agt learner guide dec 4

8/13/2019 AGT Learner Guide Dec 4

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AUTHORISED GAS TESTER by Nigel Pitt: - Module 1

AUTHORISED GAS TESTING



AUTHORISED GAS TESTING by Nigel Pitt: - Module 1

Managing Health andSafety at a Corporatelevel

Any reputable organisation manages Health and Safety by the imposition of the requirements of an HSEmanagement system on its employees and partners or stakeholders eg contractors etc. PDO is no exception.These management systems comprise primarily of;

Policies

Rules,

Regulations, (i.e. statutory requirements)

Standards

Practices

Procedures

Specifications

Guidelines and

Codes of practice.

The above essentially forms the “system of work” which enables individuals to be guided in the correct mannerregards the execution of any task or process management.

The PDO HSE Management System as defined in CP 122 is structured as follows:




1. Overview of Hazard Identification

Introduction All Hazardous gas exposures within PDO operations need to be carefully identified and evaluated for potential

health and safety exposures through a risk assessment and analysis process. There are several standards and

assessment techniques to identify hazards. Examples of these process would include amongst others FMECA

(Failure Modes and Effects Criticality Analysis) HAZOPS (Hazard Operability Studies) and HAZID (Hazard

Identification) which can be used to establish a list of Hazards to be considered in any risk assessment process or

review.

It is important that the process is inclusive of all the significant hazards with a potential fatality consequence and not

just the common hazards that are well known and understood. This will include all probable cases where there isthe potential for exposure to toxic, flammable gases or life threatening atmospheres.

Employers in the PDO community have to ensure that a systematic and thorough examination of the work place is

undertaken and the prevailing conditions and practices are identified, recorded and the significant findings

evaluated to determine their risk potential.

Furthermore, all contractors working for PDO are obliged in terms of PR1171 part II to identify hazards and manage

associated risks.

PR 1171 part II Section 2.6.2 Contract-Specific HSE Management Plan

Contractor(s) shall, following the Contract Award, kick-off Meeting and on site HSE Workshop, revise its original

HEMP and from that develop the Contract-Specific HSE Management Plan.

C t t ( ) h ll d ib h th HSE M t Pl ill l it t bli h d i t




4. A gas can diffuse into another gas.

Reason: Molecules in a gas move very fast. Hence the rate of diffusion is very large.

5. A gas on cooling changes into liquid state.

Reason: Cooling reduces intermolecular separation and increase intermolecular force of attraction.

6. A gas can flow in all directions. It requires a vessel closed from all sides to contain it

Source of Natural Gas Natural gas is a made up of a mixture of hydrocarbons. The main hydrocarbon in natural gas is methane, but there

are also small amounts of ethane, propane and butane.

Natural gas originates from organic matter like plants and tiny sea creatures that lived millions of years ago. As the

organic matter decayed it was covered with layers of silt and clay which over time turned into rock.

Over millions of years, the heat of the earth and the pressure from the weight of rocks above transformed some of

the organic matter into the fossil fuels coal, oil and natural gas.

The movement of water, and pressures within the earth's crust, caused the oil and natural gas to move. Some of

the oil and gas accumulated in traps or reservoirs (formed by porous rocks, covered by non-porous rocks) within

the earth's crust.

Radon Gas




Narcotic effects

Dose The severity of effects of an inhaled toxin on a body depends on:

i. Concentration of toxin (ppm) in air

ii. Duration of exposure (number of breaths)

What gases should we

be concerned about in

the oil and gas

business?




When should gas tests

be conducted?

1. Before work starts and

2. During continuous work where there is the potential for exposure to a gas leak

Gas testing is mandatory prior to work being undertaken in a process or hydrocarbon area that carries a risk to

personnel or equipment from exposure to explosive, flammable, toxic or life threatening vapours. Gas testing shall

also be required in any other area where the above risks are considered to exist which are covered by the PDO

Permit to Work (PR1172) or a 3rd Party compliant system.

Why do we need to test

for gas?

To ensure there are no toxic gases present in the work area and in the air and that the atmosphere is

breathable

To ensure the oxygen levels in the air are sufficient to support life

To ensure there are no flammable or explosive gases present and so minimise the possibility of an explosion

happening.

How does the humanbreathe?




Any increase in the oxygen level above normal during confined space entry activities shall be invest igated, aRisk Assessment completed and appropriate measures taken.

The most common oxygen containing equipment is that used in gas cutting operations. Cylinders, gas hoses,

valves and welding torches shall be handled with care and should be daily inspected for damage. Gas cylindersshall not be taken into confined spaces unless the risks have been assessed and appropriate authorisation isobtained from the Responsible Supervisor. If allowed into the confined space all such equipment shall beremoved during breaks and at the end of the working day. All O2 cylinder valves shall be closed when not in use.

