The learning objectives of this chapter are to understand that there is a
difference between routine entry into a space containing a safe and gas free
atmosphere and an extraordinary entry into a space which contains a hazardous
atmosphere to know the additional precautions that must be taken under
such conditions and to understand the arrangements of an airline system in
detail
entry into an unsafe or suspect atmosphere should not be considered an
ordinary or standard event under normal circumstances a space will be rendered
safe for unprotected entry by cleaning and ventilation there are situations
however when such conditions cannot be created or guaranteed and entry is still
required if the atmosphere is considered to be suspect for unsafe to enter then
the space should only be entered if it is essential for testing purposes that
is testing cannot be properly or adequately carried out from a remote
location for the safety of life or of the ship or for the work of the ship
under controlled conditions under such conditions breathing apparatus should
always be warm the number of persons entering the space should be the minimum
compatible with the work to be performed and necessary for any additional safety
precautions to be applied an unsafe or suspect atmosphere is a higher risk
operation and the responsible officer should maintain a higher level of
monitoring and control we have already established that there are two basic
types of breathing apparatus in use at sea the self-contained compressed air
type and the externally supplied air line type which may be connected to a
compressor or to a bank of compressed air cylinders there are particular
procedures and precautions associated with each type click on the labels for
more information on vessels using an airline system and
except in the case of an emergency or where it is impracticable because
movement in the space would be seriously impeded to air supplies should be
available while working the wearer should use the continuous primary supply
provided from outside the space in the event of an emergency the backup supply
should be engaged without delay the emergency supply is meant for evacuation
only and not the continuance of work and it will provide air for a limited period
only if the emergency supply is engaged therefore the user should immediately
cease working and exit from the space note that in some cases the user may not
realize that the supply has been changed and the watchman should therefore signal
to him to exit in determining the capacity suitable for emergency escape
Joo allowance is made for the possibility of increased demand under
stress or in difficult conditions but it must be understood that it is a limited
supply
precaution should be taken against any disruption to the air supply while the
individual is inside the enclosed space special attention should be given to
supplies originating from the engine room that is the main air supply as
opposed to a dedicated and separate supply this should be properly filtered
and continuously monitored for toxic or hazardous constituents
self-contained breathing apparatus depends on cylinders containing a finite
supply of air when the safe minimum amount of air to allow escape from the
space is reached the audible alarm sounds
at this point the user should cease working and calmly make his way to the
exit the level is preset at a safe capacity so there is no need to rush or
panic and indeed such a reaction is only likely to increase the breathing rate
and lead to slips trips and falls on hearing the audible alarm the standby
watchman should look for the user moving towards the exit and assist him once he
emerges
we're remote testing of the space is not reasonably practicable or where a brief
inspection only is required a single airline supply may be acceptable
provided the wear of the breathing apparatus is so situated that he can be
hauled out immediately in the case of an emergency
however for preference and if available a self-contained breathing operators
should be worn in such circumstances in addition to rescue harnesses wherever
practicable lifeline should be used lifelines should be attended by a person
stationed at the entrance who has been trained in how to pull an unconscious
person from a dangerous enclosed or confined space
if hoisting equipment would be required for any such rescue arrangements should
be made to ensure that personnel would be available to operate it as soon as
necessary
where appropriate portable lights and other similar equipment should be other
type approved for use in a flammable atmosphere
should there be any hazard due to chemicals whether in liquid gaseous or
vapor form coming into contact with the skin and/or eyes then protective
clothing must be worn the gas carrier happy Falcon of 3366
gross register tons arrived alongside in zebra gay Belgium early on the 10th of
January 2003 and commence preparations for inerting and gas freeing operations
the nitrogen was being supplied by Asher side contractor the ship was to load a
full cargo of propylene in her two tanks number one tank had previously been
loaded with raffinate 1 and required inerting with nitrogen 2 below the lower
explosive limit and then gas freeing the tank was then to be inspected and if
accepted by the severe purged again with nitrogen prior to loading number 2 tank
had previously contained propylene and did not require inspection or purging at
Oh 1:45 hours prior to inerting number one tank readings of the atmosphere in
the tank were taken and gas concentrations of 5.7% at the top 5.2
percent in the middle and 3.7 percent at the bottom were observed hoses were
connected at o2 Oh five hours and the tank was depressurized to shore this was
completed at oh three thirty five hours and nitrogen was started into the tank
at oh three forty hours nitrogen was being supplied into the top of the tank
with the gas vapor being expelled out through the liquid line in the bottom of
the tank and to a flare onshore
readings were taken at intervals showing a progressive drop in the gas
concentration at a 8:30 hours nitrogen was stopped and the tank dome lid was
opened in preparation for inserting the Shore ventilation hose the chief officer
third officer and an a/b were attending to this task the a beyond the jetty
the third officer pulling the hose towards the tank lid and the chief
officer guiding it into position at the lid the third officer was facing out
towards the ship's side rail as he was working and was not aware of the
activity actually taking place at the tank lid he heard a noise and turned
around but could not see the chief officer he moved towards the dome and
looked down into the tank where he saw the chief officer lying on the middle
platform of the ladder halfway down into the tank the third
officer ran into the accommodation raised the alarm shouted to the
personnel present in the mess room telephoned a bridge and made a broadcast
on the PA system before returning to the deck it was a 851 hours
the a be returned on board and prepared to enter the tank with a safety line the
shore supervisor also climbed on board and warned the a B not to enter without
breathing apparatus personnel and equipment were arriving on site however
and the a B donned a self-contained breathing apparatus and entered the tank
the shore supervisor raised the alarm on shore and call the emergency services at
approximately Oh 8 55 hours the chief officer supported by the a/b from
underneath was lifted using the safety line and manhandled out onto deck the
second officer commenced administering oxygen and it was noted that the chief
officer was still breathing at this time however a noise was heard
from inside the tank and it was found that the a B had himself fallen and was
lying on the same middle platform that the chief officer had been rescued from
an OS and the mess man now donned a breathing apparatus and entered the tank
with a safety line the a B was retrieved to deck at Oh nine hundred hours but
found not to be breathing or to have a pulse efforts continued to revive him
and hidden ambulance arrived and took both the chief officer and a B to
hospital the a B was declared dead some hours later when the life-support
machine to which he had been connected on arrival was finally switched off the
chief officer partially recovered and was repatriated to the Philippines it
has never been conclusively established whether the chief officer actually
climbed into the tank to position the ventilation hose fell into the tank from
deck or slipped and fell from a position at or near the top of the tank given the
limited size of the access hatch and the injuries he sustained the third
possibility is considered more likely
the rapid and efficient action of the third officer and the a/b undoubtedly
saved the life of the chief officer how the a became to fall is unknown but it
is believed to be either due to the facemask of the breathing apparatus
being knocked off during the removal of the chief officer or due to him slipping
during the same phase of the recovery and being overcome in the nitrogen-rich
atmosphere within the tank