This interactive guide identifies external and internal fiberglass-reinforced plastic tank failure conditions, common locations, service context, and visible indicators.
External FRP tank failures
EXTERNAL TANK FAILURE · ETF-001
EXTERIOR DISCOLORATION, STAINING, AND LOSS OF GLOSS
Color change, streaking, dullness, and deposits are frequent visual findings caused by UV, weather, spills, permeation, heat, or process vapors. They are condition indicators, not proof of structural failure by themselves.
- LOCATION
- Exterior shell below the roof seam, nozzles, fittings, and near the base
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Irregular amber-gray streaks descend from the upper shell across a broad matte area, with residue collecting toward the lower edge.
EXTERNAL TANK FAILURE · ETF-002
UV DEGRADATION, CHALKING, AND EXTERIOR RESIN WEATHERING
Sunlight and weather degrade the resin-rich exterior, producing powdering, fading, roughness, surface cracks, and eventual fiber exposure.
- LOCATION
- Upper sun-facing shell, domed roof, and upward-facing transitions
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A broad sun-facing weathered region conforms directly to the domed roof, with faded resin, powdery chalk deposits, and no floating or planar patch.
EXTERNAL TANK FAILURE · ETF-003
FIBER BLOOMING, FIBER PROMINENCE, AND EXPOSED GLASS
Glass becomes visible or raised as exterior resin erodes or microcracks. Blooming may reflect weathering or stress and is not automatically a through-wall defect.
- LOCATION
- Localized mid-to-upper shell laminate
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Fine whitish glass-fiber strands break through a localized resin-starved surface, with tiny loose hairs visibly projecting into the air.
EXTERNAL TANK FAILURE · ETF-004
EXTERNAL CRAZING AND FINE SURFACE CRACKING
Networks of fine hairline cracks develop from UV aging, thermal cycling, strain, chemical exposure, or local stress.
- LOCATION
- One localized curved shell panel
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A dense but shallow network of branching hairline cracks catches the light on one curved shell panel without opening through the wall.
EXTERNAL TANK FAILURE · ETF-005
NOZZLE-TO-SHELL BOND CRACKING
Cracks form at the secondary bond, fillet, or shell transition because this geometry concentrates pipe load, thermal movement, vibration, and workmanship variability.
- LOCATION
- Rear secondary inspection-nozzle fillet and shell transition
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A dark curved separation follows the rear inspection-nozzle fillet, with stress whitening and two short radial branches into the shell overlay.
EXTERNAL TANK FAILURE · ETF-006
NOZZLE-NECK CRACKING
Axial, circumferential, or local cracks develop in the exposed nozzle neck under piping dead load, misalignment, thermal expansion, vibration, impact, or inadequate laminate.
- LOCATION
- Rear secondary inspection-nozzle neck between shell and flange
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A circumferential fracture crosses the rear inspection-nozzle neck, turns into short axial branches, and releases a dark-yellow caustic drip from the lower crack.
EXTERNAL TANK FAILURE · ETF-007
NOZZLE WEEPING OR LEAKAGE
Fluid appears at the neck, flange, repad, or shell bond after cracks, porosity, chemical damage, or bond defects create a path through the laminate.
- LOCATION
- Process nozzle-to-shell bond
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A bright caustic-yellow seep is visible at the lower nozzle-to-shell bond, with a narrow wet trail, a small damp area near the base, and a subtle hairline bond crack.
EXTERNAL TANK FAILURE · ETF-008
FLANGE LEAKAGE
Loss of gasket compression, misalignment, damaged faces, bolt-load error, or flange cracking allows seepage or active leakage.
- LOCATION
- A selected visible tank flange and gasket line
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Bright caustic-yellow wetness emerges from the lower gasket line, forms several droplets, and leaves a short restrained streak below the intact flange.
EXTERNAL TANK FAILURE · ETF-009
FLANGE-FACE DAMAGE AND NON-FLATNESS
Scratches, chips, cracks, warpage, chemical attack, or poor fabrication prevent uniform gasket seating.
- LOCATION
- Rear secondary inspection-flange rim and mating-face interface
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- One flange sector carries a shallow chip and face scratch beside a narrow uneven mating gap; the bolted connection remains recognizable and dry.
EXTERNAL TANK FAILURE · ETF-010
FLANGE LAMINATE CRACKING OR DELAMINATION
The flange ring, hub, neck, or transition separates under bolt load, piping load, creep, fatigue, or deficient fabrication.
- LOCATION
- Rear secondary inspection-flange ring and outer edge near adjacent bolts
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Separated FRP plies lift along one flange-ring sector near adjacent bolts, creating a narrow dark delamination shadow and whitening around the contact zone.
EXTERNAL TANK FAILURE · ETF-011
IMPROPER BOLT TORQUE DAMAGE OR LEAKAGE
Over-torque can crush or crack FRP and extrude a gasket; under-torque or uneven tightening produces nonuniform sealing.
- LOCATION
- Rear secondary inspection-flange bolt seat, washer zone, and gasket gap
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The laminate is locally crushed under one washer with fine radial cracks, while the adjacent gasket line opens into a subtle uneven gap.
EXTERNAL TANK FAILURE · ETF-012
FLANGE MISALIGNMENT AND FORCED FIT-UP
Pulling a misaligned pipe into place imposes sustained bending and axial stress on the tank nozzle and flange.
- LOCATION
- Rear secondary inspection pipe spool, flange pair, and nozzle axis
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A ghosted pipe segment shows the connection pulled slightly out of square, leaving a wedge-shaped flange gap and directional strain at the nozzle hub.
EXTERNAL TANK FAILURE · ETF-013
CONNECTED-PIPE DEAD-LOAD DAMAGE AT NOZZLES
Unsupported pipe, valves, or fittings transfer weight into the tank connection, causing distortion, cracks, creep, or bond failure.