Oxygen Depleted(deficient) Atmosphere

Atmospheres containing less that 20% vol. oxygen shall be treated asoxygen depleted (deficient) or hypoxic .Such atmospheres can occur when gas freeing or purging has been carried out to remove hydrocarbons / toxics

or air. The oxygen in the atmosphere shall have been normally replaced / diluted with an inert gas i.e. nitrogen.Oxygen deficiency in an atmosphere can result in asphyxiation. A relatively small reduction in the oxygen levelcan lead to impaired mental ability and can provoke a feeling of euphoria or wellbeing leading to anoveroptimistic judgment of the situation. The effects generally occur without alerting the senses. Loss ofconsciousness can occur without warning. This can happen even in circumstances where only a person’s headis inside a confined space. Very low oxygen concentrations, below 10%, can lead to unconsciousness anddeath. Inhaling an atmosphere with no oxygen results in instant death. There is no panic or discomfort; death isswift and silent.

Oxygen deficiency can result from:

i. Displacement of air from low points in a confined space by heavier gases such as hydrocarbons orcarbon dioxide;

ii. Purging of the confined space with an inert gas to remove flammable or toxic gases, fumes, vapours oraerosols;




Flammable gas testing Gas testing shall be carried out to detect accumulations of flammable vapours, fumes or dust in atmosphereswhich could ignite in the presence of a source of ignition.

Flammable vapours or fumes typically result from:

i. Materials previously processed or stored in the vessel or tank;

ii. Sludge or other deposits disturbed during cleaning;

iii. Material left under scale, even after cleaning;

iv. Material leaking through the tank floors;

v. Material leaking from behind vessel linings (lagging, refractory etc.) or from vessel fittings such as tankfloating roof pontoons and legs, instrument connections or pipes;

vi. Materials leaking from flanges or vents on process pipes running through the confined space, e.g.process tubes in a furnace combustion chamber;

vii. Vapour entering the confined space from nearby process plant that has not been effectively isolated orfrom nearby work that is not well controlled;

viii. Solvents brought into the space for cleaning, painting, dye penetration tests or in adhesives;

ix. Gases brought into the space / area for welding or gas cutting, including leakage from cylinders, valvesand hoses;

x. Contaminated firewater / process water used to wash the confined space and introduced by hoses;

xi. Vapour or fumes that build up in sewers, manholes, contaminated ground or excavations.

A source of ignition can be any heat source having enough energy to ignite a flammable vapour air mixture, or toraise the temperature above the auto-ignition temperature. Possible ignition sources include:

i. Open flames and sparks resulting from welding, gas cutting and grinding;

ii. Sparks or arcs produced by electrical equipment, lightning and electrostatic charges;

iii H i h h i h fl bl i b h i i i




Toxic gas testing Toxic gas testing shall be carried out to identify and detect toxic substances either in or adjacent to the confinedspaces or other places of work. Substances can be solids, liquids or gases. Toxic vapours can cause injury,acute or long-latency illness, or death, depending on the characteristics of the substances, the concentration andthe duration of exposure. For example, prolonged exposure to benzene can cause kidney damage or even

leukaemia. Toxic hazards in confined spaces can result from the same sources as the flammable hazards.Common toxic substances in the oil and gas industry are:

Acute toxic gases such as hydrogen sulphide, carbon monoxide, hydrogen fluoride, ammonia and chlorine;

Hazardous liquids such as benzene, polycyclic aromatics, lead/anti-knock compounds, hydrazine and biocides;

Narcotic gases and vapours such as butane, pentane, hexane, gasoline and gas condensate;

Toxicity data for specific substances, e.g. Material Safety Data Sheets (MSDS) or Safe Handling Of ChemicalCards (SHOC), shall be required from the supplier of materials or from government authorities, and shall be

made available on site. If these are not available then a competent industrial hygienist shall assess the toxicity ofthe intermediates and products.

Crude oil and refinery process streams are mixtures of many hydrocarbons that individually have significant toxicor narcotic effects. The Health Risk Assessment (HRA), as input to the Job Hazard Analysis (JHA), shall assessthe hazards of the mixture in the situation / areas where persons could be exposed. Specifically, the HRA shouldmake a recommendation on whether flammability measurements are sufficient to detect harmful levels of thepotentially toxic substance.

Different criteria may be needed for:

i. Confirming that the atmosphere in the confined space is safe for entry, for planned work, and

ii. Requiring persons to leave the space in case of an increased level during the work

Substances that are harmful by inhalation normally have an assigned Occupational Exposure Limit (OEL). An Action Limit of 50% of the published OEL shall be applied as the trigger for implementing specific measures forcontrolling exposure to the toxic substance during the confined space work, but the target should be to reducethe airborne concentration to ALARP. OEL data may not be available for some toxic dusts, sludge and othersubstances, in which case specialist occupational hygiene advice should be sought.




