Compressed Gas SafetyUniversity of NebraskaEHS Lab Safety Colloquium Series Initiative

The information and recommendations contained herein have been compiled from sources believed to be reliable and represent the current opinion on the subject. No warranty guarantee or representation is made by Linweld Inc. as to the correctness or sufficiency of any information contained herein and Linweld Inc. assumes no responsibility therewith. The content in this document is not to be construed as legal advice or the final authority regarding OSHA, EPA, DOT or any other government agencies.

When it comes to handling compressed gas cylinders and cryogenics; there are only three potential problems.

The Containers, The Contents And The Pressure.

Other Than That - There Is No Problem!

The Containers

Gas Packs

Gas Packs

Handling Compressed Gas CylindersNever use cylinders as rollers.Never lift a cylinder by the cap.Never move or transfer cylinders without their caps.Never allow cylinders to be exposed to flame or extreme temperatures. Never tamper with valves.

Lets Talk About The Container

Cylinder Securement All compressed gas cylinders MUST be secured from falling at ALL times.

Use a chain or other substantial restraint devices whether or not the cylinders are in storage or in use.

29CFR 1910.101(b) & CGA 3.7.4

Visually Inspect All Cylinders

Watch for asymmetrical ice patches on the side of the cylinder. Watch for excessive ice build up on the pressure relief valves. Arc burns, excessive heat, corrosion and gouges are a few things that can weaken the walls of a cylinder.

Protect Valves Use caps on all cylinders that are able to receive a cap except when connected for use.

Any cracked or dented caps should be brought to the attention of your Linweld Representative. 29CFR 1910.101(a) & CGA 3.4.1

Regulators are designed to reduce compressed gas pressures to usable pressures.Regulators come in high & low pressure designs.Incorrectly exchanging or interchanging regulators can have catastrophic consequences.

Gas Regulators

Gas Regulators Compressed Gas Regulators are sophisticated and exact metering devices that are required to be used and maintained according to manufacturer recommendations.

Gas RegulatorsThe internal working parts of the regulator are precision units. Only qualified technicians should clean or repair a regulatorThe low pressure gauge indicates the delivery pressure to the hoses & torchThe inlet connections -More just right & left hand thread regulators and connectors are specific to their application. Keep free of oil, grease, & dirt The Pressure adjusting screw turning clockwise allows the gas to flow turning counter clockwise reduces or stops the gas flow The High pressure gauge Indicates the pressure from tank

Interchanging gas regulators has severalpotentially hazardous outcomes. The density and the viscosity of various gases change their flows through flow meters. Thus interchanging flow meters between different gases may result in inaccurate readings. The 02 flow meter is not accurate with Helium, or with air.

Gas RegulatorsPotential Hazards

Interchanging gas regulators has severalpotentially hazardous outcomes. Different gases have different effects with the internal components of the various regulators. Some gases can deteriorate the diaphragms and other working parts.

Gas RegulatorsPotential Hazards

Gas Regulators Handling & Use Regulators are gas specific and not necessarily interchangeable!

Always make sure that the regulator and valve fittings are compatible.

Never use adapters beyond manufacturers recommen- dation.

After the regulator is attached, the cylinder valve should be opened just enough to indicate pressure on the regulator gauge (no more than one full turn) and all the con- nections checked with a soap solution for leaks.

Gas Regulators Handling & Use

Interchanging gas regulators has severalpotentially hazardous outcomes. Oxidizing, Flammable, Toxic, Corrosive and Strong Oxidizing gasses are incompatible and auto-reactive. Even trace amounts in the regulators or gas lines could have potentially catastrophic results.Gas RegulatorsPotential Hazards

Further information can be found in ANSI/CGA V-1-1994 Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections.UNL SOP http://ehs.unl.eduGas RegulatorsPotential Hazards

The ContentsHazardous Material is any material known to create a danger to any persons health, life, or property through contact, exposure, inhalation, fire, explosion or environmental pollution.

All compressed & cryogenic gases are considered Hazardous Materials.

Content IdentificationAll compressed gas cylinders are required to be identified as to their contents.

