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CONFINED SPACE WORKING

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1 CONFINED SPACE WORKING في الجمعة 15 يناير 2010, 1:59 pm

safetyhand


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2 رد: CONFINED SPACE WORKING في الجمعة 15 يناير 2010, 2:02 pm

safetyhand


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Revised Jan 2003
CONFINED SPACE WORKING
A This section has been drawn up to indicate good practice in relation to confined
spaces.
The term 'Confined Space' has a wide application throughout industry. Some
situations are fairly obviously confined spaces e.g. closed tanks, large ducts,
sewers, deep manholes and deep chambers, but others which are less obvious
can be equally dangerous, e.g. open topped tanks (particularly where heavierthan-
air gases or vapours may be present), and closed and unventilated rooms,
in which dangerous accumulations of gases can build up because of the
restricted air circulation.
If there is any doubt whether or not a particular workplace presents the
problems of a confined space, atmosphere testing must be carried out to
determine what are the hazards, if any.
PERSONS WORKING IN CONFINED SPACES MUST BE TRAINED SEE
SECTION N to U.
HAZARDS
TOXIC AND FLAMMABLE ATMOSPHERE
B The following are examples:-
1. Manholes and Sewers have problems regarding toxic and flammable
gases e.g. Hydrogen Sulphide, a toxic gas which is produced as a by
product of organics breaking down in sewage. Methane, a highly
flammable gas also produced as a by-product of organics breaking down
in sewage.
2. The space itself (e.g. leaded petrol tanks)
3. Earlier process (e.g. degreasing, in which case a residue of
trichloroethylene solvent in the tank could emit fumes when the sludge is
cleaned off).
4. Previous contents: special care is needed where confined spaces such as
tanks have previously contained flammable, explosive or toxic materials,
and where the work being done could create vapour from the remains of
the previous contents. This particularly refers to hot work (e.g. cutting
and welding) and also to the use of solvents, since 'empty' containers
invariably contain sufficient residue to create a hazard in such
circumstances. It is therefore essential to know the previous contents so
that the planned precautions are appropriate for the particular substance.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
5. Adjoining plant: gas or vapour may enter the confined space from
adjoining plant if it has not been effectively isolated. To prevent exhaust
fumes from entering a confined space and causing a hazard, vehicles
should not be sited near the entrance.
6. Nearby undertakings: where any deep narrow excavation (e.g. borehole)
is adjacent to spoil heaps,sewage works, gas works, old drainage
systems,chemical works or refineries there is the danger of seepage
into the confined space. Air testing must be carried out before entering
manhole or chamber.
7. An atmosphere which is not fit to breathe may exist at the bottom of a
hole from stagnant water or from the subsoil itself; the passage of water
through chalk, for instance, can release carbon dioxide.
OXYGEN DEFICIENCY
C Without any poisonous gas being present the atmosphere may become lethal
through depletion of oxygen.
D The person working in an oxygen-deficient atmosphere may not be aware that
he is in danger, consequently symptoms such as breathlessness, faintness, lack
of physical co-ordination, should lead to immediate evacuation, since
unconsciousness can follow rapidly and unexpectedly.
Several different situations can lead to an oxygen-deficient atmosphere:
1. After purging with gas i.e. carbon dioxide or nitrogen.
2. Rusting process where a steel vessel has been closed for some
considerable time.
3. Contaminated soil.
4. Decay of organic matter; oxygen deficiency can result (for example in
sewers or excavations in contaminated soil) from the absorption or
biochemical depletion of the available oxygen by organic matter.
OXYGEN ENRICHMENT
E The opposite condition, an oxygen-enriched atmosphere, can be equally
dangerous. With an excess of oxygen in the air some substances become liable
to spontaneous combustion. Grease and oil, for instance, may self-ignite, and
also paint, plastics, textiles, paper and wood.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
F The atmosphere can accidentally become too rich in oxygen as a result of work
which releases extra oxygen into the air, for instance oxy-propane cutting.
It is dangerous to purge with oxygen instead of air, and in no circumstances
should oxygen be introduced into a confined space to 'sweeten' the air or to
provide ventilation. A leak of liquid oxygen or oxygen gas must be treated as a
serious matter.
WARNING
NO smoking is permitted in a confined space.
NO naked lights are permitted in a confined space.
Materials/substances which give off vapours should be subject to special
arrangements.
NO internal combustion engine is permitted in a confined space.