- LOCATION
- Lower connected pipe, process nozzle, and upper bond fillet
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A displaced pipe overlay sags below its intended axis and pulls down on the nozzle, whitening the upper bond and opening a short upper-fillet crack.
EXTERNAL TANK FAILURE · ETF-014
THERMAL-EXPANSION LOAD DAMAGE AT NOZZLES
Restrained piping growth or contraction imposes cyclic or sustained loads that crack or deform the nozzle and shell bond.
- LOCATION
- Connected pipe and opposing sides of the nozzle-to-shell bond
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The connected pipe is laterally displaced as if thermal growth pushed the nozzle sideways, producing opposing crescent cracks and directional stress whitening.
EXTERNAL TANK FAILURE · ETF-015
VIBRATION AND FATIGUE DAMAGE AT NOZZLES OR ATTACHMENTS
Pumps, mixers, rotating equipment, and flow-induced vibration progressively grow matrix cracks, delamination, and bond damage.
- LOCATION
- Nozzle or attachment bond at a cyclic-load location
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Several short repeated hairline cracks radiate from the attachment edge in a consistent cyclic pattern with localized stress whitening.
EXTERNAL TANK FAILURE · ETF-016
EXTERNAL CHEMICAL ATTACK FROM SPILLS, OVERFLOW, OR VAPORS
Process chemicals degrade exterior resin, reinforcement, base laminates, attachments, and nearby piping.
- LOCATION
- Path from a selected upper fitting down the shell to the base and containment
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A bright yellow spill path begins at the upper overflow fitting and runs toward containment, bleaching and roughening the resin within a narrow damaged track.
EXTERNAL TANK FAILURE · ETF-017
SURFACE SCRATCHES, GOUGES, CUTS, AND GRINDING DAMAGE
Handling, access work, tools, or maintenance remove protective resin and may cut reinforcement.
- LOCATION
- Top roof manway lid and access surface
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Two shallow scratches and a wider maintenance gouge cross the top manway lid, removing the smooth resin coat and exposing a restrained strip of pale fiberglass.
EXTERNAL TANK FAILURE · ETF-018
IMPACT DAMAGE, INDENTATION, AND CRUSHING
Vehicles, dropped objects, rigging, ladders, or concentrated contact produce dents, cracks, whitening, and hidden delamination.
- LOCATION
- Lower shell · equipment-contact height
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A modest oval indentation deforms the lower shell without perforating it. A pale stress-whitening halo and several short radial cracks show the concentrated impact zone.
EXTERNAL TANK FAILURE · ETF-019
EXTERNAL MATRIX CRACKING AND LARGER SHELL CRACKS
Cracks extend beyond crazing because of load, aging, impact, settlement, thermal cycling, or inadequate laminate.
- LOCATION
- Limited mid-shell wall panel
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A narrow vertical structural crack with several short branches and whitened edges crosses a limited mid-shell area without becoming a through-wall opening.
EXTERNAL TANK FAILURE · ETF-020
EXTERNAL DELAMINATION AND HOLLOW AREAS
Laminate plies separate because of impact, fatigue, poor cure, water ingress, or fabrication defects; the visible surface may understate subsurface extent.
- LOCATION
- Broad oval region on the shell wall
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A worn oval laminate region lifts from a deep irregular shadow, with peeling faded resin, exposed fiber-cloth texture, and chipped weathered edges.
EXTERNAL TANK FAILURE · ETF-021
REPAD OR SECONDARY-LAMINATE DISBONDING
Nozzle, manway, lug, platform, or repair laminates separate from the parent shell after inadequate preparation, contamination, cure problems, or cyclic load.
- LOCATION
- A selected reinforcement pad; lower process-nozzle repad is the recommended default
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- One sector of the lower nozzle reinforcement pad lifts from the shell, revealing a dark crescent gap and cracked bond perimeter while most of the pad stays attached.
EXTERNAL TANK FAILURE · ETF-022
MANWAY-NECK AND MANWAY-TO-SHELL CRACKING
The manway transition develops cracks from access loading, bolting, deformation, field installation, or poor secondary bonding.
- LOCATION
- Front manway neck-to-shell transition
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Cracks follow both the manway-to-shell bond and the exposed manway neck, with circumferential separation, short axial branches, and stress whitening.
EXTERNAL TANK FAILURE · ETF-023
MANWAY FLANGE, COVER, GASKET, OR FASTENER LEAKAGE
Warpage, cracked laminate, incompatible gasket material, uneven tightening, or damaged hardware defeats containment.
- LOCATION
- Lower manway cover, gasket line, and nearby fasteners
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Caustic-yellow wetness forms directly on the cover-to-flange seam just behind the bolted cover and drops from the visibly compressed lower gasket sector.
EXTERNAL TANK FAILURE · ETF-024
REPAIR-PATCH OR EXTERNAL-OVERLAMINATE FAILURE
A prior repair cracks, peels, blisters, or delaminates because it did not address the cause, used incompatible materials, or was poorly prepared/cured.
- LOCATION
- A selected visible shell repair location
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- An older mismatched FRP repair patch follows the curved shell, with one lifted edge, a narrow perimeter crack, and several small blisters.
EXTERNAL TANK FAILURE · ETF-025
DRY GLASS AND INCOMPLETE WET-OUT
White or opaque reinforcement with too little resin has reduced chemical protection and interlaminar strength.
- LOCATION
- Localized shell laminate panel
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A cloudy matte patch reveals woven and chopped glass beneath a thin uneven resin surface while remaining flat and fabrication-like.
