Hydrogen Safety

Introduction

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• Millions of workers are exposed to hydrogen hazards daily
• Hydrogen is very safe under controlled conditions
• Each year, numerous accidents with hydrogen result in death
• Workers must know the hazards associated with hydrogen
• Safety can be greatly enhanced if training is provided
• Standards require:
• Hazards be assessed
• Training be conducted
• Hazards and precautions be explained
• Emergency response capability be established

Objectives

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• Provide an Introduction to the Toxicology of Hydrogen
• Discuss Hydrogen’s Usage in Today’s Industry
• Discuss General Terms Used in Hydrogen Safety
• Discuss Methods of Compliance with Hydrogen Safety
• Discuss the Routes of Entry Into the Human Body
• Discuss the Hazards of Hydrogen in the Human Body
• Discuss Any Medical Surveillance Requirements
• Discuss Personal Protective Equipment Requirements
• Discuss Hazard Recognition and Control Skills

Learning Outcome

UNDERSTAND THE FOLLOWING:

• Why Hydrogen Safety Is Important
• The Basics of Toxicology as it Relates to Hydrogen
• Basic Safety Precautions Related to Hydrogen Safety
• Specific Hazards Associated with Hydrogen Exposure
• The Training Requirements Associated with Hydrogen
• Housekeeping Requirements Where Hydrogen is Present
• The Use of Personal Protective Equipment to Prevent Exposure

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Use of Hydrogen in Industry

USES OF HYDROGEN IN INDUSTRY:

• Dental industry
• Glass manufacturing
• Tool making industry
• Proprietary processes
• Production of methanol
• Low-temperature research
• Hydrogenation of fats and oils
• Embrittlement of stainless steel
• Fixation of atmospheric nitrogen

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Hydrogen Hazards

• Hydrogen usage is very common and extremely hazardous
• Deaths from hydrogen include both responders and on-site workers
• Injuries and deaths from hydrogen accidents are 100% preventable
• Hydrogen inhalation exposure can result in asphyxiation
• Inhalation is the primary route of entry for hydrogen into the body
• Skin exposure can cause frostbite and loss of limbs
• Work area releases of hydrogen can displace oxygen
• Hydrogen may ignite when mixed with ambient air
• Hydrogen fires are nearly impossible to extinguish
• Hydrogen emergencies can happen instantaneously

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Physical Properties

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• Hydrogen
• Liquefied hydrogen
• Protium

SYNONYMS AND TRADE NAMES:

• Colorless, odorless gas when pure

PHYSICAL DESCRIPTION:

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Vapor Density is the mass of gases and vapors as it is compared to the mass of an equal volume of air or other reference gas.

VAPOR DENSITY:

VAPOR DENSITY OF HYDROGEN IS: 0.07

(Continued)

Physical Properties

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Liquid boils at the point when vapor pressure equals atmospheric pressure. The corresponding temperature is called the boiling point of liquid.

BOILING POINT:

BOILING POINT OF HYDROGEN IS: - 423 Degrees F

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Physical Properties

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Physical Properties

The numerical difference between the upper and lower explosive limits. In other words, the range that the vapors of a flammable liquid (when ignited) will burn when mixed with ambient air.

FLAMMABLE RANGE:

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0%

4.0%

25%

50%

76%

100%

FLAMMABLE RANGE OF HYDROGEN 4 to 76%

PERCENTAGE OF ATMOSPHERE

HYDROGEN

9.5%

Physical Properties

FLAMMABLE RANGE OF HYDROGEN IS: 4% TO 76 %

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Less Than - 423F

865 ft

3

+65F

1ft

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Expansion Ratio compares the amount of gas produced when a certain volume of liquid is vaporized. The expansion ratio of hydrogen is 865 to 1. In open air, one gallon of hydrogen becomes 865 gallons of hydrogen gas.

EXPANSION RATIO:

Physical Properties

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• When mixed with oxygen across a wide range of proportions, hydrogen explodes upon ignition
• Reacts directly with other oxidizing elements
• Hydrogen burns violently in air
• Hydrogen gas is highly flammable and will burn at concentrations of 4% to 76% in air
• Hydrogen mixed with Halogens can produce acids

HYDROGEN ARE INCOMPATIBLES AND REACTIVES:

(Continued)

Physical Properties

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• Toxicity: Non-toxic
• Color: Colorless
• Odor: Odorless
• Vapor density: 0.082
• Range of Flammability: 4 to 76%
• Expansion Factor: 865 Cu. Ft. To 1
• Boiling point: - 423 deg. F

SPECIFIC PROPERTIES:

Physical Properties

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LETS DISCUSS SOME OF THE TERMS THAT WILL BE HELPFUL IN UNDERSTANDING THE AFFECTS OF HYDROGEN ON YOUR BODY.

