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Respiratory Protective Equipment Used For Enclose or Confined Space entry

A number of different types of respiratory protective equipment are
available for use on board ship. Some respiratory protective equipment is required to be carried to meet the fire safety provisions of SOLAS.
However, under the provisions of the ISM Code, the shipowner is responsible for providing the level of equipment needed to safely manage all aspects of shipboard operational and safety activities. Respiratory protective equipment necessary to meet these provisions will, in most cases, exceed the minimum requirements under SOLAS.

1. 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 enclose or confined spaces as these, as
their name implies, maintain a positive pressure within the face mask at all times.
When using the equipment, the following should be noted:
  • The pressure gauge must be checked before use.
  • The operation of the audible low pressure alarm should be tested before use.
  • The face mask must be checked and adjusted to ensure that it is airtight.
  • In this regard, the presence of any facial hair may adversely affect the mask’s seal and, should this be the case, another person should be selected to wear the apparatus.
  • The pressure gauge should be monitored frequently during use to check on remaining air supply.
  •  Ample time should be allowed for getting out of the hazardous atmosphere. In any event, the user must leave immediately if the low pressure alarm sounds. It should be remembered that the duration of the air supply depends on the weight and fitness of the user and the extent of his exertion.
  • If the user suspects at any time that the equipment may not be operating satisfactorily or be concerned that the integrity of the face mask seal may be damaged, he should vacate the space immediately.

2. AIR LINE BREATHING APPARATUS

Air line breathing apparatus enables compressed air equipment to be used for longer periods than would be possible using self-contained equipment. This equipment consists of a face mask which is supplied by air through a small diameter hose leading
outside the space where it is connected to either compressed air cylinders or an air line served by a compressor. If the ship’s air supply is used, it is essential that it is properly filtered and adequately monitored for toxic or hazardous constituents. The hose is attached to the user by means of a belt or other arrangement, which enables rapid disconnection in an emergency. Air to the face mask is regulated by a flow control valve or orifice. If the air supply is from a compressor, the arrangement will include an emergency supply of air cylinders for use in the event of the compressor failing. In such an emergency, the user should be signaled to vacate the space immediately. 

A trained and competent person must be in control of the air line pressure and be alert to the need to change over to the alternative supply should normal working pressure not be maintained. 

When using the air line breathing apparatus:

  • Check and ensure that the face mask is adjusted to be airtight.
  • Check the working pressure before each use.
  • Check the audible low pressure alarm before each use.
  • To avoid damage, keep the air lines clear of sharp projections.
  • Ensure that the air hose does not exceed 90 metres in length.
  • Allow ample time to vacate the space when the low pressure alarm sounds. The duration of the emergency air carried by the user will depend on an individual’s weight and fitness and each user should be aware of his particular limitations.
  • Should there be any doubt about the efficiency of the equipment, the user should vacate the space immediately. The user should carry a completely separate supply of clean air for use in emergency evacuation from the space in the event of the air line failing. It is recommended that the user should carry an Emergency Escape Breathing

3. EMERGENCY ESCAPE BREATHING DEVICE (EEBD)

This is a compressed air or oxygen breathing device used for escape from a compartment that has a hazardous atmosphere. It is primarily for use in accordance with the SOLAS requirements for escape from machinery or accommodation spaces in the event of a fire. Additional sets should be provided for use as emergency escape equipment during enclosed space entry. Each set has a duration of not less than 10 minutes. The device can be one of two types:

Compressed Air Type
These sets consist of an air bottle, reducing valve, air hose, facemask or hood and a flame retardant high visibility bag or jacket. They are normally constant flow devices providing compressed air to the wearer at a rate of approximately 40 litres per minute, giving a duration of 10 (as a minimum) or 15 minutes, depending on the capacity of the bottle.

Compressed air EEBD’s can normally be recharged onboard with a conventional SCBA compressor. The pressure gauge, supply valve and hood should be checked before use.

Re-breathing Type
These sets normally consist of a robust watertight carrying case, compressed oxygen cylinder, breathing bag, mouthpiece and a flame retardant hood.

They are designed for single use by the wearer. When the hood is placed over the user’s head and the set activated, exhaled air is mixed with compressed oxygen inside the breathing bag to allow the wearer to breath normally when escaping from a hazardous atmosphere.

EEBD should not be used for fighting fires or for entering oxygen deficient compartments. A self contained breathing apparatus, which is specifically suited for such purposes, should be used.

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