Xerxes Fiberglass Underground Storage Tanks User manual

Installation Manual
and
Operating Guidelines
For Single-Wall and Double-Wall
Fiberglass Underground Storage Tanks
Owner should retain this manual for
reference to operating guidelines.

TABLE OF CONTENTS
Section 1. Introduction.........................................................p.2
1.1. Safety
1.2. General
1.3. Definitions
Section 2. Preparation for Installation...............................p.3
2.1. General
Section 3. PreinstallationTesting.......................................p.4
3.1. General
3.2. Single-WallTank
3.3. Double-WallTank with Dry Interstitial Space
3.4. Double-WallTank withWet Interstitial Space
3.5. Single-Wall Multicompartment Tank with
Single-Wall Bulkhead
3.6. Single-Wall Multicompartment Tank with
Double-Wall Bulkheads
3.7. Double-Wall MulticompartmentTank with Dry
Interstitial Space
3.8. Double-Wall MulticompartmentTank withWet
Interstitial Space
Section 4. Backfill Material................................................p.10
4.1. General
Section 5. Excavation Parameters....................................p.11
5.1. General
5.2. Tank Spacing
5.3. Geotextile
Section 6. AnchoringTanks ..............................................p.13
6.1. Deadman Anchors
6.2. Xerxes Deadman Anchors
6.3. Anchor Slab
6.4. Hold-down Straps
6.5. Hardware and Anchoring Points
6.6. Man-Out-of-Hole Anchoring
6.7. Alternate Anchoring Methods in Wet-Hole
Installations
Section 7. Bottom Sumps and Fittings............................p.17
7.1. General
Section 8. Installation.........................................................p.17
8.1. General
8.2. Dry-Hole Installation
8.3. Wet-Hole Installation
Section 9. PostinstallationTesting...................................p.18
9.1. General
Section 10. Ballasting ..........................................................p.19
10.1. General
Section 11. Piping andVenting...........................................p.19
11.1. Internal Piping
11.2. External Piping
11.3. VentingTank
11.4. Venting Interstitial Space
Section 12. FillingTank........................................................p.20
12.1. General
Section 13. Backfilling to Grade.........................................p.20
13.1. General
Section 14. Deflection Measurement.................................p.20
14.1. General
14.2. Diameter Measurement without a Standpipe
14.3. Diameter Measurement with a Standpipe
14.4. Calculation and Comparison
Section 15. Monitoring.........................................................p.21
15.1. Single-WallTank
15.2. Double-WallTank
15.3. Tank with Dry Interstitial Space
15.4. Tank with Wet Interstitial Space
Section 16. Installing Attached Collar Risers (ACR)........p.22
16.1. General
16.2. Preinstallation
16.3. Preparing the Collar and Riser Body
16.4. Sealing and Assembly
16.5. HydrostaticWaterTest
16.6. Watertight Cover Installation (WT)
16.7. Final ACR Installation
Section 17. AddingTanks at Existing Locations..............p.25
17.1. General
17.2. Preferred Method
17.3. Alternate Method
Section 18. Operating Guidelines.......................................p.26
18.1. General
18.2. FillingTank
18.3. EnteringTank
Section 19. LimitedWarranties...........................................p.26
19.1. General
Section 20. Selected List of Supplemental Materials ......p.26
20.1. General
Section 21. Retaining Installation Manual.........................p.27
21.1. General
Addenda. Tank Installation Checklist..............................p.28
Tank Handling Data..........................................p.29

2
1. INTRODUCTION
1.1. SAFETY
1.1.1. Before beginning the tank installation, read through the
entire Installation Manual and Operating Guidelines
(subsequently referred to as “Installation Manual” . It is the
responsibility of the owner, installer and operator to follow all
requirements contained in this Installation Manual and comply
with all federal, state and local safety regulations that may apply
to tank installations and operations.
1.1.2. No instructions or procedures presented in this Installation
Manual should be interpreted so as to put at risk any person’s
health or safety, or to harm any property or the environment.
1.1.3. The following definitions will serve as a guide when
reading the Installation Manual:
Indicates an imminently hazardous situation, which, if not
avoided, will result in death or serious injury.
Indicates a potentially hazardous situation, which, if not
avoided, could result in death or serious injury.
Indicates a potentially hazardous situation, which, if not
avoided, may result in minor or moderate injury.
A Caution without the safety alert symbol indicates a
potentially hazardous situation, which, if not avoided, may
result in property damage.
1.1.4. Keep this Installation Manual available at the installation
site to refer to safety procedures as needed.
Follow O HA regulations for tank excavations. Collapse of
excavation walls could result in death or serious injury.
1.1.5. Working in and around excavations is dangerous. The
Occupational Safety and Health Administration (OSHA has
specific requirements that must be followed. Prior to beginning
work at the site, the installer must obtain a copy of OSHA’s
Standard, Part 1926, Subpart P(Excavations , 650-652. A copy
of this standard is available free of charge at OSHA’s Website:
www.osha.gov.
Read all instructions and operating guidelines before installation.
To Installer: Before installation, read Installation Manual and Operating Guidelines. After installation,
give Installation Manual and Operating Guidelines to owner.
To Owner: After installation, retain Installation Manual and Operating Guidelines for future reference to
operating guidelines.
1.1.6. Careless activity or reckless operation of equipment can
cause death, serious injury or property damage.
1.2. GENERAL
1.2.1. It is important to follow the procedures and instructions in
this manual in order to safely and properly install a Xerxes
underground storage tank and accessories. Failure to follow
these instructions will void the tank warranty and may cause
tank failure, serious personal injury or property damage.
1.2.2. The Xerxes warranty applies only to a tank installed
according to these instructions. Since Xerxes does not control
the parameters of any installation, Xerxes’ sole responsibility in
any installation is that presented in our warranty.
1.2.3. It is the responsibility of the owner and operator to always
follow the operating guidelines set forth in Xerxes’ applicable
warranty and Section 18 of this Installation Manual. A Xerxes
warranty is found in each product brochure or is available upon
request from the UST coordinator at the Xerxes plant nearest
you. It is the responsibility of the owner to retain this Installation
Manual for future reference to operating guidelines.
1.2.4. Use the Tank Installation Checklist (included in this
manual for all single-wall tanks (SWT , double-wall tanks
(DWT , oil/water separators (OWS and multicompartment tanks
(MCT as the installation proceeds. Retain a copy of the
completed Tank Installation Checklist, and any correspondence,
certification, etc., related to the tank. Each tank requires a
separate Tank Installation Checklist. Consult your Xerxes
representative or distributor if additional Tank Installation
Checklist forms are needed.
1.2.5. The tank owner and/or installing contractor should retain a
copy of the Tank Installation Checklist to facilitate any warranty
claim.
1.2.6. Comply with all applicable regulations and standards,
such as:
• federal, state and local construction, health, safety and
environmental codes;
• National Fire Protection Association standards (for example,
NFPA 30, 30A and 31 ;
• industry standard practices (for example, PEI RP100, API
RP1615 ;
• EPA reference materials (for example, “Doing It Right” .
1.2.7. For additional information, contact your state, county and
city storage-tank authorities, including health, fire or building
departments, and environmental agencies. All work must be
performed according to standard industry practices and OSHA
regulations.

