Chapter 6: Tank Types and Applications

Learning Objectives

By the end of this chapter, you will be able to:

Classify tanks by construction type, material, and application
Calculate tank volumes for common geometries
Select the appropriate TankScan monitor for each tank type
Explain the unique monitoring challenges for underground, field, and pressurized tanks
Design monitoring strategies for tank farm configurations

6.1 Introduction: Why Tank Type Matters

Not all tanks are created equal. A 30,000-gallon aboveground steel fuel tank at a distribution terminal bears little resemblance to a 275-gallon polyethylene tote holding industrial lubricant in a warehouse, yet both require accurate, reliable level monitoring. The physical characteristics of a tank -- its geometry, material, installation environment, and the product it contains -- directly determine which monitoring technology will work, how it should be installed, and what accuracy can be achieved.

The Tank-Monitor Relationship

The single most important factor in selecting a wireless tank monitor is understanding the tank itself. A monitor perfectly suited for an open-top aboveground steel tank will fail completely on a pressurized fiberglass underground tank. This chapter provides the foundation for making correct selections.

The TankScan product family addresses this diversity with purpose-built monitors for different tank categories:

Tank Category	Typical Monitor	Primary Technology
Aboveground storage tanks (ASTs)	TSR (TankScan Radar)	Radar level measurement
Underground storage tanks (USTs)	TSC (TankScan Cellular)	ATG integration / probe-based
Totes and IBCs	TSU (TankScan Universal)	Ultrasonic / float gauge
Pressurized tanks	TSD (TankScan Dial)	Mechanical gauge reader
Field tanks (remote)	TSR with satellite	Radar with extended connectivity

6.2 Tank Classification Systems

Tanks can be classified along several independent axes. Understanding these classifications is essential for both regulatory compliance and monitor selection.

6.2.1 By Installation Position

graph TD
    A[Tank Classification<br>by Position] --> B[Aboveground<br>AST]
    A --> C[Underground<br>UST]
    A --> D[Partially Buried<br>Mounded]
    A --> E[Elevated<br>on Stands/Stilts]

    B --> B1[Horizontal Cylinder]
    B --> B2[Vertical Cylinder]
    B --> B3[Rectangular]

    C --> C1[Single Wall]
    C --> C2[Double Wall]
    C --> C3[Secondary Containment]

    D --> D1[Mounded Horizontal]
    D --> D2[Vault Enclosed]

    E --> E1[Gravity Feed]
    E --> E2[Day Tanks]

Aboveground Storage Tanks (ASTs) are the most common type monitored by TankScan. They are accessible for installation, visible for inspection, and typically have top or side openings suitable for radar-based monitors. ASTs range from 100-gallon day tanks to 100,000+ gallon bulk storage.

Underground Storage Tanks (USTs) present unique challenges. Physical access is limited to risers and fill ports. USTs are subject to strict EPA regulations (40 CFR 280) requiring leak detection. Most USTs already have Automatic Tank Gauges (ATGs) installed, so TankScan integrates with existing ATG systems rather than replacing them.

Partially buried (mounded) tanks are covered with earth for thermal insulation or blast protection but remain accessible from one end. They combine characteristics of both ASTs and USTs.

Elevated tanks use gravity for product dispensing. They require monitors that can withstand vibration from wind loading and provide accurate readings despite the elevation change between the tank and the receiving equipment.

6.2.2 By Geometry

Tank geometry determines how liquid level (a linear measurement) translates to volume (a cubic measurement). This relationship is straightforward for vertical cylinders but complex for horizontal cylinders and irregular shapes.

Geometry	Cross-Section	Level-to-Volume Relationship	Common Use
Vertical cylinder	Circle	Linear (proportional)	Large bulk storage, water tanks
Horizontal cylinder	Circle	Non-linear (requires strapping table)	Fuel storage, transport
Rectangular	Rectangle	Linear (proportional)	Chemical tanks, IBCs
Spherical	Circle (varying)	Non-linear (cubic function)	Pressurized gas storage
Vertical cylinder with cone bottom	Circle + cone	Piecewise linear	Chemical processing
Horizontal capsule (rounded ends)	Complex	Non-linear (requires calculation)	Propane, LPG

6.2.3 By Material

graph LR
    A[Tank Materials] --> B[Metals]
    A --> C[Plastics]
    A --> D[Composites]

    B --> B1[Carbon Steel]
    B --> B2[Stainless Steel]
    B --> B3[Aluminum]

    C --> C1[Polyethylene<br>HDPE/XLPE]
    C --> C2[Polypropylene]
    C --> C3[PVC]

    D --> D1[Fiberglass<br>FRP]
    D --> D2[Fiberglass-Clad<br>Steel]

    B1 --> |"Most common<br>for fuel"| E[Monitor Compatibility]
    C1 --> |"Radar signal<br>may penetrate"| E
    D1 --> |"Common for<br>USTs"| E

Carbon steel is the most common tank material for fuel and petroleum products. Steel tanks are durable, weldable, and provide excellent radar signal reflection from the liquid surface. Steel does not interfere with radar signals -- the metal walls act as a waveguide, containing the signal within the tank.

Radar and Non-Metallic Tanks

Radar signals can penetrate non-metallic tank walls (fiberglass, polyethylene). In non-metallic tanks, the radar beam may partially escape through the walls, causing signal loss and false echoes. Special installation techniques -- such as using a metallic still pipe or installing the sensor inside a metallic riser -- may be required.

