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TABLE
OF CONTENTS
A.
THE BACKGROUND
B. ENGINEERED
FOR SAFETY
C. THE
MANUFACTURING PROCESS
- The Steel Tank
Construction
- Secondary Containment
- Concrete Vault
- Coating and Finishing
D. ADDITIONAL
FEATURES
- Complying with
Environmental and Fire Safety
Requirements
- UL/ULC Listed
- Overfill Protection
- Venting
- Support Legs
- Thermal and Corrosion
Protection
- Spill Containment
- Vehicle Impact Resistance
- Bullet Resistance
- Non-Metallic Secondary Containment
E. TANK
WEIGHTS AND DIMENSIONS
F. PERMITS
AND APPROVALS
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A.
The Background
- You are probably aware that underground fuel storage tanks are a main source of soil contamination in this country. Underground fuel storage tanks corrode, leak fuel oil and gas into the soil and cause soil contamination. The contaminants may reach the underground water streams and could be carried into the drinking water systems. Decontamination of the underground fuel storage tank’s location is extremely costly and can have a devastating financial burden on tank’s owners and operators.
- Regulatory agencies have enacted many guidelines requiring the owners and operators of the underground fuel storage tanks to install expensive leak detection and monitoring facilities to prevent costly contamination problems.
- There are also many regulations covering installation and operation of “non-protected” aboveground steel storage tanks.
- To solve the problems associated with the underground storage tanks and the non-protected aboveground steel storage tanks, ConVault® developed a breakthrough idea of constructing a tank that does not have the costly underground tank’s leak monitoring system and contamination problem and at the same time has overcome the problems associated with the unprotected aboveground steel tanks. Because of its unique monolithic concrete construction features, the ConVault® tank system provides two (2) hour fire protection, vehicle impact resistance and ballistic resistance proven by the tests carried out by the Underwriters Laboratories of USA (UL) and Canada (ULC).
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B.
Engineered for safety
- The design and manufacturing concept of the Convault® is simple and at the same time very practical. In a nut-shell, Convault’s® design concept consists of:
a) Constructing a welded steel tank to store and contain flammable and combustible liquid fuels.
b) Insulating the steel tank exterior by a minimum of 1/4” thick Styrofoam and wrapping it in a 30 Mil high-density polyethylene (HDPE) membrane to provide a 100% secondary containment for the remote possibility of a fuel leak through the steel tank.
c) Encasing both the poly and the steel tank in 6” thick monolithic reinforced concrete vault to provide two-hour fire protection, ballistic and vehicle impact protection.
- Convault® has even designed a simple leak detection system that enables checking the tank for leaks on a regular basis. Using a stick, the operator can easily check the leak detector chamber for liquid. A dry leak detector chamber indicates no leak. Mechanical or electronic monitoring systems can also be used to monitor the tank for potential leaks.
- Convault® is so confident of its superior design that it gives 20 to 30 years of warranty for its steel tanks. Provided that the tank is installed, operated, maintained and tested in accordance with Convault’s® specifications, Convault® will replace your tank without charge if it develops a leak. See your standard warranty for its actual number of years and its conditions.
Since you have purchased one of over 30,000 tanks, which remain in service since 1987, you may wish to understand the unique manufacturing process of Convault® tanks. The following paragraphs will explain the construction process of the Convault® tanks. |
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C.
The Manufacturing Process
ConVault® tanks
construction process consists of four main steps, namely:
1. Steel tank
construction
2. Secondary
containment
3. Concrete
Vault
4 .Coating
and Finishing
Figure
No. 1 is
an isometric view of a typical ConVault® tank with a cutaway
section to show details of a ConVault® tank system. The four main manufacturing steps are further described below:
1.
Steel Tank Construction
a. ConVault®
steel tanks are made of 1/8", 3/16" or 1/4" thick steel,
depending on warranty and tank size. The steel tank contains
and holds the liquid fuel, which is the primary function
of the tank. To make the steel tank systems fit for their
function; the tanks are made in accordance with the UL standard
142 and ULC standard S601. The UL/ULC standards cover all the aspects of tank fabrication including material specification, fabrication, welding and testing. The tanks are listed in accordance with UL/cUL Standards and carry UL/ cUL labels as such.
b. At the fabrication shop, the tanks undergo a number of quality control and test procedures including a 24 to 48 hour pressure test at five (5) psig.
