Section 170.530  Methods and Requirements of Release Detection for Tanks

 

Owners and operators of petroleum UST systems shall provide release detection on tanks.  These tanks must be monitored at least every 30 days for releases using one or more of the methods listed below:

 

a)         Monthly inventory control.

 

1)         Product inventory control (or another test of equivalent performance) shall be conducted monthly to detect a release of at least 1.0 percent of the flow-through plus 130 gallons on a monthly basis in the following manner:

 

A)        Inventory volume measurements for regulated substance inputs, withdrawals and the amount still remaining in the tank are recorded each operating day;

 

B)        The equipment used is capable of measuring the level of product over the full range of the tank's height to the nearest one-eighth of an inch;

 

C)        The regulated substance inputs are reconciled with delivery receipts by measurement of the tank inventory volume before and after delivery;

 

D)        Deliveries are made through a drop tube that extends to within 6 inches of the tank bottom;

 

E)         Product dispensing is metered and recorded pursuant to Section 8 of the Weights and Measures Act [225 ILCS 470/8];

 

F)         The measurement of any water level in the bottom of the tank is made to the nearest one-eighth of an inch at least once a month (practices described in API Recommended Practice 1621, incorporated by reference in Section 170.410, may be used, where applicable, as guidance in meeting the requirements of this subsection (a));

 

G)        To the extent the above measurements or recordkeeping are the responsibility of the UST owner, the owner or whoever performs those activities on the owner's behalf, shall be knowledgeable in such performance;

 

H)        Monthly inventory control records for the previous 3 years must be kept on site;

 

I)          This method can only be used for a period of 10 years from the date cathodic protection was installed on the tank.  A precision tank test must be performed at 5 years and 10 years and these records kept on site for 10 years.  At 10 years, another form of leak detection is required;

 

J)         Inventory control will only be allowed on sites currently using this method until the 10-year time allowance expires.  No new sites will be allowed to use this method after May 1, 2003;

 

K)        Inventory control may not be used on systems with blending pumps or siphon tanks.

 

2)         Monthly inventory control cannot be used as a method of release detection for any tank that, after passing only a noninvasive tank integrity assessment, was upgraded using the cathodic protection method.

 

b)         Manual tank gauging.  Only tanks of 600 gallons or less nominal capacity may use the method described in this subsection as the sole method of release detection.  For tanks of 601 to 2,000 gallons, this method may be used for a period of 10 years from the date cathodic protection was installed on the tank.  For tanks over 2,000 gallons, this method shall not be used.  Tanks 601 to 2,000 gallons must receive a precision tank test once every year.  The monthly records required for manual tank gauging and the yearly tank tests must be kept for 3 years on site.  At the end of 10 years, another form of tank leak detection is required for tanks 601 gallons to 2,000 gallons.

 

1)         Manual tank gauging shall meet the following requirements:

 

A)        Tank liquid level measurements are taken at the beginning and ending of a period of at least 36 hours during which no liquid is added to or removed from the tank;

 

B)        Level measurements are based on an average of two consecutive stick readings at both the beginning and ending of the period;

 

C)        The equipment used is capable of measuring the level of product over the full range of the tank's height to the nearest one-eighth of an inch;

 

D)        A leak is suspected and subject to the requirements of Sections 170.560 through 170.610, if the variation between beginning and ending measurements exceeds the weekly or monthly standards in Table B;

 

E)         The measurement of any water level in the bottom of the tank is made to the nearest one-eighth of an inch at least once a month (practices described in API Recommended Practice 1621, incorporated by reference in Section 170.410, may be used, where applicable, as guidance in meeting the requirements of this subsection (b)); and

 

F)         To the extent the above measurements or recordkeeping are the responsibility of the UST owner, the owner or whoever performs those activities on the owner's behalf, shall be knowledgeable in such performance.

 

2)         Manual tank gauging cannot be used as a method of release detection for any tank that, after passing only a noninvasive tank integrity assessment, was upgraded using the cathodic protection method.

 

3)         This method will not be allowed for tanks 601 to 2,000 gallons after May 1, 2003, except that, for those tanks for which this method was being used on May 1, 2003, the method may be used until the 10-year allowance expires.

 

c)         Precision tank tightness testing, as approved by the Office of the State Fire Marshal. 

 

1)         Tank tightness testing (or another test of equivalent performance) shall be capable of detecting a 0.1 gallon per hour leak rate from any portion of the tank that routinely contains product while accounting for the effects of thermal expansion or contraction of the product, vapor pockets, tank deformation, evaporation or condensation, and the location of the water table.  There are four types of precision testing:

 

A)        100 percent volumetric overfill;

 

B)        Volumetric underfill with an approved ullage test of negative pressure or inert gas as approved by the Office of the State Fire Marshal;

 

C)        A negative pressure; or

 

D)        Other approved methods, in accordance with subsection (i).

 

2)         In the case of a suspected release, tracer elements and ATGs are not an approved method of precision tank testing.

