hydrogen sulfide and iron sulfide
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© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved.
Hydrogen Sulfide and Iron Sulfide Course Number
NSTC-21
Revised 11–2010
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
2Goal
To ensure participants can recognize the hazardous characteristics of Hydrogen Sulfide (H2S) and Iron Sulfide (FeS) and be able to correctly apply the standards and procedures to safely perform work in areas where H2S and FeS are found.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
3Objectives
Participants will be able to:
Identify the characteristics of H2S.
List the hazards of H2S.
Describe the effects of the various H2S concentration levels on humans.
Recognize the need for monitors and alarms which identify the specific levels of H2S concentrations.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
4
Participants will be able to:
Describe the proper notification procedures for an H2S emergency.
Describe the appropriate rescue and emergency treatment for a person exposed to high levels of H2S.
Objectives
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
5
Introduction to H2S
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
6Characteristics of H2S
Highly toxic gas (deadly)
Colorless
Burns w/blue flame and produces Sulfur Dioxide (SO2)
Highly corrosive to certain metals (hydrogen embrittlement)
Flammable (LEL 4%~UEL 44% by volume)
Odor of rotten eggs or sulfur at low concentrations
Soluble in water
Heavier than air (VD=1.19)
Readily dispersed by wind movement
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
7How Is H2S Formed?
H2S may be found naturally in swamps and sewers where it is formed during the decomposition of organic material.
It is present in unrefined carbon fuels and is formed during production when sulfate-reducing bacteria are introduced into an O2 deficient atmosphere where those materials are present. An example would be the injection of untreated sea water into a well to increase formation pressure.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
8Where Is H2S Found?
Natural & Industrial Settings
Produced Water Systems
Ullage/Headspace (temporary overflow)
Drain Systems
Vent Gas Systems
TEG Effluent Streams
Crude Streams
Dead Legs
Abandoned Systems
Wellhead Cellars
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
9
ASH, page 157; BP ASH , page 77
Warning Signs for H2S Designated Areas
Modules and facilities will be designated as H2S areas when they contain a process stream with H2S concentrations in the vapor phase greater than 100 ppm. Entrances to these areas are marked with a CAUTION sign.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
10
H2S designated wellhouse shelters with a process stream at or greater than 300 ppm will be identified with a Danger Sign and shall be tested prior to each entry.
Warning Signs for H2S Designated Areas
ASH, page 158; BP ASH, page 78
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
11
Effects of H2S Exposure
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
12How H2S Enters the Body
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
13Effects of Inhaling H2S
Loss of smell occurs within 2–2.5 minutes at 100 ppm.
Loss of consciousness occurs at 500 ppm.
Asphyxiation occurs at concentrations greater than 1000 ppm.
Exposure to high concentrations of H2S should have not lasting effects if the person is quickly revived.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
14Factors that Affect Exposure
Duration (Time)
Frequency (Number of exposures)
Intensity (Concentration)
Individual Susceptibility
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
15
Physical Symptoms of Short Term, Low Level H2S Exposure
Skin / eye irritation (10–50 ppm)
Dryness in throat and mouth (50–100 ppm)
Nausea (100–200 ppm)
Headache / dizziness (100–200 ppm)
Coughing (100–200 ppm)
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
16
Skin / eye irritation
Fatigue
Loss of appetite
Headaches
Illogical thinking
Physical Symptoms of Long Term, Low Level H2S Exposure
Irrational behavior
Dryness in throat and mouth
Coughing
Loss of consciousness
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
17Responses to H2S
Concentration Response
< 1 ppm Lower odor threshold
10 ppm Personal alarm should sound
>10 ppm Supplied air respirator required
100 ppm IDLH (NIOSH)
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
18Responses to H2S
Concentration Response
150–500 ppm Olfactory nerve paralysis
500–700 ppm Loss of consciousness; death 30+ minutes
700–1000 ppm Rapid unconsciousness; death
1000–2000 ppm Immediate unconsciousness; death in a few minutes
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
19
H2S Detection Devices
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
20Types of Monitors
Personal Monitors
Examples: ISC T40 Rattler, Gas Badge Plus, BW, MS Tox: worn by employee on outside of clothing
Electronic Portable Monitors
Examples: ISC LTX 310/312 Multi-Gas Monitor (1–3 gas)
TMX 410/412 Multi-Gas Monitor (1–4 gas)
ITX Multi-Gas Monitor (1–6 gas)
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
21Types of Monitors
Fixed Electronic Sensors
Hardwired gas detection
Visual/audible alarms and display monitors
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
22
Protection Against H2S Hazards
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
23Protection Measures
Personnel Training, Roles and Responsibilities
Safety Equipment: Supplied Air or Self-Contained Breathing Apparatus (SCBA)
Emergency Procedures and Contingency Plans
Safe Work Practices and Permits
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
24
Unit Operator or Issuing Authority Responsibilities
Perform necessary H2S gas checks.
Note on permits where H2S could be present.
Check that personnel are using personal monitors in H2S designated areas.
