may be attached to the self-closing gasketed cover so that the cover can be opened

from the platform.

3.15 Guidepole: an anti-rotation device that is fixed to the top and bottom of a tank,

passing through a well in a floating roof. A guidepole may be solid or be equipped

with slots or holes for gauging purposes provided the guidepole is equipped with an

appropriate sealing device that prevents openings that expose the stored liquid to the

atmosphere.

3.16 Internal Floating Roof: a pan type, pontoon type, or double-deck type cover located

inside a fixed roof tank that rests upon and is supported by the organic liquid being

contained. An internal floating roof is equipped with closure seals to close the space

between the roof edge and tank shell.

3.17 Leak-Free: a condition without a gas leak or a liquid leak.

3.18 Liquid Leak: the dripping of organic liquid at a rate of more than 3 drops per

minute.

3.19 Maximum Operating Level: the highest achievable level of fluid within a tank, as

determined by the structural design of the tank. In the absence of tank specific

design information, the maximum operating level is equal to tank capacity.

3.20 Metallic-Shoe Type (Mechanical Shoe) Seal: a metallic sheet (the shoe) that is held

vertically against the vertical tank wall. The shoe is connected by braces to the
floating roof and is held tightly against the wall by springs or weighted levers. A

flexible coated fabric (envelope) is suspended from the shoe seal to the floating roof

to form a vapor barrier over the annular space between the roof and the primary

seal.

3.21 Non-contact Floating Roof: a roof that is located inside an internal floating roof

tank that is supported on pontoons several inches above the liquid surface.

3.22 Organic Liquid: any liquid which contains volatile organic compounds (VOCs)

including, but not limited to, crude oils and petroleum distillates.

3.23 Petroleum Distillate: the product of a crude oil distillation or condensation process

obtained by condensing the vapors for the purpose of purification, fractionation, or

the formation of new substances.

3.24 Pressure Vessel: a tank, reservoir, or container that is capable of maintaining

working pressures sufficient to prevent organic liquid loss or VOC loss to the

atmosphere at all times.

3.25 Resilient-Toroid-Type seal: a core of open-cell foam encapsulated in a coated

fabric that is attached to a mounting on the deck perimeter, and is continuous

around the floating roof circumference.

3.26 Rim Vent: a vent used on tanks equipped with a seal design, such as a mechanical

shoe seal, that creates a vapor pocket in the seal and rim area. The vent is used to

release excess pressure or vacuum that is present in the vapor space bounded by the

primary-seal shoe, the floating roof rim, the primary seal fabric, and the liquid level.

 A rim vent usually consists of a weighted pallet that rests on a gasketed cover.

3.27 Roof Drain: a drain that permits the removal of rainwater from the surface of

external floating roofs. A roof drain may be a closed drainage system that carries

rainwater from the surface of the floating roof to the outside of the tank, or an open

drainage system consisting of an open pipe that extends a short distance below the

bottom of the deck allowing rainwater to drain from the surface of the floating roof

into the organic liquid contents of the tank.

3.28 Roof Leg: an adjustable or fixed leg that is attached to the floating roof deck to

support or hold the floating roof deck at a predetermined distance off the tank

bottom to prevent damage to the fittings located underneath the deck and to allow

for tank cleaning or repair. For adjustable legs, the load-carrying element passes

through a well or sleeve in the deck.

3.29 Small Producer: an operator in the business of crude oil production who:
3.29.1 Produces an average of less than 6000 barrels per day of crude oil from all

operations within the county; and

3.29.2 Does not engage in refining, transportation, or marketing of refined

petroleum products.

3.30 Tank: any stationary container, reservoir, or vessel, in which an organic liquid is

placed, held, or stored.

3.31 Tank Battery: for crude oil production facilities, a tank battery is an aggregation of

two or more tanks where the tanks are located so that no one tank is more than 150

feet from another tank as measured from the closest tank edges, and the tanks are

located in the same crude oil production field. For non-crude oil production

facilities, a tank battery is an aggregation of two or more tanks located within the

same facility, regardless of the distance of the tanks from each other.

3.32 True Vapor Pressure (TVP): the equilibrium partial vapor pressure exerted by an

organic liquid at actual storage temperature.

3.33 Uncontrolled Fixed Roof Tank: a fixed roof tank that is not connected to an APCOapproved vapor recovery system operated as specified in Section 5.6.

3.34 Vacuum Breaker: a device that equalizes the pressure of the vapor space across the

floating roof deck as the deck is either being landed on or off its legs. A vacuum

breaker consists of a well with a cover. Attached to the underside of the cover is a

guided leg long enough to contact the tank bottom as the floating deck approaches. 

When in contact with the tank bottom, the guide leg mechanically opens the breaker

by lifting the cover off the well; otherwise the cover closes the well. Because the

purpose of the vacuum breaker is to allow for the free exchange of air and/or vapor,

the well does not extend appreciably below the deck.

3.35 Visible Gap: an opening that exceeds 0.060 inch.

3.36 Volatile Organic Compound (VOC): as defined in Rule 1020 (Definitions).

3.37 Zero Gap: no gap between the tank shell and the seal shall exceed 0.06 inch. The

cumulative length of all gaps exceeding 0.02 inch shall not be more than five (5)

percent of the circumference of the tank, excluding gaps less than 1.79 inches from

vertical seams.

3.38 Zero Gap Pole Wiper Seal: a seal with no gap exceeding 0.06 inches between outer

surface of the guidepole or gauge well and pole wiper seal.

4.0 Exemptions

4.1 The provisions of this rule shall not apply to:
4.1.1 Pressure vessels.

4.1.2 Gasoline storage tanks with a capacity of less than 19,800 gallons that are

subject to the requirements of Rule 4621 (Gasoline Transfer Into Stationary

Storage Containers, Delivery Vessels, and Bulk Plants).

4.1.3 Tanks that are used for storage/processing of clean produced water, or other

water that meets the VOC standard specified in the definition of “clean

produced water” in Rule 1020 (Definitions).

4.1.4 Tanks used in wine fermentation and for storage of resulting products, byproducts, and spirits.

4.2 Except for complying with Sections 6.3.2, 6.3.3 and 7.2, the requirements of this

rule shall not apply to:

4.2.1 Emergency standby tanks, in existence prior to May 1, 1979, which

exclusively store petroleum distillates or crude oil. Prior to return to

Emergency Standby status, the contents of each tank shall be drained to the

maximum extent feasible. After a tank has been used (filled or partially

filled) and draining of the tank has begun, any further filling of the tank shall

constitute a separate use of the tank, and the number of days the tank is used

shall be counted towards the 60 cumulative days limit specified in the

definition of an emergency standby tank in Section 3.8. Fixed roof

emergency standby tanks shall be equipped with a pressure-vacuum relief

valve that meets the requirements of Section 5.2.

4.2.2 Temporary tanks, with capacities of 21,000 gallons (500 barrels) or less, left

on site for six months or less.

4.3 Except for complying with Sections 6.3.4 and 7.2, a small producer’s tank with a

throughput of 50 barrels of crude oil per day or less is exempt from the requirements

of this rule. All other small producer tanks that do not qualify for exemption under

Section 4.4 shall comply with all the requirements of this rule.

4.4 Tanks exclusively receiving and/or storing an organic liquid with a TVP less than 0.5

psia are exempt from all other requirements of the rule except for complying with the

following provisions:

4.4.1 TVP and API Gravity Testing provisions pursuant to Section 6.2,

4.4.2 Recordkeeping provisions pursuant to Section 6.3.6,

4.4.3 Test Methods provisions pursuant to Section 6.4, and
4.4.4 Compliance schedules pursuant to Section 7.2.

The requirements of Section 4.4 shall not apply to tanks that are exempt pursuant to

Sections 4.1 through 4.3.