 

d)         Automatic tank gauging (ATG).  Equipment for automatic tank gauging that tests for the loss of product and conducts inventory control shall meet the following requirements:

 

1)         The automatic product level monitor test can detect a 0.2 gallon per hour leak rate from any portion of the tank that routinely contains product.

 

2)         The ATG must be third party evaluated by and listed in the NWGLDE publication "List of Leak Detection Evaluations for Underground Storage Tank Systems".  The ATG must be installed, calibrated and in compliance with the protocol of the third party evaluation.

 

3)         All new or replacement ATG monitors shall be mounted no more than 6 feet from the floor and must remain unobstructed and accessible.

 

4)         All new ATG systems must be equipped with printers.  Existing ATG systems must be equipped with printers by May 1, 2004.  If a system has to be retrofitted, a permit will be required.  Systems with remote printers will be accepted.

 

e)         Vapor monitoring.  Testing or monitoring for vapors within the soil gas of the excavation zone shall meet the following requirements:

 

1)         The materials used as a backfill are sufficiently porous (e.g., gravel, sand or crushed rock) to readily allow diffusion of vapor from releases into the excavation area;

 

2)         The stored regulated substance or a tracer compound placed in the tank system is sufficiently volatile (e.g., gasoline) to result in a vapor level that is detectable by the monitoring devices located in the excavation zone in the event of a release from the tank;

 

3)         The measurement of vapors by the monitoring device is not rendered inoperative by groundwater, rainfall, soil moisture or other known interferences so that a release could go undetected for more than 30 days;

 

4)         The level of background contamination in the excavation zone will not interfere with the method used to detect releases from the tank;

 

5)         The vapor monitors are designed and operated to detect any significant increase in concentration above the background of the regulated substance stored in the tank system, a component or components of that substance, or a tracer compound placed in the tank system; vapor monitor sensors must be permanently installed in the vapor monitor wells; a monthly inspection of the vapor monitoring system must be made and a log maintained showing the date of inspection, results, and initials of the party doing the inspection;

 

6)         In the UST excavation zone, the site is assessed to ensure compliance with the requirements in subsections (e)(1) through (4) of this Section and to establish the number and positioning of monitoring wells that will detect releases within the excavation zone from any portion of the tank that routinely contains product;

 

7)         Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering;

 

8)         Vapor monitoring wells shall be of sufficient design to allow vapors to be detected from any portion of the tank being monitored and shall be a minimum of four inches in diameter or as approved by the Office of the State Fire Marshal on the applicable permit; and

 

9)         An adequate number of vapor monitoring wells shall be provided to ensure that a release can be detected from any portion of the tank.  Adequacy of such wells is subject to approval of the Office of the State Fire Marshal on the applicable permit.

 

f)          Groundwater monitoring.  Testing or monitoring for liquids on the groundwater shall meet the following requirements:

 

1)         The regulated substance stored is immiscible in water and has a specific gravity of less than one;

 

2)         Groundwater is never more than 20 feet from the ground surface, the hydraulic conductivity of the soil between the UST system and the monitoring wells or devices is not less than 0.01 cm/sec (e.g., the soil should consist of gravels, coarse to medium sands, coarse silts or other permeable materials), and groundwater shall be present in the groundwater monitoring wells at all times;

 

3)         The slotted or perforated portion of the monitoring well casing shall be designed to prevent migration of natural soils or filter pack into the well and to allow entry of regulated substance on the water table into the well under both high and low groundwater conditions;

 

4)         Groundwater monitoring wells shall be sealed from the ground surface to the top of the filter pack;

 

5)         Monitoring wells or devices intercept the excavation zone or are as close to it as is technically feasible;

 

6)         The continuous monitoring devices or manual methods used can detect the presence of at least ⅛ of an inch of free product on top of the groundwater in the monitoring wells.

 

A)        The continuous monitoring devices must be fixed sensors mounted permanently inside the well or samples must be taken by a mechanical bailer capable of detecting the presence of at least ⅛-inch of free product on top of the groundwater in the monitoring wells.

 

B)        Groundwater monitoring must be done monthly and a log of the inspection made showing the date of the inspection, initials of the person conducting the inspection, and results of the well sampling.  This log must be done every 30 days and kept on-site, or available within 30 minutes, for 3 years.

 

7)         Within and immediately below the UST system excavation zone, the site is assessed to ensure compliance with the requirements in subsections (f)(1) through (5) of this Section and to establish the number and positioning of monitoring wells or devices that will detect releases from any portion of the tank that routinely contains product;

 

8)         Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering;

 

9)         The minimum diameter of groundwater monitoring wells shall be 8 inches or as approved by the Office of the State Fire Marshal on the applicable permit; and

 

10)         An adequate number of groundwater monitoring wells shall be provided to ensure that a release can be detected from any portion of the tank. Adequacy of such wells is subject to approval of the Office of the State Fire Marshal on the applicable permit.  On new installations, there shall be two 8-inch diameter monitoring wells for the first tanks and 1 additional well for each additional tank installed.  The wells will be of manufactured slotted or perforated type.  They shall be at opposite ends and corners, one foot below the invert elevations of the lowest UST.

