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 Chemical Data Guide (e.g., Witherby's) or a tanker company's tank cleaning guide provides cargo-by-cargo cleaning sequences, compatibility matrices, and wall wash criteria.

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

Water-miscible cargoes dissolve in wash water and are effectively removed by water washing, while water-immiscible cargoes require a compatible solvent pre-flush before water washing can be effective.

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

Elevated water temperature increases the vapor pressure of cargo residues, generating more vapors and potentially creating or worsening a flammable or toxic atmosphere during washing.

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

Wall wash testing involves wiping a solvent across cleaned tank surfaces and analyzing the solution to confirm residue levels are below limits that would contaminate the next 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 USCG is the primary federal agency responsible for enforcing MARPOL requirements, including Annex II cargo tank cleaning and washings discharge rules, in US waters.

(CMC) Certified Marine Chemist Practice Test

(CMC) Certified Marine Chemist Practice Test

CMC Cargo Tank Cleaning Procedures & Residue Management 2