Hazardous areaclassification

Zone 0: An area in which an explosive gas atmosphere is present continuously or for long periods;

Zone 1: An area in which an explosive gas atmosphere is likely to occur during normal operation;

Zone 2: An area in which an explosive gas atmosphere is not likely to occur under normal operations and, if itoccurs, will only exist for a short period of time.

Methane UEL - LEL

Explosive limit All combustible gases and vapours have an “explosive limit” between which the gas or vapour, mixed with air,is

capable of sustaining the spread of flame.These can be referred to as the explosive or flammable range or limit

H2S UEL and LEL




For most practical gas testing purposes it is the LEL which is significant.

100% of LEL for Methane means 5% by volume.

50% of LEL for Methane means 2.5% by volume

The AGT is responsible for recording the percentage of LEL for the specific flammable gas being tested on thepermit.

Activity 4 How many parts ppm of H2S are there in 25% lel

How many parts ppm of H2S are there in 50% lel

How many parts ppm of H2S are there in 100% lel

% b

y v o

l u m e




Exposure to low levels of carbon monoxide can cause fatigue, chest pain, shortness of breath, memory loss, skinlesions, sweating, and flu-like symptoms. In the long term, exposure to low levels can cause heart disease anddamage to the nervous system. Skin contact with liquid carbon monoxide in the workplace can cause frostbite.

Carbon monoxide poisoning is caused by inhaling combustion fumes. When there's too much carbon monoxide in

the air, your body replaces the oxygen in the haemoglobin of your red blood cells with carbon monoxide. This keepslife-sustaining oxygen from reaching your tissues and vital organs. The effects of CO exposure can vary greatlyfrom person to person depending on age, overall health condition i.e. physiology of the individual subject and theconcentration and length of exposure

Various appliances fuelled by wood or gas produce carbon monoxide, including:

Car and truck engines

Portable generators Furnaces Water heaters Cooking ranges Charcoal grills Fireplaces Fuel-burning space heaters

Wood-burning stoves

Normally the amount of carbon monoxide produced by these sources isn't cause for concern. But if appliancesaren't kept in good working order or if they're used in a closed or partially closed space— such as using a charcoalgrill indoors or running your car in a closed garage— the carbon monoxide can build to dangerous levels. Smokeinhalation during a fire also can cause carbon monoxide poisoning

Normally the amount of carbon monoxide produced by these sources isn't cause for concern. But if appliancesaren't kept in good working order or if they're used in a closed or partially closed space— such as using a charcoalgrill indoors or running your car in a closed garage— the carbon monoxide can build to dangerous levels. Smoke

h l d f l b d




Carbon Dioxide CO2 What is carbon dioxide?

Carbon dioxide is a colourless, odourless gas that has a faint acid taste. It can also be a liquefied compressed gasor white flakes or cubes. In solid form, it is used as dry ice. Carbon dioxide can be found naturally in spring waterand is released when volcanoes erupt and trees are cut down. When people breathe, they exhale carbon dioxide.

Carbon dioxide is also produced by burning fossil fuels, such as coal, oil, gasoline, natural gas, and diesel fuel. Thechemical formula for carbon dioxide is CO2.

In the atmosphere, carbon dioxide is part of the global carbon cycle between the atmosphere, oceans, land, marinelife, and mineral reservoirs. It is a “greenhouse gas” because it absorbs heat in the atmosphere, sending some ofthe absorbed heat back to the surface of the earth and contributing to global warming. Carbon dioxide emissionsrepresent about 80 percent of all greenhouse gas emissions in the United States. Sources of carbon dioxideemissions, which contribute to climate change, include fossil fuel burning, electricity generation, transportation

vehicles, cement or lime manufacturing, waste burning, andnatural gas flaring

How can carbondioxide affect myhealth?

Carbon dioxide in its gaseous form is an asphyxiant, which cuts off the oxygen supply for breathing, especially inconfined spaces.

Exposure to concentrations of 10 percent or more of carbon dioxide can cause death, unconsciousness, orconvulsions.

Exposure may damage a developing foetus.Exposure to lower concentrations of carbon dioxide can cause hyperventilation, vision damage, lung congestion,

central nervous system injury, abrupt muscle contractions, elevated blood pressure, and shortness of breath.Exposure can also cause dizziness, headache, sweating, fatigue, numbness and tingling of extremities, memoryloss, nausea, vomiting, depression, confusion, skin and eye burns, and ringing in the ears.

If your skin touches dry ice, you can get frostbite or blisters.You may be more affected by exposure to carbon dioxide if you have a cardiac, lung, or blood disease or condition.

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Sulphur Dioxide What is sulphur dioxide?

