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..…Making Our Planet More Productive
Safe Handling and
Storage of Compressed
Gases
2
Introduction
All compressed gases by definition can be
hazardous.
Know the properties of the gases with
which you are working. Flammable ?
Corrosive. Toxic?
When working with compressed gases, it
is important to be aware of the hazards
involved with the chemical properties of
the gas itself as well as the hazards of the
physical state of the gas. Will it react to
something.
COMPRESSED GASES ARE SAFE
WHEN HANDLED PROPERLY
3
Overview
Compressed Gas Properties
General Categories of Compressed Gases
Storage and Handling of Compressed
Gases
Regulators For Use With Compressed
Gases
4
Compressed Gas Properties
High Pressure:All compressed gases have an inherent potential energy which
can be released by accidental container rupture or component
failure.
AsphyxiantGases that displace and dilute oxygen in air to unsafe levels.
Pyrophoric:Gases which, under normal conditions, spontaneously ignite on
contact with air.
Cryogenic:Gases which are at very low temperatures and can cause burns
or frostbite if they come in contact with skin
Poison/Corrosive:
Even low concentrations can be lethal or cause long term
health issues
.
5
General Categories
Inert GasesNon-reactive gases that do not cause a change or reaction
when they come in contact with another gas and/or
humans. Inert gases are asphyxiants
Flammable Gases
Gases which, when mixed with air or another oxidizer, in a
given range of concentrations, can burn.
Oxidizing Gases
Gases which do not burn, but do support and aid
combustion.
Corrosive GasesGases which cause destruction of material or tissue when
contact is made, or do so in the presence of moisture.
Poison GasesGases which can chemically produce injurious or lethal
effects in humans.
6
Inert Gases
Definition:
An inert gas is a non-reactive gas.
Examples:
Helium, Neon, Nitrogen, and Krypton
TC Classification:
Non-Flammable Gas
Reason for Hazardous Material Classification:
1. Compressed gas
2. Can cause asphyxiation
Recommended Safety Equipment:
1. Safety Glasses
2. Gloves
3. Oxygen monitoring - When used in a
confined space.
7
Flammable Gases
Definition:
Flammable gases burn when mixed with air in the proper
proportions and exposed to an ignition source.
Examples:
Hydrogen, Methane, Acetylene, and Propane
TC Classification:
Flammable Gas
Reason for Hazardous Material Classification:
1. Compressed gas
2. Displaces oxygen from atmosphere
3. Will burn under the right conditions
4. Can be toxic and/or reactive.
Common Sense Practices to be Followed:
1. Do not vent near an ignition source
2. Vent through a vent line.
3. Purge only with an inert gas.
4. Use a flash arrestor in the regulator outlet.
5. Use stainless steel piping with minimal
fittings and connections.
6. Never interchange flammables and
oxidizing gases on the same equipment.
Recommended Safety Equipment:
1. Safety Glasses
2. Gloves
3. Fire Extinguisher
4. Flammable gas leak detector
8
Oxidizing Gases
Definition:
Support combustion of flammable gases, but do not burn.
Examples:
Oxygen and oxygen mixtures where the O2 level is greater
than 23%, Chlorine, Fluorine
TC Classification:
Oxidizing Gas
Reason for Hazardous Material Classification:
1. Compressed gas
2. Supports combustion
3. Can also be reactive and/or toxic
4. Can cause asphyxiation.
Most Dangerous Situation:
Reactivity of an oxidizer with a flammable gas in a
transmission line.
Common Sense Practices to be Followed:
1. Always use regulators cleaned and labeled for oxygen
service.
2. Only use regulators for the gas service for
which they are specified.
3. Never interchange flammable and oxidizing
gases on the same equipment.
Recommended Safety Equipment:
1. Safety Glasses
2. Gloves
3. Fire Extinguisher
9
Corrosive Gases
Definition:
Gases that “eat” or wear away substances they come in
contact with via chemical reaction.
Examples:
Ammonia, Hydrogen Chloride, Sulfur Dioxide
TC Classification:
Corrosive Gas (international)
Reason for Hazardous Material Classification:
1. Compressed gas
2. Causes irritation in eyes, lungs, and
mucous membranes.