2.
Secondary Containment
a. The second stage of manufacturing consists of wrapping the steel tank with a minimum of 1/4” thick Styrofoam (foam) insulation and an impervious barrier of 30-Mil high-density polyethylene membrane (HDPE). The 30-Mil HDPE provides containment for the remote possibility of a fuel leak through the steel tank. A leak detector pipe terminating in the secondary containment provides a positive-proof that the tank is not leaking.
b. Another advantage of the 30-Mil HDPE is that it shields and protects the steel tank exterior from coming in direct contact with concrete and thus minimizes the potential risk of tank external corrosion.
c. Certain Authorities Having Jurisdiction require metallic secondary containment. Convault® manufactures double wall steel tanks to meet the above requirements. The secondary steel containment is wrapped in 30-Mil poly to prevent external corrosion. In effect this tank system provides triple containment; namely, primary steel tank, the secondary steel tank and tertiary 30 Mil poly.
3.
The Concrete Vault
The next step of manufacturing
a ConVault® tank is to encase the tank in a six (6) inch
thick reinforced concrete vault. Simply put, the six inches
of concrete is poured on all sides bottom and top of the tank
in one step and hence the phrase "monolithic". This
process assures that there are no joints and no heat sinks
in the concrete to carry heat from a fire into the primary
containment. The combination of the 30 mil poly and six (6) inch concrete provides a protected secondary containment system.
The concrete pouring process also goes through a strenuous quality control procedure to make sure the Convault® tank withstands all performance tests; namely the two (2) hour fire test, the vehicle impact resistance test and ballistic impact resistant test. Convault® tanks are listed by UL 2085 Standard and ULC S655 (ULC/ORD 142.16) Standards as fire resistant, insulated and protected tanks.
4.
Coating and Finishing
At the final stages of manufacturing, the concrete exterior of the tank is vacuum coated using a two-part water based epoxy paint to protect the tanks from the inclement weather conditions. Concrete exterior can also be produced in exposed aggregate with a clear coat of sealant, in STO finish or in Perma Crete finish. All nipples protruding from the tank are powder-coated to protect them from corrosion.
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D.
Additional features
The following is a
list of some of the major features and advantages of the ConVault®tanks:
1. Complying with Environmental and Fire Safety Requirements
a) Convault® tanks meet applicable safety requirements for secondary containment, leak monitoring, and spill protection. Convault® tanks are approved by regulators and fire officials in most local jurisdictions of the United Sates and many foreign countries. Convault® tanks are installed in 26 different countries worldwide.
b) Convault® tanks meet NFPA 30, NFPA 30A, UFC, BOCA, SBCCI, and IFC model fire codes safety standards. The units also comply with the 1996 Uniform Fire Code (UFC) Appendix A-II-F for the aboveground storage and dispensing of motor fuels.
c) Convault® tanks are certified by the California Air Resources Board for Balanced Phase 1 and Phase 2 Vapor Recovery including methanol and ethanol.
2. UL/ULC Listed
The Convault® tanks have been tested and have passed all requirements of the following UL and ULC Standards:
a) UL - 142, aboveground tanks for flammable and combustible liquids.
b) UL - 2085, two-hour furnace fire test and two hour simulated pool fire test for insulated fire resistant and protected tank.
c) UL - 2085, insulated and protected secondary containment aboveground tanks for flammable and combustible liquids.
d) UL - 2085 and UFC SECTION (79-7) vehicle impact and ballistic impact test for protected tank.
e) UL – 2085/ULC S655 (CAN ORD-C 142.16) Non-Metallic Secondary Containment and Venting by Form-of-Construction.
f) UL – Standard 2244 Systems Listing for Motor Vehicle Fuel Dispensing.
g) UL CAN/ORD - C 142.16, protected aboveground tank assemblies for flammable and combustible liquids.
h) UL CAN/ORD - C 142.5, concrete encased aboveground tank assemblies for flammable and combustible liquids.
i) UL CAN/ORD - 142.16, the furnace burn and 142.5, the open (pool) fire testing for two-hour fire rating.
