The 5 Minute Safety Thinker
For The Construction Industry
Do you know ---- about GAS WELDING & CUTTING?
There are three citations that are most often cited concerning gas
welding and cutting. They are: (1) Valve protection caps are not
in place on compressed gas cylinders; compressed gas cylinders
are not secured in an upright position; and lastly, welders do not
know additional rules about welding hazards as provided in the
ANSI standards. What can we do about the hazard?
Let's discuss below.
H A Z A R D
Many welding and cutting fatalities occur from cutting on tanks, vessels,
and drums that have contained flammable or combustible liquids. This is
prevalent for companies involved in underground storage tank removals.
Many of the tanks are too large to be transported and must be cut up into
smaller sections.
When the tanks are not properly cleaned first and
either filled with water, inerted, or ventilated before cutting, disaster can
occur. Testing the atmosphere is not sufficient because some chemicals
do not give off flammable vapors at room temperature. However, when
heated with a cutting torch, these chemicals release trapped flammable
and combustible products creating an explosive atmosphere.
Other hazards which are associated with compressed gas cylinders involve
damage to cylinders by heat or the weather. Cylinders can be knocked
over and if the valve caps are off and the cylinder is unsecured, the danger
of a rocket exists if the valve is knocked off. There is the possibility of
cylinders being knocked over by passing or falling objects.
A hazard with acetylene, a fuel gas cylinder, is its flammability
characteristic. Acetylene can become unstable when laying on its side,
ABATEMENT
SUGGESTED SAFETY MEETING AGENDA:
Review topic below and discuss the ANSI standards,
review the diagram drawings of the oxygen and acetylene cylinders. See ANSI Z49.1-1967, summary of
Safety in Welding and Cutting, in reference materials
behind this safety meeting.
Oxygen cylinders unsecured.
One cylinder
is missing
valve cap.
therefore, acetylene shall
be stored in a vertical
position.
Finally,
welders need to know
hazards associated with
gas cutting and welding.
The ANSI standard
Z49.1, 1967, should be kept available on the jobsite and
reviewed often to ensure that all welders and cutters are
familiar with the rules.
OXYGEN / ACETYLENE
STORAGE REQUIREMENTS
The construction standard under 29 CFR 1926.350 has some basic rules
to remember about gas welding and cutting. They are: (1) When
transporting, moving, and storing compressed gas cylinders, valve caps
shall be in place and secured. (2) Cylinders are not to be hoisted by
means of a magnet or choker slings. (3) Cylinders shall be moved by
tilting and rolling them on their bottom edges. (4) When transported
by powered vehicles, they shall be secured in a vertical position. (5)
Do not use valve protection caps to lift cylinders. (6) Use a cylinder
truck, chain or steadying device to keep cylinders in place while in use.
(7) Remove regulators from cylinders when transporting unless they
are firmly secured on a special carrier. (8) Close cylinder valve when
not in use. (9) Separate oxygen from fuel gas while in storage by 20' or
by a noncombustible barrier at least 5' high with a fire resistant rating of
.5 hours. (10) Store fuel gas cylinders in a well ventilated building.
When welding or cutting, place cylinders far enough away so that sparks,
slag or flame will not reach them. If not practical, place fire resistant
shields between the cylinders and the work. Do not take oxygen or
acetylene cylinders into confined spaces. Do not use cylinders as rollers
or supports. Be sure that your employer thoroughly instructs you in
the safe use of fuel gas concerning regulators, cylinder use, fuel gas and
oxygen manifolds, hoses and torches, and oil and grease hazards.