3
2.1.2. Before the tank is unloaded or relocated on the job site
(and before preinstallation testing at job site , complete the
following steps:
2.1.2.1. Visually inspect the entire exterior surface of the tank to
make sure that no shipping or handling damage has occurred.
Look particularly for holes, cracks or deep scrapes.
2.1.2.2. Sign the shipping papers accepting the tank as
delivered.
2.1.2.3. Be sure that all equipment used to lift the tank is rated
to handle the load. Refer to the Tank Handling Data section at
the end of the Installation Manual to determine the weight of the
tank and to select the proper lifting equipment.
2.1.2.4. Select a solid, level area to place the tank, and clear
that area of all rocks, trash and debris.
2.1.3. When hoisting the tank, follow these instructions: (See
FIGURE 2-1 and FIGURE 2-2.)
2.1.3.1. When the tank is not rotated (the tank is upright , use all
lifting lugs to unload and install the tank.
2.1.3.2. Some tanks are rotated on the truck for shipping
purposes and some rotated tanks have extra lifting lug(s to aid
in the loading/unloading process. If the tank is rotated on the
truck, determine if extra lifting lug(s are provided for this
purpose.
2.1.3.2.1. When the tank is rotated but does not have extra
lifting lugs, use all lifting lugs to unload and install the tank.
2.1.3.2.2. When the tank is rotated and has extra lifting lugs, to
unload the tank use all lifting lugs that are situated on top of the
tank in its rotated position. To install the tank, use all lifting lugs
that are situated on top of the tank in its upright position.
FIGURE 2-1
30°
Max.
1.2.8. Federal, state and local codes and regulations always
take precedence over a Xerxes requirement.
1.2.9. Xerxes must authorize – in writing and prior to tank
installation – any variation to, or deviation from, these
Installation Manual instructions.
1.2.10. All correspondence regarding variations must be
retained for any warranty claim to be valid.
1.2.11. If you have questions or encounter situations not
covered in this Installation Manual, contact technical
support at Xerxes Minneapolis, 952-887-1890.
1.3. DEFINITIONS
1.3.1. For terms related to Xerxes tanks, see FIGURE 1-1.
FIGURE 1-1
2. PREPARATION FOR INSTALLATION
2.1. GENERAL
2.1.1. Although Xerxes corrosion-resistant tanks are rugged,
care must be taken so they are not dropped or damaged during
delivery, unloading and handling on the job site.
2.1.1.1. When unstrapping the tank from the truck, make sure
that the tank is secured in such a way that it does not roll off the
truck.
Do not release straps securing the tank to the truck until
crane or other lifting equipment is secured to the tank’s
lifting lug(s). Failure to do so could result in death or
serious injury.
Always chock the tank. The tank is heavy and has a large
surface area. The tank will roll on sloped surfaces and
could be blown about by the wind. Movement of the tank
could cause death or serious injury.
Anchor Strap
Location
Arrows
Service Fitting
Standard 4” NPT Half-Coupling
(access to primary tank only
Monitor Fitting
(access to interstitial
space only
Gauge Plates
(under all fittings
and manways
Seam
Flat
Rib
Flat Number
Dome
Spring
Line
Reservoir
(access to
interstitial
space only
Manway with Fittings
Attached Collar (AC
Lifting Lug

4
3.1.3. Construct a test manifold as shown in FIGURE 3-1. The
air-supply gauge must have a maximum full-scale reading of 15
psig with 1/4-lb. or 1/10-lb. increments, and a pressure-relief
device set at 6 psig [4 psig for 12-foot-diameter tanks].
FIGURE 3-1
3.1.4. In air tests, temperature change could be a factor in
changes in gauge readings.
Note: Multiple test m nifolds will be required to test
multicomp rtment t nks.
3.1.5. It is the installer’s responsibility to select a thread sealant
that is compatible with the product being stored. Some sealants
cannot be used with some products. Remove, clean and redope
all factory-furnished temporary plugs with appropriate thread
sealant. Install permanent plugs in all openings where piping will
not be installed. Make sure all manway bolts are tightened, and
fitting plugs are properly doped and sealed.
3.1.6. When checking the tank for leaks during an air/soap test,
rotate the tank to check the bottom, unless it is a tank filled with
monitoring fluid.
Never rotate a tank filled with monitoring fluid. ee ECTION
3.4. and ECTION 3.8. for instructions regarding these tanks.
3.1.7. Before rotating the tank during an air/soap test, place
protective material on the area on which the tank will be rotated.
Make sure the area is flat and is free of large or sharp objects,
such as rocks, which may damage the tank.
3.1.8. Rotate the tank slowly and carefully to avoid developing too
much momentum. Momentum can grow because fittings on top of
the tank make it top heavy. Make sure the tank’s fittings and
manways never touch the ground. Do not rotate the tank more
than 120° from the initial starting point.
Always secure the tank before moving or lifting it. This is
commonly done by connecting a crane or backhoe to the
lifting lugs. Failure to do so could result in death or serious
injury.
From Air Supply
Air-Supply
Valve
Air-Supply
Gauge
Service Fitting
Pressure-Relief
Device
FIGURE 2-2
2.1.3.3. Do not wrap chain or cable around the tank.
2.1.3.4. Use guy ropes to guide the tank when needed.
2.1.3.5. Do not roll the tank to move it.
2.1.3.6. If the tank has a bottom sump or fitting, take extra care
that the tank does not rest or roll on the bottom sump or fitting
prior to installation.
2.1.4. Whenever a tank is stored at the site, chock it in place to
prevent rolling. (See FIGURE 2-3.) Tie the tank down if high
winds are expected.
FIGURE 2-3
3. PREINSTALLATIONTESTING
3.1. GENERAL
3.1.1. Xerxes tanks are tested prior to shipment, but the tank
must be retested at the site prior to installation – even if shipped
with vacuum – in order to verify the absence of shipping and
handling damage.
3.1.2. The tester is responsible for verifying that all of the test
equipment is in good working condition, and is properly
configured and calibrated.
Tie
Downs
Tires
Tank
Sandbags
Top of tank in upright positon
Lifting lugs to be
used when tank is
in upright positon
Top of tank in rotated position on truck
Top of tank in rotated position on truck
Lifting lugs to be
used when tank is
in rotated positiion

5
FIGURE 3-2
The pressure-relief device or regulated air source must be
rated at a maximum of 6 psig [4 psig for a 12-foot-diameter
tank] to reduce the risk of overpressurizing the tank.
3.2. TESTING A SINGLE-WALL TANK
3.2.1. Remove all temporary service-fitting plugs.
3.2.2. Redope fittings and install plugs in all openings, except
one service fitting (needed for the test manifold . Follow
instructions in Point 3.1.5.
3.2.3. Install the test manifold in the open service fitting. Connect
the pressure source to the test manifold. (See FIGURE 3-3.)
FIGURE 3-3
3.2.4. Pressurize the tank to 5 psig [3 psig for a 12-foot-diameter
tank]. Allow the pressure to stabilize by adding or removing air
as necessary.
3.2.5. Close the air-supply valve on the test manifold. Disconnect
the air-supply line.
3.2.6. Soap the entire exterior of the tank, checking for leaks.
(Follow instructions in Points 3.1. . through 3.1.8., including
Warnings following 3.1.8. Watch for active air bubbles, which
indicate a leak. Pay special attention to fittings and manways.
3.2.7. Monitor the pressure for one hour.
Pressure-Relief Device
Air-Supply Valve
Air-Supply
Gauge
Service Fitting
From Air Supply
Max
5 psig
While moving or lifting the tank, do not position any part of
your body underneath the tank. This could result in death
or serious injury.
Do not lift or hoist a tank under pressure. This could result
in death or serious injury.
3.1.9. Refer to the appropriate section below for instructions for
the following situations:
3.1.9.1. For testing a single-wall tank, see SECTION 3.2.
3.1.9.2. For testing a double-wall tank with a dry interstitial
space, see SECTION 3.3.
3.1.9.3. For testing a double-wall tank with a wet interstitial
space, see SECTION 3.4.
3.1.9.4. For testing a single-wall multicompartment tank with a
single-wall bulkhead, see SECTION 3.5.
3.1.9.5. For testing a single-wall multicompartment tank with a
double-wall bulkhead(s , see SECTION 3. .
3.1.9.6. For testing a double-wall multicompartment tank with a
dry interstitial space, see SECTION 3.7.
3.1.9.7. For testing a double-wall multicompartment tank with a
wet interstitial space, see SECTION 3.8.
3.1.10. If damage is detected, do not attempt repairs. Contact
the UST coordinator at the Xerxes plant nearest you. Telephone
and fax numbers are found on the back cover of this manual.
3.1.11. After installation and before backfilling to grade, testing
must be repeated to verify that no damage has occurred during
installation.
When the tank is under pressure, the manways and/or
fittings may dislodge, or the tank could rupture and result
in death or serious injury. Before beginning the test, notify
all people on the test site to remain in a safe location.
ALWAY ATTEND TO THE TANK DURING THE TE T. tand
clear of manways, fittings and tank ends during the test.
The maximum test pressure is 5 psig [3 psig for a 12-foot-
diameter tank]. Position the pressure gauge so that the
pressure readings can be clearly read at all times. ee
FIGURE 3-2.