3. Overfill Protection
Tanks can be provided with the following methods to protect them against overfill:
(a) direct reading level gauge at the tank which is visible from fill pipe location;
(b) valve located within fill-pipe access to close or restrict flow automatically at a
specified fill level;
(c) audible high level alarm activated by a float switch at a specified fill level.
4. Venting
The Convault® tank systems are furnished with a 2 inch normal vent and an emergency pressure relief system. The emergency relief system furnished with the tank normally opens if the tank pressure exceeds 1/2 psig. The tank systems conform to the national model fire codes and UL/ULC Standards for venting.
Convault® secondary containment is listed by UL/ULC for “Venting by Form of Construction” and therefore is not required to be equipped with emergency venting device for secondary containment.
5. Support Legs
Vaults have concrete support legs of unitized monolithic construction that provide visual inspection capability. Tanks do not require cathodic protection system as no steel part of the tanks comes in direct contact with the ground.
6. Thermal and Corrosion Protection
The tank construction includes thermal insulation to protect against temperature extremes and corrosion by separating the steel tank from the concrete. No part of the steel tank comes in direct contact with concrete or other corrosive materials. All nipples, manway and spill container are powder coated for protection against corrosive elements.
7. Spill Containment
The tank system includes a 5 to 15 gallon, powder-coated UL-Listed and patented, spill containment surrounding the fill pipe. The spill container is equipped with a normally closed hand operated valve that can be actuated to drain the spilled fuel liquids into the primary steel tank.
8. Vehicle impact resistance
Convault®tanks are designed to have a low center of gravity that can withstand vehicle impact and tipping during earthquakes and other natural disasters. Convault® tanks have withstood even phenomenal tests such as C-130 aircraft impact at Dobbins AFB in Georgia, Hurricane Andrew and the 1989 Loma Prieta earthquake.
9. Bullet Resistance
Convault® tanks withstand bullet resistance tests in compliance with UFC SECTION (79-7) APPENDIX # A-II-F-1 and UL 2085 Standard for Protected tanks.
10. Non-Metallic Secondary Containment and Venting by Form of Construction.
The UL 2085 Standard listing officially recognizes Convault® tank of having a secondary containment. Technically, this is equivalent to a protected and insulated double wall steel tank. Therefore, the Convault® tank provides you a secondary containment equivalent to a double wall steel tank plus protection of six-inch reinforced concrete.
11.
California Air Resources Board (CARB) Certified
ConVault AST's are
CARB certified for use with Phase I and Phase II vapor recovery
systems under Executive Order G-70-116 and revisions A through
F. California is recognized as the national air quality expert
and, having passed all field examinations by CARB, ConVault
AST's are generally regarded as having met the severest air
quality compliance standards.
- NOTICE: UL Standard 2085 requires Aboveground Storage Tanks (AST) to be evaluated to determine acceptability for continued use after fire exposure, physical damage, or misuse.
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E.
Tanks’ Weights and Dimensions
Figures No. 2, 3, 4 and 5
give nominal capacities, the outside dimensions, general fittings layout and approximate weights of some popular Convault® systems. These are representative sizes, dimensions and weights only. While all sizes and shapes listed are available, they may not be available from your local plant. Also, most plants have additional size and dimension options that are not listed here. To prevent installation problems, and to optimize your fuel storage site, please check with your local Convault® representative before specifying or beginning site development plans. More accurate tank weights can also be obtained from your local Convault® representative to help you in arranging proper equipment for the safe unloading and setting of tanks.