3. Most are also toxic and/or reactive.
4. In the presence of moisture, acid gases generate heat
and can cause a cylinder explosion..
Common Sense Practices to be Followed:
1. Use traps and check valves so water and organic
materials cannot be sucked back into the cylinder.
2. Strictly observe the threshold limit value (TLV) for the
gas in service.
3. Have a full body shower and eye-wash station available
in the immediate work area.
4. Keep all aisle ways clear.
Recommended Safety Equipment:
1. Safety Glasses
2. Gloves
3. Gas mask
4. Shower and eye-wash station.
10
Poison Gases
Definition:
Gases that can severely injure or cause death at low concentrations.
Examples:
Arsine, Hydrogen Cyanide, Hydrogen Sulfide, Chlorine, Carbon
Monoxide, and Nitric Oxide.
TC Classification:
Poison Gas
Reason for Hazardous Material Classification:
1. Compressed gas
2. Can cause death.
3. Reactive
4. Can be non-flammable, flammable, oxidizer, toxic, or any
combination of these.
Common Sense Practices to be Followed:
1. Read and understand the Material Safety Data Sheet (MSDS)
information.
2. Have a working knowledge of how to work with the gas before
you start..
3. NEVER WORK ALONE!
4. Purge lines with inert gas before opening cylinder valve. Leak
test with an inert gas.
5. Keep a minimum inventory of these gases. Long term storage
can lead to misuse.
Recommended Safety Equipment:
1. Safety glasses, gloves
2. Self-contained breathing apparatus (gas masks and special
clothing).
3. Gas detectors
4. Know the location of shower, eye-wash station and alarms.
Make sure they are easily accessible.
11
Pure Gases
Praxair offers multiple assay
certification for specific applications.
(see gas guide). What does the assay
mean?
Purity? What does 5.0 mean,
Purity not effected by cylinder pressure-
will not become less pure as used.
No such thing as 100% absolutely pure.
All cylinders returned are completely
vented and vacuumed prior to re-filling.
Lot tagged for reference (batch
numbers)
12
Gas Blends.
- Restricted by gas reactivity ,
chemically or by Flammability. Mixing
flammable gas with oxidizer gas.
Blend Options- Blend tolerance and
Accuracy of reported Analysis.
Primary Standard/ Certified Standard.
EPA Protocols. (tracaeble to NIST).
Shelf Life. Max 36mnth. (no shelf life on
pure gases).
Certificates of Analysis.
Lead time expectation. Where is blend
prepared..
13
14
Labels/Tags
Required by law- shoulder and body
decals.
Generic gas name, UN number, TDG
symbols- indicating quick hazard
reference.
Cylinder tags- date filled/batch filled
from,
Do not remove/alter .
Do not use gas if unable to confirm by
label.
Optional empty/full tags.
15
Moving Cylinders
Always move with safety caps in place
Do not lift cylinders by safety caps
Do not lift cylinders by magnets
Use approved cylinder carts, check
condition prior to using each time
Avoid uneven surfaces , wet surfaces.
Avoid Stairs, Severe inclines
Never attempt “rolling” cylinders unless
properly trained.
Observe all TDG requirements
16
Storing Cylinders
Store in dry, well ventilated area. Gas
monitors recommended.
Separate and Identify empty and full
cylinders
Group by Hazardous Class. Separate
oxidizers and flammables by 10’
Use signage to alert for Hazardous
Gases.
Toxic gas should be kept secured and
only enough for immediate needs.
Return empty cylinders promptly
17
Before Using..
Check the Label, confirm gas/Purity is
correct.
Know the gas hazard. Refer to MSDS
Secure cylinder .
Insure Gas is compatible with all
material before using.
Insure all equipment downstream is in
good condition and leak tested.
18
Unable to remove Cap?
Never us a lubricant solution. Could
violently react with gas.
Never use a screwdriver to slide thru
cap vents. This can accidently open a
cylinder valve !!