6
3.2.8. When the test is complete, carefully release the air
pressure from the tank by opening the air-supply valve.
3.2.9. When airflow stops, remove the test manifold.
3.2.10. Replace the protective covers in the service fittings.
3.3. TESTING A DOUBLE-WALL TANK WITH A DRY
INTERSTITIAL SPACE
3.3.1. GENERAL
3.3.1.1. The tank will arrive with a quick-disconnect assembly.
(See FIGURE 3-4.)
3.3.1.2. If the tank is not configured as shown in FIGURE 3-4
prior to preinstallation testing, call the UST coordinator at the
Xerxes plant nearest you.
3.3.2. PRIMARY TANK (INTERNAL)
3.3.2.1. Remove all temporary service-fitting plugs.
3.3.2.2. Redope fittings and install plugs in all openings, except
one service fitting (needed for the test manifold . Follow
instructions in Point 3.1.5.
3.3.2.3. Install the test manifold in the open service fitting. Connect
the pressure source to the test manifold. (See FIGURE 3-4.)
FIGURE 3-4
3.3.2.4. In order to test the primary tank alone, the quick-
disconnect assembly must not be connected to the service
fitting – keep the nylon tie in place.
3.3.2.5. Pressurize the primary tank to 5 psig [3 psig for a 12-
foot-diameter tank]. Allow the pressure to stabilize by adding or
removing air as necessary.
3.3.2.6. Close the air-supply valve on the test manifold.
Disconnect the air-supply line.
3.3.2.7. Soap all service fittings and manways. Watch for active
air bubbles, which indicate a leak.
3.3.2.8. Monitor the pressure for one hour.
Monitor Fitting
Quick-Disconnect
Assembly
Nylon
Tie
3.3.3. SECONDARY TANK (EXTERNAL)
3.3.3.1. Maintain the pressure in the primary tank.
Do not connect air supply directly to the interstitial-space
monitor fitting. Pressurizing the secondary tank (interstitial
space) by itself may damage the primary tank or cause
tank failure.
3.3.3.2. Free the hose from the service fitting by cutting the
nylon tie.
3.3.3.3. Insert the hose into the quick-disconnect fitting. This will
allow air to transfer from the primary tank to the secondary tank.
3.3.3.4. Reconnect the air-supply line. Allow the pressure to
stabilize at 5 psig [3 psig for a 12-foot-diameter tank] by adding
or removing air as necessary.
3.3.3.5. Close the air-supply valve on the test manifold.
Disconnect the air-supply line.
3.3.3.6. Soap the entire exterior of the tank, checking for leaks.
(Follow instructions in Points 3.1. . through 3.1.8., including
Warnings following 3.1.8. Watch for active air bubbles, which
indicate a leak. Pay special attention to fittings and manways.
3.3.3.7. Monitor the pressure for one hour.
3.3.3.8. When the test is complete, carefully release the air
pressure from the tank by opening the air-supply valve.
3.3.3.9. When the airflow stops, remove the test manifold.
3.3.3.10. Replace the protective covers in the service fittings.
3.4. TESTING A DOUBLE-WALL TANK WITH A WET
INTERSTITIAL SPACE
Never pressurize a wet interstitial space. Doing so may
damage the primary tank or cause tank failure.
3.4.1. PRIMARY TANK (INTERNAL)
3.4.1.1. Keep the tank vertical (the reservoir on top at all times
or the monitoring fluid may drain from the reservoir.
3.4.1.2. Remove all temporary service-fitting plugs and the
reservoir-fitting plug.
3.4.1.3. Check the monitoring-fluid level in the reservoir. It
should be about 1/4 full.
3.4.1.4. Visually check the interior of the tank for monitoring
fluid. There should not be ny.
3.4.1.5. Redope fittings and install plugs in all openings, except
one service fitting (needed for the test manifold and the reservoir
fitting. Follow instructions in Point 3.1.5. Do not open the
monitor fitting (if present) or monitoring fluid could be lost.

7
3.4.2.3. Replace the protective covers in the service fitting and
the reservoir fitting.
3.5. TESTING A SINGLE-WALL MULTICOMPARTMENT TANK
WITH A SINGLE-WALL BULKHEAD
3.5.1. GENERAL
3.5.1.1. Remove all temporary service-fitting plugs.
3.5.1.2. Redope fittings and install plugs in all openings, except
one service fitting in each compartment (needed for the test
manifolds . Follow instructions in Point 3.1.5. (See FIGURE 3-
and FIGURE 3-7.)
3.5.1.3. Before doing the air test of the base tank (described in
SECTION 3.5.2.) and the air test of the end tank(s (described in
SECTION 3.5.3.), install the test manifolds on the base and end
tank(s .
FIGURE 3-6
FIGURE 3-7
FIGURE 3-8
Air Test of End T nk(s)
Air Test of B se T nk
Typical Service Fitting
Monitor Fitting
When Double-Wall
Bulkhead Is Used
Seam for
End Tank
Seam for
Base Tank
Flat
Rib
Seam for
End Tank
Bulkhead
End Tank
Typical Manway with Fittings
Lifting Lug
End Tank
Base Tank
3.4.1.6. Install the test manifold in the open service fitting. Connect
the pressure source to the test manifold. (See FIGURE 3-5.)
FIGURE 3-5
3.4.1.7. Pressurize the primary tank to 5 psig. Allow the
pressure to stabilize by adding or removing air as necessary.
3.4.1.8. Close the air-supply valve on the test manifold.
Disconnect the air-supply line.
3.4.1.9. Soap all service fittings and manways. Watch for active
air bubbles, which indicate a leak. Look through the laminate for
any active air bubbles rising to the top. Their presence would
indicate an internal leak. Also, check the reservoir for bubbles in
the monitoring fluid. (The monitoring-fluid level will rise
during the ir test.)
3.4.1.10. Monitor the pressure for one hour.
3.4.1.11. When the test is complete, carefully release the air
pressure from the tank by opening the air-supply valve.
3.4.1.12. When the airflow stops, remove the test manifold.
3.4.1.13. Check the level of the monitoring fluid in the reservoir.
It should be at approximately the same level as the pretest level.
3.4.2. SECONDARY TANK (EXTERNAL)
Never pressurize a wet interstitial space. Doing so may
damage the primary tank or cause tank failure.
3.4.2.1. Check the exterior of the tank for monitoring fluid. (The
monitoring fluid is dyed blue to distinguish between moisture
and monitoring fluid. If monitoring fluid is found, wipe the tank
dry and verify that the monitoring fluid does not reappear. Lift
the tank to check the bottom. Do not roll the t nk.
Do not lift the tank when the tank is under pressure. This
could result in death or serious injury.
3.4.2.2. Visually check the interior of the tank for monitoring
fluid. There should not be ny.
Reservoir Fitting
Pressure-Relief
Device
From Air Supply
Air-Supply
Valve
Air-Supply
Gauge
Service
Fitting