EXTERNAL TANK FAILURE · ETF-026
VOIDS, AIR POCKETS, POROSITY, AND BUBBLES
Entrapped air or unfilled spaces reduce strength and can seed moisture entry, blistering, and delamination.
- LOCATION
- Localized subsurface shell-laminate area
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A localized cluster of small subsurface bubbles and two larger shallow void indications disrupts the laminate without becoming a uniform surface pattern.
EXTERNAL TANK FAILURE · ETF-027
RESIN-STARVED OR RESIN-RICH AREAS
Too little resin leaves exposed reinforcement; too much resin creates brittle, shrinkage-prone zones with inadequate glass.
- LOCATION
- Two adjoining irregular zones on one shell panel
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A matte fiber-prominent zone sits beside a glossy amber resin-rich zone, where only the richer material carries faint shrinkage cracks.
EXTERNAL TANK FAILURE · ETF-028
WRINKLES, BRIDGING, WAVINESS, AND FIBER DISTORTION
Misplaced reinforcement or poor consolidation creates weak zones, resin pockets, local thin spots, and stress concentrations.
- LOCATION
- Localized band within the shell laminate
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A localized wavy laminate band contains one raised fold and a shallow bridged hollow, with fiber direction visibly distorted through the defect.
EXTERNAL TANK FAILURE · ETF-029
FOREIGN INCLUSIONS OR LAMINATE CONTAMINATION
Dirt, moisture, wax, dust, or other material trapped in a laminate or bond reduces adhesion and durability.
- LOCATION
- Small embedded area within shell resin or laminate
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- An irregular dark inclusion appears trapped below the resin surface with a faint discolored halo and several nearby microbubbles.
EXTERNAL TANK FAILURE · ETF-030
IMPROPER CURE, LOW HARDNESS, OR EXTERIOR SOFTNESS
Undercure leaves the laminate chemically and mechanically weak; excessive exotherm can burn, crack, distort, or delaminate it.
- LOCATION
- Localized shell-surface patch
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- An amber, uneven-gloss patch carries shallow fingerprint and tool impressions with soft edge deformation, representing an undercured exterior surface.
EXTERNAL TANK FAILURE · ETF-031
UNEVEN THICKNESS, THIN LAMINATE, OR MISSING REINFORCEMENT
Fabrication variation reduces local structural capacity and accelerates deformation or cracking.
- LOCATION
- Broad shallow shell panel
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A broad oval laminate area transitions from a shadowed thicker perimeter into a shallow highlighted center, clearly revealing localized thickness and reinforcement loss.
EXTERNAL TANK FAILURE · ETF-032
PRINT-THROUGH, WAVINESS, AND GEOMETRIC IRREGULARITY
Reinforcement pattern, ripples, or uneven geometry may be cosmetic or may reveal shrinkage, poor consolidation, or local load concentration.
- LOCATION
- Broad shell surface visible under glancing light
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A faint reinforcement pattern becomes visible through the finish under glancing light, accompanied by several broad low-amplitude surface ripples.
EXTERNAL TANK FAILURE · ETF-033
SHELL DEFORMATION, BULGING, AND OUT-OF-ROUNDNESS
Hydrostatic load, creep, pressure, inadequate stiffness, poor support, or fabrication geometry distorts the wall.
- LOCATION
- Rear-left mid-to-lower shell quadrant
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A broad rear-left section of the mid-to-lower shell bows outward with smooth transitions. The changed silhouette and highlight flow show loss of roundness without a crack or through-wall breach.
EXTERNAL TANK FAILURE · ETF-034
CREEP DEFORMATION
Sustained hydrostatic, nozzle, attachment, or roof loads produce time-dependent strain that may precede cracking or rupture.
- LOCATION
- Upper-right platform attachment and shell directly below
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A loaded platform attachment sags permanently and draws the shell into a broad low-amplitude bulge, with only a faint whitened line at the highest-strain edge.
EXTERNAL TANK FAILURE · ETF-035
MECHANICAL OR THERMAL FATIGUE CRACKING
Repeated filling, wind, vibration, agitation, pressure, or temperature cycling grows cracks and delamination.
- LOCATION
- Roof-to-shell transition beside the platform attachment
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A family of short parallel and branching cracks wraps the roof-to-shell transition beside the platform attachment; varied lengths and tight white stress halos show progressive cyclic growth.
EXTERNAL TANK FAILURE · ETF-041
SHELL BUCKLING OR WRINKLING
Compressive instability occurs under vacuum, wind, handling load, settlement, or uneven restraint.
- LOCATION
- Rear-right mid-shell quadrant
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Three broad circumferential wrinkles alternate inward and outward through one shell quadrant, reading as continuous structural buckling while the tank remains approximately cylindrical.
EXTERNAL TANK FAILURE · ETF-042
VACUUM BUCKLING OR IMPLOSION
Blocked or undersized venting, rapid pump-out, or steam collapse draws the shell or roof inward.
- LOCATION
- Rear upper-shell quadrant and adjacent domed roof
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A major upper-shell concavity and shallow roof depression pull inward beneath radiating buckle ridges, clearly reading as suction collapse rather than impact while the tank remains standing.
EXTERNAL TANK FAILURE · ETF-043
OVERPRESSURE BULGING AND CRACKING
Air loading, blocked venting, gas generation, or process upset exceeds the pressure capability of an atmospheric or low-pressure tank.
- LOCATION
- Front process-side upper shell, roof transition, and nearby roof fittings
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The upper shell and roof transition bulge outward, nearby roof fittings are strained, and several tensile cracks cross the highest-curvature zone without becoming a full rupture.
EXTERNAL TANK FAILURE · ETF-044
ROOF CRACKING OR COLLAPSE
Vacuum, live loads, UV degradation, attachments, or inadequate design damages the roof laminate.
