What is Mesa 2D? How Underground Tank Testing Equipment Works
How the MESA 2D Improves Underground Tank Testing Accuracy and Speed
Most tank testing equipment was designed by engineers who don’t run compliance jobs every day. The MESA 2D was built by people who do.
ATS Environmental designed the MESA 2D from the ground up based on real-world field experience; every frustration with competitor systems, every limitation that cost contractors time and money, addressed in one unit. If you’re evaluating tank testing equipment, here’s exactly what the MESA 2D is, how it works, and what sets it apart.
The MESA 2D is a digital underground storage tank testing system that uses computer-analyzed acoustic signals to detect leaks in fuel tanks and associated piping. A digital probe (sonde) is placed in the ullage portion of the tank. The system utilizes a controlled vacuum, monitors acoustic data, and uses a computer analysis program to determine pass or fail, with results available on-site in just 10 minutes. It requires no minimum fuel level, no annual calibration, no external electrical power source, and no per-report licensing fees. It is independently third-party certified by Ken Wilcox Associates and listed by the National Work Group on Leak Detection Evaluations (NWGLDE) as an EPA-approved testing method.
What Is the MESA 2D?
The MESA 2D is the first major advancement in tank testing technology in over a decade. It represents a shift from purely operator-dependent acoustic testing toward fully computerized digital analysis, a change that matters enormously for accuracy, documentation, and regulatory defensibility.
Here’s who uses it:
- Environmental service contractors running high-volume compliance programs
- Gas station operators managing their own UST testing
- Environmental engineers performing site assessments
- Compliance contractors working across the U.S. and international countries
- Even state environmental officials responsible for USTs
The system was designed by ATS Environmental, a company that performs UST testing every day from its base in New Jersey. That’s not a marketing line. It’s the actual reason the MESA 2D solves problems that other systems ignore. When you build the equipment you depend on yourself, the tolerance for downtime, calibration costs, and operator error drops dramatically.
Visit the Mesa 2D Tank Testing System page for full product details.
How the MESA 2D Works – Step by Step
The MESA 2D tests the integrity of underground storage tanks using digital acoustic technology combined with a controlled vacuum environment. Here’s the process:
- Probe placement. A small digital sonde is lowered into the fill pipe and positioned in the ullage (vapor) portion of the tank.
- Vacuum application. The technician applies a precise vacuum in inches of water column, starting at 60 inches of water column (-2.16 psig), to the tank. The vacuum pump is a multi-stage venturi that operates off of any compressed gas, for safety a noble gas is encouraged. No generator, no extension cords, no electrical hookup required.
- Acoustic monitoring. The sonde monitors acoustic signals inside the tank digitally. Unlike older acoustic systems, the signals are not interpreted by human ear alone; they’re captured, digitized, and sent directly to the computer for analysis.
- Computer analysis. The computer analysis program focuses on the most relevant acoustic data, those most consistent with air intrusion and determines whether the system passes or fails leak testing standards. The field testing form automatically calculates pressure adjustments for both interior product levels and exterior water levels, something no other system on the market does automatically.
- Instant results. A clear, concise graph is charted and printed on-site. Results are available immediately for your client and ready for regulatory submission. Just an email away!
The entire acoustic test takes only 10 minutes once the tank reaches test pressure. Competing systems require 90 minutes to 3 hours per test. That’s not a small efficiency gain, it’s the difference between completing one job and completing four.
See how the MESA 2D works in detail →
The Two Types of Leaks the MESA 2D Identifies
One of the MESA 2D’s most practical features is its ability to indicate where in the system a leak is occurring, not just confirm that one exists.
Dry Portion Leaks/Ullage Leaks.
The Mesa 2D Tank Testing system includes a secondary listening device for the technician to use in analyzing any failure that may occur. Trained technicians will be able to determine if a failure detected by the computer is occurring within the dry or wetted portion of the vessel under test. This knowledge can be invaluable in deciding the appropriate next steps in an investigation.
The ACTV2 Water Sensor: Why It Matters
When any portion of a tank is submerged in water, that water masks acoustic signals making accurate acoustical testing of the wetted portion of the tank improbable.
The ACTV2 Water Sensor is designed to detect water entering the tank system and is fully compatible with the MESA 2D sonde. One of few if not the only water intrusion test that is certified for ethanol blended fuels. The two tests can be run concurrently, which eliminates the need for a separate water intrusion test. That saves time and money on every job where groundwater is a factor.
ATS Environmental provides the only water intrusion test certified for testing ethanol blended fuels and diesel fuels with the same water sensor. The new ACTv2 Ethanol & Diesel Water Sensor is an advancement specifically designed to handle ethanol-blended fuels and diesel, which present different conductive properties than standard gasoline. As ethanol blends have become the market standard, this update keeps the MESA system accurate across all commonly stored fuel types.
The water sensor requires a conductive liquid of a minimum height of 0.014 inches (0.036 cm) measured from the tank base. If no water is present, a minimal amount must be added before testing begins.