FIGURE 3-9
3.5.2. AIR TEST OF BASE TANK
3.5.2.1. Connect the pressure source to the test manifold on the
base tank. (See FIGURE 3-3 and FIGURE 3-7.)
3.5.2.2. Pressurize the base tank to 5 psig [3 psig for a 12-foot-
diameter tank]. Allow the pressure to stabilize by adding or
removing air as necessary.
3.5.2.3. Close the air-supply valve on the test manifold in each
compartment. Disconnect the air-supply line.
3.5.2.4. Monitor the pressure for one hour. Do not rele se ir
pressure.
3.5.3. AIR TEST OF END TANK(S)
3.5.3.1. Connect the pressure source to the test manifold on the
end tank(s . (See FIGURE 3-3 and FIGURE 3-8.)
3.5.3.2. Pressurize the end tank(s to 5 psig [3 psig for a
12-foot-diameter tank]. Allow the pressure to stabilize by adding
or removing air as necessary.
3.5.3.3. Close the air-supply valve on the test manifold.
Disconnect the air-supply line.
3.5.4. EXTERNAL SOAP TEST
3.5.4.1. Soap the entire exterior of the tank, checking for leaks.
(Follow instructions in Points 3.1. . through 3.1.8., including
Warnings following 3.1.8. Watch for active air bubbles, which
indicate a leak. Pay special attention to fittings and manways.
3.5.4.2. Monitor the pressure for one hour.
3.5.4.3. After the test is completed, release all tank air pressure
and remove gauges.
3.5.4.4. Replace the protective covers in the service fittings.
3.6. TESTING A SINGLE-WALL MULTICOMPARTMENT TANK
WITH DOUBLE-WALL BULKHEAD(S)
Do not connect air supply directly to the interstitial-space
monitor fitting. Pressurizing the secondary tank (interstitial
space) by itself may damage the primary tank or cause tank
failure.
Air-Test Monitoring of Double-W ll Bulkhe d(s)
8
3.6.1. GENERAL
3.6.1.1. Remove all temporary service-fitting plugs.
3.6.1.2. Redope fittings and install plugs in all openings, except
one service fitting in each compartment (needed for the test
manifolds . Follow instructions in Point 3.1.5. (See FIGURE 3-
and FIGURE 3-7.)
3.6.1.3. Before doing the air test of the base tank (described in
SECTION 3. .2.) and the air test of the end tank(s (described in
SECTION 3. .3.), install the test manifolds on the base and end
tank(s .
3.6.2. AIR TEST OF BASE TANK
3.6.2.1. Connect the pressure source to the test manifold on the
base tank. (See FIGURE 3-3 and FIGURE 3-7.)
3.6.2.2. Pressurize the base tank to 5 psig [3 psig for a 12-foot-
diameter tank]. Allow the pressure to stabilize by adding or
removing air as necessary.
3.6.2.3. Close the air-supply valve on the test manifold on the
base tank. Disconnect the air-supply line.
3.6.2.4. Soap the fittings on top of the base tank to make sure
fittings are not leaking. Watch for active air bubbles, which
indicate a leak.
3.6.2.5. Monitor the pressure for one hour. Do not rele se ir
pressure.
3.6.3. AIR TEST OF END TANK(S)
3.6.3.1. Connect the pressure source to the test manifold(s on
the end tank(s . (See FIGURE 3-3 and FIGURE 3-8.)
3.6.3.2. Pressurize the end tank(s to 5 psig [3 psig for a
12-foot-diameter tank]. Allow the pressure to stabilize by adding
or removing air as necessary.
3.6.3.3. Close the air-supply valve on the test manifold.
Disconnect the air-supply line.
3.6.3.4. Soap the exterior of all compartments of the end
tank(s , checking for leaks. (Follow instructions in Points 3.1. .
through 3.1.8., including Warnings following 3.1.8. Watch for
active air bubbles, which indicate a leak. Pay special attention to
fittings and manways.
3.6.3.5. Monitor the pressure for one hour.
3.6.4. TEST OF DOUBLE-WALL BULKHEAD(S)
3.6.4.1. Install a 4-inch NPT plug with a 0-15 psig gauge (1/4-lb.
or 1/10-lb. increments into all monitor fittings leading into the
double-wall bulkhead(s . (See FIGURE 3-9.)
3.6.4.2. Closely monitor all these gauges for any pressure
increase.
3.6.5. EXTERNAL SOAP TEST
3.6.5.1. Soap the entire exterior of the tank, checking for leaks.
(Follow instructions in Points 3.1. . through 3.1.8., including

Warnings following 3.1.8. Watch for active air bubbles, which
indicate a leak. Pay special attention to fittings and manways.
3.6.5.2. Monitor the pressure for one hour.
3.6.5.3. Monitor all gauges for either a loss in pressure from the
tanks or an increase in pressure in the bulkhead interstitial
space.
3.6.5.4. After the test is completed, release all tank air pressure
and remove gauges.
3.6.5.5. Replace the protective covers in the service fittings.
3.7. TESTING A DOUBLE-WALL MULTICOMPARTMENT
TANK WITH A DRY INTERSTITIAL SPACE
Do not connect air supply directly to the interstitial-space
monitor fitting. Pressurizing the secondary tank (interstitial
space) by itself may damage the primary tank or cause
tank failure.
3.7.1. GENERAL
3.7.1.1. Remove all temporary service-fitting plugs.
3.7.1.2. Redope fittings and install plugs in all openings, except
one service fitting in each compartment (needed for the test
manifolds . Follow instructions in Point 3.1.5. (See FIGURE 3-10
and FIGURE 3-11.)
3.7.1.3. The tank will arrive with a quick-disconnect assembly.
(See FIGURE 3-4.)
3.7.1.4. If the tank is not configured as shown in FIGURE 3-4
prior to preinstallation testing, call the UST coordinator at the
Xerxes plant nearest you.
FIGURE 3-10
FIGURE 3-11
Air Test of B se T nk
Typical Service Fitting
Seam for
End Tank
Seam for
Base Tank
Flat
Rib
Seam for
End Tank
End Tank End Tank
Lifting Lug
Typical Manway with Fittings
Optional
Reservoir
Monitor
Fitting
Base Tank
9
FIGURE 3-12
FIGURE 3-13
3.7.2. AIR TEST OF BASE TANK
3.7.2.1. Connect the pressure source to the test manifold on the
base tank. (See FIGURE 3-3 and FIGURE 3-11.)
3.7.2.2. Pressurize the base tank to 5 psig. Allow the pressure to
stabilize by adding or removing air as necessary.
3.7.2.3. Close the air-supply valve on the test manifold on the
base tank. Disconnect the air-supply line.
3.7.2.4. Soap all service fittings and manways on the base tank.
Watch for active air bubbles, which indicate a leak.
3.7.2.5. Monitor the pressure for one hour. Do not rele se ir
pressure.
3.7.3. AIR TEST OF END TANK(S)
3.7.3.1. Connect the pressure source to the test manifold on the
end tank(s . (See FIGURE 3-3 and FIGURE 3-12.)
3.7.3.2. Pressurize the end tank(s to 5 psig. Allow the pressure
to stabilize by adding or removing air as necessary.
3.7.3.3. Close the air-supply valve on the test manifold on each
end tank. Disconnect the air-supply line.
3.7.3.4. Soap all service fittings and manways on the end
tank(s . Watch for active air bubbles, which indicate a leak.
3.7.3.5. Monitor the pressure for one hour.
3.7.4. AIR TEST OF SECONDARY TANK
3.7.4.1. Attach the quick-disconnect hose assembly from the
monitor fitting to the primary-tank service fitting (with a female
quick-disconnect fitting in place . This will allow air to transfer to
the interstitial space. (See FIGURE 3-4 and FIGURE 3-13.)
Air-Test Monitoring of Second ry T nk
Air Test of End T nk(s)

