There is significant increase in metro tunneling, underwater piping and similar projects in India where workers are involved in a compressed air environment. These workers are exposed to health hazards if compressed air work is not managed properly. This presentation will highlight various risk factors and the approach to prevent and manage compressed air works as per the relevant prevailing guidelines.

1. 1
Technical Seminar
On
‘Occupational Health and Safety of Compressed Air Tunnel Workers’
(Coordinated by Advent Healthcare Services)
Organized by Delhi Metro Rail Corporation & Apollo Hospitals

2. 2
Context
• There is significant increase in metro tunneling, underwater piping and similar projects in India
where workers are involved in a compressed air environment. These workers are exposed to
health hazards if compressed air work is not managed properly.
• It is the collective duty of the company , contractor and the health and safety team to be familiar
and comply with work safety guidelines to ensure a productive work force and safety of their
team.
• Risk management is essential in tunnel design and construction to prevent potential for
accidents both while the tunnels are being constructed and during operation of the completed
tunnel. It is important to ensure an adequate level of safety in a cost-efficient way. This
requires a systematic approach to the analysis of occupational "accidents", and occupational
diseases
• This seminar will highlight various risk factors and the approach to prevent and manage
compressed air works as per the relevant prevailing guidelines.
• We hope this will lead to an alignment of initiatives being carried out by various team leaders
and agencies of differing nationalities and with a past expertise in other parts of the world who
are working together for the Delhi Metro Phase III

3. 3
Technical Seminar – Schedule
07 April 2014,Monday

4. 4
Session I
Welcome & Overview
Scheme of Presentation

5. 5
Context – key participants
• DMRC : Delhi Metro Rail Corporation Limited (DMRC), a state-owned company with equal equity
participation from Government of India and Government of National Capital Territory of Delhi built
and operates the Delhi Metro.
Besides construction and operation of Delhi metro, DMRC is also involved in the planning and
implementation of metro rail, monorail and high-speed rail projects in India and providing
consultancy services to other metro projects in the country as well as abroad.
This technical seminar is the brain child of Mr. Davinder Gill Additional General Manager
Safety & Mr. FM Dohadwala (Din) Chief Safety Expert
• Apollo Hospital : Apollo Hospital, New Delhi is a 850 bedded hospital and India’s First Hospital
to be Internationally Accredited by Joint Commission International (JCI).With a mission to provide
affordable healthcare services within reach of every individual, it is Rated as one of the best
super specialty tertiary care hospitals in India.
This is the only hospital with a “man lock” = Hyperbaric Chamber with a hyperbaric expert Dr
Tarun Sahni which has provided service to the Metro in Phase I , II and now Phase III. .
• Advent Hyperbaric & Occupational Services : Advent Hyperbaric Service is a pioneer in the
field of diving and hyperbaric medicine and the only agency in India, which can offer complete
solutions in this field. Advent is committed to fill in the gap in the health support of available
national resources in the field of diving, hyperbaric and compressed air work.

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Session 2
Overview on Health and Safety Issues in Compressed Tunneling Workers
Scheme of Presentation

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Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
 Regulations for Safety in tunneling operations (BS 6164), compressed air works (HSE
Regulations – 1996) and Indian Standards for tunneling operations
 Occupational health Aspects (Health Issues, Medical Examinations, Duties of Health Medical
Adviser)
Session 3: Man and Medical Lock Management
Session 4: Emergency Medical Response
Session 5: Closing
Scheme of Presentation

8. 8
route
duration
concentration
Individual
Occupational
hazard
Conditions
1. Occupational related
2. Non occupational related
exposure
Occupational Health & Safety
Occupational Health is the promotion and maintenance of the highest degree of physical, mental
and social well-being of workers in all occupations by preventing departures from health, controlling
risks and the adaptation of work to people, and people to their jobs.
(ILO / WHO 1950)

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Safety Guidelines for Tunnelling operations
Many Guidelines are prevalent in different parts of the world