- LOCATION
- Rear-left domed roof near a top fitting
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A localized section of the domed roof is depressed around a top fitting, with six radial cracks and slight fitting misalignment while the roof perimeter and shell remain intact.
EXTERNAL TANK FAILURE · ETF-036
FOUNDATION SETTLEMENT AND TANK TILT
Differential movement distorts the shell and bottom and overloads knuckles, anchors, nozzles, and connected piping.
- LOCATION
- Whole tank and base interface, with the high-side gap at front-right
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The tank leans slightly while the containment remains level: the settled knuckle is compressed, the opposite base edge opens into a narrow gap, and connected piping is mildly misaligned.
EXTERNAL TANK FAILURE · ETF-037
BOTTOM-SUPPORT VOIDS OR FOUNDATION IRREGULARITY
Missing grout, pad washout, debris, or uneven support permits bottom flexure and knuckle stress.
- LOCATION
- Rear-left support sector beneath the tank base and adjacent lower knuckle
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A localized support gap is visible beneath the base, with shallow downward flexure above it and a short whitened crack following the adjacent lower knuckle.
EXTERNAL TANK FAILURE · ETF-038
ANCHOR-LUG OR HOLD-DOWN DAMAGE
Lug laminates, bolts, or parent shell crack or delaminate under wind, seismic, buoyancy, or pressure loads.
- LOCATION
- Front-left anchor lug, bolt, reinforcement overlay, and lower shell
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The anchor overlay is cracked and partly lifted, its bolt hole is elongated, the metal anchor is slightly bent, and radial cracks enter the lower shell while the assembly remains connected.
EXTERNAL TANK FAILURE · ETF-039
LADDER, PLATFORM, HANDRAIL, MIXER, AND ROOF-ATTACHMENT DAMAGE
Concentrated and cyclic loads crack attachment laminates or the underlying shell/roof.
- LOCATION
- Right-side ladder-to-shell attachment pad
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A ladder attachment pad presses into the shell, surrounded by stress whitening and short cracks; the bracket has shifted slightly while the platform remains safely aligned.
EXTERNAL TANK FAILURE · ETF-040
CORRODED, LOOSE, OR FAILED METALLIC ATTACHMENTS AND HARDWARE
Deteriorated bolts, clips, ladders, supports, and fasteners can lose function or impose damaging point loads on FRP.
- LOCATION
- Right-side platform-support fasteners and FRP contact point
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- Corrosion remains confined to selected bolts and bracket edges; one fastener is loose, a small rust stain runs onto the FRP, and a localized pressure mark shows where the hardware contacts the shell.
EXTERNAL TANK FAILURE · ETF-045
WIND DAMAGE
Strong wind can buckle the shell or roof, fail anchors, overturn the tank, or damage attachments.
- LOCATION
- Right shell quadrant, opposing anchor, and roof vent or overflow attachment
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A single left-to-right wind load buckles one shell quadrant, strains the opposing anchor, and bends the lightweight roof vent or overflow attachment while the tank remains upright.
EXTERNAL TANK FAILURE · ETF-046
UPLIFT OR FLOTATION
Floodwater or groundwater lifts an empty or inadequately anchored tank and damages the bottom, anchors, and piping.
- LOCATION
- Rear-right base, one anchor, lower piping, and containment high-water line
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- One side of the base is lifted slightly, its anchor is stretched and fractured, lower piping is pulled out of line, and a damp high-water residue band marks the containment wall.
EXTERNAL TANK FAILURE · ETF-047
FREEZE DAMAGE
Trapped liquid expands in nozzles, drains, jackets, or low points and cracks the laminate.
- LOCATION
- Lowest front-left drain or small-nozzle neck and adjacent laminate
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The lowest drain neck is locally swollen and split, with a short crack entering the adjacent laminate and a restrained patch of pale crystalline frost around the retained-liquid zone.
EXTERNAL TANK FAILURE · ETF-048
FIRE, HEAT, CHARRING, OR THERMAL DECOMPOSITION
Resin softens, burns, discolors, delaminates, and loses strength under external heat.
- LOCATION
- Rear-left mid-shell heat-exposure zone
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A localized heat gradient runs from tan discoloration to a blistered brown-black char core with exposed glass fibers and slight distortion; no active flames are present.
EXTERNAL TANK FAILURE · ETF-049
SEISMIC DAMAGE
Earthquake loading can damage anchors, shell, bottom, roof, nozzles, and connected piping simultaneously.
- LOCATION
- Front-right anchor, lower knuckle, and connected process piping along one load direction
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The tank has shifted slightly along one coherent earthquake-load direction, cracking one anchor overlay, whitening the lower knuckle, and pulling the connected pipe and nozzle out of alignment.
EXTERNAL TANK FAILURE · ETF-050
NOZZLE PULLOUT OR SEPARATION
The connection loses structural continuity with the tank after severe pipe load, impact, deficient bonding, or progressive cracking.
- LOCATION
- Lower primary process-nozzle shell bond and connected pipe
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- The lower primary process nozzle is partly separated from the shell: one bond edge remains attached while the lifted side reveals layered FRP, radial cracks, and a narrow dark gap beneath the supported pipe.
EXTERNAL TANK FAILURE · ETF-051
THROUGH-WALL SHELL CRACK OR ACTIVE SHELL LEAK
A crack breaches the corrosion barrier and structural wall, producing seepage, a stream, or a spray.
- LOCATION
- Left lower shell and containment directly below the breach
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A narrow vertical crack opens through layered pale FRP and releases a continuous bright-yellow caustic stream down a wet shell line into secondary containment; the tank remains mostly intact.
EXTERNAL TANK FAILURE · ETF-052
CREEP RUPTURE OR CATASTROPHIC SHELL RUPTURE
Sustained load or an upset culminates in rapid structural separation and major loss of containment.
