Chemical cargo closed unloading safety procedure for chemical tankers
Chemical cargo closed unloading means discharging with securely closed ullage, sounding and sighting
ports. Additionally the venting must be controlled. For gauging e.g. ullaging, sounding closed
devices must be used. The level alarm systems must be operated during the entire closed
cargo operation.
Closed cargo operations must be stopped as soon as any essential system for safe loading or discharging becomes inoperative. Sampling will be closed by sampler where possible.
Closed cargo operations must be stopped as soon as any essential system for safe loading or discharging becomes inoperative. Sampling will be closed by sampler where possible.
Vessels equipped with a system such as Skarpenord (pressure gauges in the tanks) or radar
ullage systems shall at all times carry out closed unloading procedures for all cargoes except
when cargo system is defective and approved by Management Office and agreed by Terminal.
The Master has overall responsibility for compliance with closed unloading procedures. Closed loading has to be carried out as a requirement of the:
Gauging, sounding and sampling
A closed gauging device penetrates the cargo tank, but is part of a closed system and prevents the cargo or its vapour being released. Examples are the float-type systems, radar systems, electronic probe, magnetic probe and protected sight-glass.
For sampling and sounding the Dovianus or Hermetic portable gauging and sampling systems may be used. It is important that sufficient of these devices are carried onboard and maintained in a fully operational and certified calibrated condition.
Vapour locks, where fitted, are to be calibrated and certified by a recognised cargo inspection company which will also approve the datum level corrections including list and trim corrections for tank volumes. The approval certificate is to be readily available during cargo surveys.
Cargo tank venting
Controlled venting must be established if closed cargo operations are required. A controlled tank venting system is a system with pressure and vacuum-relief valves (P/V valve) fitted on each tank in order to limit the pressure or vacuum in the tank. The P/V valve should operate in such a manner that neither pressure nor vacuum is created in the cargo tank during cargo operations that exceed the tank design parameters.
Continuously monitor the secondary venting system onboard to prevent damage from under pressurization.
Vapour return
Vapour return should be used in accordance with local, terminal or customer’s requirements. VECS manual to be complied with. Vapour returned to be used as per IBC code.
Customers’ requirements
Specific closed cargo operations may be required by the customer under the Charter Party or Contract of Affreightment (COA). The management office will inform the Master when such requirements exit.
Reference publications
Related Info:
Preparation for chemical cargo loading
Voyage planning and related considerations
Cargo sampling safety precautions
Preparing a cargo tank atmosphere
Cargo unloading operation safety precautions
Liaison between ship and shore
Cargo care during transit
Ship shore safety checklist while alongside a terminal
Cargo calculation
Signing a bill of lading and related guideline
Preparation for cargo operation
Cargo line leakage countermeasures
Checklist for handling dangerous liquid chemicals in bulk
Recommended temperature monitoring equipments onboard
Practical example of solving tank cleaning problems
Pre-cleaning /washing of cargo tanks
Risk & hazards of chemical contamination onboard
Cargo compatibility and reactivity of various chemical cargo
Poisoning and required first aid treatment onboard
Chemical tanker safe mooring practice
Determining presence of contaminants in chemical cargo
Handling various grade liquid chemicals during loading
How to prepare a cargo loading or discharge program ?
How to avoid solidification in cargo tanks ?
Cargo segregation requirement for chemical tankers
How to arrange disposal of tank cleaning waste ?
Restrictions on discharge cargo residue into sea
Retention of slops on chemical tankers
Vapour emission control requirement for chemical tankers
Handling self reactive chemicals
Handling of toxic chemical cargoes
Pre-loading meeting safety consideration
How to determine chemical cargo temperatures at different level ?
How to take cargo samples ?
How to avoid solidification in cargo tanks ?
Cargo line clearance requirement for chemical tankers
How to arrange disposal of tank cleaning waste ?
Care of cargo pums - risk of pump overload or underload
Main Info pages!
Home page ||| Chemical hazards ||| Cargo planning & Stowage ||| Cargo loading ||| Cargo documents ||| Safe stability ||| Cargo care ||| Preparation for unloading ||| Inert gas systems |||Gas freeing ||| Nitrogen handling ||| Chemical handling Safe practice |||Handling equipments ||| Cargo & Ballast pumps ||| Cargo tanks |||Tank cleaning |||Special cargoes |||Spills emergencies |||Fire protection
Chemicaltankerguide.com is merely an informational site about various aspects of chemical tankers and safety tips that may be particular value to those working in: Chemical Handling, Chemical Storage, Liquefied Chemical Suppliers, Chemical Shipping, Chemical Transportation, Chemical Terminals, Bulk Chemical Services and Chemical Processing. If you are interested in finding out more about chemical tanker guideline please visit IMO official website. For any comment please Contact us
Copyright © 2011 Chemical Tanker Guide.com All rights reserved.