Sulphur dioxide is a colourless gas with a pungent and suffocating odour, similar to the smell from a struck match. Ithas an acidic taste and is a liquid when under pressure. Sulphur dioxide is formed when fuel containing sulphur,such as coal and oil, is burned. The chemical symbol for sulphur dioxide is SO2.

Most sulphur dioxide in the air comes from the burning of coal and oil at electric power generation plants. Othersources of sulphur dioxide in the air are industrial facilities that use coal or oil, petroleum refineries, cementmanufacturing, metal processing, paper pulp manufacturing, and copper smelting. Trains, large ships, andsome diesel equipment burn high sulphur fuel, which releases sulphur dioxide into the air. It can also be releasedinto the air by mother nature ie from volcanic eruptions.

How can sulphurdioxide affect myhealth?

Short-term exposure to high levels of sulphur dioxide in the air can be life-threatening by causing breathingdifficulties and obstructing airways, especially for people with lung disease. Long-term exposure to persistent levelsof sulphur dioxide can cause chronic bronchitis, emphysema, and respiratory illness. It can also aggravate existingheart disease.

When sulphur dioxide reacts with other chemicals in the air to form tiny sulfate particles, these particles can gatherin the lungs and cause increased respiratory problems and difficulty breathing. Long-term exposure to sulphate

particles can cause respiratory disease and even premature death.

Prolonged industrial exposure to sulphur dioxide may decrease fertility in men and women.

Breathing sulphur dioxide can irritate the nose, throat, and lungs, and cause coughing and shortness of breath.Short-term exposure to sulphur dioxide can cause stomach pain, menstrual disorders, and watery eyes, inhibition ofthyroid function, loss of smell, headache, nausea, vomiting, fever, convulsions, and dizziness.








Hydrogen Sulphide Hydrogen Sulphide (H2S) is an extremely dangerous substance and can cause fatalities if not managed correctly.

H2S can be present in the gas and liquid streams within the PDO operations.

H2S in the upstream oil and gas industry comes from:

i. the original reservoir, as a result of the hydrocarbon source material and the conditions under which it was

converted to oil and gas. If this is the case then H2S will be produced with the fluids

ii. the reservoir after prolonged injection of water with oxygen (brackish or formation water) which may result

in 'souring' of the fluids within it due to the action of sulphate reducing bacteria (SRB) introduced during the

injection process. Any H2S will be subsequently produced with fluids.

Why are oil and gasfields a safetyconcern?

Oil and gas fields are areas where oiland natural gas have accumulated under the land’s surface. Oil and gas fieldscan also be offshore in lakes and oceans. Oil and gas exploration operations drill in these fields to extract oil and

gas for sources of energy.

These operations pose many health, environmental, and safety concerns. Health concerns in oil and gas fields

include air emissions of toxic chemicals, drilling waste, radioactive waste, and contaminated water produced by

drilling operations. Oil and gas production can emit hazardous air pollutants, including benzene, toluene, and

xylenes. These activities can emit carbon dioxideand methane, which are greenhouse gases that contribute to

global warming and climate change. Operations at oil and gas fields can also emit nitrogen oxides, volatile organic

compounds2, carbon monoxide, sulphur, and particulate matter.

Air emissions can come from several sources in oil and gas fields. Sources include equipment engines, drilling rigs,






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potable coastal waters.

An estimated 35 percent of produced water requires disposal because it cannot be recycled. Past disposal practices

and accidental releases of produced water could contaminate groundwater.

Health and safety concerns at oil and gas fields include possible exposure to hydrogen sulphide, a poisonous and

flammable gas that occurs naturally in oil and gas. It is an extreme health hazard because it can be fatal or harmful

if inhaled. Hydrogen sulphide occurs in many areas marked with warning signs, but can be present in unidentified

spaces.

Other safety concerns at oil and gas fields are open waste pits, abandoned wells, drilling equipment, cleaning and

pumping activities, fires, explosions, and confined spaces where gases can accumulate.

A major environmental concern is natural gas flaring, which is the process of burning off gas during oil production.

Gas flaring emits millions of tons of carbon dioxide each year. Other environmental concerns are damage to land

and habitat, leakage of drilling fluids, and fires.

PDO have special procedures for managing H2S in the Southern fields of Al Noor, Birba and Harweel

Properties of H 2S Colourless

Highly toxic

Heavier than air




Nitrogen Nitrogen

Nitrogen is a common normally colourless, odourless, tasteless and mostly diatomic non-metal gas. It has fiveelectrons in its outer shell, so it is trivalent in most compounds.

Nitrogen in the environment

Nitrogen constitutes 78 percent of Earth's atmosphere and is a constituent of all living tissues. Nitrogen is anessential element for life, because it is a constituent of DNA and, as such, is part of the genetic code.

Nitrogen molecules occur mainly in air. In water and soils, nitrogen can be found in nitrates and nitrites. All ofthese substances are a part of the nitrogen cycle, and there are all interconnected.