Check that personnel are wearing supplied breathing air when working in an area where H2S exceeds 10 ppm.
ASH, page 155; BP ASH, page 76
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
25
First Line Supervisor or Area Authority Responsibilities
Ensure all H2S related activities are in accordance with company standards.
ASH, page 155; BP ASH, pages 76-77
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
26
Company or Contractor Work Group Leader Responsibilities
Contact Control Room/DS/Well Pad Operator for approval to enter the H2S designated area.
Ensure personnel are H2S trained and provide documentation on request.
Provide pre-job review with personnel of facility alarms, evacuation routes, assembly points, etc.
Provide protective equipment and monitors.
ASH, pages 155–156; BP ASH, page 77
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
27
Company or Contractor Work Group Leader Responsibilities
Be aware of the wind direction and choose an evacuation path accordingly.
Conduct personnel head count after an evacuation, H2S or gas alarm and report status to Control Room or Drillsite / Well Pad Operator.
Assign a trained back-up, with ready access to supplied breathing air, when working in H2S atmospheres of 10 ppm or greater.
ASH, page 156; BP ASH, page 77
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
28
Know and understand the H2S facility alarms.
Provide evidence of required H2S training upon request.
Have the training and ability to properly use supplied air breathing apparatus if required to assist in rescue or facility isolation.
Report to the designated briefing area for accountability upon hearing an alarm.
Leave the area at once if levels of H2S are 10 ppm or greater and notify Operations personnel.
Worker Responsibilities
ASH, page 156; BP ASH, page 77
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
29
Safety Measures at the Job Site
Identify site specific rules, routes, and primary and secondary safe areas.
Observe conditions, signs, and audio/visual alarms.
Check wind direction.
Evacuate up wind.
Look for personnel and their activity.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
30
Safety Measures at the Job Site
Enter the job site cautiously.
Have a minimum of two escape routes.
Always be aware of surrounding conditions.
Provide for continuous gas monitoring.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
31
Safety Measures at the Job Site
Personal gas monitors shall be worn at all times in an H2S designated area.
When more than one individual will be working in the same area, at least one personal monitor shall be assigned to the group as determined by the Work Group Leader or Supervisor.
ASH, page 158; BP ASH, page 78
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
32
Information for Reporting Emergencies
Your name
Location of the emergency
Nature of the emergency
What is involved
Number of personnel involved, if any
Other information that you have
Your phone, beeper & radio call sign
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
33Rescue Procedures
Evacuate the area
Activate the emergency response system
Call the emergency number from safe phone
Warn other people away from the affected area
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
34Trained Rescuers
Contact qualified back-up help
Don SCBA
Move victim to fresh air (TWO individuals rescue while TWO stand by)
Begin CPR
Do not leave victim unattended
Report the incident to the Medical Facility
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
35
Always Be Aware of the Hazards of H2S
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
36
Introduction to Iron Sulfide (FeS)
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
37Objectives
Participants will be able to:
Identify iron sulfide sources in the workplace.
Explain the hazards of iron sulfide.
Identify appropriate practices to minimize exposures to personnel and property while opening any tank, vessel, or piping which has contained a hydrocarbon product and may contain iron sulfide.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
38What Is Iron Sulfide?
Iron sulfide is iron that has reacted with hydrogen sulfide (H2S) in an oxygen deficient environment.
Iron sulfide has the formula FeS.
Iron sulfide may be commonly referred to as ferrous sulfide.
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
39Where is Iron Sulfide Found?
Iron sulfide may be present in petroleum process equipment that is in H2S service such as piping, vessels, tanks, and exchangers.
It may be present in scale, sediment or sludge inside process equipment and piping.
ASH, page 158; BP ASH, pages 78-79
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
40Iron Sulfide Hazards
Iron sulfide is pyrophoric. It will ignite in the presence of ambient air without an ignition source.
Burning iron sulfide may emit toxic fumes of sulfur dioxide (SO2).
ASH, page 158; BP ASH, pages 78-79
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
41
Iron Sulfide Control Measures
Prior to opening process equipment that potentially contains iron sulfide, every effort shall be made to clean the equipment by water washing or steam cleaning.
Keep equipment and vessel internals wetted until laboratory analysis determines if the sludge or scale is non-pyrophoric.
ASH, page 158; BP ASH , pages 78-79
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
42
Iron Sulfide Control Measures
All iron sulfide removed from equipment should be immediately discarded into metal containers with tight fitting lids and wetted thoroughly.
It should then be labeled and disposed of according to the Alaska Waste Disposal & Reuse Guide (Red Book).
If iron sulfide does ignite, SCBA’s must be used while extinguishing the fire with water.
ASH, page 158 ; BP ASH, pages 78-79
© 1997-2010 North Slope Training Cooperative—revised 2010. All rights reserved. Course Number: NSTC-21
43Summary
Know the hazards of hydrogen sulfide and iron sulfide and where they are located.
Take precautions to protect yourself and others against these dangerous hazards.
Follow proper procedures for entering areas which may contain hydrogen sulfide and/or iron sulfide.
Follow proper emergency procedures.
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