- LOCATION
- Rear-right mid-to-lower shell and containment basin
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A large irregular shell opening exposes peeled composite plies and long glass-fiber bundles with adjacent stress whitening, while a broad bright-yellow release enters containment and the original cylinder remains recognizable.
EXTERNAL TANK FAILURE · ETF-053
BOTTOM BLOWOUT
The bottom or bottom-to-shell connection separates catastrophically; a supplied FRPI case links anchor-system failure to a bottom blowout.
- LOCATION
- Rear bottom-to-shell joint, anchor details, and containment basin
- TANK SERVICE
- Sodium hypochlorite
- WHAT YOU ARE SEEING
- A substantial bottom-to-shell joint sector is torn outward and upward, exposing delaminated plies, broken fibers, and failed anchors while a large bright-yellow release remains contained within the berm.
Internal FRP tank failures
INTERNAL TANK FAILURE · ITF-001
INNER-SURFACE RESIN ATTACK AND NORMAL-TO-ABNORMAL RESIN DEGRADATION
Chemical service first affects the resin-rich surface, producing dullness, roughening, softening, hardness change, discoloration, and eventual matrix loss. Normal aging must be distinguished from significant progressive damage.
- LOCATION
- Concave inner lower shell below the normal liquid line
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- Broad irregular pale yellow-gray patches dull and roughen the inner lower shell. The resin surface shows shallow mottled loss while the wall profile, veil, and fibers remain intact.
INTERNAL TANK FAILURE · ITF-002
CHEMICAL ATTACK OF THE CORROSION BARRIER
Incompatible chemistry, concentration, temperature, oxidizers, or vapor conditions progressively degrade the veil and resin-rich liner.
- LOCATION
- Internal wetted shell band, strongest at the lower shell and process-nozzle bore
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- An uneven wetted-zone band shows whitening, amber discoloration, lost gloss, fine pitting, and roughness, intensifying at the lower shell and process-nozzle bore without changing the structural wall.
INTERNAL TANK FAILURE · ITF-003
PERMEATION AND CHEMICAL ABSORPTION
Fluid or vapor diffuses into the resin, potentially causing plasticization, swelling, discoloration, hardness loss, blistering, and deeper degradation.
- LOCATION
- Internal shell below the historical liquid line with a localized laminate cross-section
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- Diffuse translucent yellow-gray mottling and subsurface darkening spread below the historical liquid line. A shallow swell and a small cut-edge inset show the color gradient entering the laminate, with no blister or leak.
INTERNAL TANK FAILURE · ITF-004
VEIL EROSION
The surfacing veil wears away, commonly at bottoms, knuckles, drain nozzles, impingement zones, and turbulent-flow areas.
- LOCATION
- Inner lower knuckle and full-bottom-drain approach
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- Two shallow, feather-edged patches on the lower knuckle and drain approach have lost the smooth resin-rich veil, exposing only a coarser pale glass texture beneath.
INTERNAL TANK FAILURE · ITF-005
CORROSION-BARRIER THINNING, EROSION, OR WASHOUT
Flow, solids, cleaning, chemical attack, and oxidation reduce liner thickness and move damage toward the structural laminate.
- LOCATION
- Internal bottom channel leading into the full-bottom drain
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- A broad worn channel converges on the bottom drain. Its smooth thinned center and rough feathered margins remove shallow corrosion-barrier thickness, while the structural laminate remains continuous.
INTERNAL TANK FAILURE · ITF-006
INTERNAL DISCOLORATION, STAINING, DEPOSITS, AND LOSS OF GLOSS
These common findings can show service exposure or aging, but may conceal the surface and do not establish remaining strength by themselves.
- LOCATION
- Historical liquid line, upper wetted shell, and isolated inner-bottom areas
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- A thin historical liquid-level ring crosses broad dull resin zones, with pale tan and gray vertical streaks and isolated white crystalline deposits. The underlying FRP remains readable and intact, with no cracks, deformation, or exposed fiber.
INTERNAL TANK FAILURE · ITF-007
CRAZING AND FINE INNER-SURFACE CRACKS
Networks of hairline cracks arise from strain, chemical attack, thermal cycling, shrinkage, or local geometry.
- LOCATION
- Localized inner lower-shell to knuckle transition
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- A dense localized network of extremely fine hairline crazing follows the lower shell-to-knuckle transition. Selected lines show slight whitening, but the marks remain surface-scale with minimal depth, no open gaps, and no visible structural fibers.
INTERNAL TANK FAILURE · ITF-008
OSMOTIC, CHEMICAL, GAS, OR VAPOR BLISTERING
Fluid or gas accumulates beneath a surface layer, forming raised blisters that may remain intact or progress.
- LOCATION
- Concave inner shell below the historical liquid line
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- An irregular cluster of intact rounded and elongated blisters rises gently from the concave liner. Their dimensions vary, their edges remain smoothly bonded, and subtle darker centers suggest subsurface fluid without any ruptured skins.
INTERNAL TANK FAILURE · ITF-009
BLISTER RUPTURE
An opened blister exposes glass or deeper laminate and accelerates chemical entry, erosion, and leakage.
- LOCATION
- Localized inner mid-shell blister field
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- One shallow ruptured blister has a slightly curled irregular resin skin, pale glass reinforcement, and damp discoloration inside its cavity. Several smaller nearby blisters remain intact; none of the damage opens through the wall.
INTERNAL TANK FAILURE · ITF-011
EXPOSED GLASS FIBERS AND FIBER ATTACK
Loss of protective resin exposes reinforcement directly to chemicals, permitting glass corrosion and progressive strength loss.