5.0 Requirements

5.1 VOC Control System Requirements

5.1.1 General VOC Control System Requirements

Except for small producers who are required to comply with the VOC control

system requirements in Section 5.1.2, an operator shall not place, hold, or

store organic liquid in any tank unless such tank is equipped with a VOC

control system identified in Table 1. The specifications for the VOC control

system are described in Sections 5.2, 5.3, 5.4, 5.5, and 5.6.

Table 1 – General VOC Control System Requirements

Tank True Vapor Pressure (TVP) of Organic Liquid

Capacity

(Gallons) 0.5 psia to <1.5 psia 1.5 psia to <11 psia ≥11.0 psia

(Group A)

1,100 to

19,800

Pressure-vacuum relief valve,

or internal floating roof, or

external floating roof, or

vapor recovery system

Pressure-vacuum relief

valve, or internal

floating roof, or

external floating roof,

or vapor recovery

system

Pressure vessel or

vapor recovery

system

(Group B)

>19,800 to

39,600

Pressure-vacuum relief valve,

or internal floating roof, or

external floating roof, or

vapor recovery system

Internal floating roof,

or external floating

roof, or vapor recovery

system

Pressure vessel or

vapor recovery

system

(Group C)

>39,600

Internal floating roof, or

external floating roof, or

vapor recovery system

Internal floating roof,

or external floating

roof, or vapor recovery

system

Pressure vessel or

vapor recovery

system

5.1.2 Small Producer VOC Control System Requirements

A small producer shall not place, hold, or store crude oil in any tank unless

such tank is equipped with a VOC control system identified in Table 2. For

storage of any organic liquid except crude oil, a small producer shall comply
with the requirements of Section 5.1.1. The specifications for the VOC

control system are described in Sections 5.2, 5.3, 5.4, 5.5, and 5.6.

Table 2 – Small Producer VOC Control System Requirements for Crude Oil Storage Tanks

TVP and Crude Oil Throughput

Tank

Capacity

(gallons)

0.5 psia to <11 psia and a

tank throughput of >50 to

<150 barrels of crude oil

per day

0.5 psia to <11 psia and a

tank throughput ≥150

barrels of crude oil per

day

≥11 psia and

regardless of

crude oil tank

throughput

(Group A)

1,100 to

39,600

Pressure-vacuum relief

valve, or internal floating

roof, or external floating

roof, or vapor recovery

system

Pressure-vacuum relief

valve, or internal floating

roof, or external floating

roof, or vapor recovery

system

Pressure vessel

or vapor

recovery system

(Group B)

>39,600

Pressure-vacuum relief

valve, or internal floating

roof, or external floating

roof, or vapor recovery

system

Internal floating roof, or

external floating roof, or

vapor recovery system

Pressure vessel

or vapor

recovery system

5.1.3 All tanks subject to the control requirements of this rule shall be maintained in

a leak-free condition, except for the following components and as allowed by

Section 5.2 and applicable provisions of Table 3 through Table 5, and Section

5.7.5.4:

5.1.3.1 Primary seals and secondary seals of external floating roof tanks

that are in compliance with the applicable requirements specified

in Sections 5.3.2.1, 5.3.2.2, and 5.3.2.3.

5.1.3.2 Primary seals and secondary seals of internal floating roof tanks

that are in compliance with the applicable requirements specified

in Section 5.4.1.

5.1.3.3 Floating roof deck fittings that are in compliance with the

applicable requirements specified in Sections 5.5.2.1.5, 5.5.2.2.5,

5.5.2.3.3, 5.5.2.4.2, and 5.5.2.4.3.

5.1.3.4 Floating roof automatic bleeder vents that are in compliance with

requirements specified in Sections 5.5.2.1.3 and 5.5.2.2.3 during

product change provided product change is accomplished as

expeditiously as practicable.
5.2 Specifications for Pressure-Vacuum Relief Valve

The pressure-vacuum relief valve shall be set to within ten (10) percent of the

maximum allowable working pressure of the tank. The pressure-vacuum relief valve

shall be permanently labeled with the operating pressure settings. The pressurevacuum relief valve shall be properly installed and maintained in good operating order

in accordance with the manufacturer’s instructions, and shall remain in leak-free

condition except when the operating pressure exceeds the valve set pressure.

5.3 Specifications for External Floating Roof Tanks

5.3.1 An external floating roof tank shall be:

5.3.1.1 Equipped with a floating roof consisting of a pan type that is

installed before December 20, 2001, pontoon-type, or double-deck

type cover, that rests on the surface of the liquid contents; and

5.3.1.2 Equipped with a closure device between the tank shell and roof

edge consisting of two seals, one above the other; the one below

shall be referred to as the primary seal, and the one above shall be

referred to as the secondary seal.

5.3.1.3 The floating roof shall be floating on the surface of the stored

liquid at all times (i.e., off the roof leg supports) except during the

initial fill until the roof is lifted off the leg supports and when the

tank is completely emptied and subsequently refilled. When the

roof is resting on the leg supports the processes of filling or

emptying and refilling the tank shall be continuous and shall be

accomplished as rapidly as possible. Whenever the operator

intends to land the roof on its legs, an operator shall notify the

APCO in writing at least five calendar days prior to performing the

work. The tank must be in compliance with this rule before the

operator may land the roof on its legs. The required information to

be included in the written notification as well as the recordkeeping

requirements is specified in Section 6.3.7.

5.3.2 Seal designs shall be submitted to the APCO and shall not be installed or used

unless they are approved by the APCO as meeting the criteria set forth in

Sections 5.3.2.1 through 5.3.2.3 as applicable. Seal designs other than set

forth in Sections 5.3.2.1 through 5.3.2.3 may be approved provided that a

notice allowing the use of such design has been published in the Federal

Register pursuant to CFR 40 Part 60: Subpart Kb paragraph 60.114b.

5.3.2.1 Welded Tanks with Primary Metallic-Shoe Type Seal
5.3.2.1.1 No gap between the tank shell and the primary seal

shall exceed one and one half (1-1/2) inches. The

cumulative length of all gaps between the tank shell and

the primary seal greater than one-half (1/2) inch shall

not exceed ten (10) percent of the circumference of the

tank. The cumulative length of all primary seal gaps

greater than one-eighth (1/8) inch shall not exceed 30

percent of the tank circumference. No continuous gap

greater than one-eighth (1/8) inch shall exceed ten (10)

percent of the tank circumference.

5.3.2.1.2 No gap between the tank shell and the secondary seal

shall exceed one-half (1/2) inch. The cumulative length

of all gaps between the tank shell and the secondary

seal, greater than one-eighth (1/8) inch shall not exceed

five (5) percent of the tank circumference.

5.3.2.1.3 Metallic-shoe-type seals shall be installed so that one

end of the shoe extends into the stored liquid and the

other end extends a minimum vertical distance of 24

inches above the stored liquid surface.

5.3.2.1.4 The geometry of the metallic-shoe type seal shall be

such that the maximum gap between the shoe and the

tank shell is no greater than double the gap allowed by

the seal gap criteria specified in Section 5.3.2.1.1 for a

length of at least 18 inches in the vertical plane above

the liquid surface.

