DCP UTM Dry Power Fire Tank

DCP UTM Dry Power Fire Tank

DCP UTM (Ultrasonic Thickness Measurement ) for Dry Powder Fire Tanks on LPG (Liquefied Petroleum Gas) vessels is a critical part of safety and maintenance procedures .

LPG vessels carry highly flammable and volatile cargo, and the integrity of the fire suppression systems is vital for preventing catastrophic incidents in case of a fire or gas leak.

The dry powder fire tanks onboard store fire extinguishing agents used for combating Class B (flammable liquids) and Class C (electrical) fires, which are especially relevant in LPG transport due to the nature of the cargo.

What is the meaning of UTM ?

Ultrasonic Thickness Measurement (UTM) is a non-destructive testing (NDT) method used to measure the thickness of a material, typically metal, by using sound waves. This technique is commonly employed in industries such as shipbuilding, manufacturing, aerospace, and oil & gas to detect wear, corrosion, or material degradation without damaging the object being tested.

Why UTM is Essential for Dry Powder Fire Tanks on Ships ?

• Corrosion Detection: Marine Environment: Ships operate in a highly corrosive environment with constant exposure to saltwater, humidity, and temperature variations. This can accelerate corrosion on metal surfaces, including fire suppression tanks.
• Internal Corrosion: If moisture enters the tank (due to faulty seals or other issues), the dry powder can react with the moisture, potentially leading to internal corrosion. UTM can detect wall thinning before it becomes a critical safety issue.
• Pressure Retention: The tanks are pressurized with gases like nitrogen to expel the dry powder during a fire emergency. UTM ensures that the tank walls are thick enough to maintain pressure safely, preventing leaks or tank ruptures.
• Compliance with Maritime Safety Standards: Ships are subject to strict safety regulations, including regular inspections of fire suppression systems. These inspections are mandated by international bodies like the International Maritime Organization (IMO), SOLAS (Safety of Life at Sea), and classification societies such as Lloyd’s Register, DNV GL, and others. UTM ensures that tanks meet these safety standards.

UTM Procedure for Dry Powder Fire Tanks on Ships:

• Preparation for UTM Inspection:

  • Surface Cleaning: Before taking UTM measurements, the tank’s external surface needs to be cleaned of any dirt, marine growth, or corrosion to ensure accurate readings.

  • Visual Inspection: A preliminary visual inspection is often conducted to identify obvious signs of corrosion, pitting, or wear. Areas of concern can be targeted during the UTM inspection .

• Couplant Application:

  • A couplant gel (typically a special gel or oil) is applied to the surface of the tank to ensure good contact between the ultrasonic transducer and the tank. This helps the ultrasonic waves travel through the tank material without interference.

• Ultrasonic Measurement:

  • The UTM device emits high-frequency ultrasonic sound waves through the tank material. These waves bounce back from the opposite side of the tank wall, and the device measures the time it takes for the waves to return. This time, along with the known speed of sound in the material, is used to calculate the thickness of the tank wall.

Critical Areas to Inspect:

• Tank Bottom: The bottom of the tank often collects moisture and sediment, which can accelerate corrosion. This area should be thoroughly checked for thinning or pitting.

• Welds and Seams: The areas around welds and seams are more prone to cracking or weakening over time due to the stress of pressure changes and vibrations on board the ship.

Regulatory Compliance:

• SOLAS (Safety of Life at Sea): SOLAS regulations mandate regular inspections and maintenance of fire suppression systems on ships. UTM forms a part of these inspections, ensuring that the tanks remain functional and safe.

• IMO (International Maritime Organization) Standards: IMO sets guidelines and safety standards for ships, which include routine inspections of critical safety equipment like fire suppression tanks. UTM helps ensure compliance with these standards.

• Classification Societies (e.g., Lloyd’s Register, DNV GL, ABS): Classification societies require routine UTM inspections as part of their certification processes. Ships must provide proof of UTM inspections and maintenance to remain classified and seaworthy.

Conclusion:

• UTM inspections for Dry Powder Fire Tanks on board ships are essential for ensuring the safety and effectiveness of fire suppression systems.
• By detecting corrosion, thinning, or other material degradation early, UTM helps ship operators maintain compliance with maritime regulations and prevent system failures in emergency situations.
• Additionally, UTM allows for cost-effective maintenance, reducing the risk of tank failure and ensuring the vessel’s safety and operational readiness.

Would you like to know more about the equipment used in UTM, calibration techniques, or any other specific aspects of the process?