© 1997 Safety Consulting, Inc., Revised Topic 2005
Barrier between
oxygen/fuel gas
should be a
MINIMUM:
5 Ft. High and a 30
minute Fire Rating
CI3-J-01
SAFETY MEETING ATTENDANCE ROSTER
Page 1 of _____
Company: ____________________________________________
Date: ___________________
Meeting conducted by: (Name)______________________________________________________
Topic of Meeting: The 5 Minute Safety Thinker entitled CI3-J-01, Gas Welding & Cutting
Other Subjects/Hazards Discussed: __________________________________________________________
_______________________________________________________________________________________
Video: _________________________________________________________________________________
Other Training Aids Used: _________________________________________________________________
Meeting Attended By: (Please have employee sign below)
1_________________________________________
17
____________________________________
2_________________________________________
18
____________________________________
3_________________________________________
19
____________________________________
4_________________________________________
20
____________________________________
5_________________________________________
21
____________________________________
6_________________________________________
22
____________________________________
7_________________________________________
23
____________________________________
8_________________________________________
24
____________________________________
9_________________________________________
25
____________________________________
10
_________________________________________
26
____________________________________
11
_________________________________________
27
____________________________________
12
_________________________________________
28
____________________________________
13
_________________________________________
29
____________________________________
14
_________________________________________
30
____________________________________
15
_________________________________________
31
____________________________________
16
_________________________________________
32
____________________________________
If additional signature space is needed, please photocopy this page.
© 1997 Safety Consulting, Inc., Revised Topic 2005
Are there any storage
requirements necessary for
oxygen and acetylene?
POSTER
© 1997 Safety Consulting, Inc., Revised Topic 2005
CI3-J-01
AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) Z49.1-1967
SAFETY IN WELDING AND CUTTING
Cited in 1926.350(j)
A SUMMARY
This summary is intended solely as an introduction to ANSI Z49.1-1967. It cannot be substituted for a thorough
knowledge of the standard.
SCOPE
This standard is for the protection of workers from injury and illness and the protection of property from damage by
fire and other causes resulting from welding and cutting.
3.
Installation and Operation of Oxygen, Fuel/Gas Systems for Welding and Cutting
3.1
General Provisions
3.1.1
Mixtures of fuel gases and air or oxygen shall be guarded against. No device or attachment facilitating or
allowing mixtures of air or oxygen with flammable gasses prior to consumption, except at the burner or in
a standard torch, shall be allowed unless approved for the purpose.
3.1.2
Under no condition shall acetylene be generated, piped (except in approved cylinder manifolds) or used
at a pressure in excess of 15 psi gauge pressure or 30 psi absolute pressure.
3.1.3
Only approved apparatus such as torches, regulators or pressure-reducing valves, acetylene generators
and manifolds shall be used.
3.1.4
Workers in charge of oxygen or fuel-gas supply equipment, including generators, and oxygen or fuel-gas
piping systems shall be instructed and judged competent by their employers for this work before being
left in charge. Rules and instructions covering operation and maintenance of systems shall be readily
available.
3.2
Cylinders and Containers
3.2.1
Approval and Marking
All portable cylinders used for the storage and shipping of compressed gases shall be constructed and
maintained in accordance with Interstate Commerce Commission regulations. Compressed gas cylinders
shall be legibly marked to identify their gas content.
3.2.2
Storage of Cylinders – General
· Cylinders shall be kept away from sources of heat.
· Empty cylinders shall have their valves closed.
· Valve protection caps shall always be in place, hand tight, except when cylinders are in use or
connected for use.
3.2.2.2
Inside of buildings, cylinders must be stored in a well-protected well-ventilated dry location at least 20
feet from highly combustible materials such as oil or excelsior. Assigned storage spaces shall be located
where cylinders will not be knocked over or damaged by passing or falling objects, or subject to tampering by unauthorized persons. Cylinders shall not be kept in unventilated enclosures such as lockers and
cupboards.
3.2.3
Fuel/Gas Cylinder Storage
Acetylene cylinders shall be stored valve end up. Inside a building, cylinders, except those in actual use
or attached ready for use, shall be limited to a total gas capacity of 2,000 cubic feet or 300 pounds of
LPG. Storage of more than these amounts requires a separate room, compartment, or building.
3.2.4
Oxygen Storage
Oxygen cylinders shall not be stored within 20 feet of fuel gas cylinders or highly combustible material,
especially oil and grease, unless separated by a noncombustible barrier.
3.2.5.1
Oxygen Cylinders
Cylinders, cylinder valves, couplings, regulators, hose and apparatus shall be kept free from oily or
greasy substances.