10. 10
Safety Guidelines Relevant for DMRC operations
Safety Codes for Tunneling
Operations
Safety Code for
“working ”
in Compressed Air

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Health & Safety Issues in Tunnelling Operations
Non Compressed Air Related
Compressed Air Related
The Focus during this seminar will be health & safety guidelines in Compressed Air

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A guide to work in compressed air regulations – 1996
Health & Safety Executive
• 22 Regulations
• 2 Schedules
• 17 Appendix
During the seminar we will
familiarize ourselves with the
key areas of these guidelines

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Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
 Regulations for Safety in tunneling operations (BS 6164), compressed air works (HSE
Regulations – 1996) and Indian Standards for tunneling operations
 Occupational health Aspects (Health Issues, Medical Examinations, Duties of Health
Medical Adviser)
Session 3: Man and Medical Lock Management
Session 4: Emergency Medical Response
Session 5: Closing
Scheme of Presentation

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A dynamic equilibrium is required between the worker and his occupational environment
Factors Causing Hazards in ‘Compressed Air’
Tunneling Operation
+
Compressed air related
Non Compressed air related
A physically Unfit Miner is likely to suffer from some of the above hazards

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Medical Complications of working in high barometric
pressure environments
Pressure Related Hazards
Barotraumas
Decompression Illness
Dysbaric Osteonecrosis
Non Pressure Related Hazards
Temperature
Humidity
Vibration & noise
Airborne salts, dust, sand, dirt, etc.
Sunlight, lightning, radiation
Wind, hail, heavy rain

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Hyperbaric Terminology ( ATA)
Hyperbaric Treatment Pressure Range
Atmospheric Pressure
The atmosphere above the earth
is some 150 km high. Although air
is very light, this amount of air has
significant weight and exerts
substantial pressure on the earth's
surface.
Atmospheric pressure at sea
level is referred to as "one
atmosphere" or "one bar".
Absolute Pressure
The total pressure exerted on a
diver at depth will be the
pressure due to the atmosphere
acting on the surface of the water
(atmospheric pressure) plus the
pressure due to the depth of the
water itself (hydrostatic pressure).
The total pressure acting on the
diver is termed the "absolute
pressure". It is often expressed in
terms of atmospheres and is
called "atmospheres absolute"
or "ATA".

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Pressure Related Hazards
1. Bends ‘Decompression Illness’
• The BENDS, also known as decompression
sickness (DCS) or Caisson disease occurs in
scuba divers or miners ,events when
dissolved gases (mainly nitrogen) come out of
solution in bubbles and can affect just about
any body area including joints, lung, heart,
skin and brain.
• The nervous and musculoskeletal system are
most often affected. If a diver is going to
develop symptoms they will show within 48
hours in all cases. Ninety-five percent (95%)
have symptoms within 6 hours, while 50%
develop within the first hour of surfacing from
a dive.

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2. Barotrauma
• Affect air filled spaces in the body – eg: sinuses, middle ear,
lung
• Sinuses and ears commonly affected
• Pulmonary barotrauma : may result from breath holding during
ascent from depth or trapping of air in the lung tissue
Sinus barotrauma
•May occur during descent or
ascent
• Signs and symptoms
– Sensation of tightness or
pressure over the sinuses
during descent or ascent
– Bleeding or extrusion of mucus
on ascent
– dull aching sensation
Aural barotrauma
• Damage to the ear that occurs as
a result of changes in ambient
pressure during ascent or
descent
•Signs and symptoms
- Difficulty in clearing ears
- Discomfort and pain during
the descent or ascent
- Vertigo and nausea
- Deafness, tinnitus

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3. Dysbaric Osteonecrosis
• A form of vascular necrosis where the death of a portion of the
bone that is thought to be caused by nitrogen embolization
(blockage of the blood vessels by a bubble of nitrogen coming
out of solution) .
• In a study of bone lesions in 281 compressed air workers done
by Walder in 1969, 29% of the lesions were in the humeral
head (shoulder), 16% in the femoral head (hip), 40% in the
lower end of the femur (lower thigh at the knee) and 15% in
the upper tibia (knee below the knee cap).