Hydrogen Toxicology

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ALL THINGS ARE POISONS, OR THERE IS NOTHING WITHOUT POISONOUS QUALITIES. IT IS ONLY THE DOSE WHICH MAKES A THING POISON.

PARACELSUS

(1493 - 1541)

(Continued)

Hydrogen Toxicology

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EXPOSURE TERMINOLOGY

• Ignitability: Is Flammable or Combustible
• Reactivity: Can React With Itself or Other Materials
• Corrosivity: Can Deteriorate Another Substance
• Toxicity: In Its Normal State Is Harmful to Living Things

Hazardous Material. A Material That Falls Into One or More Of the Following Categories. Hazardous Materials Can Have One or Many Characteristics That Can Add to the Intensity of the Toxic Action of a Particular Solid, Liquid, or Gas.

(Continued)

Hydrogen Toxicology

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EVERYTHING IS TOXIC;

IT ALL DEPENDS ON THE DOSE.

How Well the Body Accepts a Substance Depends on:

Hydrogen Toxicology

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THE PRIMARY ROUTE FOR HYDROGEN

INGESTION

ABSORPTION

INJECTION

Hydrogen Toxicology

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Breathing and smoking causes us to inhale substances which enter the lungs. Substances inhaled into the lungs cause scarring of the lungs or are readily absorbed into the blood stream.

• INHALATION
• INGESTION
• ABSORPTION
• INJECTION

INHALATION

Hydrogen Toxicology

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Swallowing a substance causes penetration into the blood stream via the stomach and small intestine.

• INHALATION
• INGESTION
• ABSORPTION
• INJECTION

INGESTION

Hydrogen Toxicology

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Entering the body through the skin causes substances to enter the blood stream at a slower rate than by inhalation or absorption. However, the resulting entry and distribution within the body is the same.

• INHALATION
• INGESTION
• ABSORPTION
• INJECTION

ABSORPTION

Hydrogen Toxicology

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Injection occurs when substances are forced through the skin. This can occur as a result of such means as compressed air, or by having the skin abraded by a penetrating object.

• INHALATION
• INGESTION
• ABSORPTION
• INJECTION

INJECTION

Hydrogen Toxicology

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TLV - Threshold Limit Value: One of three categories of chemical exposure levels - TLV-TWA, TLV-STEL or TLV-C.

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TLV-TWA - Threshold Limit Value Time-Weighted Average: The-time weighted average concentration for a normal 8-hour workday and a 40-hour work week to which nearly all workers may be repeatedly exposed without adverse effect.

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NOTE: Should be used as an exposure guide rather than an absolute. A physician has the final word.

Hydrogen Toxicology

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TLV-STEL - Threshold Limit Value - Short Term Exposure Limit: A 15-minute time-weighted average exposure that should not be exceeded at any time during the work day.

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TLV-C - Threshold Limit Value - Ceiling: The concentration that should not ever be exceeded, even instantaneously.

Hydrogen Toxicology

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• RATE OF ENTRY
• STATE OF HEALTH
• AGE OF INDIVIDUAL
• ROUTE OF EXPOSURE
• PREVIOUS EXPOSURE LEVELS
• WORKPLACE ENVIRONMENTAL FACTORS
• INDIVIDUAL SUSCEPTIBILITY AND HEREDITY

Factors Influencing Toxic Action

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• Acute Exposure:

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Usually Minutes, Hours, or Several Days

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• Chronic Exposure:

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Regular Exposure Over Months, Years, or a Lifetime

The Toxicity of the Chemical or Material Combined With the Susceptibility of the Individual, Determines Whether the Exposure Is Acute or Chronic.

Exposure Terminology

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• Latent Exposure: An injury or disease that remains undeveloped until an incubation period has elapsed. The period of time could be hours, days, months, or years.

The Toxicity of the Chemical or Material Combined With the Susceptibility of the Individual Is a Key Factor.

