Occupational Hygiene in the - PowerPoint Presentation

Slide1

Occupational Hygiene in the

Oil & Gas Industry

Day

4

– Section

14

Specific IssuesSlide2

Topics

Intrinsic Safety of Equipment

Explosimeters

Mercury

Inorganic Lead

Managing Maintenance Activities

Turnaround Hazards

Benzene

Hydrogen Sulphide

Some Case Studies Slide3

INTRINSIC SAFETY OF EQUIPMENT

International Electrotechnical Commission Scheme for standards relating equipment for use in explosive atmospheres is known as IECEx.

Across the world there has been a general move towards the adoption of IECEx Standards and in particular the 60079 Series for Gases and Vapours and the 61241 Series for dusts - Europe, United Kingdom, South Africa, USA, Canada, Asia and Australia and New Zealand

.Slide4

Explosive Limits

An explosion can only take place if the following three factors are present:

A flammable substance

Oxygen

An ignition source

An explosion only occurs if the substance-air mixture lies within a certain concentration range – the explosive limits. Lower Explosive Limit = LEL, Upper Explosive Limit = UEL

For petrol 1.4% LEL, 7.6%UEL, but hydrogen 4% LEL, 75%UELSlide5

Explosion Protection

The hierarchy for explosion protection is:

Reduce or avoid the use of flammable substances

Do not allow any releases of flammable substances to form potentially explosive atmospheres

Remove sources of ignition from the potentially explosive atmosphere

Use adequately designed equipment that reduces the probability of causing an explosion

Provide measure to reduce the effects of explosions

Guidance is provided in the IECEx Standards to enable the choice of suitable equipment based on the following processes.Slide6

Classifications of Zones

Gases, Vapours, Mists Dusts Explosive Atmosphere is Present

Zone 0 Zone 20 Most of the time

Zone 1 Zone 21 Some time

Zone 2 Zone 22 Seldom or short term Slide7

Explosion Groups

For zone classification, the explosive materials are examined and the explosion protected electrical equipment is divided into two groups depending on where it is used:

I equipment used in underground mining – explosive materials being mainly methane and coal dust

II equipment used in other hazardous areas i.e.: other industries with additional subgroups for Group II according to the nature of the explosive gas atmosphere for which is intended:

IIA – least readily ignited gases such as propane and benzene

IIB – more readily ignited gases such as ethylene and diethyl ether

IIC – most readily ignited gases such as hydrogen and acetyleneSlide8

Temperature Class

Temp Class Maximum Permissible Surface Temp (°C)

T1 450

T2 300

T3 200

T4 135

T5 100

T6 85 Slide9

Ex marking label

Only appropriate certified and marked electrical equipment may be used in hazardous areas.

Users of electrical equipment must ensure that the equipment complies with the relevant regulations and local standards.

The information of the name of the manufacturer, model number, Ex code and certificate number is attached to the equipment.

Smith Electronics, Model TRE

,

Ex ia IIC T4

Cert 098X, Serial No 8765

“ia” equipment is suitable for zone 0 application

IIC the equipment is suitable for Groups IIA, IIB, IIC

T4 the equipment is suitable for gases with auto ignition temperature greater than 135°CSlide10

Intrinsic Safety of Equipment Petroleum Industry

Petroleum industry requires all equipment used in the field must be intrinsically safe

Most IH equipment is intrinsically safe

Not battery powered e.g. colourmetric tubes

Meets intrinsic safety requirements

Ex ia IIC T4

Some equipment no intrinsically safe models,

Sound level meters (Dosimeters usually are OK)

Mercury meters

Radiation meters

For these, use Hot Work Permit+Explosimeter (continuous mode)

Special cases - Hydrogen rich atmospheres – Reformer recycle gas 80% H2 require higher standard of intrinsic safetySlide11

Hazardous ZonesSlide12

Explosimeters

“Nitrogen Blankets”

vessels purged with nitrogen gas (‘nitrogen blanket’) to minimise the flammability of the product contained in the vessel.

insufficient oxygen to support life,

explosive limits measured in this nitrogen blanket with an explosimeter (LEL or Lower Explosive Limit) a false low reading can be obtained underestimating the risk

Lead Alkyl Interference

Lead alkyls causes rapid poisoning of catalyst material in the meter. This could result in a false reading and indicate a safe condition where a potential hazard exists.

