Thursday 21 May 2015

Permit to work system

Permit to Work systems are widely used throughout the petroleum industry. The permit is essentially a document which describes the work to be done and the precautions to be taken in doing it, and which sets out all the necessary safety procedures and equipment.

For operations in hazardous and dangerous areas, permits should normally be used for tasks such as:

- Hot Work.
- Work with a spark potential.
- Work on electrical equipment.
- Diving operations.
- Heavy lifts.
- Enclosed space entry.
- Cold work
- Working aloft
- Working on pressurized vessel
- Working over side
- Other hazardous tasks
The permit should specify clearly the particular item of equipment or area involved, the extent of work permitted, the conditions to be met and the precautions to be taken and the time and duration of validity. The latter should not normally exceed a working day. At least two copies of the permit should be made, one for the issuer and one for the person at the work site.

The layout of the permit should include a check-list to provide both the issuer and the user with a methodical procedure to check that it is safe for work to begin and to stipulate all the necessary conditions. If any of the conditions cannot be met, the permit should not be issued until remedial measures have been taken.

It is advisable to have distinctive Permit to Work systems for different hazards. The number of permits required will vary with the complexity of the planned activity. Care must be taken not to issue a permit for subsequent work that negates the safety conditions of an earlier permit. For example, a permit should not be issued to break a flange adjacent to an area where a Hot Work permit is in force.

Before issuing a permit, the Terminal Representative must be satisfied that the conditions at the site, or of the equipment to be worked on, are safe for the work to be performed, taking due account of the presence of any ships that will be alongside while the work is being carried out.

While companies will develop their own procedures for managing all aspects of operations and tasks undertaken, many operators choose to incorporate a Permit to Work system into their SMS in order to manage hazardous tasks.
A Permit to Work system is a formal written system that is used to control certain types of work. It delivers a risk based approach to safety management and requires personnel to undertake and record risk assessments in the development of a safe system of work.

Guidance for establishing a Permit to Work system is contained in a number of publications issued by industry organizations and various international safety bodies.

Copies of all permits should be posted as may be necessary. Copies should also be retained by the person in charge of the operation. If any repairs are to be carried out concurrent with cargo handling operations, specific permission should be granted by the terminal operators. Whenever practicable, a drill should be held prior to commencing repair work. Subsequent drills should be arranged when the repairs are to be carried out over an extended period. A dedicated Safety Officer should be appointed by the Master to co-ordinate the permit and certification processes associated with the repair period.

Safeguards for Enclosed Space Entry

Before allowing access to the space, the Responsible Officer should ensure that:

- Appropriate atmosphere checks have been carried out.
- Piping, inert gas and ventilation systems have been isolated.
- Effective ventilation will be maintained continuously while the enclosed space is occupied.
- Fixed lighting, such as air-turbo lights are ready for extended entry periods.
- Approved self-contained, positive pressure breathing apparatus and resuscitation equipment is ready for use at the entrance to the space.
- A rescue harness, complete with lifeline, is ready for immediate use at the entrance to the space.
- A fully charged approved safety torch is ready for immediate use at the entrance to the space.
- A responsible member of the crew is in constant attendance outside the enclosed space, in the immediate vicinity of the entrance and in direct contact with the Responsible Officer.
- All persons involved in the operation should be trained in the actions to be taken in the event of an emergency.
- Lines of communications have been clearly established and are understood
by all concerned.
- Names and times of entry will be recorded and monitored by personnel outside the space.

The personnel undertaking the task should ensure that such safeguards are put into effect prior to entering the space. The same precautions apply as for entering cargo tanks. Toxic gas must be suspected to be present in spaces into which volatile petroleum may have leaked.

Pump Room Entry

Measures to minimize pump room hazards.

Ventilation must be switched on at least 30 minutes. Prior pump room entry.
Before starting any cargo operation:
1. An inspection should be made to ensure that strainer covers, inspection plates and drain plugs are in position and secure.
2. Drain valves in the pump-room cargo system, especially those on cargo oil pumps, should be firmly closed.
3. Any bulkhead glands should be checked and adjusted or lubricated, as necessary, to ensure an efficient gas-tight seal between the pump-room and the machinery space.
4. During all cargo operations, including loading:
5. The pump-room should be inspected at regular intervals to check for leakages from glands, drain plugs and drain valves, especially those fitted to the cargo pumps.
6. If the pumps are in use, pump glands, bearings and the bulkhead glands (if fitted) should be checked for overheating. In the event of leakage or overheating, the pump should be stopped.
7. No attempt should be made to adjust the pump glands on rotating shafts while the pump is in service.