- LOCATION
- Upper wetted inner shell below the historical liquid line
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- A localized resin-loss patch exposes pale directional glass fibers. Several fibers are chemically etched and partially frayed with yellow-gray staining, but remain attached to the wall and do not read as loose fuzzy fabric.
INTERNAL TANK FAILURE · ITF-015
INLET, RETURN, SPARGER, OR JET IMPINGEMENT DAMAGE
Direct flow locally erodes the veil and corrosion barrier opposite entry points or mixing devices.
- LOCATION
- Inner shell directly opposite the process-inlet flow path
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- An elongated impact-wear patch has a smooth eroded center, fan-shaped directional scoring, a rough feathered perimeter, and limited veil exposure aligned to the fluid jet.
INTERNAL TANK FAILURE · ITF-016
INTERNAL ABRASION
Slurry, crystals, sediment, scraping, or aggressive cleaning removes resin and reinforcement.
- LOCATION
- Inner lower wall continuing across the adjacent bottom
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- Overlapping curved scrape marks and a shallow worn track follow plausible cleaning-tool or sediment movement. Gloss is reduced and only small areas of coarse veil texture are visible.
INTERNAL TANK FAILURE · ITF-017
PITTING, PINHOLES, AND LOCALIZED RESIN LOSS
Small cavities or porous openings form permeation or leak paths and may expose deeper laminate.
- LOCATION
- Localized inner mid-shell corrosion barrier
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal surface and corrosion barrier
- WHAT YOU ARE SEEING
- An irregular cluster of pin-sized pits surrounds three slightly larger shallow cavities with softened edges, darker centers, and mild discoloration.
INTERNAL TANK FAILURE · ITF-010
INTERNAL MATRIX OR RESIN CRACKING
Cracks extend through the resin matrix without necessarily breaking all fibers; they may precede delamination or leakage.
- LOCATION
- Isolated inner mid-shell resin-rich and near-surface laminate
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- One narrow branching recessed matrix crack crosses the inner mid-shell. Subtle edge whitening distinguishes it from fine crazing while the crack remains contained near the surface with no exposed or broken fibers and no exterior change.
INTERNAL TANK FAILURE · ITF-012
KNUCKLE-RADIUS EROSION AND CRACKING
The shell-to-bottom radius experiences bending stress, sediment wear, cleaning damage, and chemical exposure; veil erosion commonly appears here.
- LOCATION
- One quadrant of the internal shell-to-bottom knuckle
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- A curved worn-veil patch follows the knuckle radius, crossed by two fine parallel cracks. Mild whitening marks the highest-strain area and shallow scoring continues toward the bottom.
INTERNAL TANK FAILURE · ITF-013
BOTTOM-SURFACE DEGRADATION AND CRACKING
Settlement, poor support, deposits, chemical exposure, abrasion, and concentrated loads damage the bottom corrosion barrier and structure.
- LOCATION
- Off-center internal bottom between the drain and knuckle
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- A broad dull bottom patch combines shallow resin loss, deposit staining, and one narrow branching dry crack where bottom flexure is readable.
INTERNAL TANK FAILURE · ITF-018
LINER CRACKING
The corrosion liner cracks locally under chemical, thermal, or mechanical strain, sometimes before visible structural-wall damage.
- LOCATION
- Inner lower-shell geometric transition above the knuckle
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- A narrow defined crack crosses the liner and one short edge lifts enough to show the liner as a thin distinct layer over intact structural laminate.
INTERNAL TANK FAILURE · ITF-034
RADIAL, AXIAL, CIRCUMFERENTIAL, OR HELICAL STRUCTURAL CRACKS
Larger cracks indicate load paths around penetrations, knuckles, attachments, bottom support, or hoop and axial stress.
- LOCATION
- Axial structural crack on the internal mid-shell wetted zone
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- One dominant axial structural crack opens narrowly through the inner laminate, with edge whitening and a restrained set of broken surface fibers that follow the vertical load path.
INTERNAL TANK FAILURE · ITF-035
FIBER FRACTURE
Broken reinforcement follows overload, fatigue, impact, severe degradation, or crack growth and reduces structural capacity.
- LOCATION
- Localized internal upper-wetted shell laminate
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- A narrow fracture contains snapped pale glass bundles crossing the opening in the laminate direction, surrounded by a restrained white stress halo without a full through-wall gap.
INTERNAL TANK FAILURE · ITF-036
WALL THINNING AND STRUCTURAL-LAMINATE LOSS
Advanced erosion, abrasion, chemical attack, or repair grinding reduces effective wall thickness.
- LOCATION
- Broad internal lower-shell region with a localized thickness section
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- A broad shallow depression removes the corrosion barrier and part of the structural laminate. A small adjacent section shows reduced total thickness and short exposed reinforcement ends while the outer wall remains continuous.
INTERNAL TANK FAILURE · ITF-037
SWELLING, SOFTENING, EMBRITTLEMENT, OR DIMENSIONAL CHANGE
Absorption, heat, chemicals, aging, or cure condition changes resin properties and creates secondary stresses.
- LOCATION
- Localized embrittled material-state patch on the inner wetted shell
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- This variant isolates dry embrittlement: a matte pale patch carries fine shrink cracks, and a small section cue shows the shallow affected-layer depth without any soft swelling.
INTERNAL TANK FAILURE · ITF-038
THERMAL-SHOCK OR THERMAL-FATIGUE CRACKING
Rapid or repeated temperature changes crack resin, liner, bonds, and interfaces.
- LOCATION
- Internal upper-shell temperature-transition zone near an inlet
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- Several closely spaced cracks follow one thermal boundary, progressing from short hairlines to one longer crack with subtle whitening and heat discoloration but no impact dent.
INTERNAL TANK FAILURE · ITF-039
MECHANICAL FATIGUE CRACKING
Fill-and-empty cycles, agitation, piping loads, vibration, and pressure cycling progressively grow cracks and delamination.
