Page 47 - International safety guide for oil tankers and terminals

HAZARDS OF PETROLEUM

Exposure to concentrations in excess of 1,000 ppm can lead to
unconsciousness and even death. Benzene can also be absorbed
---ใช้เพื่อการศึกษาเท่านั้น---
through the skin and is toxic if ingested.

Practical guidance on measures that can be taken to minimise the risks
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
associated with loading cargoes containing benzene is given in Section
11.1.10.

Exposure Limits
IMO gives the TLV-TWA for benzene as 1 ppm over a period of eight
hours. However, working procedures should aim at ensuring the lowest
possible gas concentrations are achieved in work locations.

Personal Protective Equipment (PPE)
Personnel should be required to wear respiratory protective equipment
under the following circumstances:

Whenever they are at risk of being exposed to benzene vapours in
excess of the TLV-TWA.

When TLV-TWAs specified by national or international authorities are
likely to be exceeded.
When monitoring cannot be carried out.

When closed operations cannot be conducted for any reason.
ึ
The respiratory protective equipment to be worn at any given time should
be determined by the ship operator, but should not fall below that required
in the IMO standards. The need to use respiratory protective equipment
may be extended, by local regulations or by Company procedures, to
personnel not directly involved in cargo operations. (See also
Chapter 10.)

Ship operators should be aware that gas measuring equipment on board
tankers will only provide spot readings and that personnel may experience
concentrations of vapour in excess of the reading obtained. Careful
consideration should therefore be given to the type of respiratory
protective equipment employed for specific tasks.

Records should be kept by ship operators of all employees who are
engaged in the handling of cargoes containing benzene. Personnel
performing operations such as cargo gauging and sampling, or
disconnection of cargo hoses after transfer, should be made aware of the
benzene content.

Tank Entry
Prior to entry into a tank that has recently carried petroleum products
containing benzene, the tank should be tested for benzene
concentrations. This is in addition to the requirements for enclosed space
entry detailed in Chapter 10.

2.3.6 Hydrogen Sulphide (H S)
2
Hydrogen Sulphide (H 2 S) is a very toxic, corrosive and flammable gas. It has a
very low odour threshold and a distinctive odour of rotten eggs. H 2 S is
colourless, is heavier than air, has a relative vapour density of 1.189, and is
soluble in water.

© ICS/OCIMF/IAPH 2006 13