5.3.2.1.5 There shall be no holes, tears, or openings in the

secondary seal or in the primary seal envelope that

surrounds the annular vapor space enclosed by the roof

edge, seal fabric, and secondary seal.

5.3.2.1.6 The secondary seal shall allow easy insertion of probes

up to one and one-half (1-1/2) inches in width in order

to measure gaps in the primary seal.

5.3.2.1.7 The secondary seal shall extend from the roof to the

tank shell and shall not be attached to the primary seal.

5.3.2.2 Riveted Tank with Primary Metallic-Shoe Type Seal
5.3.2.2.1 No gap between the tank shell and the primary seal

shall exceed two and one-half (2-1/2) inches. The

cumulative length of all primary seal gaps greater than

one and one-half (1-1/2) inches shall be not exceed ten

(10) percent of the circumference of the tank. The

cumulative length of all gaps between the tank shell and

the primary seal greater than one-eighth (1/8) inch shall

not exceed 30 percent of the circumference of the tank. 

No continuous gap greater than one-eighth (1/8) inch

shall exceed ten (10) percent of the tank circumference.

5.3.2.2.2 No gap between the tank shell and the secondary seal

shall exceed one-half (1/2) inch. The cumulative length

of all gaps between the tank shell and the secondary

seal greater than one-eighth (1/8) inch shall not exceed

five (5) percent of the tank circumference.

5.3.2.2.3 Metallic shoe-type seals shall be installed so that one

end of the shoe extends into the stored liquid and the

other end extends a minimum vertical distance of 24

inches above the stored liquid surface. The geometry of

the metallic-shoe type seal shall be such that the

maximum gap between the shoe and the tank shell is no

greater than double the gap allowed by the seal gap

criteria specified in Section 5.3.2.2.1 for a length of at

least 18 inches in the vertical plane

5.3.2.2.4 There shall be no holes, tears, or openings in the

secondary seal or in the primary seal envelope that

surrounds the annular vapor space enclosed by the roof

edge, seal fabric, and secondary seal.

5.3.2.2.5 The secondary seal shall allow easy insertion of probes

up to two and one-half (2-1/2) inches in width in order

to measure gaps in the primary seal.

5.3.2.2.6 The secondary seal shall extend from the roof to the

tank shell and shall not be attached to the primary seal.

5.3.2.3 Tanks with Primary Resilient Toroid Seal:
5.3.2.3.1 The primary resilient toroid seal shall be mounted on

the perimeter of the roof such that it is in contact with

the tank’s liquid contents at all times while the roof is

floating.

5.3.2.3.2 No gap between the tank shell and the primary seal

shall exceed one-half (1/2) inch. The cumulative length

of all primary seal gaps greater than one-eighth (1/8)

inch shall not exceed five (5) percent of the tank

circumference. No continuous gap greater than oneeighth (1/8) inch shall exceed ten (10) percent of the

tank circumference.

5.3.2.3.3 No gap between the tank shell and the secondary seal

shall exceed one-half (1/2) inch. The cumulative length

of all gaps between the tank shall and the secondary

seal, greater than one-eighth (1/8) inch shall not exceed

five (5) percent of the tank circumference.

5.3.2.3.4 There shall be no holes, tears, or openings in the

secondary seal or in the primary seal envelope that

surrounds the annular vapor space enclosed by the roof

edge, seal fabric, and secondary seal.

5.3.2.3.5 The secondary seal shall allow easy insertion of probes

up to one-half (1/2) inch in width in order to measure

gaps in the primary seal.

5.3.2.3.6 The secondary seal shall extend from the roof of the

tank to the shell and not be attached to the primary seal.

5.3.2.4 The following seal designs have been found to be equivalent to

seals meeting the criteria set forth in Sections 5.3.2.1 through

5.3.2.3:

5.3.2.4.1 When installed and maintained with zero gap:

MANUFACTURER MODEL

Republic Fabricators WeatherGuard Seal

5.3.2.4.2 When installed and maintained to meet the gap criteria

for primary and secondary seals set forth in Sections

5.3.2.1 through 5.3.2.3:
MANUFACTURER MODEL

"HMT" Dual/Multi Blade Wiper Seals

5.4 Specifications for Internal Floating Roof Tanks

5.4.1 Internal floating roof tanks shall be equipped with seals that meet the criteria

set forth in Section 5.3, except for complying with the requirement specified

in Section 5.3.2.1.3. For internal floating roof, the metallic-shoe type seals

shall be installed so that one end of the shoe extends into the stored liquid and

the other end extends a minimum vertical distance of 18 inches above the

stored liquid surface.

5.4.2 The following seal designs have been found to be equivalent to seals meeting

the criteria set forth in Section 5.3:

5.4.2.1 When installed and maintained with zero gap:

MANUFACTURER MODEL

Ultraflote Single Ultraseal

5.4.2.2 When installed and maintained to meet the gap criteria for primary

and secondary seals set forth in Sections 5.3.2.1 through 5.3.2.3:

MANUFACTURER MODEL

Ultraflote Dual Ultraseal

Altech Double Wiper Seal

5.4.3 The operator shall comply with the floating roof landing requirements

specified in Section 5.3.1.3.
5.5 Floating Roof Deck Fitting Requirements

5.5.1 All openings in the roof used for sampling or gauging, except

pressure-vacuum valves complying with Section 5.2, shall provide a

projection below the liquid surface to prevent belching of liquid and to prevent

entrained or formed organic vapor from escaping from the liquid contents of

the tank and shall be equipped with a cover, seal, or lid. The cover, seal, or lid

shall at all times be in a closed position, with no visible gaps and leak-free,

except when the device or appurtenance is in use for sampling or gauging.

5.5.2 Tanks shall meet the requirements of Sections 5.1.3, 5.5.1, and Sections

5.5.2.1 through 5.5.2.4.

5.5.2.1 Requirements for Internal Floating Roof Deck Fittings

5.5.2.1.1 Each opening in a non-contact internal floating roof

except for automatic bleeder vents (vacuum breaker

vents) and rim space vents shall provide a projection

below the liquid surface.

5.5.2.1.2 Each opening in the internal floating roof except for leg

sleeves, automatic bleeder vents, rim space vents,

column wells, ladder wells, sample wells, combination

manway/vacuum breakers, and stub drains shall be

equipped with a cover, or a lid shall be maintained in a

closed position at all times (i.e., no visible gap) except

when the device is in use. The cover or lid shall be

equipped with a gasket. Covers on each access hatch

and automatic gauge float well shall be bolted in place

except when they are in use.

5.5.2.1.3 Automatic bleeder vents shall be equipped with a

gasket and shall be closed at all times when the roof is

floating except when the roof is being floated off or is

being landed on the leg roof supports.

5.5.2.1.4 Rim vents shall be equipped with a gasket and shall be

set to open only when the internal floating roof is not

floating or set to open at the manufacturer’s

recommended setting.

5.5.2.1.5 Each penetration of the internal floating roof for the

purpose of sampling shall be a sample well. The well

shall have a slit fabric cover that covers at least 90
percent of the opening. The fabric cover must be

impermeable.

5.5.2.1.6 Each penetration of the internal floating roof that allows

for passage of a column supporting the fixed roof shall

have a flexible fabric sleeve seal or a gasketed sliding

cover. The fabric sleeve must be impermeable.

5.5.2.2 Requirements for External Floating Roof Deck Fittings

5.5.2.2.1 Except for automatic bleeder vents and rim vents and

pressure vacuum relief vents, each opening in a noncontact external floating roof shall provide a projection

below the liquid surface.