10
3.7.4.2. Add air as required and stabilize the air pressure in the
total tank system to 5 psig.
3.7.5. EXTERNAL SOAP TEST
3.7.5.1. Soap the entire exterior of the tank, checking for leaks.
(Follow instructions in Points 3.1. . through 3.1.8., including
Warnings following 3.1.8. Watch for active air bubbles, which
indicate a leak. Pay special attention to fittings and manways.
3.7.5.2. Monitor the pressure for one hour.
3.7.5.3. When the test is completed, carefully release the air
pressure from the tank by opening the air-supply valve.
3.7.5.4. When the airflow stops, remove the test manifold.
3.7.5.5. Replace the protective covers in the service fittings.
3.8. TESTING A DOUBLE-WALL MULTICOMPARTMENT
TANK WITH A WET INTERSTITIAL SPACE
Never pressurize a wet interstitial space. Doing so may
damage the primary tank or cause tank failure.
3.8.1. GENERAL
3.8.1.1. See FIGURE 3-10 and FIGURE 3-11.
3.8.2. BASE TANK’S PRIMARY (INTERNAL) TANK
3.8.2.1. Keep the tank vertical (the reservoir on top at all times
or the monitoring fluid may drain from the reservoir.
3.8.2.2. Remove all temporary service-fitting plugs and the
reservoir-fitting plug.
3.8.2.3. Check the monitoring-fluid level in the reservoir. It
should be about 1/4 full.
3.8.2.4. Visually check the interior of each compartment for
monitoring fluid. There should not be ny.
3.8.2.5. Redope fittings and install plugs in all openings, except
one service fitting in each compartment (needed for the test
manifolds and the reservoir fitting. Follow instructions in Point
3.1.5. (See FIGURE 3- and FIGURE 3-7.)
3.8.2.6. Before doing the air test of the base tank (described in
SECTION 3.8.3.) and the air test of the end tank(s (described in
SECTION 3.8.4.), install a test manifold in the open service
fitting on both the base and end tank(s .
3.8.3. AIR TEST OF BASE TANK’S PRIMARY TANK
3.8.3.1. Connect the pressure source to the test manifold on the
base tank. (See FIGURE 3-3 and FIGURE 3-11.)
3.8.3.2. Pressurize the primary tank of the base tank to 5 psig.
Allow the pressure to stabilize by adding or removing air as
necessary.
3.8.3.3. Close the air-supply valve on the test manifold on the
base tank. Disconnect the air-supply line.
3.8.3.4. Soap all service fittings and manways. Watch for active
air bubbles, which indicate a leak. Look through the laminate for
any active air bubbles rising to the top.Their presence would
indicate an internal leak. Also, check the reservoir for bubbles in
the monitoring fluid. (The monitoring-fluid level will rise
during the ir test.)
3.8.3.5. Monitor the pressure for one hour. Do not rele se ir
pressure.
3.8.4. AIR TEST OF END TANK(S)’ PRIMARY TANK(S)
3.8.4.1. Connect the pressure source to the test manifolds on
the end tank(s . (See FIGURE 3-3 and FIGURE 3-12.)
3.8.4.2. Pressurize the primary tank of the end tank(s to 5 psig.
Allow the pressure to stabilize by adding or removing air as
necessary.
Note: The monitoring-fluid level will rise during the ir test.
3.8.4.3. Close the air-supply valve on the test manifolds on the
end tanks. Disconnect the air-supply line.
3.8.4.4. Soap all service fittings and manways. Watch for active
air bubbles, which indicate a leak. Check the reservoir for
bubbles in the monitor fluid. (The level of the monitor fluid will
n tur lly rise due to the pressure in the prim ry t nk.)
3.8.4.5. Monitor the pressure for one hour.
3.8.4.6. When the test is complete, carefully release the air
pressure from all compartments by opening the air-supply valve.
3.8.4.7. When the air flow stops, remove the test manifolds.
3.8.4.8. Check the monitoring-fluid level in the reservoir. It
should be at approximately the same level as the pretest level.
3.8.5. SECONDARY TANK (EXTERNAL)
Do not connect air supply directly to the interstitial-space
monitor fitting. Pressurizing the secondary tank (interstitial
space) by itself may damage the primary tank or cause tank
failure.
3.8.5.1. Check the exterior of the tank for monitoring fluid.
(The monitoring fluid is dyed blue to distinguish between
moisture and monitoring fluid. If monitoring fluid is found, wipe
the tank dry and verify that the monitoring fluid does not
reappear. Lift the tank to check the bottom. Do not roll the t nk.
3.8.5.2. Visually check the interior of the tank for monitoring
fluid. There should not be ny.
3.8.5.3. Replace the protective covers in the service fittings and
the reservoir fitting.
4. BACKFILL MATERIAL
4.1. GENERAL
4.1.1. Xerxes tanks must be installed using either pea gravel or
crushed stone as backfill material.

4.1.2. Using other than approved bedding and backfill materials
without prior written authorization from Xerxes will void the tank
warranty.
Use of unapproved backfill material could cause tank
failure and result in death or serious injury.
4.1.3. Approved backfill material must meet the following specifi-
cations:
4.1.3.1. The material is washed, free-flowing, and free of ice,
snow and debris.
4.1.3.2. The material conforms to the specification of ASTM
C-33, par. 9.1, size numbers 6 through 8 of Table 2.
4.1.3.3. When using pea gravel, the material is to be a mix of
rounded particles, sizes between 1/8 inch and 3/4 inch. (See
FIGURE 4-1.)
FIGURE 4-1
4.1.3.4. When using crushed stone, the material is to be a mix of
angular particles, sizes between 1/8 inch and 1/2 inch. (See
FIGURE 4-2.)
FIGURE 4-2
4.1.3.5. No more than 5% (by weight of the material may pass
through a #8 sieve.
4.1.3.6. It is recommended that the materials supplier certifies
that the material conforms to ASTM C-33 and any other
applicable specifications.
1/8”
1/2”
1/8”
3/4”
11
4.1.4. For additional information, refer to the Xerxes document,
Fiberglass Tank Backfill Guidelines.
4.1.5. If material which meets these specifications is not
available, contact technical support at Xerxes Minneapolis for
information on alternate materials and the process for approval.
5. EXCAVATION PARAMETERS
Follow O HA regulations for tank excavations. Collapse of
excavation walls could result in death or serious injury.
5.1. GENERAL
5.1.1. The installing contractor must take all precautions
necessary to protect employees working in or near a tank
excavation. These precautions should include, but are not
limited to the following:
5.1.1.1. Locate and protect any utility installations near the
excavation before opening the excavation.
5.1.1.2. Secure the walls of the excavation.
5.1.1.3. Prevent exposure of employees to hazardous fumes
from the excavation.
5.1.1.4. Protect employees from hazards associated with water
accumulation in the excavation.
5.1.1.5. Erect barricades, etc., to prevent unauthorized vehicle
or pedestrian traffic.
5.1.1.6. Inspect, a minimum of once a day, the excavation and
surrounding area.
5.1.2. For additional information on excavation, trenching and
shoring safety practices, consult OSHA’s Standard, Part 1926,
Subpart P(Excavations , 650-652; and “Fall Protection Rules
and Regulations.”
5.1.3. The minimum depth of the excavation is normally
determined by the presence or absence of groundwater and the
presence or absence of traffic at the site. These dimensions are
critical to the successful installation of a tank and are often
regulated by code.
5.1.4. For additional requirements and specifications, refer to
federal, state and local codes; NFPA 30, 30A and 31; API RP
1615; PEI RP100; and FIGURE 5-1 and FIGURE 5-2.
5.1.5. In all cases, the depths of cover given in 5.1.5.1. and
in 5.1.5.2. are minimums.
5.1.5.1. Tanks subjected to traffic loads (H-20 loads must have
a cover depth of at least 36 inches of backfill [48 inches for
12-foot-diameter tanks], or 18 inches of backfill [36 inches for

