underground storage tanks (usts)
TRANSCRIPT
Underground Storage Tanks (USTs)
NCDENRDivision of Waste Management
Underground Storage Tank Section
Rev 12-10
USTs
Release prevention
Release detection
Release Prevention
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection5. Compatibility
Release PreventionVapor Recovery
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection5. Compatibility
Vapor Recovery
We DO NOT regulate this
Inspector checks:
•Present
•Operational
•Exceptions
Dual Point
Coaxial
Spill and overfill prevention
Eliminate the potential for a release during fuel deliveries
Spill and overfill prevention
UST-10B
What’s the difference?
Spill prevention:◦ Contains drips and spills of fuel that occur when delivery hose is uncoupled from fill port
Overfill prevention◦ Provides transporter with indication that tank is approaching full during delivery
Release PreventionSpill Prevention
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection5. Compatibility
Spill prevention on UST-10B
Spill prevention equipment
Fuel delivered to tank here
Spill prevention equipment
Fill port/spill bucket
Spill prevention equipment
Fill ports must have spill buckets
Temporarily contains product
Typically 5 – 25 gallons
Spill bucket maintenance**
Not designed to “store” fuel
Free of water, fuel, and debris
Free of holes or defects
If there is already liquid inthe spill bucket before youget a delivery, then the spill
bucket can’t do it’s job
UST Site Diagram
UST Site Diagram for: _____________________________________________
*
USTRaleigh Blvd
Fuel Mart 27
Hart Road
Fuel Mart 27
Spill Bucket
Vapor Recovery
•
•
Release PreventionOverfill Prevention
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection5. Compatibility
Overfill prevention on UST-10B
Overfill prevention equipment**
Ball float valve
Overfill alarm
Flapper valve
Overfill prevention equipment
Ball float valve at
vapor recoveryport
Fill tube with flapper valve
Release PreventionOverfill Prevention
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention
• Ball float valve• Overfill Alarm• Flapper Valve
4. Corrosion Protection5. Compatibility
Ball float valves
Reduces product flow
Installed to slow delivery at 90% capacity or 30 min
before overfilling
Ball float valve restrictions**
Incompatible with UST systems that:
◦ Receive pressurized deliveries
◦ Have suction piping
◦ Have coaxial vapor recovery
Release PreventionOverfill Prevention
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention
• Ball float valve• Overfill Alarm• Flapper Valve
4. Corrosion Protection5. Compatibility
Overfill alarms
Activates an audible and/or visual warning
Alerts at 90% capacity
Must be located where alarm can be seen and/or heard from delivery site
Unable to restrict or stop flow
Release PreventionOverfill Prevention
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention
• Ball float valve• Overfill Alarm• Flapper Valve
4. Corrosion Protection5. Compatibility
Flapper valves (automatic shutoff devices)
Slows down and then stops delivery
Installed to stop fuel at 95% capacity
Not for systems that receive pressurized deliveries
Flapper valves
Your overfill responsibilities
Ensure amount of product ordered will fit
Monitor deliveries◦ Lock any extra fill ports that don’t have overfill equipment
◦ Have response supplies ready
Use signs◦ Notify delivery person of overfill device
UST Site Diagram
UST Site Diagram for: _____________________________________________
*
Fuel Mart 27
Raleigh Blvd
Hart Road
Fuel Mart 27
UST
Spill Bucket
Overfill PreventionFlapper Valve
*
*
*
Vapor Recovery
•
•
Release PreventionCorrosion protection
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection5. Compatibility
Compliance Plan
Compliance Plan
Refer to your inspection checklist and site diagram
For each topic we cover, fill in the blanks with the correct info for YOUR facility
End result should be a basic compliance plan for your facility
Corrosion protection on UST-10B
Corrosion protection on compliance plan
Corrosion protection
Non-corrodible material
Internal lining
Cathodic protection
Release PreventionCorrosion protection
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection
• Non-corrodible material• Internal lining• Cathodic Protection
5. Compatibility
Non-corrodible material on UST-10B
Non-corrodible material**
FRP Tank
Non-corrodible material**
Jacketed Tank
Non-corrodible material records
Written verification of tank material◦ Installation invoice