Fiberglass Reinforced Plastic (FRP) is widely used for underground storage tanks and chemical storage where corrosion resistance is critical. FRP tanks are transparent to radar, requiring careful monitor selection and installation planning.

Polyethylene (HDPE and cross-linked XLPE) is standard for totes, IBCs, and small chemical tanks. These lightweight tanks are often moved, stacked, and replaced, making wireless monitoring with the TSU an ideal fit.

6.2.4 By Pressure Rating

Classification	Pressure Range	Examples	Monitor Approach
Atmospheric	0 - 0.5 psig	Open-top and vented tanks	Direct top-mount radar
Low pressure	0.5 - 15 psig	Sealed tanks with vent valves	Sealed sensor housing
Medium pressure	15 - 100 psig	Propane, LPG tanks	TSD dial gauge reader
High pressure	100+ psig	Industrial gas cylinders	TSD or specialized transducers

6.3 Tank Geometry and Volume Calculation

6.3.1 Vertical Cylinders

Vertical cylinders offer the simplest level-to-volume relationship. Volume is directly proportional to height.

\[V = \pi r^2 h\]

Where:

$V$ = volume
$r$ = tank radius
$h$ = liquid height (measured by the sensor)

The fill percentage is simply:

\[\text{Fill \%} = \frac{h}{H} \times 100\]

Where $H$ is the total tank height.

Vertical Tank Calculation

A vertical cylindrical tank has a diameter of 8 feet and a total height of 12 feet. The TankScan radar reports a liquid level of 7.5 feet.

Radius: $r = 4 \text{ ft}$
Volume at current level: $V = \pi \times 4^2 \times 7.5 = 376.99 \text{ ft}^3$
Converting to gallons: $376.99 \times 7.481 = 2,820 \text{ gallons}$
Fill percentage: $\frac{7.5}{12} \times 100 = 62.5\%$

6.3.2 Horizontal Cylinders

Horizontal cylinders are the most common tank geometry for petroleum storage, yet they present a significant mathematical challenge. The cross-sectional area of liquid changes non-linearly with height.

graph LR
    subgraph "Horizontal Cylinder Cross-Section"
        direction TB
        A["Full circle = tank diameter"]
        B["Liquid level h creates<br>a circular segment"]
        C["Area depends on<br>cos⁻¹ function"]
    end

For a horizontal cylinder of length $L$ and radius $r$, the volume at liquid height $h$ is:

\[V(h) = L \left[ r^2 \cos^{-1}\left(\frac{r - h}{r}\right) - (r - h)\sqrt{2rh - h^2} \right]\]

This equation has no simple closed-form inverse, which is why TankScan's AIP platform uses strapping tables -- pre-calculated lookup tables that map level readings to volumes for specific tank dimensions.

Strapping Tables in AIP

When configuring a horizontal tank in the AIP platform, you enter the tank's diameter and length. The system automatically generates a strapping table with volume calculations at each measurement increment. For unusual tank shapes (such as horizontal tanks with dished or hemispherical heads), custom strapping tables can be uploaded.

6.3.3 Horizontal Cylinder with Dished Heads

Most real-world horizontal tanks have dished (elliptical or hemispherical) ends rather than flat ends. These heads add volume that must be accounted for.

For 2:1 elliptical heads (the most common), each head adds approximately:

\[V_{\text{head}} = \frac{2}{3} \pi r^2 \times \frac{r}{2} = \frac{\pi r^3}{3}\]

The total volume of a horizontal tank with two dished heads is:

\[V_{\text{total}}(h) = V_{\text{cylinder}}(h) + 2 \times V_{\text{head}}(h)\]

Where the head volume at height $h$ must also be calculated using integration of the elliptical cross-section -- another reason strapping tables are essential.

6.3.4 Rectangular Tanks and IBCs

Rectangular tanks (including IBCs) have the simplest calculation:

\[V = L \times W \times h\]

Where $L$ is length, $W$ is width, and $h$ is liquid height. Volume is directly proportional to level, making monitoring straightforward.

Standard IBC dimensions:

IBC Size	Length	Width	Height	Capacity
275 gallon	45"	40"	46"	275 gal (1,041 L)
330 gallon	48"	40"	46"	330 gal (1,249 L)
550 gallon	48"	40"	54"	550 gal (2,082 L)

6.3.5 Spherical Tanks

Spherical tanks are used for pressurized gases (propane, butane, LPG). Volume at height $h$ in a sphere of radius $r$:

\[V(h) = \pi h^2 \left(r - \frac{h}{3}\right)\]

These tanks are typically monitored with the TSD dial gauge reader rather than direct level measurement, since they are pressurized and sealed.