SAFETY EQUIPMENT/PROTECTIVE CLOTHING
G The following is a list of equipment and clothing which must be available and
used where appropriate:-
1. Safety Helmet
2. Protective Overalls
3. Safety Footwear
4. Gloves
5. Safety Lamp (intrinsically safe) i.e. no source of ignition given
6. Atmosphere monitor which detects - hydrogen sulphide, flammable
gasses and lack of oxygen
7. First Aid Equipment
8. Manriding Winch and Tripod
9. Full Safety Harness
10. Life Line
11. Resuscitator
This list is not exhaustive and may be added to.
All equipment must be in good condition and inspected in accordance with the
Manufacturers instructions, by trained personnel.
All equipment should be regularly maintained and test certificates should be
available for those items which are covered by Statutory Regulations.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
H ENTRY INTO DEEP MANHOLES
Obtain permit to enter.
Open manhole.
Lower in gas monitor.
Watch and listen to gas monitor for 5 minutes.
Ventilate by opening manholes either side of manhole chamber to be entered.
Ensure all open manholes are protected with barriers.
Check and erect safety equipment over manhole.
1) TRIPOD AND RESCUE HOIST
2) SAFETY HARNESSES
3) SAFETY LINES
Dress in personal protective equipment.
1) SAFETY HELMET
2) PROTECTIVE OVERALLS
3) SAFETY FOOTWEAR
4) GLOVES
5) SAFETY HARNESS
6) SAFETY LAMP (BASEEFA APPROVED)
H
Entry procedure into manhole chamber only.
No entry is to be made if gas monitor is alarming.
The minimum number of men required to enter a manhole or chamber is two.
One Topman and one to enter.
Each man entering chamber will be fully dressed in the above equipment and
attached to a separate safety line .
The topman will attach the rescue hoist to the harness of the man entering the
chamber.
The topman controls the cable of the rescue hoist while man descends.
The rescue hoist cable must not be detached under any circumstances.
The topman is to have no other duties than care of the man in chamber.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
Whilst in the chamber the gas monitor will remain with the man.
If the gas monitor alarms or the man appears to be distressed or he fails to
communicate he is to be hoisted to the surface immediately.
TRAVELLING UNDERGROUND BETWEEN MANHOLES
I Additional equipment required.
Escape breathing apparatus or rescue breathing equipment. Gas Monitor.
Minimum number of men three.
1 Topman
1 man at bottom of manhole chamber
1 man travelling underground
PROCEDURE FOR VISUAL INSPECTIONS.
J All operatives travelling underground between manholes will additionally wear
escape breathing apparatus.
Topman will remain at the top of the manhole chamber in control of the operation
and the winch.
The man at the bottom of the manhole chamber will keep visual and voice
communication with the man travelling underground. He will remain in sight of
the topman at all times and have a gas monitor.
The man travelling between manholes underground will wear escape breathing
apparatus, be attached to a lifeline and carry a gas monitor. He will remain in
sight of the man at the base of the entry chamber and maintain voice
communication.
Where the man at the base of manhole will lose sight of the travelling man a man
is to be placed in an intermediate position where he can see both the travelling
man and the man in the manhole chamber and maintain communication with
both.
The intermediate man will be equipped with escape breathing apparatus and be
attached to a safety line.
If either of the gas monitors alarm the travelling man will return to the manhole
chamber and both men will leave the manhole chamber.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
No further entry is to be made until the chamber has been ventilated and is safe
to enter.
Work will not be undertaken using escape breathing apparatus under any
circumstances.
EMERGENCY PROCEDURE/RESCUE
K Whilst training will address the issue of rescue this is a matter which must be
treated with caution. In particular operatives must
never attempt lone rescue of a
colleague.
CLASS A
1. Top man to summon assistance.
2. Test is atmosphere safe for entry.
CLASS B
1. Top man to summon assistance.
2. Where the operative is in a position to be hoisted out by his safety line,
this should be done immediately. If this is not possible the following
applies.
3. Test if atmosphere is safe for entry.
4. If atmosphere is safe and the operative is in no further danger he should
be left until specialist help is available. First aid, if appropriate, should be
given.
Permit to work
L To ensure the safety of persons working in a confined space it is essential to
operate a permit to work system for classes B and C.
Personnel Selection
M Persons who will be expected to work in confined spaces must be physically and
mentally suitable. It is recommended that persons employed for such work are
over 18 years and preferably under 50 years of age
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