Vapours containing sufficient lead alkyl to seriously affect the operation of an explosimeter may be found in:

Tanks that contain or have contained leaded gasoline

Sewers, service tunnels and other enclosed spaces where spilled leaded gasoline could collect

Places where leaded gasoline sludge has been buriedSlide13

MERCURY

Mercury can be found in trace amounts in some crudes and gas streams

Because it can form a vapour, it can be transferred from the field through the production process into the refinery.

Amalgamates with aluminium components in heat exchangers and may cause catastrophic failures in cryogenic units.Slide14

Mercury

Mercury f

ound in exchangers and vessels during shutdowns

Exchangers and vessels are steamed out prior to entry. Usually steaming is done into a closed process

Mercury vapour monitors can been used to “sniff” for mercury in and around steam plumes bled off from vessels and equipment

Mercury can condense to free liquid and be trapped in the steel walls of the vessels and piping, even after cleaning

Some mercury is likely to remain in walls of vessels and may leach out during hot work

Mercury vapour measurements should be done prior to any Confined Space Entry to vessels, which are suspected of containing mercury. Slide15

Exposure Standards - Mercury

Exposure standard for elemental mercury vapour in air is Time Weighted Average (TWA) 0.025 milligrams/cubic metre (0.025 mg/m3) or 25 micrograms/cubic metre (25 μg/m3). [Australia, ACGIH TLV]

No STEL for Mercury

When evaluating 12 hour shifts this equates to 0.012 mg/m3 (12 μg/m3)Slide16

Atmospheric Testing & Monitoring

Most likely locations for mercury deposits are:

exchangers,

towers,

knockout pots

accumulators.

In general, the air around refinery does not contain mercury. Most mercury will be removed following steaming/cleaning.Slide17

Mercury

Free Mercury Leading From a Partly Opened Exchanger Flange

Slide18

Mercury Vapour Analyser

Jerome 431X Mercury Vapor Analyzer

sensitivity range of 0.003 to 0.999 mg/m3 Hg

Other makes are:

EMP-1A Mercury Meter

OhioLumex Co. RA-915+ Portable Mercury Vapor AnalyzerSlide19

Mercury Testing - Other

Colorimetric detector tubes available - Kitigawa or Dräger,

Only give a spot reading

Less accurate.

Dräger tube + or – 20% of the actual concentration

Kitigawa + or - 15%.

Dräger/Kitigawa tubes are used if the mercury meter cannot be used for testing in a hazardous area (the mercury meters are not intrinsically safe), or if readings are above 1.0 mg/m3 (1000 ug/m3) as this exceeds the mercury meter range.

High standards of personal hygiene must always be maintained to avoid contamination.Slide20

Cold Work?

Hot Work?Slide21

Cold Work & Hot Work Permits

COLD WORK

–

does not involve use of powered equipment, no possibility of sparks, ignition sources

.

Examples – digging trench, inspections, use of intrinsically safe equipment.

Identifies work to be undertaken, safety precautions, gas testing (explosimeter), other activities in the area. JSA, Sign in/Sign

out

HOT WORK

–involves use of powered equipment, flame, sparks, and possibility of ignition sources.

Examples – welding, grinding, cameras, use of non-intrinsically safe equipment.

Identifies work to be undertaken, safety precautions, gas testing (explosimeter) other activities in the area. JSA, Sign in/Sign outSlide22

Other Permits

Confined Spaces

Identifies work

in

a confined space, safety precautions, gas testing (explosimeter), other activities in the area. Sign in/Sign out, Standby-person, radio communications. Examples – tank cleaning, turnarounds

Special (Asbestos Removal)

Identifies

work to be done,

safety precautions, gas testing (explosimeter), other activities in the area. Sign in/Sign out, isolation of area. Standby-person, radio communicationsSlide23

Cold Work in a Confined Space

Confined Space Entry Permit

Test atmosphere inside vessel and

results

entered on permit under ‘Other Tests’, or as an additional

the

mercury vapour concentration < 0.012 mg/m3, then no respiratory protection is required.

If the mercury vapour concentration > 0.012 mg/m3,

<

0.6 mg/m3, wear a full face respirator with a canister/cartridge type Hg filter.

If

mercury

vapour concentration > 0.6 mg/m3, then the vessel should be further cleaned and/or ventilated prior to entry, and retested until

levels

are acceptable.