6.4 Aboveground Storage Tanks (ASTs)

6.4.1 Characteristics and Configurations

ASTs are the primary target market for TankScan wireless monitoring. They are found at fuel distribution terminals, convenience stores (day tanks), farms, construction sites, fleet fueling locations, and industrial facilities.

graph TD
    subgraph "Typical AST Installation"
        A[Vent / Gauge Opening] --> B[TSR Monitor<br>Mounted on Top]
        B --> C[Tank Shell<br>Steel Construction]
        C --> D[Concrete Pad /<br>Secondary Containment]
        E[Fill Port] --> C
        F[Discharge Line] --> C
        G[Level Indicator<br>Sight Glass] --> C
    end

    B --> |Cellular Signal| H[Cell Tower]
    H --> I[AIP Cloud Platform]

Common AST configurations:

Configuration	Volume Range	Typical Product	Monitoring Approach
Single horizontal cylinder	500 - 25,000 gal	Diesel, gasoline, heating oil	TSR top-mount radar
Vertical cylinder (welded)	1,000 - 100,000 gal	Bulk fuel, chemicals	TSR top-mount radar
Vertical cylinder (bolted)	5,000 - 500,000 gal	Water, crude oil	TSR with extended range
Farm tank (horizontal)	250 - 2,000 gal	Diesel, gasoline	TSR compact
Day tank (vertical)	50 - 500 gal	Generator fuel	TSR or TSU

6.4.2 Monitoring with TSR

The TSR (TankScan Radar) is the flagship product for aboveground tank monitoring. It combines a radar level sensor with integrated cellular communication in a single, battery-powered unit.

Key TSR specifications:

Parameter	Value
Measurement technology	Pulse radar (time-of-flight)
Measurement range	0.3 m to 20 m (1 ft to 65 ft)
Accuracy	+/- 3 mm (0.12 in)
Resolution	1 mm (0.04 in)
Beam angle	8 degrees (typical)
Operating temperature	-40F to +185F (-40C to +85C)
Power source	Lithium battery (5+ year life)
Communication	Cellular (LTE Cat-M1 / NB-IoT)
Reporting interval	Configurable (1x to 24x per day)
Housing	NEMA 4X, UV-resistant
Hazardous area rating	Class I, Div 1 (intrinsically safe)

Intrinsic Safety

The TSR is rated for Class I, Division 1 hazardous locations, meaning it can be installed directly on tanks containing flammable liquids and vapors. The device's electrical energy is limited to levels below what could ignite the surrounding atmosphere. This is discussed in detail in Chapter 11.

TSR Installation on ASTs:

Identify a suitable opening on the tank top (typically a 2" NPT bung)
Ensure the opening is not directly above fill pipes, mixers, or other obstructions
Thread the TSR into the opening using the integrated mounting adapter
Activate the cellular connection via the AIP platform
Configure tank dimensions and product type in AIP

6.4.3 AST-Specific Challenges

Challenge	Cause	Solution
Condensation on sensor	Temperature cycling	TSR includes hydrophobic lens coating
Foam on liquid surface	Turbulence during filling	Configure foam rejection algorithm in AIP
Multiple product layers	Water bottom under fuel	Configure water-cut monitoring if supported
Tank deformation	Age, settling, corrosion	Recalibrate strapping table periodically
Extreme temperatures	Summer heat / winter cold	TSR rated -40F to +185F covers most environments
Vapor interference	Dense hydrocarbon vapors	Radar compensates; velocity correction in AIP

6.5 Underground Storage Tanks (USTs)

6.5.1 UST Characteristics

Underground storage tanks are buried beneath the surface, typically at gas stations, convenience stores, and commercial fueling facilities. In the United States, there are approximately 553,000 active USTs regulated under EPA 40 CFR Part 280.

graph TD
    subgraph "Underground Tank Installation"
        A[Ground Level] --- B[Manway / Riser]
        B --- C[Fill Port]
        B --- D[ATG Probe]
        B --- E[Submersible<br>Pump]
        F[Tank Shell<br>Fiberglass Double-Wall] --- B
        F --- G[Product<br>Fuel]
        G --- H[Water Bottom]
        F --- I[Interstitial<br>Space]
        I --- J[Leak Sensor]
    end

    D --> |Wired to| K[ATG Console<br>Veeder-Root / Gilbarco]
    K --> |Serial/Network| L[TSC Gateway]
    L --> |Cellular| M[AIP Cloud Platform]

USTs differ from ASTs in several critical ways:

Factor	AST	UST
Physical access	Easy (walk up to tank)	Limited (through risers/manholes)
Visual inspection	Possible	Not possible
Environmental risk	Visible leaks	Hidden leaks (soil/groundwater)
Regulatory burden	Moderate (SPCC)	High (EPA 40 CFR 280)
Existing instrumentation	Often none	Usually has ATG system
Typical material	Steel	Fiberglass (FRP)
Thermal stability	Exposed to ambient	Stable (ground temperature)
Typical products	Fuel, chemicals	Retail fuels (gasoline, diesel)

6.5.2 ATG Integration with TSC

Because most USTs already have Automatic Tank Gauges (ATGs), TankScan's approach to underground monitoring is integration rather than replacement. The TSC (TankScan Cellular) gateway connects to existing ATG systems and transmits their data to the AIP cloud.