Figure No. 2
Tank Weights and Dimensions *
Single Primary Tank
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SIZE |
LENGTH |
WIDTH |
HEIGHT |
WEIGHT * |
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125 |
4’ – 1" |
4’ – 1" |
3’ – 11" |
6,000 |
|
250 |
7’ – 8" |
3’ – 9" |
3’ – 3" |
8,000 |
|
500 |
11’ – 0" |
4’ – 6" |
3’ – 4" |
12,000 |
|
1000 |
11’ – 0" |
5’ – 8" |
4’ – 4" |
18,000 |
|
2000 |
11’ – 3" |
8’ – 0" |
5’ – 6" |
30,000 |
|
3000 LP (Low Profile) |
11’ – 3" |
8’ – 0" |
7’ – 3" |
35,500 |
|
4000 LP (Low Profile) |
17’ – 7" |
8’ – 0" |
6’ – 5" |
45,000 |
|
4000 DW |
12’ – 2" |
8’ – 0" |
8’ – 9" |
40,000 |
|
5200 G (General) |
15’ – 6" |
8’ – 0" |
8’ – 9" |
47,000 |
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6000 |
17’ – 7" |
8’ – 0" |
8’ – 9" |
59,000 |
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8000 |
23’ – 1" |
8’ – 0" |
8’ – 9" |
72,000 |
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10000 |
28’ – 7" |
8’ – 0" |
8’ – 9" |
87,500 |
|
12000 |
34’ – 1" |
8’ – 0" |
8’ – 9" |
101,000 |
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The above sizes are typical, however some plants may not offer all tank sizes listed above.
For additional sizes, or specific needs in your area, refer to your Convault® distributor/salesman.
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Double-wall steel tanks are optional and external dimensions are identical to single wall tank.
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Nipple layout and designs vary according to customer needs.
*
NOTE:
These are nominal weights of the tanks.
Check with your distributor/salesperson for accurate weights.
Figure No. 3
Multi-Compartment
Tank Weights and Dimensions *
The
"D" Design
|
SIZE |
LENGTH |
WIDTH |
HEIGHT |
WEIGHT |
|
D250 |
11’ – 0" |
4’ – 6" |
3’ – 4" |
12,000 |
|
D500 |
11’ – 0" |
5’ – 8" |
4’ – 4" |
15,500 |
|
D1000 |
11’ – 3" |
8’ – 0" |
5’ – 6" |
30,000 |
|
D1500 LP (Low Profile) |
11’ – 3" |
8’ – 0" |
7’ – 3" |
35,500 |
|
D2000 LP (Low Profile) |
17’ – 7" |
8’ – 0" |
6’ – 5" |
45,000 |
|
D2000 DW |
12’ – 2" |
8’ – 0" |
8’ – 9" |
40,000 |
|
D2,600 G (General) |
15’ – 6" |
8’ – 0" |
8’ – 9" |
47,000 |
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D3000 |
17’ – 7" |
8’ – 0" |
8’ – 9" |
59,000 |
|
D4000 |
23’ – 1" |
8’ – 0" |
8’ – 9" |
72,000 |
|
D5000 |
28’ – 7" |
8’ – 0" |
8’ – 9" |
87,500 |
|
D6000 |
34’ – 1" |
8’ – 0" |
8’ – 9" |
101,000 |
Figure No. 4
Multi-Compartment
Tank Weights and Dimensions *
The
"E" Design
|
SIZE |
LENGTH |
WIDTH |
HEIGHT |
WEIGHT |
|
E250 |
11’ – 0" |
4’ – 6" |
3’ – 4" |
12,000 |
|
E500 |
11’ – 0" |
5’ – 8" |
4’ – 4" |
18,000 |
|
E1000 |
11’ – 3" |
8’ – 0" |
5’ – 6" |
30,000 |
|
E1500 LP (Low Profile) |
11’ – 3" |
8’ – 0" |
7’ – 3" |
35,500 |
|
E2000 LP (Low Profile) |
17’ – 7" |
8’ – 0" |
6’ – 5" |
45,000 |
|
E2000 DW |
12’ – 2" |
8’ – 0" |
8’ – 9" |
45,000 |
|
E2600 G (General) |
15’ – 6" |
8’ – 0" |
8’ – 9" |
47,000 |
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E3000 |
17’ – 7" |
8’ – 0" |
8’ – 9" |
59,000 |
|
E4000 |
23’ – 1" |
8’ – 0" |
8’ – 9" |
72,000 |
|
E5000 |
28’ – 7" |
8’ – 0" |
8’ – 9" |
87,500 |
|
E6000 |
34’ – 1" |
8’ – 0" |
8’ – 9" |
101,000 |
Figure No. 5
Cylindrical
Tank Weights and Dimensions *
|
SIZE |
LENGTH |
WIDTH |
HEIGHT |
WEIGHT |
|
4000 |
11’ –11" |
9’ – 2.5" |
9’ – 4.5" |
46,000 |
|
5200 |
15’ – 1.5" |
9’ – 2.5" |
9’ – 4.5" |
52,000 |
|
6000 |
17’ – 3" |
9’ – 2.5" |
9’ – 4.5" |
60,000 |
|
8000 |
22’ – 7" |
9’ – 2.5" |
9’ – 4.5" |
74,000 |
|
10000 |
27’ – 11" |
9’ – 2.5" |
9’ – 4.5" |
88,000 |
|
12000 |
33’ – 3" |
9’ – 2.5" |
9’ – 4.5" |
102,000 |
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F.