Humans have changed natural nitrate and nitrite proportions radically, mainly due to the application of nitrate-containing manures. Nitrogen is emitted extensively by industrial companies, increasing the nitrate and nitritesupplies in soil and water as a consequence of reactions that take place in the nitrogen cycle. Nitrateconcentrations in drinking waterwill greatly increase due to this.

Health Effects

Nitrates and nitrites are known to cause several health effects. These are the most common effects:

- Reactions with haemoglobin in blood, causing the oxygen carrying capacity of the blood to decrease (nitrite)- Decreased functioning of the thyroid gland (nitrate)- Vitamin Ashortages (nitrate)- Fashioning of nitro amines, which are known as one of the most common causes of cancer (nitrates and nitrites

Properties of Nitrogen 78% of air Gases asphyxiate by displacing oxygen Odourless, colourless, tasteless

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Health effects

The above table is for ref purposes only

Permitted exposurelevel (PEL)

PEL refers to the concentration of a toxic substance that is judged safe for a worker to be exposed to.

- Also known as WEL (Workplace Exposure Limit)

- Also known as Threshold Limit Value (TLV)

Based on an average concentration measured over an 8 hour work day. (TWA )

Worker may be exposed for 8 hrs per day, 5 days per week for years without ill health effects.

European and international safety laws limit the amount of a toxic substance that it is legal to expose a worker to.These limits are chosen to ensure that continued exposure over months and years will result in no harm and nodiscomfort. So, at 5 ppm ( the WEL for H2S gas ) the worker will not be coughing or suffer from stinging eyes orother discomfort. This is based on an average concentration over 8 hours.

PEL’s for many chemicals are listed in a document called EH40 available on the hse.gov.uk website




Immediate Danger toLife and Health (IDLH)

This is the concentration level of a toxic substance at which it may cause harm or make self rescue difficult.

For example, H2S at 100 ppm causes eye irritation which may make it difficult for a worker without eyeprotection to see clearly while trying to escape a hazardous environment.

PTW Refers PTW standards applicable to all gas testing requirements in PR 1148 and PR 1172

Activity 5 Establish the PTW and gas testing requirements for entry into a well cellar for maintenance of an

annulus valve?




Activity 6

Tool box talk (TRIC)

Complete a TRIC for an activity with which you are familiar and explain through demonstrating how you would

deliver this to the work crew on site.

Dangerous/hazardous work: Any work which has the potential to cause harm to employees

Critical Task: A task if not performed properly has the potential to produce major loss to people, property,

process and/or environment

Practice: A set of positive guidelines helpful to performing a specific type of work that may not always be done in

a set way.

Procedure: A step-by-step description of how to proceed, from start to finish, in performing a task properly to

completion.

Task: Segment of work which requires a set of specific and distinct actions for its completion.

Examples include:

Performing the pre-use inspection on an overhead crane.

Setting up the wrapping machine for a pipeline joint.

Performing an emergency shut down on the preheat furnace.

Step: One segment of the total task where something happens to advance the work involved

Activity 7 Complete a JHA




Flow chart for criticaltask analysis

Critical Task Analysis

Identify Critical Tasks

Responsible Person:Break each task down into arequired sequence of steps

Note:

Step - one segment of the total task wheresomething happens to advance the work involved.Experience shows that many tasks will break downinto ten to fifteen or twenty key steps

Overview:Critical task - a task which has the potential toproduce major loss to people, property, processand/or environment when not performed properly

Responsible Person:Pinpoint loss exposures Note:

Every aspect of the task, including safety, quality andproduction, should be considered. Also consider losses tothe area or environment where the task is being done and thepossible long-term consequences of improper performance.Consider the following four subsystems:- People- Property- Process- Environment

Responsible Person:Conduct an improvement

check

Note 1:To conduct an improvement check, one needonly ask the right questions and seek answers.- What is the purpose of this step?- Why is this step necessary?- How can it be done better?- Who is best qualified to do it?- When should it be done?There are seven major ways to make the

improvements:- Eliminate the task / step- Combine tasks / steps- Rearrange the sequence of steps- Simplify the task- Reduce the frequency- Substitute material- Relocate the task

Responsible Person:Develop controls to prevent

a potential loss

Note:Controls include such things as engineeringchanges, work rotation, personal protectiveequipment programs, etc.

Developprocedure?

Create New Document

Responsible Person /Employees:

Implement the task

End

Note:Use the following techniques:- Employee orientation- Proper task instruction- Planned task observation- Personal contacts, coaching and tipping- Safety talks- Skill training

Yes

No

QR:Critical task analysis

Form: (mouseover)Critical task analysis worksheet

Trainingrequired?