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Importance of Medical Examination of Tunneling workers
1. To detect early abnormalities and prevent workers from
developing occupational diseases
Regular medical examination of workers who are exposed to
particular health hazards at work can detect abnormalities or
diseases at the early stage so that timely treatment can be
given to increase the prospect of cure and reduce the cost of
care
2. To verify the effectiveness of existing preventive
strategies
The detection of index cases of over-exposure or early
diseases in medical examinations will alert the employer
concerned to review and enhance, as appropriate, the existing
preventive and control measures to protect other workers from
being affected by the health hazards.
3. To provide occupational health education and advice to
workers
Medical examination is a good opportunity for doctors to
educate workers of the health risks necessary preventive
measures to minimize the risks of contracting occupational
diseases
4. Prevent Medicolegal issues relating to work related
disease compsnsation

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Session 3
Man and Medical Lock Management
Scheme of Presentation

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Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
Session 3: Man and Medical Lock Management
• Guidelines for availability & usage of Medical Lock
• Our experience in the managing Man lock Operations
• Visit to Man Lock (Hyperbaric chamber, Apollo Delhi)
Session 4: Emergency Medical Response
Session 5: Closing
Scheme of Presentation

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Medical Lock
• Where there is pressure in a working chamber , a medical lock will need to be provided and
maintained.
• It needs to be of an appropriate size and consist of an inner (treatment) chamber and an outer
(entrance) chamber.
• The medical lock needs to be adequately ventilated, heated and lit by means of an external
lighting system or by an internal explosion-protected system.
• The medical lock needs to be fitted with equipment to allow the administration of oxygen, by built-
in breathing system (BIBS), to people being treated in the lock, and with a suitable supply of
oxygen.
• Should be used for lock testing of new starters and in emergencies, the medical lock should be
used for therapeutic recompression .
• The medical lock must be kept ready for immediate use while people are working in compressed
air and for 24 hours .

24. 24
Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
Session 3: Man and Medical Lock Management
• Guidelines for availability & usage of Medical Lock
• Our experience in the managing Man lock Operations
• Visit to Man Lock (Hyperbaric chamber, Apollo Delhi)
Session 4: Emergency Medical Response
Session 5: Closing
Scheme of Presentation

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Advent Hyperbaric & Occupational Health Services Team
• Advent Hyperbaric and Occupational Health Services
have a skilled team supported by the best of medical
care and services of a hyperbaric physician and hospital
based medical lock.
• We have worked in Phase I and Phase II and are
committed to be part of the current growth of Delhi
Metro and are willing to go to the extreme of our
resources to provide these services
• This Team consists of ex navy divers who have worked
as supervisors in a variety of locations in diving and
compressed air across the world. They are is trained to
manage extremely tough conditions and emergency
situations
• The Team is supported by an expert occupational
physician and hyperbaric trained expert in this field

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Intervention Activation Process (Flow Chart)
Intervention date and time announced
(Action: Tunnel Manager or nominated representative of the contractor)
Intimation to Operations Manager Manlock Operations team
(Mr Surinder Sobti Ops Manager Advent to be intimated ideally 24 hrs before
intervention planned)
1. Operations Manager mobilizes
supervisors
(2 Supervisors will be available at all
times 24/7 during intervention)
2. Operations Manager mobilizes hyperbaric team as
standby
(Dr Tarun Sahni Hyperbaric Physician (or nominated suitable
doctor) will be ready to reach at short notice, either at site or at
Apollo Manlock as required )
3. Onsite Medical services (doctor & Ambulance) ready for examination of operators pre and
post intervention & for any emergency
(Action Tunnel / project manager)

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Our Experience in managing man lock operations
Working Chamber
Locco- For Medical Emergencies
Exiting From the ChamberEntry Lock Main Chamber Lock