Lightly tap around the base and top to
remove any rusting
Use approved cylinder cap remover
wrench.
Call Praxair.
19
Cryogenic Gases
Extremely cold. Use approved PPE.
Store in protected well ventilated areas
constantly changing from liquid to gas. Dewars may vent thru safety relief devices. Do not tamper/alter.
Ice may form on dewar during applications
Contents gauge not accurate.
Dewars may deliver gas or liquid. Insure you are connecting to correct port.
Do not trap liquid – wil lexpand 700/1. Require PRV valves.
20
Liquid Cylinders
21
Result of tampering with
relief valve
22
Storing cylinders
Keep in protected well ventilated ,dry
environment. Secure areas, Especially
Poisons/Toxics/Flammables
Observe Local NFPA Requirents.
keep flammables and oxidizers 20ft apart.
Toxics/Poisons special storage precautions.
Rated Firewall Barrier.
Insure cylinders properly labeled. Do not group
by color of cylinder.
Insure proper signage available to alert
potential hazards. Ie; Flammable,
Separate Full and Empties , use signage
Store with Safety Caps ,properly secured.
23
Pressure Regulators
24
Regulator Safety
Regulators should be placed in dedicated service
for use with a specific gas or gas blend.
Adapters should never be used to adapt a regulator
with one type of CGA connection to a compressed
gas cylinder with a different type of CGA
connection.
Regulators should be visually inspected with each
use to make sure they have not been dropped or
damaged.
A compressed gas cylinder valve should be opened
slowly to avoid internal damage to the regulator.
A regulator should not be used as a cylinder shut-off
valve. Shut off the gas supply by closing the
compressed cylinder valve.
When the regulator is not in use, the adjusting
screw should be backed off all the way.
25
Continued
Do not attempt any repairs .
Incompatable material or incorrectly
installed parts could cause regulator to
fail. Return o Praxair for service.
Do not use Teflon tape on gas
connection to cylinder. Potential to be
impacted into regulator. Replace fitting
on regulator if needed.
Washers are used in some corrosive
toxic gases on cylinder connection to
provide better seals- insure in place and
in good condition.
26
Gas Fittings
Insure material compatible for gas
service. IE corrosive
CGA fittings. Why different. Where to
confirm what style. What is NPT?
What is a Swage – Lock Fitting?
Push Fittings? Not High Purity
Replace worn or damaged fittings
immedietly.
Do not attempt to remove or replace,
27
Safety Options
Wall mount protocol stations
Pipe away relief valves
Purge Valves
Heated Regulators
Flash Back Arrestors
Gas cabinets
High flow cut off valves
28
Protocol Stations
29
How to order a
Regulator
Confirm gas and Purity
Confirm gas CGA
Confirm Material compatibility
Confirm delivery/flow requirement
Confirm outlet connection needed
Call Praxair to assist.
30
31
How to Connect a
Regulator
Check Cylinder label to insure correct
gas or grade required.
Secure new cylinder
Thread regulator to cylinder valve .Do
not force. Insure any washers in place
Avoid overtightening. Position regulator
away from persons.
Back off pressure adjustment on
regulator completely. Purge line if req’d
Slowly open cylinder valve. Check
contents. Leak test .
Turn off cylinder when not in use. Bleed
pressure from regulator.
32
How to Disconnect a
Regulator
Turn off cylinder valve.
Disconnect regulator. Insure any
washers do not fall off gas connections.
Carefully set regulator down.avoid
stress on outlet gas lines.
move empty cylinder with safety cap in
place by proper cylinder cart.
Reconnect new cylinder.
33
Dry Ice Safety
Compressed Carbon Dioxide.
Extremely cold- Frostbite/ wear all PPE
-109F
Will sublime into gas- can create an
oxygen deficient environment in non
ventilated areas.
Do not store in Airtight container-
34
Questions
Why so many CGA connections?
How to tell if they are reverse threaded
How often do cylinders leak? What is
response?
What is a Hydrostatic test.
Can a cylinder become a rocket? How
likely?
What happens if a cylinder falls over?
What happens to a cylinder exposed to
high heat ?
Thank You