Conduct Training

Yes

No




Standard References PR1154 and PR1148

Gas Test

Requirements

PR-1172 – Permit to Work System Section 3.5shall be referenced to determine the frequency of gas testing and the

specific work it is required for.

In general gas testing is required for the following types of work;

Breaking containment

Hot work in a process or hydrocarbon area

Gas freeing and purging

Confined space entry / work within a confined space

Checking for suspected gas leaks Providing clearance for work activities

Use of diesel engines in a process / hydrocarbon area

Vehicle entry to a process / hydrocarbon area

Breaking

Containment

Gas testing shall be required when containment is broken on any system containing hydrocarbon or toxic liquids /

solids / vapours. Appropriate PPE and safety equipment i.e. SCBA, masks, face visors etc, shall be worn as

necessary.

The type of gas tested for shall be indicated on the PTW by the Area Authority in addition to the frequency of testing.

Types of gas can include one or all of the following;

Hydrocarbons

H2S

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Providing Clearance

for Work Activities

Work activities in hazardous area shall require that the atmosphere at the work site and in the surrounding areas is

safe before permission is given to carry out the work activity.

Use of Diesel Enginesin a Process /

Hydrocarbon Area

The use of internal combustion engines (diesel driven) within a process or hydrocarbon area shall be subject toauthorisation and require gas testing in accordance with PR-1172 – Permit to Work System Section 3.5.

Diesel driven plant i.e. mobile cranes, air compressors etc, shall be subject to continuous gas monitoring while in use.

The units shall also be subject to a gas test prior to starting.The gas test shall primarily be to check for

hydrocarbons.

Vehicle Entry to a

Process /

Hydrocarbon Area

Vehicles shall only be allowed into a process area if covered by a PTW. A PTW is not required for a hazardous area

but gas testing is mandatory for both.

Vehicles shall be subject to continuous gas monitoring while inside the area.

The gas test shall be to check for an explosive or flammable atmosphere.

Testing Instruments Gas testing shall only be carried out by authorised ‘gas testing’ personnel who havecompleted the necessary

training. These personnel shall be registered in PDO.

Testing can be carried out using approved instruments. The following types are in use by PDO:

- Multigas monitors (indication usually in % LEL or % Vol or ppm dependant on the gas being monitored)

- Explosimeters (indication usually in % LEL)








Detector Tubes Detector tubes are single ‘spot’ check devices for detection of gases in the direct vicinity of where the sample is

taken. Different detector tubes are provided for different gases, the selection of the detection tube being dependant

on the gas being detected.

A ‘fixed volume3’ sample is drawn through the detector tube by a hand pump. The detector tubes are calibrated and

the change in colour observed will indicate the concentration of the gas present.

In PDO the typical gas sampled for using detector tubes is H2S and CO2.

Pre-User Checks Before using a portable gas detector (with exception of detector tubes) the following shall be observed:

i. Ensure that the gas detector ‘test’ is in date. Do not use a gas detector that is ‘out of test’

ii. Check the gas detector for signs of damage. If damaged record and report the nature of the damage and

exchange the gas detector for one that is undamaged (if possible)

iii. Before using the gas detector ensure the ‘battery’ is fully charged

iv. After switching on purge the gas detector with uncontaminated air




procedures can be developed to conduct the required work safely.

Evaluation and interpretation of the gas measurement data, and development of the procedure, should be done by,

or reviewed by technically qualified personnel based on a Risk Assessment.

Verification Testing The atmosphere of a permit space which may contain a hazardous atmosphere shall be tested, using the appropriate

gas test equipment to evaluate conditions are safe, at the time of analysis, to commence the required work. Results

of testing (i.e., actual concentration, etc.) shall be recorded on the Permit to Work (PTW).

“Measurement is by volume of the total atmosphere. ”

Duration of Testing Measurement of values for each atmospheric parameter should be made for at least the minimum response time of

the test instrument specified by the manufacturer.

Testing Stratified

Atmospheres

When monitoring for entries involving a descent into atmospheres that may be stratified, the atmospheric envelope

shall be tested a distance of approximately 4 feet (1.22 m) in the direction of travel and to each side. If a sampling

probe is used, the entrant's rate of progress should be slowed to accommodate the sampling speed and detector

response.

Order of Testing A test for oxygen is performed first because most combustible gas meters are oxygen dependent and will not provide

reliable readings in an oxygen deficient atmosphere. Combustible gases are tested for next because the threat of fire

or explosion is both immediate and more life threatening, in most cases, than exposure to toxic gases and vapours.If

tests for toxic gases and vapours are necessary, they are performed last.