 

g)         Interstitial monitoring.  Interstitial monitoring between the UST system and a secondary barrier immediately around or beneath it, or interstitial monitoring meeting the requirements of this Section as required by Sections 170.420(a) and 170.421(a), may be used but only if the system is designed, constructed and installed to detect a leak from any portion of the tank that routinely contains product and, also, meets one of the following requirements:

 

1)         For double-wall UST systems, the sampling or testing method can detect a release through the inner wall in any portion of the tank that routinely contains product; the provisions specified in STI, "Standard for Dual Wall Underground Storage Tank", incorporated by reference in Section 170.410, may be used as guidance for aspects of the design and construction of underground steel double-wall tanks.

 

2)         For UST systems with a secondary barrier within the excavation zone, the sampling or testing method used can detect a release between the UST system and the secondary barrier.

 

A)        The secondary barrier around or beneath the UST system consists of artificially constructed material that is sufficiently thick and impermeable (not in excess of 0.000001 cm/sec for the regulated substance stored) to direct a release to the monitoring point and permit its detection;

 

B)        The barrier is compatible with the regulated substance stored so that a release from the UST system will not cause a deterioration of the barrier allowing a release to pass through undetected;

 

C)        For cathodically protected tanks, the secondary barrier shall be installed so that it does not interfere with the proper operation of the cathodic protection system;

 

D)        The groundwater, soil moisture or rainfall will not render the testing or sampling method used inoperative so that a release could go undetected for more than 30 days;

 

E)         The site is assessed to ensure that the secondary barrier is always above the groundwater and not in a 25-year flood plain unless the barrier and monitoring designs are for use under such conditions;

 

F)         Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering; and

 

G)        An adequate number of monitoring wells shall be provided to ensure that a release can be detected from any portion of the tank.  Adequacy of the number of such wells is subject to the approval of the Office of the State Fire Marshal.

 

3)         For tanks with an internally fitted liner, an automated device can detect a release between the inner wall of the tank and the liner, and the liner is compatible with the substance stored.

 

4)         The interstitial monitoring system must be tested every 3 years to verify its operation and records from the previous test must be kept on-site, or available within 30 minutes.  Testing of the system sensors shall be done in such a way as to verify their function but not damage the sensors.

 

5)         Recordkeeping requirements for interstitial monitoring of tanks and lines requires an inspection once every 30 days and records for the previous 3 years must be kept on-site or available within 30 minutes.  The records can be from an ATG system showing the interstitial monitors' status (pass/normal/other/) on a print out tape or by maintaining a log showing date of inspection, initials of inspector, status of system (pass/normal/ other).

 

h)         Statistical Inventory Reconciliation (SIR).

 

1)         The company that uses this method shall provide the Office of the State Fire Marshal a written affirmation that their data collection staff is trained in the data gathering procedures and that only trained staff will be utilized for data collection.  Each tank monitored by SIR shall be identified to the Office in writing within 30 days of the commencement of such monitoring, specifying tank size, product stored, facility location and any other pertinent identification information necessary.

 

2)         SIR methods may only be used in conjunction with precision tank tightness testing conducted yearly.

 

3)         A precision tank tightness test, as approved by the Office of the State Fire Marshal, shall be mandatory, if any data analysis indicates a possible release or is inconclusive or indeterminate, or for any test result other than a pass.  

 

4)         The measurement of any water level in the bottom of the tank is made to the nearest ⅛-inch at least once a month (practices described in API Recommended Practice 1621, incorporated by reference in Section 170.410, may be used, where applicable, as guidance in meeting the requirements of this subsection (h)).

 

5)         SIR test records for the previous 3 years must be kept on-site (a lag time of 60 days will be allowed for on-site records) or available within 30 minutes.

 

6)         New requests to use SIR after May 1, 2003 will no longer be accepted.  If SIR is discontinued at a site, it will not be allowed again.

 

7)         After January 1, 2006, SIR may not be used on systems with blending pumps or siphon tanks.

 

i)          Other methods.  Any other type of release detection method or combination of methods, approved by the Office of the State Fire Marshal, may be used if the owner or operator can demonstrate that the method can detect a release as effectively as any of the methods allowed in subsections (c) through (h) of this Section.  Demonstration of any such method shall be in writing submitted to the Office of the State Fire Marshal.  In comparing methods, the Office shall consider the size of release that the method can detect and the frequency and reliability with which it can be detected.  If the method is approved, the owner or operator shall comply with any conditions imposed by the Office on its use to ensure the protection of human health or the environment.  Before the utilization of the method, the Office shall issue written approval.

 

j)          One copy of each independent third-party evaluation and its protocol, for the release detection methods in subsections (c), (d), (e), (g), (h) and (i), shall be submitted to the Office of the State Fire Marshal.  Any deviation from the third-party evaluation shall be resubmitted for approval.

 

k)         Only one approved method of primary release detection is required for each tank, although multiple methods are acceptable.

 

l)          No method of release detection shall be used unless that method has been approved by the Office of the State Fire Marshal.

 

(Source:  Amended at 32 Ill. Reg. 1428, effective February 1, 2008)