Supported ATG Systems:

Manufacturer	Model	Protocol	Connection
Veeder-Root	TLS-350 / TLS-450	Veeder-Root serial	RS-232
Veeder-Root	TLS-4	TCP/IP, serial	Ethernet, RS-232
Gilbarco	EMC / EMC+	Gilbarco serial	RS-232
Franklin Fueling	EVO 200 / 550	Modbus RTU	RS-485
OPW	SiteSentinel	Modbus TCP	Ethernet
Petro Vend	Various	Proprietary	RS-232

The TSC periodically polls the ATG console for inventory data, translates it into the standard TankScan data format, and transmits it to AIP. This provides:

Unified dashboard: UST data appears alongside AST data in the same AIP interface
Alert consistency: The same alert rules (low level, high level, consumption anomaly) apply to all tanks
Historical trending: UST data is stored with the same granularity as AST data
Multi-site visibility: Operators managing both ASTs and USTs see everything in one platform

TSC Installation Advantage

The TSC does not require any modification to the UST itself. It connects to the existing ATG console's communication port. Installation typically takes less than 30 minutes and requires no tank entry, no hot work, and no disruption to fueling operations.

6.5.3 UST Data Points

Through ATG integration, the TSC can report:

Product level (inches or centimeters)
Product volume (gallons or liters, calculated by the ATG's strapping table)
Water level (detected by the ATG probe's water float)
Temperature (from the ATG probe's thermistor array)
Volume-corrected inventory (temperature-compensated, net standard volume)
Delivery detection (automatic identification of fuel deliveries)
Leak test results (if the ATG performs statistical leak detection)

6.5.4 UST-Specific Challenges

Challenge	Description	Mitigation
Communication path	Cellular signal must reach below-grade enclosure	TSC can use external antenna above grade
Power availability	Some sites lack power at the ATG console area	TSC available with solar power option
ATG protocol diversity	Many different ATG manufacturers and models	TSC firmware supports all major protocols
Data freshness	ATG may only update inventory every few minutes	TSC polls at configurable intervals
Water intrusion	Manhole areas prone to flooding	TSC housing rated NEMA 4X / IP66
Multi-product tanks	Single tank with compartments for different fuels	Each compartment configured separately in AIP

6.6 Field Tanks and Remote Locations

6.6.1 The Remote Monitoring Challenge

Field tanks are found in oil and gas production, agriculture, mining, and remote industrial sites. They operate in locations where:

Cellular coverage may be limited or non-existent
Power grid access is unavailable
Ambient temperatures range from -40F to +130F
Wind, rain, dust, and UV exposure are extreme
Site visits are infrequent (weekly, monthly, or less)
Access roads may be unpaved or seasonal

graph TB
    subgraph "Remote Field Tank Monitoring"
        A[Field Tank<br>Remote Location] --> B{Connectivity<br>Available?}
        B -->|Cellular| C[TSR with Cellular<br>Standard Configuration]
        B -->|Satellite| D[TSR with Satellite<br>Iridium / Orbcomm]
        B -->|None| E[TSR with Local Storage<br>Manual Download]

        C --> F[AIP Cloud]
        D --> F
        E --> |Site Visit| G[Technician<br>Mobile App]
        G --> F
    end

6.6.2 Oil and Gas Field Tanks

In oil and gas production, field tanks serve several purposes:

Tank Type	Purpose	Typical Size	Monitoring Priority
Production tank	Collects crude oil from wells	200 - 1,000 bbl	High (revenue, theft prevention)
Water tank	Collects produced water	200 - 500 bbl	Medium (disposal scheduling)
Condensate tank	Collects natural gas liquids	100 - 500 bbl	High (volatile product, value)
Chemical tank	Stores treatment chemicals	50 - 200 gal	Medium (run-out prevention)
Fuel tank	Powers on-site generators	100 - 500 gal	High (prevents production shutdown)

Hazardous Environments in Oil Fields

Oil field tanks often contain volatile hydrocarbons with low flash points. The area around tank openings is typically classified as Class I, Division 1 or Division 2. Only intrinsically safe monitors (like the TSR with IS certification) may be installed in these zones. Using non-certified equipment risks explosion.

6.6.3 Agricultural Field Tanks

Farms and ranches use field tanks for:

Diesel fuel for tractors, combines, and other equipment
Gasoline for smaller equipment and vehicles
Fertilizer solutions (liquid nitrogen, UAN) in large poly tanks
Herbicide/pesticide concentrates in smaller chemical tanks
Water for irrigation and livestock

Agricultural tanks are often spread across large properties. A single farming operation may have tanks at multiple locations miles apart. TankScan monitoring enables centralized visibility and timely reordering.

6.6.4 Satellite Connectivity for Remote Sites

When cellular coverage is unavailable, TankScan offers satellite communication options:

Satellite Network	Coverage	Latency	Data Cost	Best For
Iridium (LEO)	Global	1-5 seconds	High	Remote oil fields, international
Orbcomm (LEO)	Near-global	Minutes	Moderate	Asset tracking, brief messages
Cellular backup	Varies	Milliseconds	Low	Areas with intermittent coverage

Satellite Data Economy

Satellite communication is significantly more expensive than cellular. To manage costs, satellite-connected TSR units typically report less frequently (1-4 times per day versus up to 24 times for cellular) and transmit minimal data payloads. The AIP platform interpolates between readings to provide continuous-looking trend data.