3.2.5.4
Use – Oxygen Cylinders
Unless connected to a manifold, oxygen from a cylinder shall not be used without first attaching an
oxygen regulator to the cylinder valve. Before this connection is made the valve shall be “cracked.”
Cylinder valves shall be opened and closed by hand.
3.2.5.5
Use- Fuel/Gas Cylinders
Cylinders shall be handled carefully. Before connecting a regulator to a cylinder valve, the valve shall be
cracked. Before a regulator is removed from a cylinder valve, the valve shall be closed and the gas
released from the regulator.
3.5.3
When parallel lengths of oxygen and acetylene hose are taped together, not more than 4 inches out of 12
inches shall be covered with tape. Hose connections shall be securely clamped or fastened so as to
withstand twice the pressure to which they are normally subjected in service, but in no case less than a
pressure of 300 psi.
3.5.6
Pressure-reducing regulators shall be used only for the gas and pressures for which they are
intended. Union nuts and connections on regulators shall be inspected before use to detect faulty
seats. Damaged nuts or connections shall be destroyed.
THE SLEEPING GIANT
I AM A HIGH PRESSURE, COMPRESSED GAS CYLINDER
I stand 57 inches tall.
I am 9 inches in diameter
I weigh in at 155 pounds when filled.
I am pressurized at 2,200 pounds per square inch (psi).
I have a wall thickness of about 1/4 inch.
I wear a regulator and hose when at work.
I wear a label to identify the gas I'm holding. My color is not the answer.
I transform miscellaneous stacks of material into glistening ships and many other things-when properly
used.
I may transform glistening ships and many other things into miscellaneous stacks of materialwhen allowed to unleash my fury unchecked.
I can be ruthless and deadly in the hands of the careless or uninformed.
I am too frequently left standing alone on my small base without other visible means of supportmy cap removed and lost by an unthinking workman.
I am ready to be toppled over-when my naked valve can be damaged or even snapped off-and all
of my power unleashed through an opening no larger than a lead pencil.
I am proud of my capabilities-here are a few of them:
*I have on rare occasions been known to jetaway-faster than any dragster.
*I might smash my way through brick walls.
*I might even fly through the air.
*I may spin, ricochet, crash and slash through anything in my path.
You can be my master only under these terms:
*Full or empty-see to it that my cap is on, straight and snug.
*Never-repeat-never leave me standing along. Secure me so that I cannot fall.
CYLINDER STORAGE FOR ACETYLENE (C2H2)
Acetylene gas may be stored in cylinders specifically designed for this purpose. The
gas is first passed through filters and purifiers and then compressed into cylinders
to a pressure of approximately 250 psig. The storage of acetylene in its gaseous
form under pressure is not safe at pressures above 15 psig. The method used to
safely store acetylene in cylinders is as follows:
1.
The cylinders are filled with a substance such as pith from cornstalk, fuller's
earth, lime silica, and similar substances, which absorb acetone.
2.
The cylinders are then charged with acetone which absorbs acetylene. The
theory is that the acetylene molecules fit in between the acetone molecules.
Using both of these techniques prevents the accumulation of a pocket of high
pressure acetylene.
Safety fuse plugs have a metal center which will melt at a temperature of approximately 212 degrees F. If the cylinder should be subjected to a high temperature the
plugs will melt and allow the gas to escape before the pressure builds up enough to
burst the cylinder. These precautions are necessary as the pressure in an acetylene
cylinder builds up rapidly with an increase of temperature.
Acetylene cylinder valves come in two types. A common type is provided with a
3/8-in square shank. It is turned by means of a 3/8-in square box socket wrench.
It is recommended that this cylinder valve be opened only 1/4 to 1 1/2 turns. The
wrench should be left on the valve stem at all times that the valve is open, in order
that the valve may be closed quickly in emergencies.
Another type of acetylene cylinder valve is fitted with a handwheel. The regulator
fitting is a female fitting.
The amount of acetylene in a cylinder cannot be estimated by the pressure in the
cylinder because the gas discharge pressure will remain fairly constant (depending
on the temperature) until most of the gas is consumed.