MESA 2D vs. Competing Tank Testing Systems
Here’s a direct comparison of how the MESA 2D stacks up against older acoustic systems like the Estabrook tester and the Ezy 3 Locator:
| Feature | MESA 2D | Typical Acoustic Competitors |
| Test duration | Under 10 minutes | 90 minutes – 3 hours |
| Tests liquid + ullage | Simultaneously | Two separate tests required |
| Operator dependency | Low – computer analyzes | High – tech listens by ear |
| Water compensation | Automatic | Manual or absent |
| Minimum fuel requirement | None (0-90.6% capacity) | Varies; often requires partial fill |
| Annual factory calibration | Not required | Often required ($1,000+/year) |
| Licensing/per-report fees | None | Common with some systems |
| Power requirement | Laptop battery only | Generator often required |
| Max tank size | 30,000 gallons | Varies |
| On-site results | Yes | Limited |
| Metric conversion | Yes – button toggle | Rarely |
The core issue with older acoustic systems is operator dependency. When a technician determines pass or fail by listening through a microphone, results vary based on training, experience, and even ambient noise. Results can be disputed. The MESA 2D removes that subjectivity entirely. The computer makes the call, and the printed graph documents exactly what it found.
Also worth noting: competitor systems evaluate the liquid portion and the ullage space as two separate tests. The MESA 2D runs both simultaneously. That single-test approach cuts job time dramatically and reduces the risk of error between steps.
Key Specs and Operational Advantages
Here are the specifications and practical details that matter most to working contractors:
- Tank capacity range: 0% to 90.% full (no minimum fuel required)
- Maximum tank size: 30,000 gallons
- Vacuum pump: Multi-stage venturi, 17.0 cu/ft per minute; no electrical power needed
- Power source: Battery only
- Test time: Minimum 10 minutes under vacuum for the acoustic portion
- Calibration: No factory recalibration required, ever
- Licensing fees: None. You purchase the equipment, you own it
- Per-report charges: None
- Microphone replacement: Field-replaceable.
- Certification validity: 2 years; no physical re-training required unless test cannot be passed
- Training locations: virtual, ATS facility in Sparta, NJ, or field training at your location
ATS has trained clients in 17 countries to date.
Download the Mesa 2D Product Specification Sheet for complete technical details.
Regulatory Standards: EPA, NWGLDE, and Beyond
United States
The MESA 2D is independently certified by Ken Wilcox Associates and listed by the National Work Group on Leak Detection Evaluations (NWGLDE) as an EPA-approved test method. Under 40 CFR Part 280, all UST leak detection equipment must meet NWGLDE performance standards. The MESA 2D satisfies this requirement. Test records must be retained on-site for a minimum of 5 years and be available for inspection.
International Markets
Most countries accept NWGLDE listing as the benchmark for acceptable test methodology. The MESA 2D has been used in compliance programs across Canada, Australia, and the United Kingdom, and the system’s metric conversion capability supports international reporting requirements with a single button toggle.
ATS Environmental: Equipment Sales, Training, and Field Services
ATS Environmental is both the designer and manufacturer of the MESA 2D and an active UST compliance contractor serving New Jersey and beyond. That dual role is important. Every improvement to the MESA system comes from field experience, not a product development committee.
Equipment sales and training:
- Purchase the MESA 2D system with no hidden fees, licensing charges, or per-report costs
- Training available virtually, at our facility in Sparta, NJ, or at your location
- Financing options available – see equipment financing details
- Full technical support from the team that built the system
UST field services in New Jersey:
- Tank tightness testing using the MESA 2D
- Line leak detection for all accessible systems
- Veeder-Root ATG certification and programming
- Cathodic protection testing
- Vapor recovery testing (Stage I and Stage II)
- Complete NJDEP compliance documentation
- Compliance assessments
We’re available 7 days a week and respond to quote requests fast, often the same day.
Frequently Asked Questions
How long does a MESA 2D test actually take? The acoustic test takes only 10 minutes once the tank reaches test pressure. Total job time including setup and result acquisition is significantly shorter than competing systems, which require 90 minutes to 3 hours per test.
Does the MESA 2D require annual calibration? No. The MESA 2D uses solid-state digital technology with no mechanical moving parts requiring periodic replacement. There is no factory recalibration requirement, which eliminates the downtime and cost (often exceeding $1,000 per year) that other systems demand.
Is there a minimum amount of fuel needed to test? No. The MESA 2D has no minimum fuel requirement. Tanks between completely empty and 90% capacity can all be tested without any fuel adjustment.
Is the MESA 2D certified for use outside the United States? Yes. It is independently certified by Ken Wilcox Associates and listed by the NWGLDE as an EPA-approved test method. Most countries accept this listing as the standard for acceptable testing methodology. ATS has trained operators in 17 countries, and the system includes a metric conversion option for international reporting.
How to Choose the Right Tank Testing Equipment for Your Operation
If you’re evaluating tank testing equipment, the MESA 2D is worth a close look, especially if recurring calibration costs, operator error, or slow test times are limiting your operation.
If you’re a UST operator looking for certified compliance testing, ATS Environmental handles the full scope: tank tightness tests, line leak detection, cathodic protection, vapor recovery, and NJDEP documentation.
Contact us or review the Mesa 2D FAQs for more detail. We’re available 7 days a week, and we get back to inquiries fast.