6.6.5 Extreme Environment Considerations

Environmental Factor	Impact	Design Feature
Extreme cold (-40F)	Battery capacity reduction	Lithium chemistry maintains capacity; extended battery option
Extreme heat (+140F)	Electronics thermal stress	Passive cooling design; thermal management in housing
High winds (100+ mph)	Physical stress on mounting	Low-profile design; reinforced mounting brackets
Lightning	Surge damage	Transient voltage suppression; grounding provisions
Sand/dust storms	Abrasion, ingress	IP66/IP67 sealed housing; no external moving parts
UV exposure	Plastic degradation	UV-stabilized housing material; 10+ year outdoor rating
Corrosive atmosphere (H2S)	Metal and gasket corrosion	Stainless steel hardware; fluorocarbon seals
Vibration (wellhead sites)	Measurement noise	Signal averaging algorithm; vibration filtering

6.7 Totes and IBCs

6.7.1 Tote and IBC Overview

Intermediate Bulk Containers (IBCs) and totes are portable tanks typically ranging from 110 to 550 gallons. They are ubiquitous in manufacturing, chemical distribution, food processing, and lubricant handling.

graph TD
    subgraph "IBC/Tote Ecosystem"
        A[IBC / Tote] --> B[Metal Cage Frame]
        A --> C[HDPE Inner Bottle]
        A --> D[Pallet Base]
        A --> E[Top Fill Opening<br>6 inch diameter]
        A --> F[Bottom Discharge<br>2 inch valve]
    end

    E --> G[TSU Monitor<br>Mounted on Lid]
    G --> |Cellular or WiFi| H[AIP Platform]

    style G fill:#4CAF50,color:#fff

Key characteristics of IBCs:

Portable: Moved by forklift, designed for shipping and stacking
Standardized: ISO-standard dimensions allow universal handling
Disposable or reusable: Some are single-use; others are cleaned and refilled
Numerous: A single facility may have dozens or hundreds of IBCs
Mixed products: Different IBCs at the same location may hold different products

6.7.2 Monitoring with TSU

The TSU (TankScan Universal) is designed specifically for totes and IBCs. It addresses the unique challenges of monitoring portable, numerous, small containers.

Feature	TSU Specification
Measurement technology	Ultrasonic (non-contact)
Mounting	Snap-on or magnetic mount to IBC lid
Power	Replaceable lithium battery (3+ year life)
Communication	Cellular (LTE-M) or Wi-Fi
Size	Compact (fits standard IBC opening)
Weight	< 1 lb (does not affect IBC handling)
Water/dust rating	IP65
Container identification	QR code / NFC tag integration

TSU Workflow:

sequenceDiagram
    participant IBC as IBC/Tote
    participant TSU as TSU Monitor
    participant AIP as AIP Platform
    participant User as Operator

    Note over IBC,TSU: Monitor attached to IBC lid
    TSU->>IBC: Ultrasonic pulse (measures level)
    TSU->>AIP: Transmits level data (cellular/WiFi)
    AIP->>AIP: Calculates volume from tank profile
    AIP->>User: Dashboard shows all tote levels

    Note over User: Low level alert triggered
    AIP->>User: Alert: IBC #47 at 15% - reorder
    User->>User: Places reorder with supplier

6.7.3 Challenges Specific to Totes and IBCs

Challenge	Description	TSU Solution
Portability	IBCs are moved frequently	Monitor stays attached; reports location changes
Large quantities	Hundreds of IBCs to track	Batch configuration in AIP; QR code scanning
Product variety	Different products in different IBCs	Each TSU linked to product profile in AIP
Stacking	IBCs stacked 2-3 high	Low-profile design; no protruding antenna
Refilling	IBCs emptied and refilled on-site	Auto-detects delivery events; resets tracking
Cleaning	IBCs may be washed between uses	TSU easily removed and reattached
Cost sensitivity	Per-unit monitoring cost must be low	TSU designed as lower-cost monitor option

6.7.4 Lubricant Distribution Use Case

Lubricant distributors are among the heaviest users of tote monitoring. A typical distributor manages:

50-200 customer locations
2-10 totes per location (different viscosities, products)
Monthly or bi-monthly delivery cycles
Products ranging from motor oil to hydraulic fluid to cutting oil

Without monitoring, distributors rely on customers calling when they need product -- often too late, causing equipment downtime, or too early, resulting in partial deliveries and inefficient routing. TSU monitoring enables just-in-time delivery based on actual consumption.

6.8 Pressurized Tanks

6.8.1 Pressurized Tank Challenges

Pressurized tanks (propane, LPG, ammonia, compressed gases) present unique monitoring challenges:

Sealed vessels: No opening available for top-mount sensors
Internal pressure: Standard sensors cannot withstand the pressure environment
Pressure-temperature relationship: Liquid volume changes with temperature due to expansion
Regulatory restrictions: Pressure vessel codes (ASME) limit modifications
Safety concerns: Any penetration of a pressure vessel creates a potential failure point

Never Modify a Pressure Vessel

Drilling, welding, or otherwise modifying a pressurized tank to install a monitor violates ASME pressure vessel codes and creates a serious safety hazard. TankScan's approach for pressurized tanks uses non-invasive external monitoring.