12
In a nontraffic installation, ensure that the areas above the
tanks are not subjected to traffic or other types of loads,
which could cause tank damage and result in death or
serious injury.
5.1.5.3. The maximum burial depth is 7 feet of cover over the
top of the tank. Deviation from this may be permissible with prior
written authorization from Xerxes. Call your Xerxes representa-
tive for a special quotation prior to tank purchase if the burial
depth is to be greater than 7 feet.
5.1.5.4. Asphalt and concrete pads must extend a minimum of
12 inches beyond the tank in all directions.
5.1.5.5. An unattached manway riser (if present must not
transmit load from the concrete slab to the tank. A minimum
space of 6 inches must exist between the bottom of the riser
and the top of the tank.
5.1.5.6. Traffic loads from the top slab must not be transmitted
to an attached sump or riser. A minimum space of 3 inches must
exist between the riser or sump and the slab.
5.2. TANK SPACING
5.2.1. GENERAL
5.2.1.1. The following are minimum spacings and must be
increased as needed to accommodate deadmen or anchor
slabs. (See SECTION .)
5.2.1.2. Always provide sufficient clearance to allow the deadmen
to be set outside of the tank “shadow.” (See FIGURE 5-3.)
FIGURE 5-3
5.2.2. STABLE IN SITU (NATIVE) SOIL CONDITIONS
5.2.2.1. Where shoring is not required to maintain a vertical wall
from top to bottom of the excavation, and where the soil is
stable, the minimum spacing between the sidewall or endcap
of the tank and the side of the excavation must be 18 inches
[24 inches for 12-foot-diameter tanks].
Tank Shadow
Width (See TABLE -1.)
2 x Width
12-foot-diameter tanks] plus 6 inches of reinforced concrete or
9 inches of asphalt. (See FIGURE 5-1.) In wet condition,
sufficient overburden nd/or n ppropri te nchoring
system must be present to offset buoy ncy of the t nk.
FIGURE 5-1
5.1.5.2. Tanks not subjected to traffic loads must have a cover
depth of at least 24 inches of backfill [48 inches for 12-foot-
diameter tanks], or 12 inches of backfill [36 inches for 12-foot-
diameter tanks] plus 4 inches of reinforced concrete or 6 inches of
asphalt. (See FIGURE 5-2.) In wet condition, sufficient
overburden nd/or n ppropri te nchoring system must
be present to offset buoy ncy of the t nk.
FIGURE 5-2
No
Traffic
24”
[48”]
12”
[36”]
12”
4”
Concrete
6”
Asphalt
Note: Number in brackets refers to 12-foot-diameter tanks.
36”
[48”]
18”
[36”]
9”
Asphalt
6”
Concrete
12”
Traffic
Note: Number in brackets refers to 12-foot-diameter tanks.

5.2.3.3. A reinforced concrete slab may be required under the
tank as a foundation in the excavation where the bottom is
unstable.
5.3. GEOTEXTILE
5.3.1. The tank owner or the owner’s technical representative is
responsible for determining whether a geotextile or an alternate
filtering technique is appropriate for a specific installation.
Geotextile allows the passage of water, but prevents the
migration and mixing of in situ soil and the select backfill
material. Geotextile helps preserve the integrity of the select
backfill envelope, which surrounds and supports the tank.
5.3.2. Xerxes recommends that geotextile be used when the
tank is installed in:
• areas with frequently changing groundwater conditions or
areas subject to tidal fluctuations,
• unstable soils such as cited in SECTION 5.2.3,
• water conditions with silty in situ soil.
5.3.3. For further information concerning geotextile specifica-
tions and installation procedures, consult the geotextile
supplier’s installation guidelines or instructions.
5.3.4. Polyethylene film is not considered an effective geotextile
material. It may tear or degrade while in service.
6. ANCHORINGTANKS
Xerxes recommends that all tanks be anchored in installa-
tions in which the tank could be exposed to water. Xerxes
recommends that every site be thoroughly evaluated for the
potential of a rise in the local water table or of trapped
water. Failure to anchor a tank under these conditions may
damage the tank or surrounding property.
6.1. DEADMAN ANCHORS
6.1.1. A deadman is typically a reinforced concrete beam.
6.1.2. The length of the deadman is typically equal to the length
of the tank.
6.1.3. A deadman may be fabricated in multiple sections as long
as the total length is not decreased and each section contains at
least two balanced anchor points.
6.1.4. The width and thickness of the deadmen depend on the
tank diameter, water-table height, number of attached collar
risers and burial depth.
6.1.5. Deadmen should be designed according to the American
Concrete Institute (ACI code.
6.1.6. Refer to TABLE -1 for typical deadmen dimensions given
the situation of an empty tank with a burial depth of 3 feet, with
groundwater to grade and with one attached collar riser.
13
5.2.2.2. If more than one tank is to be installed in the same hole,
allow for at least 18 inches between the tanks. (See FIGURE 5-4.
FIGURE 5-4
5.2.3. UNSTABLE IN SITU SOIL CONDITIONS
Xerxes recommends that the tank owner seek the advice of
a local foundation professional engineer if the in situ soil is
extremely soft or inherently unstable (for example, peat,
quicksand, muck, landfill, very soft or highly expansive
clay, underground stream, etc.).
5.2.3.1. If the soil has less than 750 lbs./sq. ft. cohesion as
calculated from an unconfined compression test; or in soils
having an ultimate bearing capacity of less than 3,500 lbs./sq.
ft.; or where soil will not maintain a vertical wall, the excavation
must allow a minimum space equal to half the diameter of the
tank between the excavation wall and both the side and the endcap
of the tank, to enhance lateral resistance. (See FIGURE 5-5.)
5.2.3.2. The spacing between adjacent tanks is to be at least 18
inches. (See FIGURE 5-5.)
FIGURE 5-5
1/2
Tank
Dia.
18"
1/2 Tank Dia. 1/2 Tank Dia.
Unst ble Soil
18” 18” 18”
18” 18”
St ble Soil

6.2.7. The deadmen are to be butted together at the tank center,
on each side of the tank when multiple sections are used.
6.2.8. Use one U-bolt per strap end and only one strap per
U-bolt.
6.3. ANCHOR SLAB
6.3.1. An anchor slab is typically a reinforced concrete base.
6.3.2. The total length of the slab must be at least the same as
the length of the tank.
6.3.3. The minimum slab thickness is 8 inches.
6.3.4. The width of the slab depends on the tank diameter. The
slab must extend a minimum of 18 inches [12 inches for 4-foot-
diameter tanks] beyond each side of the tank.
6.3.5. Refer to TABLE -2 and FIGURE -1 for anchor-point
dimensions.
6.3.6. Provide a separate anchor point for each hold-down strap.
6.3.7. All anchor points must be engineered to withstand the
tank’s buoyancy forces.
6.3.8. When using a concrete base slab, allow sufficient depth in
the excavation for 12 inches of bedding material below the tank.
(See FIGURE -1.)
FIGURE 6-1
TABLE 6-2
T nk
Di meter
4’
6’
8’
10’
12’
“A”
24”
35”
43”
57”
58”
Anchoring Dimensions
“B”
18”
23”
31”
45”
50”
“C”
12”
13”
15”
15”
23”
“E”
Min.
27”
42”
52”
69”
87”
“E”
M x.
30”
48”
58”
75”
93”
“D”
8’ - 4 1/4”
12’ - 1”
15’ - 1”
18’ - 8 3/4”
22’ - 6 3/4”
Position Strap Clip
at Tank Top
D
C
B
EA
12"
Slab
Deadman
Clips
Typical Anchoring
Configuration
14
TABLE 6-1
6.1.7. Tanks of 10-foot diameter with a capacity of 30,000 gallons
or larger may require larger deadmen than those in TABLE -1,
depending on burial depth, to offset buoyancy. Contact technical
support at Xerxes Minneapolis for further information.
6.1.8. Lay the deadmen in the excavation parallel to the tank
and outside of the tank “shadow.” (See FIGURE 5-3.)
6.1.9. In multiple tank installations with deadmen:
• each tank will have its own set of deadmen (one deadman may
be used between two tanks if the deadman is double in width ;
• a separate anchor point must be provided for each hold-
down strap;
• the minimum spacing between tanks must be no less than
twice the width of a single deadman.
6.2. XERXES DEADMAN ANCHORS
6.2.1. A Xerxes-supplied deadman is pre-engineered and sized
to the tank ordered. As with any deadman, water-table height,
number of attached collar risers and burial depth must be
considered.
6.2.2. Placement of a Xerxes deadman is the same as a
standard deadman. (See FIGURE -1.)
6.2.3. A Xerxes deadman is supplied with 3/4-inch-diameter,
plated U-bolts. These bolts protrude up through the slots in the
deadman and are held in place with cotter pins.
Only use the U-bolts when lifting and positioning the
deadmen. A spreader bar may be required to lift longer
sections of deadmen. Use guy ropes to guide the deadmen
when lifting. Failure to do so could result in death or
serious injury.
6.2.4. The U-bolts can be moved and positioned to match the
hold-down strap locations on the tank (marked by arrowhead
symbols .
6.2.5. When using these deadman anchors in man-out-of-hole
strapping applications, align the U-bolts with the proper ribs
before setting them in the hole.
6.2.6. Care should be taken to keep backfill from entering the
U-bolt slot until final adjustment is made.
4’
6’
8’
10’
12’
Typic l
De dm n Dimensions
(Width x Depth
6” x 6”
12” x 12”
12” x 12”
18” x 12”
36” x 8”
T nk Di meter

