Seminar for Tunneling & Compressed Air Workers Delhi Metro 2014

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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

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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

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Technical Seminar – Schedule

07 April 2014,Monday

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Session I

Welcome & Overview

Scheme of Presentation

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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


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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


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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

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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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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 5: Closing


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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


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• Guidelines for availability & usage of Medical Lock

• Our experience in the managing Man lock Operations

• Visit to Man Lock (Hyperbaric chamber, Apollo Delhi)


Session 5: Closing


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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 .

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• Guidelines for availability & usage of Medical Lock

• Our experience in the managing Man lock Operations

• Visit to Man Lock (Hyperbaric chamber, Apollo Delhi)


Session 5: Closing


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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 Chamber Entry 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

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•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 5: Closing


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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


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• Medical Emergency (Non Pressure Related)

• Medical Emergency Response (Compressed Air Related)

Session 5: Closing


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Emergency Response in a medical emergency

Video ( 6 minutes) with explanation

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•Medical Emergency (Non Pressure Related)

•Medical Emergency Response (Compressed Air Related)

Session 5: Closing


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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 5: Closing

• Discussion & Q&A

• Vote of thanks

• High Tea


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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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