6.8.2 The TSD Dial Gauge Reader

The TSD (TankScan Dial) takes a fundamentally different approach to monitoring. Instead of measuring liquid level directly, it reads the existing mechanical gauge on the pressurized tank.

graph LR
    subgraph "Pressurized Tank with TSD"
        A[Pressurized Tank<br>Propane/LPG] --> B[Mechanical<br>Dial Gauge]
        B --> C[TSD Gauge Reader<br>Optical/Magnetic]
        C --> |Reads gauge position| D[Converts to<br>digital value]
        D --> |Cellular| E[AIP Platform]
    end

    style C fill:#FF9800,color:#fff

How the TSD works:

The existing mechanical gauge on the tank (typically a Rochester, Marshall Excelsior, or similar float gauge) displays fill percentage on a dial
The TSD attaches over the gauge face using a clamp or magnetic mount
An internal sensor reads the position of the gauge needle
The TSD converts the needle position to a digital fill percentage
This data is transmitted to AIP via cellular communication

TSD Parameter	Specification
Gauge compatibility	Most standard float gauges (Rochester, ME)
Reading accuracy	+/- 2% of gauge reading
Mounting method	Clamp-on or magnetic (no tank modification)
Power	Lithium battery (3+ year life)
Communication	Cellular (LTE-M)
Operating temperature	-40F to +140F
Hazardous area rating	Class I, Div 1 (for LPG/propane installations)
Weatherproofing	NEMA 4X, UV-resistant

6.8.3 Propane Monitoring Applications

Propane is one of the most common pressurized tank applications:

Application	Tank Size	Delivery Method	Monitoring Value
Residential heating	120 - 1,000 gal	Bobtail truck	Prevents run-out in winter
Commercial HVAC	500 - 2,000 gal	Bobtail or transport	Ensures business continuity
Agricultural drying	1,000 - 30,000 gal	Transport truck	Critical during harvest season
Forklift fuel	33 - 100 lb cylinders	Cylinder exchange	Tracks consumption rates
Industrial process	1,000 - 30,000 gal	Transport truck	Prevents production shutdown
Autogas stations	1,000 - 10,000 gal	Transport truck	Retail availability

Propane Delivery Optimization

A propane distributor serving 3,000 residential customers previously used degree-day calculations and fixed delivery schedules. After deploying TSD monitors on all customer tanks:

Run-outs decreased from 45 per winter season to 3
Delivery efficiency improved by 28% (fewer partial loads)
Customer satisfaction scores increased by 35 points
Emergency deliveries dropped by 90% (saving $150-200 per emergency call)

6.8.4 Temperature Compensation for Pressurized Liquids

Liquefied gases like propane expand significantly with temperature. A tank that reads 80% full at 60F may read 85% at 80F, even though no product was added.

The volume correction formula:

\[V_{\text{corrected}} = V_{\text{observed}} \times \left[1 + \beta (T_{\text{ref}} - T_{\text{actual}})\right]\]

Where:

$\beta$ = coefficient of thermal expansion (for propane: approximately 0.00099 per degree F)
$T_{\text{ref}}$ = reference temperature (typically 60F)
$T_{\text{actual}}$ = actual product temperature

The AIP platform applies temperature compensation when temperature data is available, providing normalized volume readings that reflect actual product quantity rather than temperature-influenced gauge readings.

6.9 Specialty Tanks and Configurations

6.9.1 Double-Wall Tanks

Double-wall tanks have an outer shell surrounding the inner (primary) tank, with an interstitial space between them for leak detection. Monitoring considerations:

Primary tank level: Monitored normally with TSR or appropriate sensor
Interstitial space: May require a separate leak detection sensor
Access limitations: The outer wall may limit access to sensor mounting points

6.9.2 Cone-Bottom Tanks

Cone-bottom vertical tanks are common in chemical processing. The cone section requires a modified volume calculation:

\[V_{\text{cone}}(h) = \frac{1}{3}\pi r_h^2 h_{\text{cone}}\]

Where $r_h$ is the radius at height $h$ within the cone section. The AIP platform supports cone-bottom tank profiles with configurable cone height and angle.

6.9.3 Bunded/Diked Tanks

Tanks within secondary containment (bunds or dikes) may have the containment area monitored in addition to the primary tank:

graph TD
    subgraph "Bunded Tank Configuration"
        A[TSR on Primary Tank] --> B[Primary Tank<br>Product Level]
        C[TSR on Bund] --> D[Secondary Containment<br>Leak Detection]
        B --> E[AIP Platform]
        D --> E
        E --> F[Alert if bund<br>level increases]
    end

6.9.4 Multi-Compartment Tanks

Some tanks, particularly transport tanks and large storage vessels, contain multiple compartments for different products. Each compartment requires its own sensor and is configured as a separate asset in AIP.

Compartment Configuration	Sensor Requirement	AIP Configuration
2-compartment (50/50)	2 x TSR	2 separate tank assets, linked
3-compartment (33/33/33)	3 x TSR	3 separate tank assets, linked
4-compartment (25/25/25/25)	4 x TSR	4 separate tank assets, linked
Irregular split	1 TSR per compartment	Custom strapping per compartment

6.10 Tank Farm Configurations

6.10.1 What Is a Tank Farm?

A tank farm is a collection of tanks at a single location, typically at fuel terminals, refineries, chemical plants, or distribution hubs. Tank farms present unique monitoring challenges due to the number of tanks, the variety of products, and the complexity of operations.

graph TD
    subgraph "Fuel Distribution Terminal"
        direction LR
        A[Tank 1<br>Regular Gas<br>30,000 gal]
        B[Tank 2<br>Regular Gas<br>30,000 gal]
        C[Tank 3<br>Premium Gas<br>20,000 gal]
        D[Tank 4<br>Diesel #2<br>25,000 gal]
        E[Tank 5<br>Diesel #2<br>25,000 gal]
        F[Tank 6<br>Kerosene<br>15,000 gal]
    end