◦ Repair invoice
Visual verification◦ Not typical for tanks
If you have non-corrodible materials…
Non-corrodible material (FRP,
CLAD)
N/A
Installation invoice
N/A
Release PreventionInternal lining
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection
• Non-corrodible material• Internal lining• Cathodic Protection
5. Compatibility
Internal lining on UST-10B
Internal lining
Applying non-corrodible lining inside UST
Internal lining testing
Internal inspection within 10 years of installation,
Then every 5 years thereafter
Tightness test after every inspection
Internal lining records
National code or standard used for installation
Repair invoices
Most recent internal inspection results
Most recent tightness test results
If you have internal lining…
Internal lining
Inspection &TTT every
5 years
Inspection results,
TTT results
--/--/--(5 years
from previous Inspection)
Release PreventionCathodic Protection
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection
• Non-corrodible material• Internal lining• Cathodic Protection
5. Compatibility
Cathodic protection on UST-10B **
Cathodic protection systems
What does “cathodic protection” mean?
Two types:
◦ Galvanic (sacrificial anode) systems
◦ Impressed current (IC or rectifier) systems
Galvanic/SA systemsImpressed current
systems
Cathodic protection systems**
BOTH types must be designed by a “corrosion expert”
◦ National Association of Corrosion Engineers (NACE)
or
◦ Professional Engineer (PE)
◦ If installed after 3/1/06, must prove system design was certified by “corrosion expert”
Release PreventionGalvanic Systems
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection
• Non-corrodible material• Internal lining• Cathodic Protection
• Galvanic/SA Systems• Impressed Current Systems
5. Compatibility
Galvanic/SA systems
Anode corrodes instead of UST
Most common: StiP3
Galvanic/SA systems
Anodes (zinc or magnesium) connected to structure by welding or lead wires
Test every three years **
Submit Galvanic test results on UST-7A form
Must be tested by a qualified cathodicprotection tester
If you have a cathodic protection system…
Galvanic/SA system(STIP-3)
Test every 3 years
System design,UST-7A
--/--/--(3 years
from previous test)
Release PreventionGalvanic Systems
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection
• Non-corrodible material• Internal lining• Cathodic Protection
• Galvanic/SA Systems• Impressed Current Systems
5. Compatibility
Impressed current systems
Anodes located in soil around structures to be protected
Electrical current is applied to anodes
Impressed current requirements
•Requires dedicated and protected circuit
•Power must not be interrupted (except during testing)
•Breaks in wiring result in system failure
Impressed current requirements
60 Day Readings from RECTIFIER BOX:
•Operator must inspect system every 60 days
•Record meter reading on UST-21 form
•Make sure meter NOT reading “zero”
•Make sure meter never loses power
Additional impressed current requirements
UST-21 form can be found on website
Additional impressed current requirements
Compare your 60-day readings to “as-left” readings on UST-7B
Add Rectifier Box to Site Diagram
UST Site Diagram
UST Site Diagram for: _____________________________________________
*
Fuel Mart 27
Raleigh Blvd
Hart Road
Fuel Mart 27
*
*
*
UST
Spill Bucket
Overfill PreventionFlapper Valve
Vapor RecoveryCoaxial
STP
ATG
Dispenser
ATG Console
Rectifier Box
probe
Test every three years**
Submit Impressed Current test results on UST-7B form
Must be tested by a qualified cathodicprotection tester
If you have a cathodic protection system…
IC system
60-day readings,
Test every 3 years
UST-21,UST-7B
--/--/--(ex. 1st of
every month)--/--/--
(3 years from previous
test)
Failed or inoperative cathodicprotection systems
IC or galvanic system test FAILS
IC system is/was without electricity
Specific requirements for each situation◦ See memo on website under “Guidance Documents”
Cathodic protection system problems
IC system lines to anodes broken
Cathodic protection system problems
No power to the rectifier
Release PreventionCompatibility
Five topics
1. Vapor Recovery2. Spill prevention3. Overfill prevention4. Corrosion Protection5. Compatibility
Most Common Alternative Fuels**
◦ E-10 10% ethanol 90% gasoline
◦ B-20 20% biodiesel 80% petroleum diesel
◦ E-85 85% ethanol 15% gasoline
Follow the same rules that apply to traditional gas and diesel
Extra requirements!