15
recommendations of wire-rope manufacturer and supplier, and
follow accepted industry standards when selecting, using,
attaching or connecting wire rope. (See FIGURE -3, FIGURE
-4 and FIGURE -5.)
Use only appropriately sized hardware with the strap eye.
Oversized hardware may damage the strap eye and result in
minor or moderate injury . ee FIGURE 6-2 for dimensions
of strap eye.
FIGURE 6-2
6.5.7. When connecting the end of a hold-down strap to the
anchor, common methods (shown in FIGURE -3) are:
A. using a drop-forged turnbuckle, B. using a looped wire rope,
or C. using a combination of both.
FIGURE 6-3
6.5.8. All exposed metal on the anchoring system must be
coated or galvanized to protect against corrosion.
6.5.9. When fastening wire rope, use a minimum of two clips for
a 3/8-inch wire rope and three clips for a 1/2-inch wire rope on
each termination. See TABLE -3 for minimum wire-rope diameter.
6.5.10. Turn back from thimble the exact amount of wire rope
specified by the manufacturer of the clips used.
6.5.11. Apply the first clip at a distance from the dead end of the
wire rope that is equal to the largest width of the clip used. (See
FIGURE -4.)
6.5.12. For each clip, apply a U-bolt over the dead end of wire
rope. (See FIGURE -4.) (Note: Live end rests in s ddle.)
1/4"
1 /8"
Strap
Clips
6.4. HOLD-DOWN STRAPS
6.4.1. Only Xerxes straps may be used when anchoring a
Xerxes tank.
6.4.2. The locations for hold-down straps on each tank are
marked on the tank by the arrowhead symbols .
6.4.3. Straps must be used on all marked hold-down locations.
Do not place straps between ribs (except on 4-foot-diameter
tanks). Failure to properly place straps may result in tank
damage.
6.4.4. Data for hold-down straps are given in TABLE -2 and
FIGURE -1.
6.4.5. Evenly distribute loads by tightening all hold-down straps
uniformly until they are snug over the ribs but cause no
deflection of the tank.
6.4.6. Take a measurement of the internal diameter of the tank to
determine whether vertical deflection is within the limits specified
by Xerxes after the straps have been installed and tightened.
(See SECTION 14 of the Installation Manual for instructions on
taking diameter measurements.)
6.5. HARDWARE AND ANCHORING POINTS
6.5.1. Anchoring hardware must be sized according to TABLE 6-3,
and manufactured to industry standards and dimensions.
TABLE 6-3
6.5.2. The installing contractor is responsible for providing
hardware and anchor points of sufficient size and strength.
6.5.3. The particular configuration of hardware will be determined
by the contractor, the owner or the owner’s representative.
6.5.4. Locate the anchor points as shown in TABLE -2 and
FIGURE -1. Refer to dimension “E.” Align all anchor points with
the marked arrowhead symbols on the tanks, within a
tolerance of ±1 inch.
6.5.5. For specific information on hardware and its use, consult
the hardware manufacturer or supplier.
6.5.6. The installer is responsible for using appropriate and ap-
proved engineering practices when fastening wire rope. Refer to
T nk
Di meter
4’
6’
8’
10’
12’
Hook
3/4”
3/4”
1 1/4”
1 1/4”
1 1/4”
Minimum Turnbuckle Di meter
(by Type)
J w
1/2”
1/2”
3/4”
3/4”
3/4”
Minimum
Wire-Rope
Di meter
3/8”
3/8”
1/2”
1/2”
1/2”
Eye
1/2”
1/2”
3/4”
3/4”
3/4”

FIGURE 6-6
6.7. ALTERNATE ANCHORING METHODS IN WET-HOLE
INSTALLATIONS
6.7.1. In wet-hole installations, when Xerxes’ preferred method
of man-out-of-hole anchoring is not available, the following
methods may be used.
6.7.1.1. With both methods, place the hold-down strap between
the wire rope and the tank so that the wire rope is never in direct
contact with the tank.
6.7.1.2. The H-shaped positioning clips around the strap are
designed to accommodate the wire rope on top of the strap
as shown in FIGURE -7 and FIGURE -8.
6.7.1.3. The following method is shown in FIGURE -7:
• attach a wire rope to each end of each hold-down strap;
• secure the termination of the wire rope (See SECTION .5.
for suggested method.);
• center each hold-down strap on each rib marked with the
arrowhead symbols ;
• place the deadmen on top of the wire ropes on each side of
the tank;
• lower the deadmen to the bottom of the excavation;
• take the slack out of each wire rope and splice the termination
of the wire ropes on top of the tank (See SECTION .5.).
FIGURE 6-7
StrapStrap
Load Binder
Tank
12"
Xerxes
Deadman
16
FIGURE 6-4
6.5.13. When two clips are required, apply the second clip as
near the loop or thimble as possible. (See FIGURE -4.)
6.5.14. When more than two clips are required, apply the
second clip as near the loop or thimble as possible, turn nuts on
second clip firmly, but do not tighten initially. (See FIGURE -4.)
6.5.15. When more than two clips are required, space additional
clips equally between the first two, take up rope slack, and
tighten nuts on each U-bolt evenly.
6.5.16. Tighten all hardware uniformly and follow the manufac-
turer’s torque specifications. Double-check the tightness once
the anchoring system is complete.
6.5.17. If forming a loop in the wire rope, a splice is required for
connecting the two ends together. Standard rigging practice for
splicing wire rope calls for using twice the number of clips
recommended for a single-end termination. Use a minimum of
four clips for a 3/8-inch wire rope and a minimum of six clips for
a 1/2-inch wire rope. Place the rope ends parallel to each other
and install the clips as shown in FIGURE -5.
FIGURE 6-5
6.6. MAN-OUT-OF-HOLE ANCHORING
6.6.1. The Xerxes man-out-of-hole (MOH strapping system is
designed for use in installations where water is in the excavation
and/or where personnel may not enter the hole because of site
restraints. An MOH strapping system can be, but need not be,
used in conjunction with Xerxes deadmen.
6.6.2. When using the MOH strapping system, the placement of
components is critical. (See FIGURE - .)
1/2" Wire Rope
3/8" Wire Rope
Dead EndLive End
Load
Dead End Live End
Load
Dead End
Live End
Load
Dead End Live End
Load
Dead End
Live End
Loop
1st Clip rd Clip 2nd Clip
Thimble