The Master has overall responsibility for compliance with closed unloading procedures. Closed loading has to be carried out as a requirement of the:
- IBC/BCH Code. The IBC-code does not use the term ‘closed unloading’ explicitly but mentions controlled venting and open/restricted/closed gauging.
- Company procedure
- Contractual obligations
- Port/ National requirements
Gauging, sounding and sampling
A closed gauging device penetrates the cargo tank, but is part of a closed system and prevents the cargo or its vapour being released. Examples are the float-type systems, radar systems, electronic probe, magnetic probe and protected sight-glass.
For sampling and sounding the Dovianus or Hermetic portable gauging and sampling systems may be used. It is important that sufficient of these devices are carried onboard and maintained in a fully operational and certified calibrated condition.
Vapour locks, where fitted, are to be calibrated and certified by a recognised cargo inspection company which will also approve the datum level corrections including list and trim corrections for tank volumes. The approval certificate is to be readily available during cargo surveys.
Cargo tank venting
Controlled venting must be established if closed cargo operations are required. A controlled tank venting system is a system with pressure and vacuum-relief valves (P/V valve) fitted on each tank in order to limit the pressure or vacuum in the tank. The P/V valve should operate in such a manner that neither pressure nor vacuum is created in the cargo tank during cargo operations that exceed the tank design parameters.
Continuously monitor the secondary venting system onboard to prevent damage from under pressurization.
Vapour return
Vapour return should be used in accordance with local, terminal or customer’s requirements. VECS manual to be complied with. Vapour returned to be used as per IBC code.
Customers’ requirements
Specific closed cargo operations may be required by the customer under the Charter Party or Contract of Affreightment (COA). The management office will inform the Master when such requirements exit.
Reference publications
- IBC Code / BCH code
- International Safety Guide for Oil Tankers and Terminals (ISGOTT)
- ICS Chemical Tanker Safety Guide
- Ship’s “Procedure and Arrangements Manual” (Approved by Class)
- Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk
- Ship’s “VEC System Operational Manual” (Approved by Class)
- Ship to Ship Transfer Guide (Petroleum)
- Tank Cleaning Manual
Related Info:
Preparation for chemical cargo loading
Voyage planning and related considerations
Cargo sampling safety precautions
Preparing a cargo tank atmosphere
Cargo unloading operation safety precautions
Liaison between ship and shore
Cargo care during transit
Ship shore safety checklist while alongside a terminal
Cargo calculation
Signing a bill of lading and related guideline
Preparation for cargo operation
Cargo line leakage countermeasures
Checklist for handling dangerous liquid chemicals in bulk
Recommended temperature monitoring equipments onboard
Practical example of solving tank cleaning problems
Pre-cleaning /washing of cargo tanks
Risk & hazards of chemical contamination onboard
Cargo compatibility and reactivity of various chemical cargo
Poisoning and required first aid treatment onboard
Chemical tanker safe mooring practice
Determining presence of contaminants in chemical cargo
Handling various grade liquid chemicals during loading
How to prepare a cargo loading or discharge program ?
How to avoid solidification in cargo tanks ?
Cargo segregation requirement for chemical tankers
How to arrange disposal of tank cleaning waste ?
Restrictions on discharge cargo residue into sea
Retention of slops on chemical tankers
Vapour emission control requirement for chemical tankers
Handling self reactive chemicals
Handling of toxic chemical cargoes
Pre-loading meeting safety consideration
How to determine chemical cargo temperatures at different level ?
How to take cargo samples ?
How to avoid solidification in cargo tanks ?
Cargo line clearance requirement for chemical tankers
How to arrange disposal of tank cleaning waste ?
Care of cargo pums - risk of pump overload or underload
Main Info pages!
Home page ||| Chemical hazards ||| Cargo planning & Stowage ||| Cargo loading ||| Cargo documents ||| Safe stability ||| Cargo care ||| Preparation for unloading ||| Inert gas systems |||Gas freeing ||| Nitrogen handling ||| Chemical handling Safe practice |||Handling equipments ||| Cargo & Ballast pumps ||| Cargo tanks |||Tank cleaning |||Special cargoes |||Spills emergencies |||Fire protection
Chemicaltankerguide.com is merely an informational site about various aspects of chemical tankers and safety tips that may be particular value to those working in: Chemical Handling, Chemical Storage, Liquefied Chemical Suppliers, Chemical Shipping, Chemical Transportation, Chemical Terminals, Bulk Chemical Services and Chemical Processing. If you are interested in finding out more about chemical tanker guideline please visit IMO official website. For any comment please Contact us
Copyright © 2011 Chemical Tanker Guide.com All rights reserved.