Example of Accelerated Corrosion
Standard, non-E85 fuel STP E85 STP
Photos courtesy Iowa DNR
Same facility, same install date
UST-20 Form**
PRIOR to dispensing >10% ethanol or >20% biodiesel
UST-20 Form
Sections completed by UST owner/operator AND equipment contractor or PE
Include◦ Documents verifying compatibility OR
◦ Compatibility analysis by PE
EXAM
Tank Release PreventionPlease answer questions # 11-17
USTs
Release prevention◦ Spill prevention
◦ Overfill prevention
◦ Corrosion protection
Release detection
Release Detection
What is leak detection?
The activities and equipment used to detect releases from UST systems
Why conduct leak detection?
REQUIRED for all regulated systems
Discover a release before a major contamination incident occurs
Leak detection on UST-10B
Leak detection on compliance plan
Monthly methods
Leak detection requirements**
Must be conducted monthly (at least once every 30 days)
Must detect a release from any portion of the tank
Must be installed, calibrated, operated, and maintained per manufacturer’s instructions
Leak detection requirements**
Third Party Certified
◦ Documentation that your leak detection method works for your UST system
◦ http://www.nwglde.org
◦ Keep documents for inspection
◦ Pay attention to limitations Tank size Manifolded tanks Throughput Etc.
Monthly methods – most common**
Automatic Tank Gauging (ATG)
Systems
Secondary Containment with
Interstitial Monitoring
Statistical Inventory
Reconciliation (SIR)
ATG System
How do I know if I use an ATG?
Console located inside facility
Probe installed at tank
ATG Probe
Check:
•Capped
•Wires intact
ATG Console
•Present and powered on
•No warnings or alarms
UST Site Diagram
UST Site Diagram for: _____________________________________________
*
Fuel Mart 27
Raleigh Blvd
Hart Road
Fuel Mart 27
UST
Spill Bucket
Overfill PreventionFlapper Valve
*
*
*
Vapor RecoveryCoaxial
STP
ATG
Dispenser
ATG Console
probe
ATG system on UST-10B
ATG system description
Probe permanently installed
Wired to monitor
Product level and temperature info recorded
Calculates changes in product volume
ATG system testing modes
Periodic (static) test mode◦ Tank needs “quiet” time
◦ Data collected over a period of time
Continuous test mode◦ Data gathered during many short
periods when no product is being
added to or taken from tank
◦ Ex. CSLD or SCALD
ATG system operation and maintenance
Tank size
Manifolded tanks
Minimum fuel levels
Type of product (e.g. waste oil, E-85)
Maximum allowable monthly throughput
Duration of test
Waiting period after fuel delivery before test
Make sure your system is certified for your particular facility:
ATG system operation and maintenance
Know how to access and printout leak test results
Check testing printouts routinely
Follow manufacturer’s recommendations for system tests and service
Check console after electrical storms
Do not ignore warnings or alarms
ATG system testing **
How much is 0.2 gph leak?
ATG system records
Must keep one valid 0.2 gph test result per tank, per month, for 12 months
If you have an ATG system…
ATG system
12 months test results
--/--/--(ex. Every Monday)
Conduct test every
30 days
Secondary Containment with Interstitial Monitoring
How do I know if I use Secondary containment with interstitial monitoring?