PPE Respiratory protective equipment

Gloves

Helmet

Chemical Resistant Clothing




Hazardous

environments




Working in Confined Spaces

Potential Hazards

Associated with

Confined Space Entry

In preparing for confined space entry ensure the potential hazards associated with confined space entry arerecognised. These hazards can be any or all of the following:

Oxygen deficiency or enrichmentFlammability (fire and / or explosion)

Residual liquids, or solids and associated toxic or other noxious gases

Chemical hazards

Physical hazards

Number of personnel working within the confined space and rescue access to them

Restricted entry / exit

Narcotic and anaesthetic effect of hydrocarbon gas and vapours

Emergency rescue equipment and methods

Planning and RiskAssessment

The first priority is to consider if the work in the confined space can be limited or avoided. Alternatives may be:

i. Residues may be removed from the outside using water jetting or in place cleaning systems.

ii. In some cases it may be possible to see inside without entering by using a boroscope.

iii. Use of non-invasive inspection techniquesIf the work is to be carried out in a confined space a risk assessment shall be completed covering all activities thatwill be carried out both inside and outside of the space.

Personnel selected for confined space entry shall have the correct level of competence, experience and knowledgeas indicated by the risk assessment. It will be necessary to include Vendors / 3rd parties or HSE professionals in thistask.

The risk assessment will consider but is not limited to:




The Permit Applicant The Permit Applicant shall prepare a rescue plan as part of the Risk Assessment Process suitable for the agreedmaximum number of personnel and covering each entry. This document should be reviewed and approved by theResponsible Supervisor. Some examples of possible inclusions to the rescue plan are:

i. Number of personnel required to provide effective rescue.ii. The equipment required for immediate use

iii. Contingency plans for loss of communication

iv. Safest route of access and egress with respect to casualty handling

v. Removal of unnecessary obstacles, which will hinder rescue operations

The Permit Applicant must appoint a trained rescue team before work begins. For efficient functioning, a rescue teammust consist of at least two persons. The Permit Applicant must be sure that the designated rescue team can bedeployed quickly in an emergency and that they will be able to function effectively. If assistance is required this shallbe provided by the Area Fire Service.

The rescue team must be equipped with suitable personal protective equipment to enable them to function efficiently.

Rescue plans covering the maximum permitted number of personnel will be agreed and practiced before any entrytakes place. If it is not possible or practicable to perform training exercises before entry, it is the Permit Applicantresponsibility to ensure all parties with responsibilities under this plan are competent in their roles.

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vi. When a person is in a confined space a standby person shall be in attendance at all times and theresponsible supervisor shall ensure that this person is authorised and fully briefed on the activity to beundertaken

vii. Additional hazards, including concurrent activities in the vicinity of, or within, the confined space are

consideredviii. When entry to a confined space is required using breathing apparatus, only those persons trained and

deemed competent in the use of the breathing apparatus shall be allowed to enter the confined space

ix. All personnel involved in the confined space entry shall made aware of the hazards

CAUTION: Additional to the use of Portable Multi-Gas Testers confined spaces that have contained hydrocarbonsshall be tested using a Photo-Ionization Detector (PID – e.g. Draeger tube) to confirm that Occupational ExposureLevels are complied with before an entry is made. This is particularly important for the very low exposure limits of thecarcinogenic compounds such as Butane, Pentane and Benzene

Gas Freeing andFlushing

Tanks, towers and vessels that have contained hydrocarbon or toxic materials shall require gas freeing andventilation before entry4 can be made.

Gas freeing shall be in accordance with PDO Procedures, PR-1073 - Gas Freeing, Purging & Leak Testing ofProcess Equipment (Excluding Tanks)and PR-1079 - Gas Freeing and Purging of Tanks Procedure. Once gas freedand drained5 the confined space can be opened and ventilated. This method may be employed where highconcentrations of toxic gases are encountered.

Flushing with water (produced if available) shall be used on pipework, tanks, towers and vessels to remove heavyhydrocarbon deposits before opening for cleaning and / or maintenance and repair.

Working Atmosphere Gas testing of confined spaces shall only be carried out by an Authorised Gas Tester and shall be as specified on thePTW and recorded on the Confined Space Entry Certificate and the Additional Gas Test Record form (if required).

Oxygen Confined spaces may only be entered when the atmosphere inside has been certified as having a safe oxygen(between 20%-21%) content as indicated by approved PDO detection apparatus.

http://sww3.pdo.shell.om/getdoc?dataid=93875&objAction=download









PR-1515 - Control of HSE Risks of Dealing with Mercury in PDO Facilities

Internal temp andhumidity

For entry to spaces like Waste Heat Recovery Units of gas turbines, additional hazards may exist. These hazardsexist due to the operational service where the space has been subjected to high temperature. Hazards such asinternal temperature, humidity and hot surfaces should be included in the risk assessment, and suitable controls put

in place. These controls could for example, result in work duration being reduced accordingly.Breathing apparatus For entry in to a confined spacewithout the use of breathing apparatus , tests may include but are not limited to:

Oxygen (between 20%-21%)

H2S shall be no greater than 1ppm

Benzene shall be less than 1ppm, but preferably zero

Hydrocarbons in air less than 2% LEL but preferably zero (see Table)

<2% Entry allowed without BA

≥2% and <10 or atmosphereunsustainable

Entry only with BA

≥ 10% No entry allowed

CAUTION:If it is considered that, the breathable atmosphere cannot be guaranteed then entry shall be completedwearing breathing apparatus.