5.5.2.2.2 Except for automatic bleeder vents and rim vents, roof

drains, and leg sleeves, each opening in the roof shall be

equipped with a gasketed cover, seal, or lid that shall be

maintained in a closed position at all times (i.e., no

visible gap) except when in actual use.

5.5.2.2.3 Automatic bleeder vents shall be equipped with a

gasket and shall be closed at all times when the roof is

floating except when the roof is being floated off or is

being landed on the roof leg supports.

5.5.2.2.4 Rim vents shall be equipped with a gasket and shall be

set to open when the roof is being floated off the roof

leg supports or at the manufacturer’s recommended

setting.

5.5.2.2.5 Each emergency roof drain shall be provided with a

slotted membrane fabric cover that covers at least 90

percent of the area of the opening. The fabric cover

must be impermeable if the liquid is drained into the

contents of the tanks.

5.5.2.2.6 External floating roof legs shall be equipped with vapor

socks or vapor barriers in order to maintain a leak-free

condition so as to prevent VOC emissions from

escaping through the roof leg opening.
5.5.2.3 Solid Guidepole

Solid sampling or gauging wells, and similar fixed projections

through a floating roof such as an anti-rotational pipe, shall meet

the following requirements:

5.5.2.3.1 The well shall provide a projection below the liquid

surface.

5.5.2.3.2 The well shall be equipped with a pole wiper and a

gasketed cover, seal or lid which shall be in a closed

position at all times (i.e., no visible gap) except when

the well is in use.

5.5.2.3.3 The gap between the pole wiper and the guidepole shall

be added to the gaps measured to determine compliance

with the secondary seal requirement, and in no case

shall exceed one-half (1/2) inch.

5.5.2.4 Slotted Guidepole

Slotted sampling or gauging wells shall meet the following

requirements:

5.5.2.4.1 The well shall provide a projection below the liquid

surface.

5.5.2.4.2 The well on external floating roof shall be equipped

with the following: a sliding cover, a well gasket, a pole

sleeve, a pole wiper, and an internal float and float

wiper designed to minimize the gap between the float

and the well, and provided the gap shall not exceed oneeighth (1/8) inch; or shall be equipped with a well

gasket, a zero gap pole wiper seal and a pole sleeve that

projects below the liquid surface.

5.5.2.4.3 The gap between the pole wiper and the guidepole shall

be added to the gaps measured to determine compliance

with the secondary seal requirement, and in no case

shall exceed one-eighth (1/8) inch.

5.6 Specifications for Vapor Recovery Systems

5.6.1 Fixed roof tanks shall be fully enclosed and shall be maintained in a leak-free

condition. An APCO-approved vapor recovery system shall consist of a
closed system that collects all VOCs from the storage tank, and a VOC control

device. The vapor recovery system shall be maintained in a leak-free

condition. The VOC control device shall be one of the following:

5.6.1.1 A condensation or vapor return system that connects to one of the

following: a gas processing plant, a field gas pipeline, a pipeline

distributing Public Utility Commission quality gas for sale, an

injection well for disposal of vapors as approved by the California

Department of Conservation, Division of Oil Gas, and Geothermal

Resources, or

5.6.1.2 A VOC control device that reduces the inlet VOC emissions by at

least 95 percent by weight as determined by the test method

specified in Section 6.4.6.

5.6.2 Any tank gauging or sampling device on a tank vented to the vapor recovery

system shall be equipped with a leak-free cover which shall be closed at all

times except during gauging or sampling.

5.6.3 All piping, valves, and fittings shall be constructed and maintained in a leakfree condition.

5.7 Voluntary Tank Preventive Inspection and Maintenance, and Tank Interior Cleaning

Program

Only operators who elect to participate in the voluntary tank preventive inspection

and maintenance, and tank interior cleaning program (program) shall be allowed to

use the provisions specified in Tables 3 to 5 and Section 5.7.5. When using Tables 3

to 5 and Section 5.7.5 provisions, operators shall perform the procedures as

expeditiously as practicable and minimize emissions to the maximum extent

practicable. To participate in this program, the operator shall comply with the

requirements of Sections 5.7.1 through 5.7.4.

5.7.1 Submit a letter to the APCO prior to conducting tank inspection, maintenance,

and cleaning activities. The letter shall contain a list of each tank that will be

subject to this program. The list shall include the tank identification number

and location, and/or PTO numbers.

5.7.2 Keep in their facility at all times a copy of the letter sent to the APCO and

maintain the records of annual tank inspection, maintenance and cleaning

activities, to document their participation in the program.

5.7.3 The absence of a copy of the letter and/or failure to maintain appropriate

records shall be deemed as non-participation in the program, and therefore the

operator will not be eligible to use the provisions specified in Tables 3 to 5
and Section 5.7.5. Those who have not voluntarily participated in the program

but are found to be using the provisions of Tables 3 to 5, and Section 5.7.5

shall be deemed to be in violation of this rule.

5.7.4 Operators who elect to participate in this program but who fail to comply with

all of the requirements specified in Tables 3 to 5 and Section 5.7.5 shall be

deemed to be a violation of the provisions of this rule.

5.7.5 Storage Tank Degassing and Interior Cleaning Requirements

5.7.5.1 Notification

Operators of storage tanks subject to the requirements of Section

5.7 shall notify the APCO in writing at least three (3) days prior to

performing tank degassing and interior tank cleaning activities.

Written notification shall include the following information:

5.7.5.1.1 The PTO number and physical location of the tank

being degassed,

5.7.5.1.2 The date and time that tank degassing and cleaning

activities will begin,

5.7.5.1.3 The degassing method, as allowed pursuant to Section

5.7.5.4, to be used,

5.7.5.1.4 The method to be used to clean the tank, including any

solvents to be used, and

5.7.5.1.5 The method to be used to dispose of the removed

sludge, including methods that will be used to control

emissions from the receiving vessel and emissions

during transport.

5.7.5.2 Records

Operators shall maintain records of tank cleaning activities for a

period of 5 years and present said records to the APCO upon

request. Records should include the final details of the planned

activities submitted pursuant to Section 5.7.5.1.

5.7.5.3 Fixed-Roof Tanks Operating Only a Pressure-Vacuum Relief

Valve
5.7.5.3.1 Except for complying with Section 5.7.5.3.2

requirements, fixed-roof tanks allowed, pursuant to

Tables 1 and 2 of this rule, to operate a pressurevacuum relief valve as the primary VOC control system

are not subject to the degassing requirements specified

in Section 5.7.5.4.

5.7.5.3.2 Operators shall comply with the requirements of

Section 5.2 during the process of draining, and refilling

the tank with an organic liquid having a TVP of 0.5 psia

or greater.

5.7.5.3.3 The requirements specified in Sections 5.1 and 5.2 shall

not apply to the tank during interior cleaning or

maintenance activities.

5.7.5.4 Tank Degassing Requirements

Except for tanks satisfying Section 5.7.5.3 provisions, the process

of tank degassing shall be accomplished by emptying the tank of

organic liquid having a TVP of 0.5 psia or greater, and minimizing

organic vapors in the tank vapor space by one of the following

methods:

5.7.5.4.1 Exhaust VOCs contained in the tank vapor space to an

APCO-approved vapor recovery system until the

organic vapor concentration is 5,000 ppmv or less, or is

10 percent or less of the lower explosion limit (LEL),

whichever is less; or

5.7.5.4.2 Displace VOCs contained in the tank vapor space to an

APCO-approved vapor recovery system by filling the

tank with a suitable liquid until 90 percent or more of

the maximum operating level of the tank is filled. 