Double-walled tank
May have sensors monitoring space between inner and outer walls
May have console located at facility
Interstitial monitoring on UST-10B
Interstitial monitoring description**
Periodic monitoring◦ Check interstice manually for liquids
Continuous monitoring◦ Electronic sensors in interstice connected to console
Interstitial monitoring description**
Electronic sensors:
◦ Detect leaked substance
liquid or
gaseous
OR
◦ Detect change in condition
loss of vacuum or
monitoring liquid level change
Interstitial monitoring requirements
Periodic monitoring:
◦ Manually check interstice and document at least once every 30 days
Continuous monitoring:
◦ Continuously monitor interstice with electronic sensors
◦ Check and print sensor status at least once every 30 days
Interstitial monitoring records
Must keep all records per tank, per month, for 12 months
If you have a secondary containment system with interstitial monitoring…
Interstitialmonitoring
12 months Periodic checks OR Sensor status
results
--/--/--(ex. Every Monday)
Manually check interstice
ORCheck sensor status
every 30 days
Statistical Inventory Reconciliation(SIR)
How do I know if I use SIR?
Use a tank stick to take daily measurements
Contract with a SIR vendor
Receive monthly SIR reports
SIR on UST-10B
SIR description
Statistical analysis of inventory, delivery, and dispensing data using computer software to
detect leaks
SIR operation and maintenance**
Measure to nearest 1/8th inch daily
Measure water levels monthly
Supply daily inventory to SIR vendor at end of month
Know limitations listed in third-party certification provided by SIR vendor
SIR operation and maintenance
Use appropriate calibration charts
Replace broken or unreadable tank sticks
Have same person stick tanks every day
Stick tanks and read meters at same time every day
Review SIR reports when received from vendor
SIR records
Must keep DAILY product measurements per tank, for 12 months
Must keep one water measurement per tank, per month, for 12 months
SIR records
Must keep SIR reports per tank, per month, for 12 months
If you are using SIR…
SIR
Calibration charts,12 months daily fuel and
monthly water measurements,
12 months SIR reports
TODAY(product measurement)
--/--/--(30 days from previous
water measurement)--/--/--
(day of the month to send off data to vendor)
Measure product daily,Measure water every 30 days,
Submit to vendorevery 30 days
Other Methods of Leak Detection
Other methods on UST-10B
• Enhanced leak detection page 16
• Inventory control and tightness testing page 12
• Manual tank gauging and tightness testing page 13
• Groundwater monitoring page 15
• Vapor monitoring page 14
EXAMTank Release DetectionPlease answer questions # 18-23
Enhanced leak detection
Enhanced leak detection on UST-10B
UST systems required to conduct enhanced leak detection
Installed after Jan 1, 1991 and before May 1, 2000
AND
Within 100-500 feet of a public water supply well, and/or
Within 50-100 feet of any other well for human consumption, and/or
Within 500 feet of high class surface waters
Enhanced leak detection description
Required for certain UST systems
A combination of monitoring and well sampling
Temporary method until upgrade required
Enhanced leak detection testing
Conduct 0.1 gph ATG test at least once every 30 days OR
Conduct 0.2 gph ATG test at least once every 7 days
AND
Sample wells within zones specified at least once a year
Enhanced leak detection records
Must keep one water sampling result per well for 12 months
AND
Must keep one valid 0.1 gph ATG test per tank, per month, for 12 months OR
Must keep one valid 0.2 gph ATG test per tank, per week, for 52 weeks
Enhanced leak detection upgrade
Must upgrade to .0900 secondary containment standards by Jan 1 of:
◦ 2005 – all steel or metal connected piping and ancillary equipment
◦ 2008 – all fiberglass or non-metal connected piping AND all USTs installed on or before Jan 1, 1991
◦ 2016 – all USTs installed after Jan 1, 1991