    A & B & C & D & E & F --> G[Loading Rack]
    G --> H[Delivery Trucks]

    A & B & C & D & E & F --> |TSR Monitors| I[AIP Platform]
    I --> J[Terminal<br>Operations<br>Dashboard]
    I --> K[Dispatch<br>Planning]
    I --> L[Inventory<br>Reconciliation]

6.10.2 Tank Farm Monitoring Strategy

Factor	Consideration
Number of tanks	May range from 5 to 500+; batch configuration in AIP essential
Product diversity	Each product needs its own profile (density, dielectric constant)
Manifold connections	Tanks may be interconnected; product can be transferred between them
Custody transfer	Accurate measurement needed for financial transactions
Throughput volume	High-turnover tanks may need more frequent readings
Regulatory compliance	Tank farms often fall under EPA SPCC rules
Safety zones	Multiple hazardous areas; all equipment must be rated accordingly

6.10.3 Connectivity in Tank Farms

Large tank farms may have dozens or hundreds of monitors in close proximity. Connectivity options:

Cellular (each monitor independent):

Each TSR has its own cellular connection
Simple deployment, no infrastructure required
Higher per-unit communication cost
Best for: Small to medium tank farms (< 50 tanks)

Wi-Fi gateway model:

A central Wi-Fi gateway provides backhaul
Individual monitors communicate via Wi-Fi to the gateway
Lower per-unit communication cost
Requires gateway installation and power
Best for: Large tank farms with available power and IT infrastructure

Hybrid approach:

Critical tanks use cellular for reliability
Non-critical tanks use Wi-Fi for cost efficiency
Gateway provides local aggregation and buffering

6.10.4 Tank Farm Dashboard Design

For tank farms, the AIP platform provides specialized views:

View	Purpose	Key Information
Site map	Physical layout visualization	Tank locations, fill levels (color-coded)
Product summary	Inventory by product type	Total volume per product, percentage available
Alert board	Active alerts and warnings	Low levels, anomalies, sensor health
Delivery schedule	Incoming and outgoing product	Expected deliveries, scheduled dispatches
Reconciliation	Inventory accuracy tracking	Book vs. physical inventory variances

6.11 Monitor Selection Guide

Choosing the right monitor requires evaluating the tank type, product, environment, and operational requirements. The following decision tree provides a systematic approach.

6.11.1 Selection Decision Tree

graph TD
    A[Start: What type of tank?] --> B{Pressurized?}
    B -->|Yes| C[TSD Dial Gauge Reader]
    B -->|No| D{Underground?}

    D -->|Yes| E{Has ATG?}
    E -->|Yes| F[TSC ATG Integration]
    E -->|No| G[Install ATG + TSC<br>or special UST probe]

    D -->|No| H{Tank Size?}
    H -->|"Small (< 500 gal)<br>Tote/IBC"| I[TSU Universal]
    H -->|"Medium/Large<br>(> 500 gal)"| J{Material?}

    J -->|Metal| K[TSR Radar<br>Standard Config]
    J -->|Non-Metal<br>FRP/Poly| L[TSR Radar<br>with Still Pipe<br>or Guided Wave]

    K --> M{Location?}
    L --> M
    M -->|Cellular Coverage| N[TSR Cellular]
    M -->|No Cell Coverage| O[TSR Satellite]

    style C fill:#FF9800,color:#fff
    style F fill:#2196F3,color:#fff
    style I fill:#4CAF50,color:#fff
    style N fill:#9C27B0,color:#fff
    style O fill:#F44336,color:#fff

6.11.2 Quick Reference Selection Table

Scenario	Tank Type	Product	Environment	Recommended Monitor
Gas station day tank	AST horizontal	Diesel	Urban/suburban	TSR Cellular
Convenience store UST	UST (Veeder-Root ATG)	Gasoline	Urban	TSC Gateway
Farm fuel tank	AST horizontal	Diesel	Rural	TSR Cellular or Satellite
Propane customer	Pressurized	Propane	Residential	TSD Dial Reader
Lubricant tote	IBC 330 gal	Motor oil	Warehouse	TSU Universal (Wi-Fi)
Oil well production	AST vertical	Crude oil	Remote oilfield	TSR Satellite
Chemical plant	AST vertical (FRP)	Acid/caustic	Industrial	TSR with PVDF housing
Terminal tank farm	AST horizontal	Multi-product	Commercial	TSR Cellular (batch)
Mining site	AST horizontal	Diesel	Remote, extreme	TSR Satellite, hardened
Construction site	Portable tank	Diesel	Temporary	TSU (portable mounting)

6.11.3 Product Compatibility Matrix

Different products have different physical properties that affect sensor selection:

Product Category	Dielectric Constant	Vapor Pressure	Viscosity	Radar Suitability
Gasoline	2.0 - 2.1	High	Low	Good (strong reflection)
Diesel	2.1 - 2.4	Low	Low-medium	Excellent
Heating oil	2.0 - 2.2	Low	Medium	Excellent
Propane (liquid)	1.6 - 1.8	Very high	Very low	Use TSD (pressurized)
Motor oil	2.1 - 2.4	Very low	High	Excellent
Hydraulic fluid	2.1 - 2.3	Very low	High	Excellent
Ethanol (E100)	24.3	Moderate	Low	Excellent (very high reflection)
DEF (urea solution)	~80	Very low	Low	Excellent
Water	80	Low	Low	Excellent (reference standard)
Sulfuric acid	84	Very low	Medium	Excellent (use PVDF housing)

Dielectric Constant and Radar Performance

Radar reflection strength depends on the dielectric constant difference between the vapor above the liquid and the liquid itself. Higher dielectric constants produce stronger reflections. Water-based products (DEF, acids) give very strong returns. Low-dielectric products (propane, LPG) give weaker returns but are typically in pressurized tanks where TSD is used instead of radar.