No-one with any of the following disabilities should work in confined spaces.
1. A history of fits, blackouts or fainting attacks.
2. A history of heart disease or heart disorders.
3. Asthma, bronchitis or shortness of breath on exertion.
4. Deafness.
5. Epilepsy.
6. Any other known disability which prevents normal duties.
Training
N Work in confined spaces must only be undertaken by employees who have been
properly trained for the job. This is to be done by the Safety Manager or other
competent person but with the agreement of the Safety Manager.
Training must be planned specifically for all those involved in confined space
work.
O The precise form of the training and instruction must depend on the individual
operations, but in addition to any specialised training for particular tasks, general
training for work in confined spaces should include:
1. Observance of the safe system or work.
2. Instruction on the suitable types of breathing apparatus, and practice in
the use, care and maintenance.
3. Instruction in the use of atmosphere testing equipment.
4. Training in the procedures for rescue, including the correct use and
maintenance of rescue equipment and resuscitation equipment.
5. Instruction in first aid, treatment of shock, resuscitation.
6. Practice drills before work commences, to familiarise all concerned in
their tasks and duties.
Instruction in the use and maintenance of equipment can often be given by the
manufacturer.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
P Practice drills are an essential part of training - theoretical knowledge is not
enough to ensure that the right action will be taken in a real emergency. The
use of breathing apparatus especially should be practised regularly also the
procedures for emergency evacuations.
Q It is important that employees should learn to recognise situations requiring the
use of respiratory protective equipment and be able to identify the appropriate
atmosphere testing equipment.
R Refresher courses should be given as necessary on a regular basis. It is
important that a full and up-to-date record should be kept of the type of training
given to each individual.
Access & Egress
S The minimum size of an entrance to a confined space is:-
1. Rectangular or oval opening 458mm x 407mm.
2. Circular openings 458mm diameter. In the case of tank wagons and
other mobile plant the minimum sizes
3. Rectangular 407mm x 356mm.
4. Circular openings 407mm in diameter.
T Consideration must be given to the size of the access when formulating a Safe
System of Work i.e. sufficient clearance to give free passage to a person
wearing breathing apparatus or similar rescue gear taking account of
obstructions such as hooped ladders and shafts.
Should entry into the confined space be sited in the roadway the Supervisor is
responsible for ensuring that proper road-signing has been effected before work
etc commences. Reference
MUST be made to The Department of Transport
Traffic Signs Manual 1991. Chapter 8 - Traffic Safety Measures for Roadworks.
Adequate road signs, warning cones and night lights
MUST be provided for all
work carried out in sewers, etc., where road users and pedestrians may be at
risk from open manholes or other openings.
Vehicles should be parked in the lane of travel with the amber light flashing
(where fitted).
Man-holes
MUST be provided with barriers, so as to protect members of the
public and vehicles using the highway.
Revised Jan 2003
CONFINED SPACE WORKING (cont.)
Hygiene
U All equipment must be cleaned, dried, checked over and adjusted for future use.
Any defects or unusual conditions, including the presence or signs of vermin,
must be reported to the Supervisor.
A high standard of personal hygiene is necessary when carrying out any sewage
related work. Barrier creams should be used before entering sewers and
thorough washing of face, hands and forearms is necessary after work. All cuts
should be kept clean and covered with water-proof dressings.
Extra caution is necessary to ensure that operatives do not receive puncture
wounds from syringes or the like in sewage. Any such injuries should receive
medical attention.
Bacterial Infection - 'Weil's Disease', a type of jaundice is always a possibility in
situation where rats may inhabit sewers or other water courses etc. The
infection is caused by bacteria from rat's urine entering through cuts and
abrasions in the skin. Any feeling of influenza with a headache should receive
attention from a doctor, who should be informed of the type of work being carried
out by the operative. All operatives required to work in sewers or areas infested
by rats should be issued with advice card about Weil's Disease.
Note:
In sewers a sudden rise in water level caused by rainfall can result in a
hazardous situation arising, and will require immediate action to minimise any
danger.
For additional information reference may be made to:-

Health and Safety Executive Guidance Note GS5, Entry into Confined Spaces.

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