OSHA Required ComponentsProduct namePrecautionary statementResponsible company

Always check the cylinder label; NEVER rely on the color of a cylinder as to its contents.The Contents

ToxicIrritation

Flammable Sensitization

CarcinogenicExplosive

ReactiveBiological

RadioactiveCorrosive

Teratogenic Mutigenetic

The Contents - Types of Hazards

Gases stored as liquids at temperatures below -130o F.Helium /-452o FNitrogen /-320o FArgon /-302o FOxygen /-297o F

The Contents Cryogenic Liquids

Gases stored as liquids at temperatures above -130o F.Nitrous Oxide / -127o FCarbon Dioxide / -109o FPropane / -44o FAnhydrous Ammonia / -28o F

The ContentsNon-Cryogenic Liquids

Lack of correct PPE and exposure to Liquid Propane

Never allow liquids to contact skin or eyes.If exposed, warm area with warm water.Make a medical referral.Oxygen DisplacementCan cause asphyxiationThe Contents Low Temperature Hazards

Central nervous systemAnoxiaDirect action on neurons

Target organ effectsLiver KidneysBloodReproductive systemThe ContentsHealth Hazards

Flammable Limits (in Air)0%TOO LEANTOO RICHLELUELFIRE OR EXPLOSIONAcetylene /LEL 2.2% - UEL 82.5%Hydrogen /LEL 4.0% - UEL 74.5%Propane / LEL 2.2% - UEL 9.5%The ContentsExplosive Hazards100%

Supports combustion.Do not use near oil or grease.Never refer to oxygen as air.Liquid oxygen can saturate clothing, making them flammable.Keep 20ft away or separated by a hour rated fire resistant wall from flammable materials.

The ContentsOxidizers

Fire Triangle & Fire Tetrahedron

HEATFUELOXYGENUNINHIBITED CHEMICALREACTIONThe ContentsExplosive Hazards

Personal Protective EquipmentGlovesEye ProtectionFace ProtectionClothing and CoveringsAtmospheric MonitoringThe ContentsHandling & Storage

TemperatureWeightRapid VaporizationPressureOxygen Displacement or Enrichment (CO2 is a vasodilator)

The ContentsHazards

The PressureExpansion RatesBesides the contact of cryogenic liquid with human tissue there is the rapid vaporization that must be taken into account.

Coffee Cup IllustrationOne cup of Liquid Oxygen at an expansion rate of 860:1 will produce 649 cubic feet of gas.

One cup of Liquid Nitrogen at an expansionrate of 696:1 will produce 600 cubic feet of gas.

One cup of Liquid Argon at an expansion rate of 841:1 will produce 512 cubic feet of gas.

The PressureAsphyxiation

What does 1/2 pound of Dynamite look like?Lets Talk About The Pressure

The compression of gases is similar to the compression of a spring, the greater compression the greater the release of the stored energy there is. However, unlike a spring in which the energy is released in the opposite direction that it is compressed. Gases do not have a shape, and when accidentally released; releases its stored energy in all directions.

A K size nitrogen compressed to 2200 pounds per square inch, has the stored energy equivalent to a half pound of TNT!

If there was an uncontrolled release of energy such as a valve being sheared off, or the cylinder failed in some way, you would have a rocket or a bomb. Both are undesirable options. Thanks to Don L Wenzl, LINWELD Specialty Gas Technician

Cylinder Force - Dont Make A Rocket, Man.

Other Safety Concerns

Compressed gas streams should never be directed toward any person. CGA 3.3.10 Federal Standard: compressed air shall not be used for cleaning purposes except where reduced to less than 30 p.s.i. and then only with effective chip guarding and personal protective equipment. 1910.242(b)

Always keep the regulator free of oil, grease and other flammable substancesUse the correct regulators for the specific gas service.Never hammer or use cheater bars when connecting or disconnecting regulators or manifold connections.Never tape or attempt to wrap any leaking connections.

DO NOT change the inlet connection on a regulator in an attempt to use the regulator for a different gas service.Never stand in front or behind a regulator when opening the cylinder valve.Identify full & empty cylinders and maintain proper seperations.

The scrappers pickup truck on which the Oxygen GP was being transported.

The pressure relief devices had been removed and plugged using a threaded cap

Cylinder exploded at 12:40 PM while transport vehicle was parked on busy Interstate highwayVehicle LocationCylinder Trajectory

The blast blew one individual across 5 lanes of traffic. The other was blown approximately 40 feet. Both men survived

Cylinder flew approximately mile before plunging throughthe roof of an apartment, severing a main natural gas line andcoming to rest in the living spacePlywood applied over hole in roof

Despite heavy damage, no injuries to apartment tenants were reported

Apartment interior

Note that the media reported the event as a Butane cylinder explosion

Monday the 29th of September, 2003, a fitter with a work van left an E size Oxygen and Acetylene cylinder on the back seat of a Toyota dual cab over the weekend.