Suitable liquids are organic liquids having a TVP of

less than 0.5 psia, water, clean produced water, or

produced water derived from crude oil having a TVP

less than 0.5 psia; or

5.7.5.4.3 Displace VOCs contained in the tank vapor space to an

APCO-approved vapor recovery system by filling the

tank with a suitable gas. Degassing shall continue until

the operator has achieved a vapor displacement

equivalent to at least 2.3 times the tank capacity. 

Suitable gases are air, nitrogen, carbon dioxide, or
natural gas containing less than 10 percent VOC by

weight; or

5.7.5.4.4 For free-water knockout tanks, the operator may degas

the tank vapor space by restricting the outflow of water

and floating off the oilpad, such that at least 90 percent

of the tank volume is displaced.

5.7.5.4.5 During degassing, the operator shall discharge or

displace organic vapors contained in the tank vapor

space to an APCO-approved vapor recovery system that

is leak-free and meets the requirements of Section

5.6.1.1 or Section 5.6.1.2.

5.7.5.4.6 To facilitate connection to an external APCO-approved

vapor recovery system a suitable tank fitting, such as a

manway, may be temporarily removed for a period of

time not to exceed 1 hour.

5.7.5.4.7 Except as provided for in Section 5.7.5.4.9, the tank

shall be in compliance with the applicable requirements

specified in Section 5.1 through Section 5.6 during

draining, degassing, and refilling the tank with an

organic liquid having a TVP of 0.5 psia or greater.

5.7.5.4.8 Draining and refilling of floating roof tanks shall occur

as a continuous process and shall proceed as rapidly as

practicable while the roof is not floating on the surface

of the stored liquid.

5.7.5.4.9 For floating-roof tanks, the gap seal requirements

specified in Sections 5.3.2 and 5.4.2 shall not apply

while the roof is resting on its legs, and during the

processes of draining, degassing, or refilling the tank.

The leak-free condition specified in Section 5.1.3 shall

not apply during refilling the tank, if the operator

complies with Section 5.7.5.4.8 requirements.

5.7.5.4.10 After a tank has been degassed pursuant to the

provisions of Section 5.7.5 the requirements specified

in Section 5.1 through Section 5.6 shall not apply until

an organic liquid having a TVP of 0.5 psia or greater is

placed, held, or stored in the tank.

5.7.5.5 Tank Cleaning
5.7.5.5.1 While performing tank cleaning activities, operators

may use the following cleaning agents: diesel, solvents

with an initial boiling point of greater than 302o

F,

solvents with a vapor pressure of less than 0.5 psia, or

solvents with 50 grams per liter VOC content or less.

5.7.5.5.2 Steam cleaning shall be allowed at locations where

wastewater treatment facilities are limited or during the

months of December through March.

5.7.5.6 Removed Sludge

Operators of tanks containing an organic liquid with a TVP of 1.5

psia or greater shall control emissions from the removed sludge by

complying with all of the following provisions:

5.7.5.6.1 During sludge removal the operator shall control

emissions from the receiving vessel by operating an

APCO-approved vapor control device that reduces

emissions of organic vapors by at least 95 percent.

5.7.5.6.2 Operators shall transport removed sludge in closed,

liquid leak-free containers.

5.7.5.6.3 Notwithstanding Section 5.7.5.6.2, operators shall store

removed sludge, until final disposal, in leak-free

containers, or tanks complying with Section 5.1

requirements. Sludge that is to be used to manufacture

roadmix, as defined in Rule 2020 (Exemptions), is

exempt from this requirement. Roadmix manufacturing

operations exempt pursuant to Rule 2020, shall

maintain documentation of their compliance with Rule

2020, and promptly make said documentation available

to the APCO upon request.

Table 3: Fixed Roof Tank Preventive Inspection and Maintenance
Emission Minimization for Components Serving Organic Liquid Storage Tanks

Components

Maintenance

Schedule Emission Minimization Additional Requirements

1. Hatch

2. Tank seals and

seams

3. Cable Seals

4. Piping

components

directly affixed

to the tank and

within five feet

of the tank,

including but

not limited to:

-Valves

-Flanges

-Connectors

1. Conduct annual

inspections with

maintenance and

repair of

components.

2. Conduct visual

inspections and

inspections using

a portable

hydrocarbon

detection

instrument

conducted in

accordance with

EPA Method 21.

3. Visually or

ultrasonically

inspect as

appropriate, the

external shells

and roofs of uninsulated tanks

for integrity

annually.

1. Liquid Leak

Repair leaking components that

have a liquid leak rate of ≥30

drops per minute, within 8 hours

after detection. Repair leaking

components that have a liquid

leak rate of ≥3 to <30 drops per

minute within 24 hours after

detection.

2. Gas leak

Comply with the following

requirements to repair leaking

components that have a gas leak

>10,000 ppmv (measured in

accordance with EPA Method 21

by a portable hydrocarbon

detection instrument that is

calibrated with methane):

a. Eliminate the leak within 8

hours after detection; or

b. If the leak can not be

eliminated, then minimize

the leak to the lowest

possible level within 8

hours after detection by

using best maintenance

practices; and

c. Eliminate the leak within 48

hours after minimization;

and

d. In no event that the total

time to minimize and

eliminate the leak shall

exceed 56 hours after

detection.

3. If a component type for a given

tank is found to leak during an

annual inspection, then conduct

quarterly inspections of that

component type on the tank or

tank system for four

consecutive quarters. If a

component type is found to

have no leak after four

consecutive quarterly

inspections, then revert to

annual inspections.

1. For leaking components,

immediately affix a tag

and maintain records of

liquid leak and gas leak 

detection readings,

date/time leak was

discovered, and date/time

the component was

repaired to a leak-free

condition.

2. Leaking components that

have been discovered by

the operator that have

been immediately tagged

and repaired within the

deadlines specified in the

Emissions Minimization

requirements, shall not

constitute a violation of

this rule. However,

leaking components

discovered during

inspections by District

staff that were not

previously identified

and/or tagged by the

operator, and/or any leaks

that were not repaired

within deadlines specified

in the Emissions

Minimization

requirements, shall

constitute a violation of

this rule.

3. Any component found to

be leaking on two

consecutive annual

inspections is in violation

of this rule, even if it is

under the voluntary

inspection and

maintenance program.
Table 4: External Floating Roof Tank Preventive Inspection and Maintenance

Emission Minimization for Components Serving Organic Liquid Storage Tanks

Components

Maintenance

Schedule Emission Minimization Additional Requirements

1. Piping

Components

(valves,

flanges, and

connectors)

directly

affixed to the

tank and

within five

feet of the

tank.

1. Conduct annual

inspections with

maintenance

and repair of

components.

2. Conduct visual

inspections and

inspections

using a portable

hydrocarbon

detection

instrument

conducted in

accordance with

EPA Method 21.

3. Visually or

ultrasonically

inspect as

appropriate, the

external shells

and roofs of

uninsulated

tanks for

integrity

annually.

1. Liquid Leak

Repair leaking components

that have a liquid leak rate of 

≥30 drops per minute within 8

hours after detection. Repair

leaking components that have

a liquid leak rate of ≥3 to <30

drops per minute within 24

hours after detection.