Exposure Terminology

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The Amount Entering the Body

The Length of Time of Exposure

The Rate of Absorption Into the Blood

The Physical Nature of the Chemical

The Chemical Nature of the Chemical

The Age of the Individual

The Health of the Individual

Factors Affecting Exposure

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• Simple asphyxiation

COMMON SYMPTONS OF HYDROGEN EXPOSURE:

• None

TARGET ORGANS:

Health Effect of Hydrogen Exposure

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HEALTH AFFECTS OF HYDROGEN EXPOSURE:

• Severe Frostbite and loss of limbs or extremities
• Asphyxiation
• Respiratory Failure
• Death

Health Effect of Hydrogen Exposure

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Methods of Compliance Include:

• Implementation of a Written Program
• Establishment of Safe Work Practices
• Establishment of Engineering Controls
• Establishment of Administrative Controls
• Regular Evaluation of Mechanical Safety Systems
• Evaluation of Each Facility Where Hydrogen is Used
• Use of Personal Protective Equipment As a Last Resort
• On-Going Review of the Program’s Effectiveness

GENERAL TYPES OF CONTROLS:

Methods of Compliance

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CONSISTS OF:

ENGINEERING CONTROLS:

• Local exhaust is required
• Automatic alerting is appropriate in most cases
• Purge all systems before introducing hydrogen
• Design and install automatic safety control systems
• Detailed preventative maintenance programs
• On-going on site maintenance activities
• Proper placement of storage systems
• Detailed coordination with emergency responders

Methods of Compliance

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ADMINISTRATIVE CONTROLS:

• Assignment of Responsibility
• Support From Upper Management
• On-Site Safety Inspections and Audits
• Written Policies - Establishment of Site Safety Protocols
• Training - Job Specific Training Programs
• Checklists - Job Specific Safety Checklists
• Placement of Warning Signs and Employee Information

(Continued)

CONSISTS OF:

Methods of Compliance

PROTECTIVE EQUIPMENT AND CLOTHING:

• GENERAL REQUIREMENTS:
• Full body skin protection for potentially exposed workers
• Proper gloves to prevent hand exposure
• Adequate Eye and Face Protection
• Availability of respiratory equipment is mandatory
• Air supplied breathing apparatus is mandatory

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Methods of Compliance

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Vehicle Safety:

• Adequate Protection Against Accidental Vehicle Collisions
• Pre-Planned Traffic Routing for Forklifts and Other Vehicles

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Control of Flammable/Combustible Material in Storage Areas:

• Periodic Inspection of Process and Storage Areas
• Adherence to Safe Distance Requirements for Combustible Materials

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Waste and Empty Container Management:

• Collection and Disposal of Empty Containers
• Storage and handling of dike Containers for Disposal

HOUSEKEEPING IN PROCESS/STORAGE AREAS:

Methods of Compliance

Exposure Control

EMERGENCY ACTIONS IF LEAK IS DETECTED:

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• Stay out of leak area and avoid downwind areas
• High concentrations in the air can cause a displacement of oxygen with the risk of unconsciousness or death
• Responder: Check oxygen content before entering leak area
• Wear Self Contained Breathing Apparatus
• Allow fires to burn out (generally)
• Follow local emergency procedures

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Supervisors will maintain the following for each job:

EXPOSURE INFORMATION:

• A description of each job
• A list of tools or machinery used in the job
• Types of materials processed
• Exposure controls that are in place
• Crew size (if applicable)
• Employee job responsibilities
• Safety controls specific to the job
• Operating procedures specific to the job
• Maintenance practices specific to the job

Exposure Control

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Means to Achieve Safety Compliance:

EXPOSURE INFORMATION:

• Each job where hydrogen is used will have a written description of the specific means that will be employed to achieve compliance, including engineering plans and studies used to determine methods selected for controlling safety of hydrogen.

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• Ensuring employees are familiar with written safety policies.

Exposure Control

Warning Signs

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WARNING SIGNS:

Warning signs shall be install in the area where hydrogen are stored.

Basic Safety Rules

CONTENT IDENTIFICATION:

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• Never assume you know what it is!

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• Assuming (with gases) can kill you!

