Chemical Tankers / Day 1 / Day 1 Topic 6 Static Electricity

6.3 List of static accumulative cargoes

•Motor and Aviation Gasolines

•Jet Fuels

•Naphthas

•Heating Oils

•Heavy Gas Oils

•Clean Diesel Oils

•Lubricating Oils

6.3 List of static accumulative cargoes

Annex II

List of Oil-like substances:

6.3 List of static accumulative cargoes

Both cargo lists should not be assumed as comprehensive;

If you are in doubt as to how to treat a cargo, treat it as a static accumulator & take all necessary precautions;

6.3 List of static accumulative cargoes

Semi-conductive Materials:

The liquids that have conductivities exceeding 50 pS/m and, along with conductive liquids, are often known as static non-accumulators.

For example:

•Black oils;

•Crude Oils;

Their conductivities in the range of 10,000-100,000 pS/m

(pico Siemens/metre).

6.3 List of static accumulative cargoes

Semi-conductive Materials:

The solids in this intermediate category generally include:

•Wood;

•Cork;

•Sisal;

•Naturally occurring organic substances;

They become more conductive as their surfaces are contaminated by moisture and dirt. However, after cleaning and drying, their conductivity can be sufficiently low to bring them back into the Non-conductive range.

6.3 List of static accumulative cargoes

Conductive Materials:

In the case of solids, these are

• Metals;

In the case of liquids

•Fresh Water;

•Sea water;

•Many Alcohols;

•Human body consisting of about 60% water;

6.4 High Risk Areas / Ops and Equipment

Tank Cleaning Operations;

Loading static accumulator cargoes;

Cold and dry weather conditions (conducive to static build-up);

Portable Equipment such as tank cleaning hoses and ventilators;

6.5 Elimination of static electricity

Before cargo operations commencement.

Static accumulator oils may be electro-statically charged by pipe flow.

In order to prevent the accumulation of a dangerous voltage, all metal flanges and parts must be effectively bonded to maintain electrical continuity to earth through the shore or the ship’s hull.

Generally the bonding of metal reinforcement in the hoses to their flanges will ensure this.

6.5 Elimination of static electricity

Before cargo operations commencement.

When ship hoses are to be used for cargo transfer, the Chief Officer is

to ensure that electrical bonding is checked prior to commencing

operations.

6.5 Elimination of static electricity

Before cargo operations commencement.

Connection to the ship and subsequent disconnection may not take place unless:

•All ullage ports are securely closed and no sampling, sounding or dipping of tanks is in progress;

•No cargo, tank cleaning or gas freeing operations are in progress;