Adequately ballast the tank (add liquid) in a wet hole or in a
dry hole that may become wet (for example, from site
runoff) until the installation is totally completed. Failure to
do this may damage the tank or surrounding property.
8.1. GENERAL
8.1.1. Use only approved backfill material. (See SECTION 4.)
8.1.2. Do not mix approved material with sand or in situ soil.
8.1.3. Do not use in situ soil as backfill material.
8.1.4. All excavated in situ soil must be replaced with approved
material.
8.2. DRY-HOLE INSTALLATION
8.2.1. Prepare a smooth level bed, 12 inches thick, of approved
backfill material.
8.2.2. Refer to SECTION 2.1.3. regarding the use of lifting lugs
to hoist the tank when unloading and installing it.
8.2.3. Place the tank or tanks onto the bed. Do not set Xerxes
tanks directly onto a concrete slab, on timbers or cradles, or
onto the in situ soil.
8.2.4. As the tank is being placed, slope the tank according to site
specifications. (Xerxes does not require that a tank be sloped.
The slope is determined by the tank owner’s specifications.
8.2.5. Sloping of tanks may affect accuracy of Xerxes calibration
charts.
8.2.6. If a double-wall tank is sloped, the monitor should be at
the low end.
8.2.7. Use the tops of the ribs to establish longitudinal level.
Establish lateral level by placing the level across the top of a
fitting or a manway.
8.2.8. When the tank is placed, take a measurement of the
internal diameter of the tank. (See SECTION 14 of the
Installation Manual for instructions on taking diameter
measurements. Record this measurement as Initial Internal
Diameter on the Tank Installation Checklist, Section 4.
8.2.9. If tank is to be anchored, install the anchoring hardware at
this time. (See SECTION .)
8.2.10. Place one 12-inch lift of approved backfill material evenly
around the tank. From the edge of the hole or the top of an
adjacent tank, push the backfill in place by using a nonmetal
probe long enough to reach beneath the tank. Work the backfill
material under the tank body and domes so the tank is fully
supported – that is, so there are no voids under the tank. (See
FIGURE 8-1 and FIGURE 8-2.)
6.7.1.4. The following method is shown in FIGURE -8:
• loop a wire rope around the deadman at each location that cor-
responds to each rib marked with the arrowhead symbols ;
• secure the termination of the wire rope (See SECTION .5.
for suggested method.);
• lower each deadman to the bottom of the excavation using
the wire rope;
• center each hold-down strap on each rib marked with the
arrowhead symbols ;
• bring the live end of each wire rope up to the top of the tank
at each marked rib;
• take the slack out of each wire rope and splice the termina-
tion of the wire ropes on top of the tank (See SECTION .5.).
FIGURE 6-8
7. BOTTOM SUMPS AND FITTINGS
7.1. GENERAL
7.1.1. If the tank has a bottom sump or fitting, take extra care
that the tank does not rest or roll on the bottom sump or fitting
prior to installation.
7.1.2. During installation, provide a clear area in the backfill
bedding so that the tank rests on the backfill bedding and the
sump or bottom fitting is clear.
7.1.3. After setting the tank, fill and tamp the resulting void by
using hand tools before continuing the backfilling.
8. INSTALLATION
If product is used as ballast, exercise special care in handling.
afeguard against sparks, fire or product spills. Improper
handling of product could cause a fire or explosion, and
death or serious injury.
Do not use air pressure to test tanks that contain or have
contained flammable or combustible liquids or vapors. The
fuel and air mixture could explode and cause death or
serious injury. Tanks should be air tested before ballasting.
17

8.3.1.4. Omit Point 8.2.8.
FIGURE 8-3
8.3.2. Cover depth must meet minimum depth specified in
SECTION 5 of this Installation Manual.
8.3.3. Completely ballast the tank once backfill is even with the
top of the tank.
9. POSTINSTALLATIONTESTING
Do not use air pressure to test tanks that contain or have
contained flammable or combustible liquids or vapors. The
fuel and air mixture could explode and cause death or
serious injury. Tanks should be air tested before ballasting.
If product is used as ballast, exercise special care in handling.
afeguard against sparks, fire or product spills. Improper
handling of product could cause a fire or explosion, and
death or serious injury.
9.1. GENERAL
9.1.1. After backfill is brought to the top of the tank, take a
measurement of the internal diameter of the tank as a deflection
check. (See SECTION 14 of the Installation Manual for
instructions on taking diameter measurements.
9.1.2. After the internal diameter of the tank has been measured
and vertical deflection is determined to be within the limits
specified by Xerxes (See table in Tank Installation Checklist,
Section 4.), the tank must be pressure tested to ensure that no
damage occurred during installation.
9.1.3. Follow the procedure in SECTION 3, soaping all exposed
areas of the tank and all fittings, and monitoring the pressure for
one hour.
9.1.4. Carefully relieve the pressure in the tank. Remove the
quick-disconnect assembly from dry double-wall tanks.
12"
Do not strike the tank with the probe or tank damage may
result.
FIGURE 8-1
FIGURE 8-2
8.2.11. Repeat Point 8.2.10. with a second 12-inch lift.
8.2.12. After the second lift of material has been placed and
worked under the tank, bring the backfill to the top of the tank.
8.3. WET-HOLE INSTALLATION
8.3.1. Follow the dry-hole installation procedure with the
following modifications:
8.3.1.1. Before performing Point 8.2.1. of the dry-hole installa-
tion, take a measurement of the internal diameter of the tank
before the tank is placed in the excavation hole. (See SECTION
14 of the Installation Manual for instructions on taking diameter
measurements. Record this measurement as Initial Internal
Diameter on the Tank Installation Checklist, Section 4.
8.3.1.2. Before performing Point 8.2.1. of the dry-hole installa-
tion, pump the water from the hole and continue pumping to
maintain minimum water level during tank installation.
8.3.1.3. During Point 8.2.2. of the dry-hole installation, when
setting and leveling the tank, partially ballast the tank until it
settles firmly on the prepared bed. The ballast level in the tank
must never exceed the water level in the hole by more than 1 foot
until the backfill reaches the top of the tank. (See FIGURE 8-3.)
Wrong
Right
18

19
10. BALLASTING (ADDING LIQUID)
Do not use air pressure to test tanks that contain or have
contained flammable or combustible liquids or vapors, and
do not perform any postinstallation pressure tests. The fuel
and air mixture could explode and cause death or serious
injury. Tanks should be air tested before ballasting.
If product is used as ballast, exercise special care in
handling. afeguard against sparks, fire or product spills.
Improper handling of product could cause a fire or explo-
sion, and death or serious injury.
When ballasting the tank, make sure the tank is properly
vented. The vent must be large enough to allow the
displaced air to escape. Failure to properly vent the tank
may cause tank damage.
10.1. GENERAL
10.1.1. In most anchoring systems, a tank is not adequately
protected against flotation until the tank is fully backfilled and the
top slab is in place. Therefore, during the installation process,
the tank should be ballasted completely after the backfill is even
with the top of the tank and postinstallation testing has been
successfully completed.
10.1.2. Only under wet-hole conditions should ballast be added
before the backfill is even with the top of the tank. (See
SECTION 8.)
When filling the tank, make sure the tank is properly vented.
The vent must be large enough to allow the displaced air to
escape.
11. PIPING ANDVENTING
11.1. INTERNAL PIPING
11.1.1. All piping must conform to all applicable codes and
standards. (See SECTION 1.)
All internal piping must be at least 4 inches [6 inches for
12-foot-diameter tanks] from the tank bottom.
All metal fittings and other metal components must be coated
to protect against corrosion.
11.1.2. Refer to FIGURE 11-1 along with TABLE 11-1 to
determine the correct dimensions for sizing internal piping.
FIGURE 11-1
TABLE 11-1
11.2. EXTERNAL PIPING
When pressure testing the external piping, the tank must be
isolated from all piping. The test pressures for external
piping could cause tank failure, and result in death or
serious injury.
When extending monitoring or vapor-recovery piping to the
surface, make sure the at-grade fittings are different from
any fill fittings and will not accept standard fill hoses.
11.3. VENTING TANK
All underground tanks/compartments must be vented to
atmosphere for proper operations. Failure to vent could
result in death or serious injury.
11.3.1. In the double-wall and triple-wall tank, the primary tank is
designed to operate at atmospheric pressure.
T nk Di meter
4’
49 1/4”
54 1/2”
48”
49 1/2”
55”
48”
51 1/2”
56 5/8”
48”
6’
73”
78”
71 3/8”
72 3/4”
77 3/4”
70 5/8”
75 1/8”
80 1/4”
71 3/8”
8’
92”
98”
91 3/16”
91 1/2”
97 1/4”
90 5/8”
95 3/8”
100 1/2”
91 3/16”
10’
121”
126”
119 3/16”
120”
125 3/4”
118 1/2”
123 1/2”
128 5/8”
119 3/16”
12’
138 1/4”
143 1/4”
136 5/8”
_____
_____
_____
_____
_____
_____
Interior
Dimensions
in FIGURE
11 1
“A”
“B”
“C”
“D”
“E”
“F”
“G”
“H”
“I”
B & E
A& D
H
G
D
CBE
AFIG
H
Single-Wall Double-Wall II
Ribbed Outer Wall
Double-Wall I
Smooth Outer Wall
Dimension Line
Single-Wall & Double-Wall II
Dimension Line
Double-Wall I
Note:
1. All fitting dimensions are measured from the top of a
service fitting to the inside bottom of the tank and include
gauge-plate clearance.
2. Interior diameters do not include gauge-plate clearance.