2. Gas leak

Comply with the following

requirements to repair leaking

components that have a gas

leak >10,000 ppmv (measured

in accordance with EPA

Method 21 by a portable

hydrocarbon detection

instrument that is calibrated

with methane):

a. Eliminate the leak within

8 hours after detection; or

b. If the leak can not be

eliminated, then minimize

the leak to the lowest

possible level within 8

hours after detection by

using best maintenance

practices; and

c. Eliminate the leak within

48 hours after

minimization; and

d. In no event that the total

time to minimize and

eliminate the leak shall

exceed 56 hours after

detection.

3. If a component type for a

given tank is found to leak

during annual inspection, then

conduct quarterly inspections

on the tank or tank system for

four consecutive quarters. If a

component type is found to

have no leak after four

consecutive quarterly

inspections, then revert to

annual inspections.

1. For leaking components,

immediately affix a tag and

maintain records of liquid

leak and gas leak detection

readings, date/time leak was

discovered, and date/time

the component was repaired

to a leak-free condition.

2. Leaking components that

have been discovered by the

operator that have been

immediately tagged and

repaired within the deadlines

specified in the Emissions

Minimization requirements,

shall not constitute a

violation of this rule. 

However, leaking

components discovered

during inspections by

District staff that were not

previously identified and/or

tagged by the operator,

and/or any leaks that were

not repaired within deadlines

specified in the Emissions

Minimization requirements,

shall constitute a violation of

this rule.

3. Any component found to be

leaking on two consecutive

annual inspections is in

violation of this rule, even if

it is under the voluntary

inspection and maintenance

program.
Table 5: Internal Floating Roof Preventive Inspection Maintenance

Emission Minimization for Components Serving Organic Liquid Storage Tanks

Components

Maintenance

Schedule Emission Minimization Additional Requirements

1. Piping

Components

(valves, flanges,

and connectors)

directly affixed

to the tank and

within five feet

of the tank.

1. Conduct annual

inspections with

maintenance and

repair of

components.

2. Conduct visual

inspections and

inspections using

a portable

hydrocarbon

detection

instrument

conducted in

accordance with

EPA Method 21.

3. Externally inspect

un-insulated tanks,

tank shells, and

roofs for integrity

annually.

1. Liquid Leak

Repair leaking components that

have a liquid leak rate of ≥30

drops per minute, within 8 hours

after detection. Repair leaking

components that have a liquid

leak rate of ≥3 to <30 drops per

minute within 24 hours after

detection.

2. Gas leak

Comply with the following

requirements to repair leaking

components that have a gas leak

>10,000 ppmv (measured in

accordance with EPA Method 21

by a portable hydrocarbon

detection instrument that is

calibrated with methane):

a. Eliminate the leak within 8

hours after detection; or

b. If the leak can not be

eliminated, then minimize

the leak to the lowest

possible level within 8 hours

after detection by using best

maintenance 

practices; and

c. Eliminate the leak within 48

hours after minimization;

and

d. In no event that the total

time to minimize and

eliminate the leak shall 

exceed 56 hours after

detection.

3. If a component type for a given

tank is found to leak during

annual inspection, then conduct

quarterly inspections on the tank

or tank system for four

consecutive quarters. If a

component type is found to have

no leak after four consecutive

quarterly inspections, then revert

to annual inspections.

1. For leaking components,

immediately affix a tag and

maintain records of liquid

leak and gas leak detection

readings, date/time leak was

discovered, and date/time

the component was repaired

to a leak-free condition.

2. Leaking components that

have been discovered by the

operator that have been

immediately tagged and

repaired within the

deadlines specified in the

Emissions Minimization

requirements, shall not

constitute a violation of this

rule. However, leaking

components discovered

during inspections by

District staff that were not

previously identified and/or

tagged by the operator,

and/or any leaks that were

not repaired within

deadlines specified in the

Emissions Minimization

requirements, shall

constitute a violation of this

rule.

3. Any component found to be

leaking on two consecutive

annual inspections is in

violation of this rule, even if

it is under the voluntary

inspection and maintenance

program.
SJVUAPCD 4623-24 5/19/05

6.0 Administrative Requirements

6.1 Inspection of Floating Roof Tanks

6.1.1 The operator of external floating roof tanks shall make the primary seal

envelope available for unobstructed inspection by the APCO on an annual

basis at locations selected along its circumference at random by the APCO. 

In the case of riveted tanks with toroid-type seals, a minimum of eight (8)

locations shall be made available; in all other cases, a minimum of four (4)

locations shall be made available. If the APCO suspects a violation may

exist the APCO may require such further unobstructed inspection of the

primary seal as may be necessary to determine the seal condition for its

entire circumference.

6.1.2 Operators of floating roof tanks shall submit a tank inspection plan to the

APCO for approval. The plan shall include an inventory of the tanks subject

to this rule and a tank inspection schedule. A copy of the operator’s tank

safety procedures shall be made available to the APCO upon request. The

tank inventory shall include tank’s identification number, PTO number,

maximum tank capacity, dimensions of tank (height and diameter), organic

liquid stored, type of primary and secondary seal, type of floating roof

(internal or external floating roof), construction date of tank, and location of

tank. Any revision to a previously approved tank inspection schedule shall

be submitted to the APCO for approval prior to conducting an inspection.

6.1.3 External Floating Roof Tank Inspection

6.1.3.1 Inspect all floating tanks at least once every 12 months to

determine compliance with the requirements of this rule. The

actual gap measurements of the floating roof primary and

secondary seals shall be recorded. The inspection results shall be

submitted to the APCO as specified in Section 6.3.5. 

6.1.3.2 Inspect the primary and secondary seals for compliance with the

requirements of this rule every time a tank is emptied or degassed.

Actual gap measurements shall be performed when the liquid level

is static but not more than 48 hours after the tank roof is re-floated.

6.1.4 Internal Floating Roof Tank Inspection

6.1.4.1 For newly constructed, repaired, or rebuilt internal floating roof

tanks, visually inspect the internal floating roof and its appurtenant

parts, fittings, etc., and measure the gaps of the primary seal and/or

secondary seal prior to filling the tank. If there are holes, tears, or

other openings in the primary seal, the secondary seal, or the seal
SJVUAPCD 4623-25 5/19/05

fabric or defects in the internal floating roof or its appurtenant

parts, components, fittings, etc., the operator shall repair the

defects before filling the tank.

6.1.4.2 Visually inspect, through the manholes, roof hatches, or other

openings on the fixed roof, the internal floating roof and its

appurtenant parts, fittings, etc., and the primary seal and/or

secondary seal at least once every 12 months after the tank is

initially filled with an organic liquid. There should be no visible

organic liquid on the roof, tank walls, or anywhere. Other than the

gap criteria specified by this rule, no holes, tears, or other openings

are allowed that would permit the escape of hydrocarbon vapors. 

Any defects found are violations of this rule.

6.1.4.3 Conduct actual gap measurements of the primary seal and/or

secondary seal at least once every 60 months. Other than the gap

criteria specified by this rule, no holes, tears, or other openings are

allowed that would permit the escape of hydrocarbon vapors. Any

defects found shall constitute a violation of this rule.

6.2 TVP and API Gravity Testing of Stored Organic Liquid in Uncontrolled Fixed Roof

Tanks

Sections 6.2.1 and 6.2.2 shall not apply to tanks that exclusively store organic liquids

listed in Appendix A, provided the storage temperature indicated in Appendix A is

not exceeded at any time. An operator shall comply with Section 6.3.6 if the

information in Appendix A is used to demonstrate the TVP and/or API gravity of the

stored liquid.