Why these limits

?Slide24

Hot Work in a Confined Space

Job Safety Analysis (JSA) - appropriate Respiratory Protection and other PPE necessary.

Heating of vessel or enclosure where mercury may be present, even after the vessel or enclosure has been decontaminated

mercury may

still be liberated in high concentrations from below the immediate metal surface of the vessel.

Mercury is absorbed into, as well as

adsorbed

onto metal surfaces when it is cooled, however mercury is released when the surface is heated.

Slide25

Tips From Experience

Mercury inside vessels and exchangers can be best seen at night using a torch, the inside walls of the vessel will ‘sparkle’.

In some instances, hygienist have noted there is an odour of foul air (not H2S/RSH) when significant levels of mercury are present.Slide26

Mercury Saturated Vapour PressureSlide27

Mercury in Refineries

Determine if mercury has been detected in crude or gas processed at the facility

Review mercury content of crude or condensates. Crude containing >30 ppb mercury may result in accumulation within equipment. [Some oil companies use >8 ppb].

Typical high mercury crudes - Southeast Asia, South America Andes, North American ‘overthrust belt’ [Rocky Mountains], North Sea Gas Slide28

Mercury in Refineries

2.

Conduct assessment for potential worker exposure

to mercury when

selected equipment

is

opened for maintenance or repair

.

Desalter, crude towers, light end towers

(Gas plants) and

associated heat exchangers.

Elemental mercury tends to eventually accumulate in C3 and C4 fraction.

Perform several measurements, and average the result

Protect personnel from exposure to mercury, or other gases H2S

Use PPE as appropriate. Slide29

Mercury in Refineries

3. Implement exposure controls where mercury exposure may exceed the TLV.

Include mercury monitoring on entry permits

Require the use respirators where mercury in air exceeds the TLV or where mercury vapour may be generated from work activities

Require PPE to prevent skin contact with mercury

4. Communicate results and recommendations to management/employeesSlide30

Inorganic LEAD

Lead‑based paints & removal during maintenance activities.

Lead paint removal jobs usually done by specialised contractors

Other source of lead exposure - fumes generated during soldering; usually managed with good work practices (good personal hygiene) and local extraction ventilation and/ or respiratory

protectionSlide31

Risk Assessment for Lead Paint Management Project



Methodology



Assessing Risk to Environment



Assessing Risk to Public



Assessing Risk to Adjacent Workers



Project Emission Control Level



Containment Criteria



Monitoring Requirements

- Instrumental Air Monitoring for TSP Dust and TSP Lead for air quality (Environmental)

- Monitoring Visual Emissions of dust from containment

- Worker Exposure monitoring

- Soil Monitoring, Ground surveys, soil samples analysed for lead content



Establishing Boundaries of Regulated AreaSlide32

Lead based paint

Lead Based Paint = Lead content in excess of 1% (weight). [Some companies use >0.5%]

Small Project - Removal of less than 10 m2 area may be excluded from requirements for project

Exposure Standard for atmospheric monitoring: ACGIH (2009) TLV Exposure Standard of 0.05 mg/m3 which is 1/3 of the Safe Work Australia Standard of 0.15 mg/m3.Slide33

Steps – Lead Based Paint Project

1. Determination of the presence of lead

2. Selection of painting strategy

3. Assess risks to public, environment and other workers

4. Establishment of site-specific limitations on emissions

5. Selection of appropriate paint removal/containment system

6. Selection of appropriate monitoring systems to verify emissions are controlled

7. Establishment of worker protection requirements

8. Establishment of waste management requirements

Determination of project completion requirements

Preparation of project cost estimates

11. Preparation of a comprehensive specification to address above stepsSlide34

Step 1 - Determination of lead

1.

Do initial tests using "Lead-Check Swab" test Kit on all (continuous) surfaces.

For example: on an exchanger 10 m long - test the outer shell in two places, test each end.

2.

Take bulk sample of paint (scrapping) and submit to an approved laboratory with sample IdentificationSlide35

Lead Paint Removal Guideline

Scope -Removal of leaded paint - potential for excessive exposure to lead dust or fumes.