Permits and Approvals
Installation of fuel/oil
storage systems requires approval process from various government
agencies. List 1 shows typical approval process and documents
needed. Specific local or Authorities Having Jurisdiction
requirements may slightly differ for different locations,
but the list is a good reference and a guide for your permits
requirements.
List 1
PERMITS AND APPROVALS
- Prepare state and/or local application forms.
- Prepare system detail drawings.
- Prepare the site plan as follows:
- Draw to scale
- Show property lines and indicate occupancy or use of adjacent property.
- Show streets, intersections, and railroads.
- Show buildings on the site and indicate type of construction. Show building openings on walls adjacent to tanks.
- Show important utility lines, sewer, water, gas, and electric including fire hydrants and catch basins.
- Show any nearby waterways, streams, rivers, lakes, or retention basins.
- Show any underground or aboveground tanks.
- Show new tank location and indicate shortest distance to buildings and property lines.
- Prepare system detailed drawings to scale and show:
- Tank size, dimensions, and spacing between adjacent tanks.
- Base slab dimensions and bollard location and size.
- Vent size and location, including height of standard vent and type of cap.
- Fill details including spill and overfill protection.
- Piping details including shutoff valves and anti-siphon valves.
- Pumps and dispensing equipment including location, size, and type.
- Electrical details including shutoff switch location and grounding wire.
- Level gauges and leak detection equipment.
- Signs and decals.
- NOTICE:
It is advisable for the owners/operators to become familiar
with the codes and regulations applicable to their operation.
Table 2 lists some of the codes and regulations governing
aboveground storage tanks.
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List 2
CODES,
REGULATIONS, AND GUIDELINES
Aboveground Fuel Storage Tanks (ASTs) fall under a variety of governmental jurisdictions; therefore, the following references are provided as a general outline. You may be subject to different legislation and governing bodies’ requirements in your specific locale. A preliminary investigation must be conducted to thoroughly understand the controlling factors prior to utilizing the product in your specific area.
FEDERAL
REGULATIONS
40 CFR 112, US Coast Guard, Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA)
NOTICE: Among other requirements, EPA requires most aboveground storage tank installation sites to have a Spill Prevention, Containment and Countermeasures (SPCC) plan. The plan for tanks over 10,000 gallons must be certified by a professional registered engineer.
STATE
REGULATIONS
Federal regulations are referred to the governor of each state with the instructions that delegated duties to subordinate state agencies must provide a written plan on how the individual state will comply with the EPA’s enforcement activities.
CODES
AND STANDARDS
NFPA 30, 30A, and
31 Flammable and Combustible Liquid Code
ICBO Uniform Fire
Code section 79 APPENDIX A - II - F of 1996 UFC
Building Officials
and Code Administration (BOCA)
Southern Building
Code Congress Institute (SBCCI)
International Fire Code (IFC)
Underwriters Laboratories
(UL)
Underwriter’s Laboratories
Canada (ULC Standards/ORDs)
ENVIRONMENTAL
CAVEAT
Several regulatory
agencies have been integrally involved in the development
of the ConVault® aboveground storage tanks.
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