- LOCATION
- Internal process-nozzle bond and loaded shell transition
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Structural damage and material change
- WHAT YOU ARE SEEING
- A repeated family of small similarly oriented bond cracks grows in varied lengths around the loaded nozzle transition, with a faint delamination halo and white crack-tip stress marks.
INTERNAL TANK FAILURE · ITF-014
DRAIN-NOZZLE NECK EROSION AND DEGRADATION
High flow, solids, cleaning, and chemical exposure preferentially attack the full-bottom drain and its transition.
- LOCATION
- Internal full-bottom-drain entrance, bore, and transition lip
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal connections and hardware
- WHAT YOU ARE SEEING
- The drain entrance shows an irregularly thinned resin surface, directional flow scoring, exposed veil texture, and a pale eroded lip that follows the bore.
INTERNAL TANK FAILURE · ITF-029
INTERNAL NOZZLE CHEMICAL ATTACK
The nozzle bore, neck, flange face, and shell transition degrade under chemistry, flow, temperature, and permeation.
- LOCATION
- Internal process-nozzle bore and shell transition
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal connections and hardware
- WHAT YOU ARE SEEING
- A rough dull nozzle-transition ring combines yellow-gray attack, directional erosion, shallow pits, and restrained veil exposure extending slightly onto the inner shell.
INTERNAL TANK FAILURE · ITF-030
NOZZLE-TO-SHELL INTERNAL BOND CRACKING
Cracks develop at the fillet or secondary bond under pipe load, thermal movement, vibration, cure defects, or stress concentration.
- LOCATION
- Internal process-nozzle secondary-bond fillet
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal connections and hardware
- WHAT YOU ARE SEEING
- A crescent crack follows the nozzle-to-shell fillet with two short radial branches and a restrained stress-whitening halo on the loaded side.
INTERNAL TANK FAILURE · ITF-031
INTERNAL NOZZLE OR MANWAY DELAMINATION
The neck, repad, transition, or field-installed laminate separates between plies or from the parent wall.
- LOCATION
- Internal side-manway transition laminate
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal connections and hardware
- WHAT YOU ARE SEEING
- An irregular raised delamination follows the transition with a narrow perimeter shadow. A compact lifted edge reveals two separated laminate plies while the external cover and fasteners remain unchanged.
INTERNAL TANK FAILURE · ITF-032
MANWAY INTERNAL-SURFACE DEGRADATION
Chemical exposure, access damage, edge-sealing defects, and field-cut work attack the neck, flange, and shell transition.
- LOCATION
- Underside of the top manway bore pad and internal neck transition
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal connections and hardware
- WHAT YOU ARE SEEING
- The internal manway surface shows scuffed dull resin, roughened edge sealing, pale chemical staining, two shallow chips, and one fine neck-transition crack.
INTERNAL TANK FAILURE · ITF-033
INTERNAL HARDWARE, BAFFLE, OR MIXER ABRASION AND IMPACT
Loose or moving components strike or rub the wall, bottom, or attachment laminates.
- LOCATION
- Inner shell beside a slightly offset internal baffle edge
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Internal connections and hardware
- WHAT YOU ARE SEEING
- A slightly loosened baffle edge aligns physically with a curved wall rub track and one shallow impact mark surrounded by a white stress halo.
INTERNAL TANK FAILURE · ITF-019
LINER-TO-STRUCTURE DISBONDMENT AND PEELING
The inner liner, coating, or reline separates, curls, flakes, or peels from the structural substrate.
- LOCATION
- Localized upper wetted inner shell
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A thin irregular FRP liner sheet separates from the concave wall. One edge curls over a dark shallow gap and rougher substrate while most of the sheet remains attached.
INTERNAL TANK FAILURE · ITF-020
INTERLAMINAR DELAMINATION
Internal wall plies separate because of impact, permeation, poor cure, fatigue, chemical attack, or a weak interface.
- LOCATION
- Inner mid-shell laminate below the historical liquid line
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A localized oval subsurface delamination creates a slight irregular raised contour. A small adjacent diagnostic cutaway reveals two separated plies and a narrow internal gap.
INTERNAL TANK FAILURE · ITF-021
FIBER-MATRIX DEBONDING AND STRESS WHITENING
Resin separates from fibers, producing microscopic damage, reduced stiffness, and sometimes white regions.
- LOCATION
- Upper wetted inner shell beside a localized high-strain line
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A diffuse chalk-white stress field follows the concave liner around a narrow strain line. Fine directional reinforcement remains visible beneath the resin and all fibers stay intact.
INTERNAL TANK FAILURE · ITF-022
DRY GLASS AND INCOMPLETE WET-OUT
Inadequately resin-wetted reinforcement appears white or opaque and has weak chemical and interlaminar performance.
- LOCATION
- Embedded inner mid-shell fabrication patch
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A cloudy opaque-white patch reveals directional woven and chopped glass beneath a thin uneven resin coat. Its edges show incomplete saturation, low gloss, and increased micro-roughness.
INTERNAL TANK FAILURE · ITF-023
VOIDS, AIR POCKETS, BUBBLES, AND POROSITY
Entrapped air and unfilled areas reduce barrier continuity and can seed blisters, delamination, and leakage.
- LOCATION
- Upper wetted inner-shell laminate
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- Irregularly spaced small subsurface voids surround one shallow elongated air pocket following the laminate. Translucent centers and restrained perimeter shadows keep them visibly below the resin surface.
INTERNAL TANK FAILURE · ITF-024
RESIN STARVATION OR RESIN-RICH AREAS
Nonuniform resin-to-glass ratio creates exposed reinforcement or brittle, crack-prone zones.