Abrasive Blasting Burning

Sanding Welding

Chipping Cutting

Identification of Lead in Paint

Containment and Restrictions

WARNING

LEAD WORK AREA

NO SMOKING OR EATING

WEAR PROPER PROTECTIONSlide36

Lead Paint Removal Guideline

Personal Protective Equipment

Work Practices Safeguards

Use of mechanical methods such as chipping, sanding, grinding or buffing prior to welding, cutting, or burning leaded painted surfaces,

Do not wear street clothes under coveralls during removal operations

No smoking, eating or drinking is permitted in the work area

HEPA vacuum coveralls after use, or dispose as contaminated clothing

Do not use compressed air to clean coveralls or work areas; These should be wet clean or HEPA vacuum

Wash hands before eating, drinking or smoking and at the end of the shift

Do not exit the work area wearing contaminated clothingSlide37

Lead Paint Removal Guideline

Decontamination and Disposal

Place lead contaminated debris, including protective clothing, and used respirator filters in sealed containers

Label all containers as ‘hazardous lead’

Dispose of waste in accordance with local regulations

Remove respirator only when all cleanup and safe containment of contaminated clothing is accomplished

Wash respirator facepiece immediately

Repainting

Monitoring – Supervision

Clearance Testing -

Visual inspection, Lead Check testSlide38

Managing Maintenance Activities

Maintenance activities - three categories:

Preventative (scheduled) maintenance, includes daily/weekly inspections to determine status of equipment and need for repairs

Emergency (non-scheduled) maintenance, repairs of failed equipment (sometimes associated with fire and explosion)

“Turnarounds” – shutdown, major overhaul and inspections (taking 5 to 40 days).

In addition -

Workshops and Service ShopsSlide39

Hygienist’s Role -2

Deciding on ventilation/extraction equipment requirements for confined spaces Conducting hazard awareness training, confined spaces training

Ensuring appropriate procedures for radiation source removal/storage/re-installation

Review lighting needs

Establishing procedures for special jobs (such as abrasive blasting, asbestos removal, two pack epoxy resins/paint applications)

Ensuring appropriate emergency equipment is available (deluge shower/eye wash facilities)

Reviewing previous turnaround experienceSlide40

Occupational

Hygiene Resources during Turnaround

Depends on nature & size turnaround.

From advisory, on-site availability, day shift coverage, or through to 24 hours/day 7 days/week presence with several occupational hygienists.

Occupational hygienist should visit the worksite at least once per day, and more frequently if possible.

Provide advice/support/monitoring to supervisors,

Address worker concerns as they arise and observe the work in progress

Where appropriate assess exposure risks and/or recommend control measures to minimise exposure

.Slide41

Tank repairs

Tank Issues

Confined space

Lead-based paints

Alkyl Lead sludge

Metal fumes

Flammable vapours

Congested areaSlide42

Oxy cutting gasoline tank floor

Issues

Confined space

Lead-based paints

Alkyl Lead sludge

Asbestos

Metal fumes

Flammable vapoursSlide43

Tank Repairs

Air driven extraction fan

Improved access – hole cut in tank wall, ramp for bob-cat, scaffoldingSlide44

Cutting top strake of naphtha tank

Issues

Working at height

Lead-based paints

Metal fumes

Flammable vapoursSlide45

Some of the Issues -1

Spent Catalyst -

potential hazards catalyst dust, oxygen depleted atmosphere

Vessel Entry –

Confined Spaces (build-up of toxic vapours, oxygen depletion, obstructions, alkyl lead sludge) Oxygen Limits -

> 19.5% < 23.5%. Flammability limits

Inspection Test Hazards -

include instrumental and manual measurements of wall thickness, hammer tests, hydro or air pressure tests and visual observations. X-ray and Gamma ray testing of welds, wall thickness. Fluorescent salt in oil painted on the surface of vessels or pipes detected by illumination ultra-violet light source.Slide46

Some of the Issues - 2

Pyrophoric Materials

"

Pyrophoric material" means“ any material igniting spontaneously or burning spontaneously in air when rubbed, scratched, or struck, e.g.: finely divided metals". One example is Iron Sulphide

Iron sulphide oxidizes exothermically when exposed to air will ignite.

Rapid

exothermic oxidation with incandescence is known as ‘pyrophoric oxidation’ and it can ignite nearby flammable hydrocarbon-air mixtures.

Found in solid iron sulphide scales in refinery units (reformers where the process operates in a pressurised hydrogen atmosphere, demister pads in reformers).

