CMC Cargo Tank Cleaning Procedures & Residue Management 2

Question 1

When determining a tank cleaning procedure for a chemical tanker, which document serves as the primary operational reference for cargo-specific cleaning requirements and compatibility?

Accepted Answer

The Chemical Data Guide or the tanker company's proprietary tank cleaning guide

Answer

The vessel's ISM Safety Management System manual

Answer

MARPOL Convention Annex II alone

Answer

OSHA 29 CFR 1910.146 confined space standard

Question 2

Why is a cargo's miscibility with water an important consideration in planning tank cleaning operations?

Accepted Answer

It determines whether water washing is effective or if alternative solvents are needed first

Answer

It determines the required pump capacity for final cargo discharge

Answer

It determines the cargo's flash point and fire hazard classification

Answer

It determines the required ventilation rate during gas-freeing

Question 3

During hot-water tank washing operations, what is the primary atmospheric hazard that increases compared to cold-water washing?

Accepted Answer

Enhanced volatilization of cargo residues, potentially intensifying flammable or toxic vapor generation

Answer

Increased corrosion rate of tank coatings, releasing toxic decomposition products

Answer

Excessive water pressure causing structural fatigue and metal particle release

Answer

Crystallization of dissolved salts creating a conductive dust hazard

Question 4

What is 'wall wash testing' used for in chemical tanker operations?

Accepted Answer

Verifying that a tank has been adequately cleaned so the next cargo will not be contaminated

Answer

Testing the structural integrity and thickness of tank walls under hydrostatic pressure

Answer

Measuring the remaining thickness of anti-corrosion tank coating

Answer

Checking for crevice corrosion on tank internals before loading a corrosive cargo

Question 5

Which agency enforces MARPOL Annex II cargo tank cleaning and discharge requirements for chemical tankers operating in United States waters?

Accepted Answer

The United States Coast Guard (USCG)

Answer

The Environmental Protection Agency (EPA) under RCRA authority

Answer

The Occupational Safety and Health Administration (OSHA)

Answer

The National Transportation Safety Board (NTSB)

Question 6

What is the Marine Chemist's specific role with respect to cargo tank residue conditions before personnel may enter for cleaning?

Accepted Answer

To test the tank atmosphere and issue certification that conditions are safe for personnel entry

Answer

To determine the residue volume and update the cargo manifest accordingly

Answer

To calculate the financial liability for cargo loss attributable to residue

Answer

To approve the tank cleaning program and select the washing agent

Question 7

When a tank survey reveals that residue from a previous cargo is chemically reactive with the intended next cargo, what is the required course of action?

Accepted Answer

Perform additional cleaning until the tank is certified free of reactive residue

Answer

Load the new cargo immediately to dilute and neutralize the reactive residue

Answer

Permanently condemn the tank and notify the classification society

Answer

Apply a chemical inhibitor to the residue and seal the tank for later treatment