Formal procedures should be in place to control pump-room entry. The procedure used should be based on a risk assessment, and should ensure that risk mitigation measures are followed and that entries into the space are recorded.

A communications system should provide links between the pump-room, Navigation Bridge, engine room and cargo control room. In addition, audible and visual repeaters for essential alarm systems, such as the general alarm and the fixed extinguishing system alarm, should be provided within the pump-room.

Arrangements should be established to enable effective communication to be maintained at all times between personnel within the pump-room and those outside. Regular communication checks should be made a pre-agreed intervals and failure to respond should be cause to raise the alarm.

VHF/UHF communication should not be used as a primary communication method where it is known that reception may not be reliable or practicable due to noise. Where communication by VHF/UHF is difficult, it is recommended that a standby person is positioned on the pump-room top and that a visual and remote communication procedure is put in place.

The frequency of pump-room entry for routine inspection purposes during cargo operations should be reviewed with a view to minimizing personnel exposure.

Notices should be displayed at the pump-room entrance prohibiting entry without formal permission.

Enclosed Space Entry

Precautions to be taken when entering enclosed spaces, including correct use of different types of breathing apparatus.

Before allowing access to the space, the Responsible Officer should ensure that:

1. Appropriate atmosphere checks have been carried out.
2. Piping, inert gas and ventilation systems have been isolated.
3. Effective ventilation will be maintained continuously while the enclosed space is occupied.
4. Fixed lighting, such as air-turbo lights, are ready for extended entry periods.
5. Approved self-contained, positive pressure breathing apparatus and resuscitation equipment is ready for use at the entrance to the space.
6. A rescue harness, complete with lifeline, is ready for immediate use at the entrance to the space.
7. A fully charged approved safety torch is ready for immediate use at the entrance to the space.
8. A responsible member of the crew is in constant attendance outside the enclosed space, in the immediate vicinity of the entrance and in direct contact with the Responsible Officer.
9. All persons involved in the operation should be trained in the actions to be taken in the event of an emergency.
10. Lines of communications have been clearly established and are understood by all concerned.
11. Names and times of entry will be recorded and monitored by personnel outside the space.
12. The personnel undertaking the task should ensure that such safeguards are put into effect prior to entering the space.
13. Self-Contained Breathing Apparatus (SCBA) This consists of a portable supply of compressed air contained in a cylinder or cylinders attached to a carrying frame and harness worn by the user. Air is provided to the user through a face mask, which can be adjusted to give an airtight fit. A pressure gauge indicates the pressure in the cylinder and an audible alarm sounds when the supply is running low. Only positive pressure type sets are recommended for use in enclosed spaces because, as their name implies, these maintain a positive pressure within the face mask at all times.
14. Airline breathing apparatus enables compressed air equipment to be used for longer periods than would be possible using self-contained equipment.

Wednesday 20 May 2015

Deck Water Seal

The deck water seal is the principal barrier; a water seal is fitted that permits inert gas to be delivered to the deck main but prevents any backflow of cargo gas, even when the inert gas plant is shut down; it is vital that a supply of water is maintained to the seal at all times, particularly when the inert gas plant is shut down; in addition, drains should lead directly overboard and not pass through the machinery spaces; one of three principal types of design may be adopted.

Types of Deck Water Seal:

Wet type
This is the simplest type of water seal; when the inert gas plant is operating, the gas bubbles through the water from the submerged inert gas inlet pipe, but if the tank pressure exceeds the pressure in the inert gas inlet line, the water is pressed up into this inlet pipe, thus preventing backflow; the drawback to this type of water seal is that water droplets may be carried over with the inert gas, which, although not impairing the quality of the inert gas, could increase corrosion; a demister should, therefore, be fitted in the gas outlet from the water seal to reduce any carry-over.

Semi-dry type
Instead of bubbling through the water trap, the inert gas flow draws the sealing water into a separate holding chamber by venturi action, thus avoiding or at least reducing the amount of water being carried over; otherwise this seal is functionally the same as the wet type.

Dry type
In this type, the water is drained when the inert gas plant is in operation (gas flowing to the tanks), and filled with water when the inert gas plant is either shut down or the tank pressure exceeds the inert gas blower discharge pressure; filling and drainage are performed by automatically operated valves controlled by the levels of the water seal and drop tanks and by the operation of the blowers; the advantage of this type is that it prevents water carry-over; the drawback could be the risk of failure of the automatically controlled valves that may render the water seal ineffective.