- LOCATION
- Adjacent inner-shell fabrication regions below the liquid line
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A matte fiber-prominent resin-starved region sits beside a glossier slightly amber resin-rich pocket. The rich side has faint shrinkage lines; the starved side has restrained porosity.
INTERNAL TANK FAILURE · ITF-025
WRINKLES, FOLDS, BRIDGING, AND REINFORCEMENT DISTORTION
Fabrication defects create weak areas, resin pockets, thin spots, and stress concentrations.
- LOCATION
- Concave lower inner shell
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- One shallow reinforcement fold rises beside a bridged hollow. Directional fiber texture bends around both features and a narrow resin-rich line follows the fold.
INTERNAL TANK FAILURE · ITF-026
FOREIGN INCLUSIONS AND CONTAMINATION
Dirt, moisture, wax, dust, or other material trapped during manufacture or repair reduces adhesion and chemical resistance.
- LOCATION
- Localized upper wetted inner-shell laminate
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A small irregular dark inclusion is visibly trapped beneath the resin, surrounded by a cloudy halo and several tiny associated voids.
INTERNAL TANK FAILURE · ITF-027
IMPROPER CURE AND ABNORMAL BARCOL HARDNESS
Undercure produces softness and poor chemical resistance; excessive exotherm can cause burn, cracking, voids, and delamination.
- LOCATION
- Localized lower inner-shell undercured fabrication patch
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- An undercured amber patch has blurred edges, uneven gloss, and several shallow rounded tool impressions that communicate softness.
INTERNAL TANK FAILURE · ITF-028
UNEVEN CORROSION-BARRIER OR STRUCTURAL THICKNESS
A thin liner, missing veil, or missing plies shortens chemical life and reduces structural capacity.
- LOCATION
- Lower inner shell with an adjacent localized laminate section
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A subtle shallow depression reveals stronger reinforcement texture. A compact edge section shows the corrosion barrier tapering to a thin region with one missing veil segment.
INTERNAL TANK FAILURE · ITF-040
INTERNAL REPAIR OR RELINE FAILURE
A patch, laminate, coating, or reline blisters, cracks, peels, delaminates, or leaks after incompatible selection, poor preparation or cure, or unresolved substrate damage.
- LOCATION
- Newer internal reline patch on the mid-shell wetted zone
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Laminate and fabrication
- WHAT YOU ARE SEEING
- A newer, slightly mismatched repair remains mostly attached while one feathered edge lifts over original substrate. A perimeter crack, two small blisters, and a dark disbonded region identify the failed repair.
INTERNAL TANK FAILURE · ITF-041
THROUGH-WALL CRACK AND SEEPAGE
An internal crack crosses the corrosion barrier and structural laminate, appearing externally as wetness or weeping.
- LOCATION
- Localized lower-shell wall path from inner liner to a small exterior weep
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Containment and catastrophic failure
- WHAT YOU ARE SEEING
- A narrow internal crack exposes layered FRP and a damp dark path through the laminate. The exterior evidence is limited to one small wet weep spot with no active stream or puddle.
INTERNAL TANK FAILURE · ITF-042
THROUGH-WALL LEAKAGE
Progressive deterioration or cracking produces active loss of containment; supplied FRPI sodium-hypochlorite cases include excessive deterioration and through-wall leakage.
- LOCATION
- Localized degraded lower-shell area releasing into secondary containment
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Containment and catastrophic failure
- WHAT YOU ARE SEEING
- An eroded liner and narrow internal crack connect to a small continuous gravity-fed pale caustic stream outside, ending in a limited puddle fully contained by the secondary basin.
INTERNAL TANK FAILURE · ITF-043
SPRAY OR JET LEAKAGE
Local liquid head or pressure drives an energetic release through a hole or crack.
- LOCATION
- Small lower-to-mid-shell perforation discharging into secondary containment
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Containment and catastrophic failure
- WHAT YOU ARE SEEING
- A small through-wall perforation connects to an internal crack and layered FRP edge. A narrow plausible liquid jet exits directionally and terminates in a contained wet stain rather than an explosive spray.
INTERNAL TANK FAILURE · ITF-044
OVERPRESSURE RUPTURE
Internal pressure from air loading, blocked venting, gas generation, or process upset exceeds tank capacity.
- LOCATION
- Internal upper shell and roof-transition tensile zone
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Containment and catastrophic failure
- WHAT YOU ARE SEEING
- A broad upper-shell tensile strain field leads into radial roof-transition cracks and one developing split. The selected diagnostic overlay shows outward load progression while preserving the identifiable tank and stopping short of fragmentation.
INTERNAL TANK FAILURE · ITF-045
VACUUM COLLAPSE
Pump-out, cooling or steam condensation, or deficient venting creates external-pressure instability visible internally as buckling or collapse.
- LOCATION
- Internal upper-shell quadrant and adjacent roof transition
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Containment and catastrophic failure
- WHAT YOU ARE SEEING
- One upper-shell quadrant pulls inward into a broad bonded-edge depression with circumferential buckle ridges and compressed liner wrinkles at the fold zones. The tank remains standing with no impact debris.
INTERNAL TANK FAILURE · ITF-046
CATASTROPHIC BOTTOM OR SHELL RUPTURE
Severe structural loss, anchor or load failure, or pressure upset causes sudden major release.
- LOCATION
- Localized internal bottom-to-shell rupture origin with contained release
- TANK SERVICE
- Sodium hypochlorite
- CATEGORY
- Containment and catastrophic failure
- WHAT YOU ARE SEEING
- A large but localized rupture originates at the inner bottom-to-shell transition, with peeled layered laminate, broken glass bundles, a separated corrosion barrier, and fluid escaping into secondary containment while most of TK-101 remains intact.