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• Labels must be legible at all times

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• Labels may not be altered or removed

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• Labels may not be bypassed, ignored, or otherwise defeated

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• Labels must be understood by all

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• Illegible/missing labels must be reported

Basic Safety Rules

CONTENT IDENTIFICATION:

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• Labels and their means of attachment must withstand their normal operating environment

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• Labels may evoke a false sense of security, and their meaning needs to be understood

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• Labels must be securely attached to cylinders so that they cannot be inadvertently or accidentally detached during use

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• Each container must bear the proper label for the gas contained

Basic Safety Rules

PAINTING CYLINDERS/CONTAINERS:

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• Containers may not be painted

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• Painting may cover cylinder defects

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• Containers showing signs of corrosion must be removed from service and returned to the supplier

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• Never rely solely on the cylinder color for identification

Basic Safety Rules

LEAKING AND DEFECTIVE CYLINDERS:

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• Never underestimate the hazard!
• Notify co-workers of the hazard
• Consider evacuation of the area
• Evacuate to open air, upwind or side wind
• Report the contents, location, situation
• Begin role call to account for co-workers
• Do not return to work until all-clear is given
• Bulk Containers - follow established procedures

Basic Safety Rules

CYLINDER USAGE REQUIREMENTS:

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• Verify contents before transporting or using
• Keep cylinder caps on until ready to connect
• Keep valve caps on until ready to use
• Never use as a door stop
• Never underestimate the hazard

Basic Safety Rules

MOVEMENT OF COMPRESSED GAS CYLINDERS:

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• Never handle roughly
• Never use magnetic lifting devices
• Never lift by valves or cylinder caps
• Never roll, drag, or slide the cylinder
• Always use a hand-truck, fork truck, etc
• Cradles, ropes, chains, or slings are prohibited from use unless lugs or lifting attachments are provided by the manufacturer as with bulk containers

Gas Storage

STORAGE REQUIREMENTS (GENERAL):

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• No Smoking signs must be posted
• The name of the gas must be posted
• Specific hazards must be posted
• Containers must be stored upright
• Gases must be stored with like gases
• Do not intermingle full and empty containers
• The oldest material must be used first
• Store only on stable surfaces
• Some gases must always be shaded from sun
• Bulk Containers - follow established procedures

Gas Storage

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Gas Storage

STORAGE ROOMS (GENERAL):

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• Must be dry
• Must not exceed 130 F
• Must be well-ventilated
• Should be protected from tampering
• Local fire inspectors should evaluate
• Compressed Gas Handling Procedure should be reviewed
• Subsurface storage should be avoided
• Should be of fire-resistive construction

Gas Storage

STORAGE ROOMS (GENERAL):

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• Cylinders

- Must not impede emergency egress

- Cannot be located near exits

- Cannot be located near stairs

• Must be secured to prevent toppling
• Bulk Containers - follow established procedures

Gas Storage

OUTDOOR STORAGE (GENERAL):

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• Bottoms must be protected from corrosion
• Must be secured to prevent toppling.
• Must be shaded in extreme temperatures
• Some gases must always be shaded from sun
• Should be of fire-resistive construction
• Should be protected from tampering
• Local fire inspectors should evaluate
• Warning signs should be provided

Cylinder Inspection

GENERAL INSPECTION CRITERIA:

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INSPECT FOR: POSSIBLE RESULT:

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Dents Weakening of cylinder wall

Crevice Corrosion Weakening of cylinder wall

Bulges Weakening of cylinder wall

ARC/ Torch Burns Weakening of cylinder wall

Cuts, Gouges, or Digs Decrease in wall thickness

Corrosion Decrease in wall thickness

Pitting Decrease in wall thickness

Neck Defects Leak or cylinder explosion

Valve Ease-Of-Movement Corrosion leading to leak

Valve Thread Serviceability Leak during operation

Summary

PRE-OPERATION SAFETY RULES:

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• If you’re not trained; do not touch it
• Read the Material Safety Data Sheet before use
• Ensure tag is present
• Ensure all labels/warnings are readable
• Place upright on stable dry surface
• Ensure cylinder is restrained above midpoint
• Keep heat, flame, and electrical sources from gas
• Use in accordance with established procedures
• Bulk Containers - follow established procedures

Summary

POST-OPERATION SAFETY RULES:

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• If you’re not trained; do not touch it!
• Read the Material Safety Data Sheet before use.
• Ensure an empty label is present
• Close valve completely and cap cylinder
• Remove from operation (established procedures)
• Transport cylinder using established procedures
• Place in empty Container storage area
• Ensure empty label is readable
• Bulk Containers - follow established procedures