Ventilation Ventilation shall be employed to make the atmosphere inside of the confined space able to ‘support life’. Where theatmosphere in the confined space is flammable or toxic, forced ventilation will be employed to extract and clean airbe allowed to replace that extracted by natural circulation from a low point.

WARNING: Outside air shall not be forced in to expel the flammable atmosphere as this may cause an explosivemixture being formed.






SAFETY HARNESSES / LIFELINES

Safety harnesses shall be provided for all persons working inside the confined space if the work involves scaffoldingor ‘raised’ platforms. Suitable ‘strong points’ shall be made available if not already provided. Lifelines shall be used atall times by personnel inside the confined space.

PORTABLE POWER TOOLS

Where practical power tools used within confined spaces shall be ‘pneumatic’. Use of electrically powered equipmentshall be kept to a minimum and be in accordance with SP-1111 - Temporary Electrical Supplies for Construction &Maintenance Work.

The preference shall also be made to adopt pneumatic lighting for confined spaces rather than those powered fromelectrical circuits.

Confined Space EntryProcess

The following process shall be followed or adapted when undertaking work which requires ‘entry into a confinedspace’.

The following Permits and Certificates are associated with Confined Space Entry:

i. Permit to Work (PTW)

ii. Confined Space Entry

iii. Mechanical Isolation

iv. Additional Gas Test Record

v. Electrical Isolation

The Permits and Certificates shall be completed, signed and attached to the PTW with a Job Safety Plan (includingRisk Assessment) and all relevant drawings and documents.

Refer page 16 of PR1148 for more detail








shall be used to continuously monitor the atmosphere.

Liquid nitrogen, released into the atmosphere in an uncontrolled manner, will quickly change form to a gas, thus

producing an asphyxiation hazard from the nitrogen-enriched atmosphere.

Precautions

Prior to using nitrogen in either a gaseous or cryogenic form, an assessment of the risks to both personnel and

equipment, from leaks or spills, shall be carried out. Particular attention should be paid to:

Provision of drain paths for spills and leaks.

Routes for temporary hoses.

Provision of First Aid equipment and competent persons to use it.

Written procedures for the operation, including emergency procedures for dealing with spills and

leaks.

All work involving the use of nitrogen shall be controlled by the Permit to Work (PTW) System. Barriers and warning

notices shall be erected around the work area. All openings, man ways, pipe ends etc. must be clearly marked, and

oxygen monitoring and rescue equipment provided. All personnel involved in the operation shall be instructed in thehazards associated with nitrogen operations and the types and functions of monitoring equipment being used.

Where habitats or partial enclosures are required, these shall be treated as Confined Spaces, and the controls and

precautions associated with Confined Space entry shall be applied.

Facility H2S Currently facilities within PDO shall be classified under one of the following categories:

O S G S S G b i l i d l




Notes

AUTHORISED GAS TESTER by Nigel Pitt: - Module 1



y g

JOB SAFETY ANALYSIS WORKSHEET (EXAMPLE ONLY)

JOB: Repair Thermocouples onLiquid Burner Flare

SUPERVISOR:I Sweatalot (Rigger), R Puller (Inlec),D White (Tech haul)

TEAM MEMBERS:B Pollock, C Black(Rigging Foreman)

DATE: 29.2.99

STEP DESCRIPTION OF JOB STEP POTENTIAL ACCIDENTSOR HAZARDS

SAFE CONDITION ORACTIVITY REQUIRED

1. Isolate power services. Burner could operate. Risk of electrocution. Obtain relevant permits to work.2. Run leads up tower. Risk of falling from height (workman). Falling objects. Use licensed rigger for all work outside handrail. Wear safety harness and

lanyard. Standard PPE. Station man at chain barrier as watchman to restrictaccess.3. Communications. Not understanding signals. Have radio communications top and bottom.4. Raising tools/equipment by hand. Items may fall. Use lifting basket and inspect equipment.5. Replace earth straps under burner chamber. Risk of falling from height. (As per No. 2).6. Replace thermocouples. Use of ladder on buckled floor. Standby at base of ladder. Ladder to be lashed at top. Person on ladder to

use safety harness.7. Connect thermocouples. Dropping tools/meters. Keep tools in bag on walkway. Keep people clear below.8. QA/QC inspection. Falling objects. Restrict access. Coordinate work above to allow access.

agt learner guide dec 4

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