6.2.1 Initial TVP and API Gravity Testing 

6.2.1.1 An operator shall conduct an initial TVP testing of each

uncontrolled fixed roof tank. In lieu of testing each uncontrolled

fixed roof tank, an operator may conduct a TVP testing of a

representative tank provided the requirements of Sections 6.2.1.1.1

through 6.2.1.1.5 are met. The operator shall submit the records of

TVP and/or API gravity testing to the APCO as specified in

Section 6.3.6. The operator shall be in full compliance with the

rule by the deadline specified in Section 7.1

6.2.1.1.1 The selection of representative, uncontrolled fixed roof

tanks is submitted in writing to the APCO, and written

approval is granted by the APCO prior to conducting

the test.
SJVUAPCD 4623-26 5/19/05

6.2.1.1.2 One uncontrolled fixed roof tank represents some or all

of the tanks in a tank battery (defined in Section 3.31).

6.2.1.1.3 For crude oil production facilities, the representative

uncontrolled fixed roof tank shall be the first line tank

(or tanks) in a tank battery that is first receiving the

produced fluids (mixture of oil, water, and gases) from

the crude oil production wells.

6.2.1.1.4 The stored organic liquid in each of the represented

tanks is the same and came from the same source.

6.2.1.1.5 The TVP and storage temperature of the stored organic

liquid of the representative tank to be tested are the

same or higher than those of the tanks it is to represent.

6.2.1.2 The TVP testing shall be conducted at actual storage temperature

of the organic liquid in the tank. If the tank stores crude oil or

petroleum distillates, the operator shall also conduct an API gravity

testing.

6.2.1.3 In lieu of complying with Sections 6.2.1.1 and 6.2.1.2, an operator

shall submit a complete application for an Authority to Construct

to install and operate on each uncontrolled fixed roof tank the

appropriate VOC control system specified in Section 5.1. The

operator shall be in full compliance with the rule by the deadline

specified in Section 7.1.

6.2.2 Periodic TVP and API Gravity Testing

Effective on and after November 15, 2003, an operator shall conduct a TVP

testing of each uncontrolled fixed roof tank at least once every 24 months

during summer (July – September), and/or whenever there is a change in the

source or type of organic liquid stored in each tank. In lieu of testing each

uncontrolled fixed roof tank, an operator may conduct a TVP testing of a

representative tank provided the requirements of Sections 6.2.1.1.1 through

6.2.1.1.5 are met. The operator shall also comply with Section 6.2.1.2. The

operator shall submit the records of TVP and/or API gravity testing to the

APCO as specified in Section 6.3.6. 

6.2.3 The requirements of Sections 6.2.1 and 6.2.2 shall not apply to the following

tanks:

6.2.3.1 Tanks identified in Section 5.1.1, Table 1, Group A, that are

permitted by the District to operate a pressure-vacuum relief valve
SJVUAPCD 4623-27 5/19/05

complying with Section 5.2 requirements, and exclusively receive

and/or store crude oil with a TVP of less than 11 psia,

6.2.3.2 Tanks identified in Section 5.1.2, Table 2, Group A, that are

permitted by the District to operate a pressure-vacuum relief valve

complying with Section 5.2 requirements, and exclusively receive

and/or store crude oil with a TVP of less than 11 psia, or

6.2.3.3 Tanks identified in Section 5.1.2, Table 2, Group B, are permitted

by the District to operate a pressure-vacuum relief valve complying

with Section 5.2 requirements; exclusively receive and/or store

crude oil with a TVP of less than 11 psia; and have a permitted

throughput of less than 150 barrels of crude oil per day.

6.3 Recordkeeping

An operator shall retain accurate records required by this rule for a period of five

years. Records shall be made available to the APCO upon request, except for certain

records that need to be submitted as specified in the respective sections below.

6.3.1 An operator whose tanks are subject to the requirements of this rule shall keep

an accurate record of each organic liquid stored in each tank, including its

storage temperature, TVP, and API gravity. The requirement of 6.3.1 shall not

apply to fixed roof tanks equipped with a vapor recovery system, external

floating roof tanks, or internal floating roof tanks that meet the requirements

of this rule.

6.3.2 An operator whose emergency standby tanks are required to comply with

Section 4.2.1 shall maintain records showing date(s) the organic liquid is first

introduced into each tank, and date(s) each tank is fully drained. Such records

shall be submitted to the APCO 60 days prior to permit renewal.

6.3.3 An operator whose temporary tanks are required to comply with Section 4.2.2

shall maintain records showing the tank capacity and duration of time that the

tank is used.

6.3.4 Small producers shall maintain monthly records of average daily crude oil

production to determine compliance with Section 3.29. The monthly crude oil

production records required by the California Division of Oil, Gas, and

Geothermal Resources may be used to comply with the above requirement. 

Small producers shall also maintain monthly records of the average daily

crude oil throughput of each tank to demonstrate compliance with Sections

4.3, and/or 5.1.2. Operators shall submit the required monthly records upon

the request of the APCO.
SJVUAPCD 4623-28 5/19/05

6.3.5 An operator shall submit the reports of the floating roof tank inspections

conducted in accordance with the requirements of Section 6.1 to the APCO

within five calendar days after the completion of the inspection only for those

tanks that failed to meet the applicable requirements of Sections 5.2 through

5.5. The inspection report for tanks that have been determined to be in

compliance with the requirements of Sections 5.2 through 5.5 need not be

submitted to the APCO, but the inspection report shall be kept on-site and

shall be made available upon request by the APCO. The inspection report

shall contain all information necessary to demonstrate compliance with the

provisions of this rule, including the following:

6.3.5.1 Date of inspection and names and titles of company personnel

doing the inspection.

6.3.5.2 Tank identification numbers and PTO number.

6.3.5.3 Measurements of the gaps between the tank shell and primary and

secondary seals.

6.3.5.4 Leak-free status of tanks and floating roof deck fittings. Records

of leak-free status shall include the vapor concentration values

measured in ppmv.

6.3.5.5 Data, supported by calculations, demonstrating compliance with

the requirements specified in Sections 5.3, 5.4, 5.5.2.3.3, 5.5.2.4.2,

and 5.5.2.4.3 of this rule.

6.3.5.6 Any corrective actions or repairs performed on the tank in order to

comply with this rule and the date such actions were taken.

6.3.6 An operator shall submit the records of TVP and API gravity testing

conducted in accordance with the requirements of Section 6.2 to the APCO

within 45 days after the date of testing. The record shall include the tank

identification number, PTO number, type of stored organic liquid, TVP and

API gravity of the stored organic liquid, test methods used, and a copy of the

test results. An operator who uses the information in Appendix A to

demonstrate the TVP and/or API gravity of the stored organic liquid shall

submit information to the APCO within 45 days after the date that the type of

organic liquid stored in the tank has been determined.

6.3.7 An operator shall maintain the records of the external floating roof or internal

floating roof landing activities that are performed pursuant to Sections 5.3.1.3

and 5.4.3. The records shall include information on the TVP, API gravity, and

type of organic liquid stored in the tank, the purpose of landing the roof on its

legs, the date of roof landing, duration the roof was on its legs, the level or
SJVUAPCD 4623-29 5/19/05

height at which the tank roof was set to land on its legs, and the lowest liquid

level in the tank. The operator shall keep the records at the facility (or on-site)

for a period of five years. The records shall be made available to the APCO

upon request.

6.4 Test Methods

The following test methods shall be used unless otherwise approved by the APCO

and the United States Environmental Protection Agency (US EPA).

6.4.1 Analysis of halogenated exempt compounds shall be conducted using

California Air Resources Board (ARB) Method 432.

