Understanding Dissolved Gas Analysis (DGA) Services: Transformer Health Testing for Industrial Facilities in the USA
- Stephen Fike
- Oct 23
- 4 min read
What Is Dissolved Gas Analysis (DGA)?
Dissolved Gas Analysis (DGA) is one of the most effective diagnostic tools for assessing the internal condition of oil-filled electrical transformers. By analyzing gases dissolved in the transformer’s insulating oil, DGA provides early warning of electrical or thermal faults that could lead to equipment failure, fire, or catastrophic downtime.
Transformers are critical assets in industrial, utility, and manufacturing environments. Because most failures originate inside the oil or insulation, DGA allows maintenance teams to “see inside” the transformer — identifying issues long before visual inspection or electrical testing could detect them.
At Assured NDT, we offer professional dissolved gas analysis services USA-wide, combining laboratory precision with expert interpretation to help facilities keep their transformers reliable, safe, and compliant.
Why Transformer Health Monitoring Matters
Transformers are the backbone of power distribution systems — and also one of the most expensive components to replace. A single failure can cause:
Extended unplanned downtime
Production losses and equipment damage
Fire or explosion hazards
Insurance and compliance violations
Routine DGA testing enables predictive maintenance, turning unexpected failures into planned interventions — saving both time and money.
How Dissolved Gas Analysis Services in the USA Works
Every transformer produces small amounts of gas under normal operation. However, abnormal heating or arcing inside the unit changes the composition and concentration of these gases.
DGA identifies and quantifies the presence of key gases, including:
Gas | Indicates Possible Fault Type |
Hydrogen (H₂) | Partial discharge or corona |
Methane (CH₄) | Low-energy overheating |
Ethylene (C₂H₄) | Hot spot or thermal fault |
Acetylene (C₂H₂) | Arcing or severe electrical discharge |
Carbon Monoxide (CO) | Insulation decomposition |
Carbon Dioxide (CO₂) | Cellulose paper degradation |
By analyzing the ratio and rate of gas generation, engineers can determine fault type, severity, and progression.
Common Transformer Faults Detected by DGA
Partial Discharge: Low-energy faults that deteriorate insulation.
Overheating: Caused by poor cooling or overloaded windings.
Arcing: High-energy discharges that can cause catastrophic failure.
Oil Contamination: Resulting from oxidation or moisture ingress.
Aging Insulation: Decomposition of cellulose or paper materials.
Each condition leaves a distinct chemical signature, allowing DGA to pinpoint the issue with precision.
Frequency of Testing
According to IEEE and NFPA 70B guidelines:
Routine DGA testing should be conducted annually for most transformers.
Critical transformers (serving production lines, hospitals, or data centers) may require quarterly or continuous online monitoring.
Additional testing is recommended after fault events, load changes, or oil top-ups.
Assured NDT helps facilities design condition-based testing schedules tailored to their system criticality and maintenance goals.
Compliance and Industry Standards
DGA testing supports compliance with key standards, including:
NFPA 70B (2023): Requires condition-based electrical maintenance programs.
IEEE C57.104: Guidelines for interpretation of DGA results.
OSHA 1910 Subpart S: Electrical safety and preventive maintenance standards.
Partnering with an experienced provider ensures your reports meet documentation and audit requirements for regulatory and insurance purposes.
Why Choose Assured NDT
Assured NDT provides nationwide dissolved gas analysis services USA-wide, trusted by manufacturing, energy, and utility clients across the country.
Our capabilities include:
Laboratory-verified DGA testing for all transformer oil types
On-site oil sampling and expedited turnaround
Expert analysis by certified electrical engineers
Trend reporting and predictive maintenance planning
Compliance documentation for NFPA 70B and insurance audits
We combine cutting-edge diagnostics with actionable insights — so you don’t just get data, you get decisions.
Ready to Test Your Transformer Health?
Your transformers are too valuable to leave unmonitored.Stay ahead of failures, maintain compliance, and improve reliability with Assured NDT’s dissolved gas analysis services USA-wide.
Contact us today to schedule transformer oil testing or to discuss your predictive maintenance program.
Frequently Asked Questions: Dissolved Gas Analysis (DGA)
1) What is Dissolved Gas Analysis (DGA)?
DGA is a diagnostic method that detects electrical and thermal faults inside oil-filled transformers by measuring gases dissolved in the insulating oil.
2) Why is DGA important for industrial facilities?
It helps identify developing faults before they cause catastrophic transformer failures, ensuring reliability and safety across electrical systems.
3) How often should DGA testing be performed?
Most facilities perform DGA annually. Critical or high-load transformers may require quarterly or continuous monitoring.
4) What gases are measured in DGA testing?
Common gases include hydrogen, methane, ethylene, acetylene, carbon monoxide, and carbon dioxide — each indicating specific fault conditions.
5) What are the benefits of using DGA services?
DGA testing provides early fault detection, reduces downtime, prevents costly replacements, and supports NFPA 70B and IEEE compliance.
6) Who should perform DGA testing?
Certified electrical engineers or qualified testing firms with experience in transformer diagnostics and NFPA 70B compliance should perform DGA testing.
7) Does Assured NDT offer DGA services nationwide?
Yes, Assured NDT provides dissolved gas analysis services USA-wide, offering on-site sampling, expert analysis, and compliance-ready reporting.
8) What other services complement DGA testing?
Infrared thermography, breaker testing, and power quality analysis are ideal companion services for a complete transformer and electrical health program.
Protect your transformers. Protect your operations.
Schedule professional dissolved gas analysis services USA-wide with Assured NDT — your trusted partner in predictive maintenance and electrical safety.
Contact us today to learn more about transformer oil testing and reliability programs.