This van was destroyed by an explosion from a carbon dioxide cylinder that was allowed to be over-heated.

This is an example of why cylinders need to be correctly secured while being transported.

Always ensure the safety of yourself & those around you before starting any job.

Never look the other way if you see something that is unsafe.

Safety is a Personal Issue Safety is all about YOU!

The ConclusionConclusion

Additional InformationMSDSCompress Gas Association (CGA)Pamphlet P-39, Oxygen-Rich Atmospherewww.cganet.com UNL EHS Safe Operating Procedures http://ehs.unl.eduYour Linweld Representative

The Conclusion

There is NO time that any compressed gas cylinder is to be un-secured. All cylinders that can receive a cap should be capped whenever they are not in use.Frontal Lobe (Located under the forehead--anterior) The frontal lobes are integral to personality, involved in tracking, sense of self, arousal, and awareness of environment. They are responsible for executive functioning and judgment, emotional response and stability, language, and memory for habit. Changes in personality and social behavior Loss of spontaneity in interacting with others Sequencing (difficulties planning and completing complex tasks in correct order) Perseveration (repeating same actions and comments over without conscious awareness of having done so) Loss of flexibility in thinking (mental rigidity). Distractibility Mood swings; emotional lability Diminished abstract reasoning Difficulty with problem solving Language difficulties (usage and word finding) Loss of simple movement of various body parts

Temporal Lobes (Located on the side of the head above ears) The temporal lobes play a key role in intellect, as well as auditory perception (hearing), long-term memory, and some visual perception. Difficulty remembering names and faces Difficulty understanding spoken words Difficulty with identification of, and verbalization about objects Difficulty with concentration Short-term memory loss Interference with long-term memory Aggressive behavior Change in sexual interest Persistent talking (right lobe damage) Difficulty locating objects in environment Inability to categorize objects Religiosity Seizure disorders, auras and strange reveries

Parietal Lobes (Located near the back and top of the head) The Parietal lobe is involved in visual perception, tactile (touch) perception, integration of sensory information that allow for understanding of concepts, and goal-directed voluntary movements.Difficulties naming objects Difficulties writing words Inability to attend to more than one object at a time Inability to focus visual attention Problems with reading Poor hand-eye coordination Confusing left-right orientation Difficulty performing math calculations Difficulty drawing Poor visual perception Lack of awareness of certain body parts and/or surrounding space

Cerebellum(Located just above the brain stem and toward the back of the brain) The cerebellum is involved in coordination and control of voluntary movement, balance and muscle tone. Tremors Nystagmus (Involuntary movement of the eye). Ataxia, lack of coordination. An inability to judge distance and when to stop (dysmetria) An inability to perform rapid alternating movements Weak muscles (hypotonia) Slurred speech (ataxic dysarthria)

Pons (located superior to the medulla oblongata and inferior to the midbrain) The pons contains neural pathways rising from the cerebrum (motor) and spinal cord (sensory), as well as cerebellum It serves as a relay station for messages transmitted from these areas, as well as a center for respiratory regulation.Pinpoint pupils Semi-coma; akinetic mute; locked-in syndrome Abnormal respiration marked by sustained inhalation; hyperventilation

Medulla Oblongata The medulla oblongatafunctions asa cardiac and respiratory center. It is responsible forvasomotor control (nerves having muscular control of the blood vessel walls). It is also a centerfor cough, gag, swallow, and vomit.Movement: Ipsilateral (same side) plegia (paralysis). Dialated and fixed pupils Comatose Abnormal breathing patterns (ataxic, clustered, hiccups) Inability to control movement (absent cough, gag)

Brain Stem (Located at the juncture of the cerebrum and the spinal column, the brain stem consists of the midbrain, medulla oblongata, and the pons.) The brain stem plays a role in heart rate, swallowing, reflexes to sight and sound, sweating, blood pressure, digestion, temperature, levels of alertness, ability to sleep, and balance.Decreased vital capacity in breathing Swallowing food and water Difficulty with organization/perception of the environment Problems with balance and movement Dizziness and nausea Sleeping difficulties (Insomnia, sleep apnea)Brain Death, Death