6.4.2 The API gravity of crude oil or petroleum distillate shall be determined by

using ASTM Method D 287-92 (2000) e1 “Standard Test Method for API

Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method). 

Sampling for API gravity shall be performed in accordance with ASTM

Method D 4057-95 “Standard Practices for Manual Sampling of Petroleum

and Petroleum Products”.

6.4.3 Except for crude oil subject to Section 6.4.4, the TVP of any organic liquid

shall be determined by measuring the Reid Vapor Pressure (RVP) using

ASTM D 323-94 (Test Method for Vapor Pressure for Petroleum Products),

and converting the RVP to TVP at the tank’s maximum organic liquid storage

temperature. The conversion of RVP to TVP shall be done in accordance with

the procedures in Appendix B. Appendix B is an excerpt from the oil and gas

section of “ARB Technical Guidance Document to the Criteria and Guidelines

Regulation for AB 2588”, dated August 1989. As an alternative to using

ASTM D 323-94, the TVP of crude oil with an API gravity range of greater

than 26o

 up to 30o may be determined by using other equivalent test methods

approved by APCO, ARB and US EPA.

6.4.4 The latest version of the Lawrence Berkeley National Laboratory “Test

Method for Vapor Pressure of Reactive Organic Compounds in Heavy Crude

Oil Using Gas Chromatograph”, as approved by ARB and US EPA, shall be

used to determine the TVP of crude oil with an API gravity of 26o or less, or

for any API gravity that is specified in this test method.

6.4.5 An operator may use the information in Appendix A to determine the TVP of

the stored organic liquid in a tank provided the storage temperature listed in

Appendix A is not exceeded at any time.

6.4.6 The control efficiency of any VOC destruction device, measured and

calculated as carbon, shall be determined by US EPA Method 25, except when

the outlet concentration must be below 50 ppm in order to meet the standard,

in which case US EPA Method 25a may be used. US EPA Method 18 may be

used in lieu of US EPA Method 25 or US EPA Method 25A provided the
SJVUAPCD 4623-30 5/19/05

identity and approximate concentrations of the analytes/compounds in the

sample gas stream are known before analysis with the gas chromatograph and

the gas chromatograph is calibrated for each of the known

analytes/compounds to ensure that the VOC concentrations are neither underor over-reported.

6.4.7 Analysis of halogenated exempt compounds shall be analyzed by ARB

Method 422 “Exempt Halogenated VOCs in Gases September 12, 1990”.

6.4.8 Measurements of a gas-leak concentration shall be determined by US EPA

Method 21.

7.0 Compliance Schedule

7.1 Any tank subject to the requirements of this rule that is installed or constructed on and

after May 19, 2005, shall be in full compliance with this rule upon initial operation,

and thereafter.

7.2 Any tank that is exempted under Section 4.0 that becomes subject to the VOC control

system requirements of this rule through the loss of exemption status, shall be in full

compliance with this rule on the date the exemption status is lost.
SJVUAPCD 4623-31 5/19/05

Appendix A

STORAGE TEMPERATURE VERSUS VAPOR PRESSURE

Reference Properties

Maximum Temp °F

Not to Exceed ORGANIC LIQUID

Gravity (°API) Initial Boiling Point

(°F) 0.5 (psia) 1.5 (psia)

Middle Distillates

Kerosene 42.5 350 195 250

Diesel 36.4 372 230 290

Gas Oil 26.2 390 249 310

Stove Oil 23 421 275 340

Jet Fuels

JP-1 43.1 330 165 230

JP-3 54.7 110 --- 25

JP-4 51.5 150 20 68

JP-5 39.6 355 205 260

JP-7 44-50 360 205 260

Fuel Oil

No. 1 42.5 350 195 250

No. 2 36.4 372 230 290

No. 3 26.2 390 249 310

No. 4 23 421 275 340

No. 5 19.9 560 380 465

Residual 19.27 --- 405 ---

No. 6 16.2 625 450 ---

Asphalt

60-100 pen. --- --- 490 550

120-150 pen. --- --- 450 500

200-300 pen. --- --- 360 420
SJVUAPCD 4623-32 5/19/05

Appendix A (Continued)

STORAGE TEMPERATURE VERSUS VAPOR PRESSURE

Reference Properties

Maximum Temperature

(

o

F) Not to Exceed Organic Liquid

Density

(lb/gal)

Gravity

o

API

Initial Boiling

Point (oF)

0.5 psia 1.5 psia

Acetone 6.6 47 133 --- 35

Acrylonitrile 6.8 41.8 173 30 62

Benzene 7.4 27.7 176 34 70

Carbon Disulfide 10.6 22.1 116 --- 10

Carbon Tetrachloride 13.4 --- 170 20 63

Chloroform 12.5 --- 142 --- 40

Cyclohexane 6.5 49.7 177 30 65

1,2 Dichloroethane 10.5 --- 180 35 75

Ethyl Acetate 7.5 23.6 171 38 70

Ethyl Alcohol 6.6 47.0 173 55 85

Isopropyl Alcohol 6.6 47.0 181 62 95

Methyl Alcohol 6.6 47.0 148 30 62

Methyl Ethyl Ketone 6.7 44.3 175 30 70

Toluene 7.3 30 231 75 120

Styrene 7.5 293 128 167

Vinyl Acetate 7.8 19.6 163 30 65
SJVUAPCD 4623-33 5/19/05

Appendix B

California Air Resources Board Technical Guidance

to the Criteria and Guidelines Regulation for AB 2588

(Partial Excerpt from pages 102, 103 and 104)

True Vapor Pressure (TVP)

RVP is the absolute pressure of volatile crude oil and nonviscous petroleum liquids. 

Numerically, the relationship between TVP, RVP and temperature can be expressed by the

following equation:

TVP = (RVP) e[Co(IRTEMP - ITEMP)]

Where: Co = Constant dependent upon the value of RVP

ITEMP = (1/559.69oR)

IRTEMP = (1/(Ts + 459.69o

R))

Ts = Temperature of the stored fluid in oF

The value of the constant term Co depends upon the given value of RVP.

Values of Co for different RVP numbers are tabulated in Table C-3. It should be noted,

however, that an error was discovered in the API nomograph calculated values of TVP so

that the RVP was not equal to TVP at 100o

F as was expected given the general definition of

RVP. Using linear regression techniques, correction factors (CF) were developed and

should be added to the calculated values of TVP in order to obtain reasonable TVP

numbers. The relationship between the three values is given as follows:

Corrected TVP = Calculated TVP + CF

The correction factor was found to be dependent upon RVP according to the following

equations:

If RVP < 3,

CF = (0.04) x (RVP) + 0.1

If RVP > 3,

CF = e[(2.3452061 log (RVP)) - 4.132622]
SJVUAPCD 4623-34 5/19/05

Appendix B (Continued)

Table C-3: VALUES OF Co FOR DIFFERENT RVP NUMBERS

RVP Co

0<RVP<2 -6622.5

2<RVP<3 -6439.2

RVP = 3 -6255.9

3<RVP<4 -6212.1

RVP = 4 -6169.2

4<RVP<5 -6177.9

RVP = 5 -6186.5

5<RVP<6 -6220.4

RVP = 6 -6254.3

6<RVP<7 -6182.1

RVP = 7 -6109.8

7<RVP<8 -6238.9

RVP = 8 -6367.9

8<RVP<9 -6477.5

RVP = 9 -6587.9

9<RVP<10 -6910.5

RVP = 10 -7234.0

10<RVP<15 -8178.0

RVP > 15 -9123.2