Found in vessels which have contained sour hydrocarbon streams or product streams with sulphur compounds (H2S, SRU units) Slide47

Some of the Issues - 3

Vanadium in Heater Ash

Refinery fuel oil or heavy bottoms products can contain traces of Vanadium (refer to crude assay). This Vanadium is oxidised in the combustion process to Vanadium Pentoxide (V2O5) - deposited on the heater walls, floor, tubes with ash, carbon/soot and other combustion deposits.

Mercury in Exchangers, Pipework

Removal of Insulation

MaterialsSlide48

Start-up Hazards

After the turnaround maintenance activity is completed, the process units go through a start-up procedure.

This can include:

Steam purging,

Nitrogen purging or (hydrogen purging such as reformers).

Open vents and drain lines are progressively closed as the unit returns to normal operations;

Flushing of the unit to blowdown systems and to the atmosphere occurs.

The ‘Start-up’ of a process unit is perhaps the most dangerous operation of all.Slide49

Taking an acid sample Slide50

Taking a spent caustic sample

Before

After redesign of sample point Slide51

Flares - ‘Safety valve’ of rig, gas plant or refinery

Located well away from process units

Burns unwanted gas to protect over pressurising during upsets

Steam used to reduce smoke

Hazards – Noise, smokes, odoursSlide52

Benzene

Crude can contain (0.01 to 3.04%) Benzene

Catalytic Reformer streams (8%)

Some petrochemical streams (naphthas) up to 13%

Other sources – Coke ovens in steel works (BTX)

Exposure Standards

(ACGIH 2012) 0.5 ppm TWA, no STEL (ACGIH 2012)

Australia (Safework Australia) 1 ppm TWA, 3.2 ppm STEL

Hazard

Benzene - human carcinogen – leukemia

Flammable LEL 1.3%, UEL 7.9%, flash point -

11C (12F)Slide53

Benzene Program

Identify process streams and worker groups with potential exposure

Identify tasks with benzene exposure

Assessment procedures for open process work with streams that may emit benzene

Control systems for open process work involving benzene exposure, including temporary local exhaust ventilation, respiratory protection, gloves, and protective clothing

Policies and procedures for biological monitoring and medical assessments for benzene exposure.

Training of workers in the hazards of benzene exposure, procedures and controls for open process workSlide54

Hydrogen Sulphide – Toxic Gas

Common contaminant in crude, natural gas and present in oil and gas streams.

Deadly asphyxiant, affect olfactory senses.

Corrosive to steel process equipment.

Flammable Limits LEL 4%, UEL 44%

Exposure Standards

(ACGIH 2012) 1 ppm TWA, 5 ppm STEL

Australia (Safework Australia) 10 ppm TWA, 15 ppm STEL Slide55

Hydrogen Sulphide Program

Identify systems, equipment, or locations where H2S is present

Occupational exposure limits ― ceiling, short term, and full shift.

Procedures for monitoring H2S in process streams

Policies for installation and maintenance of fixed H2S area monitors and alarms

Policies and procedures for worker use of personal H2S monitors

Emergency response equipment and procedures for H2S releases

Worker training on hazards, characteristics of H2S, locations of hazardous process streams, use of personal H2S monitors, and what to do if there is a release in their facilitySlide56

Some case studies

Asphyxiation on LNG Construction Site

Asphyxiation of Chinese Welder on LNG Construction Site

Argon/TIG Welding Incidents from 2002 – 2009

Inert Gases (What You Need To Know)

Confined Spaces

Safety Awards

Shell Service Station VideoSlide57

Asphyxiation of Welder on LNG Construction Site

Refer to separate presentationSlide58

Asphyxiation of Chinese Welder on LNG Construction Site

Refer to separate presentationSlide59

Argon/TIG Welding Incidents from 2002 - 2009

Refer to separate presentationSlide60

Inert Gases - What You Need To Know

Refer to separate presentationSlide61

NORM & H2S Canada

Ponnachan Joseph AIHce 2010 Roundtable presentation

Refer to separate presentationSlide62

Confined Spaces

Refer to separate presentationSlide63

Crazy things people do

Refer to separate presentation

‘Safety Awards!!”Slide64

Shell Service Station

Refer to separate video presentationSlide65

End of

Section 14

Specific Issues