6.12 Volume Calibration and Strapping Tables

6.12.1 What Is a Strapping Table?

A strapping table (also called a tank capacity table or gauge table) converts a linear level measurement to a volumetric quantity. For simple geometries (vertical cylinders, rectangular tanks), the conversion is a straightforward formula. For complex geometries (horizontal cylinders with dished heads), the strapping table provides pre-calculated volume at each level increment.

6.12.2 Standard Strapping Table Formats

AIP supports several strapping table approaches:

Method	Description	Accuracy	Effort
Calculated from dimensions	Enter tank geometry; AIP calculates the table	Good (+/- 1-2%)	Low
Manufacturer's table	Upload the table provided by the tank maker	High (+/- 0.5%)	Low
Wet calibration	Fill tank incrementally, record actual volumes	Highest (+/- 0.25%)	High
API MPMS Chapter 2.2A/B	Industry-standard tables for horizontal cylinders	High (+/- 0.5%)	Medium

6.12.3 Creating a Strapping Table from Dimensions

For a horizontal cylindrical tank, the inputs required are:

Total length (shell length, end-to-end)
Diameter (internal diameter)
Head type (flat, 2:1 elliptical, hemispherical, ASME flanged & dished)
Head depth (for non-flat heads)
Deadband (minimum measurable level, below sensor range)
Maximum usable level (may be less than diameter due to overflow protection)

AIP generates the table and displays a graph of the level-to-volume relationship:

Volume (gal)
|                    ___________
|                 __/
|              __/
|           __/
|        __/
|      _/
|    _/
|  _/
| /
|/___________________________
0        Level (inches)      D

Note: Horizontal cylinder has S-curve relationship.
      Steep in middle, flat at top and bottom.

The S-Curve Effect

In a horizontal cylinder, the volume change per inch of level is smallest at the very bottom and very top (where the tank narrows), and greatest in the middle (where the tank is widest). This means that a 1-inch level change at 50% fill represents more volume than a 1-inch change at 10% or 90% fill. AIP's strapping table accounts for this automatically.

6.13 Chapter Summary

This chapter covered the major categories of tanks that TankScan monitors and the specific approaches for each:

Tank Type	Monitor	Key Advantage
Aboveground (AST)	TSR Radar	Direct, high-accuracy radar measurement
Underground (UST)	TSC Gateway	Integrates with existing ATG systems
Totes and IBCs	TSU Universal	Portable, low-cost, snap-on mounting
Pressurized	TSD Dial Reader	Non-invasive, reads existing gauges
Field/Remote	TSR + Satellite	Works beyond cellular coverage

Key principles:

Match the monitor to the tank: No single device works for all tank types
Understand the geometry: Level-to-volume conversion depends on tank shape
Consider the environment: Temperature, pressure, and atmospheric conditions affect sensor selection
Plan for connectivity: Cellular, Wi-Fi, or satellite based on location
Use strapping tables: Accurate volume calculation requires proper calibration

Review Questions

Question 1 -- Knowledge (Remember)

List the four main TankScan monitor types (TSR, TSC, TSU, TSD) and state which tank category each is designed to serve.

Question 2 -- Comprehension (Understand)

Explain why a horizontal cylindrical tank requires a strapping table for accurate volume measurement, while a vertical cylindrical tank does not. Describe the mathematical relationship that causes this difference.

Question 3 -- Application (Apply)

A fuel distributor asks you to recommend a monitoring solution for the following tanks at a single customer site:

One 10,000-gallon aboveground horizontal steel diesel tank
Two 275-gallon IBC totes containing motor oil
One 1,000-gallon underground fiberglass tank with a Veeder-Root TLS-350 ATG
One 500-gallon propane tank

Specify the TankScan monitor for each tank and explain your reasoning.

Question 4 -- Analysis (Analyze)

A TSR monitor on a horizontal 12,000-gallon steel tank reports a level of 48 inches. The tank has a 72-inch internal diameter and is 15 feet long with flat heads. Using the horizontal cylinder volume formula, calculate the approximate volume in gallons. Then explain why this calculated volume would differ slightly from the actual volume in a real-world tank with 2:1 elliptical heads.

Question 5 -- Evaluation (Evaluate)

A chemical plant has 30 fiberglass (FRP) vertical tanks containing various acids and caustics. A colleague suggests installing standard TSR monitors on all tanks using the same configuration. Evaluate this approach and identify at least three potential problems. Propose a more appropriate monitoring strategy, considering material compatibility, chemical resistance, and radar performance in non-metallic tanks.