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Challenges during the intervention
• Extremely Filthy conditions
• Cramped up spaces to work
• Vibration and Noise
• Temperatures
• Humidity
• Pressures

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Medical Team & Support stand by during intervention
• During intervention the following parallel action takes place at the Apollo Hospital
• Ambulance standby team which can rush to site in case of emergencies
• Hyperbaric Chamber and a team in Apollo is kept ready to accept any emergencies

30. 30
Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
Session 3: Man and Medical Lock Management
• Guidelines for availability & usage of Medical Lock
• Our experience in the managing Man lock Operations
• Visit to Man Lock (Hyperbaric chamber, Apollo Delhi) – Hyperbaric Team
Session 4: Emergency Medical Response
Session 5: Closing
Scheme of Presentation

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Introduction to Recompression Chambers
A chamber constructed to withstand
pressurisation so that workers can
slowly release the amount of
dissolved Nitrogen and also used to
administer oxygen under pressure
( Hyperbaric Oxygen Therapy )

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Types of Recompression Chambers
Monoplace Chamber Multiplace Chamber
Many patients can be treated at the same
time in chamber pressurized with 100%
oxygen
A single patient is placed in a chamber
which is then pressurized with 100%
Oxygen.
For Metro Intervention; Twin Lock facility is required
This is only possible in a multiplace chamber currently only available At Apollo Hospital in
Delhi

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The Center at Apollo, New Delhi
• 750 bed Super Speciality Corporate Hospital
• Site of India’s First Private Hyperbaric Treatment Center

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Session 4
Emergency Medical Response
Scheme of Presentation

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Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
Session 3: Man and Medical Lock Management
Session 4: Emergency Medical Response
• Medical Emergency (Non Pressure Related)
• Medical Emergency Response (Compressed Air Related)
Session 5: Closing
Scheme of Presentation

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Emergency Response in a medical emergency
Video ( 6 minutes) with explanation

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Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
Session 3: Man and Medical Lock Management
Session 4: Emergency Medical Response
•Medical Emergency (Non Pressure Related)
•Medical Emergency Response (Compressed Air Related)
Session 5: Closing
Scheme of Presentation

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Emergency Management of Pressure Related Diving Accidents
Phase 1 :
Immediate Emergency Care
Phase 2 :
Accurate Diagnosis
Phase 3 :
Proper Transportation
Phase 4 :
Definitive Treatment

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Accident / Emergency on site
Evacuation to Medical Room
Arrival at Medical Room
Dispersal of Emergency
• Emergency Care and transfer
( Medical Evacuation team )
• Intimate Management & Medical Team ( Duty
Tunnel Manager )
• Safety of other members ( Man Lock Supervisors )
• Emergency Medical Care
( Medical team )
• Assessment for further management ( Doctor in
consult with Hyperbaric Doctor)
• Ambulance in readiness
• Transfer to Hospital
( Ambulance with paramedic / doctor )
• Detain and Observe
( Doctor in consult with Hyperbaric Doctor)
• Send to Home & follow up
Process for “Medical emergencies during Manlock
operations”

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Session 1: Welcome and Overview
Session 2: Overview on Health and Safety Issues in Compressed Tunneling Workers
Session 3: Man and Medical Lock Management
Session 4: Emergency Medical Response
Session 5: Closing
• Discussion & Q&A
• Vote of thanks
• High Tea
Scheme of Presentation

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Summary
• Follow regulation and guidelines
• Importance of Medical examination and prior
to intervention
• Need of Medical Lock
• Record Keeping
• Selection of Qualified Team
• Good Management

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Thank you
Hyperbaric Oxygen Therapy Unit
Indraprastha Apollo Hospital
New Delhi
Prof (Dr )Tarun Sahni
Head of Hyperbaric medicine
& Senior Consultant Internal Medicine
Indraprastha Apollo Hospital
President Hyperbaric Society of India
www.hyperbaricindia.com

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