Structural Collapse Technician Training

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Structural Collapse Technician Training

• Appendix C
• Metal Burn Cutting

Jan09
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Unit Objectives

• The student will understand the capabilities and
  limitations of all the types of metal burning
  that can be used in USR operations
• Understand how to efficiently and safely cut and
  remove multiple pieces of steel from a debris
  pile

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Enabling Objectives

• Discuss how to conduct a site hazard analysis
• Select appropriate PPE
• Select the most efficient metal burning equipment
  based on needs of an incident
• Discuss safety practices associated with the
  different metal burning equipment
• Identify hazardous situations found when cutting
  and burning on a debris pile
• Understand the safety practices to minimize risk
  to rescuers.

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Enabling Objectives

• Discuss the use setup of the various types of
  metal burning equipment based on safety, material
  type thickness
• Identify special issues involved with
• Compressed gas cylinders
• Oxy / acetyleneuse and safety
• Gasoline / oxygen operation
• Discuss proper breakdown, storage and shipping
  methods for the metal burning equipment in FEMA
  USR Cache

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Topics to be discussed

• Oxy/Fuel process Safety
• Personal Protective Equipment
• Types of Metal Burning Equipment
• Oxy/Acetylene
• Oxy/Gasoline
• Exothermic/Oxygen Lance
• Plasma Arc
• Storage shipping methods

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Oxy Fuel Process
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General Safety Guidelines

• Metal burning requires strict compliance with all
  manufacturers safety guidelines
• Biggest causes of injury
• Burns from hot material or ultraviolet rays
• Breathing toxic materials
• Wear full PPE at ALL TIMES
• Wear UV rated eye protection
• Use proper respiratory protection
• Work in 2 person teams

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General Safety Guidelines (cont.)

• Inspect all equipment prior to use for damage and
  leaks
• Have a fire extinguisher or small hose line
  available for spot fires
• Hydrate often
• Consider the reaction of your actions before and
  while cutting a piece of steel or cable

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Have a safety person watch the area for fire and
other hazards
Be aware of heavy equipment and other people
working above and below
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Two Person Team
The tender is the burners second set of eyes
because the person burning is focused on the
progress of the cut
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Personal Protective Equipment

• In addition to the Std USR PPE
• Shaded eye protection
• Leather gauntlet gloves
• Respiratory protection ( Organic Vapor)
• Consider the PAPR
• The level of protection will be dependant on the
  Situation and type of Metal to be removed

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4 different scenarios requiring PPE selection
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Personal Equipment

• Crescent wrench
• Striker/spare flint
• Tool belt
• Tip Cleaners
• Spare Tips
• Marking Paint
• Tape Measure
• Soapstone

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Oxy-Acetylene
Most common Oxy-fuel Process
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Oxy/Acetylene

• Advantages
• Commonly used in many industries
• Wide variety of accessory equipment
• Disadvantages
• Has wide flammable limits
• Limited by the withdrawal rate of 1/7 per hr

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Oxy-Acetylene - Safety Practices

• Do not operate Acetylene above 15 PSIG
• Do not withdraw more than 1/7 of the cylinder
  contents per hour
• Do not drain all of
• cylinder contents
• Keep components and
• area clear of grease, oil and
• other oxidizers/flammables

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Oxy-Acetylene - Safety Practices

• Always operate with cylinder secured in an
  upright position
• Do not operate without Flashback Arrestors and
  reverse flow check valves
• Always perform a
• mechanical check for
• leaking components

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A small Leak can create a BIG event
This event was caused by a leaking 12 cubic ft.
acetylene cylinder similar to what may be carried
in your USR cache
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Oxy Acetylene Equipment
Acetylene cylinder
Must be stored operated in upright position
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Acetylene Cylinder
Open cylinder 1 to 1 ½ turns
Compressed to a pressure of 200-250 PSIG Unstable
in a gas form if above 15 PSIG
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Oxygen Cylinder

• Compressed to a pressure of 2250 PSIG
• Must be secured at all times
• Must be capped in an upright position for
  transport or when not in use

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Alternative oxygen sources - Liquid Oxygen

• The Dewar can evaporate 4500 Cu. Ft. of gas from
  a liquid contained in cylinder
• External evaporator may be needed
• Must be kept in an upright position
• The Green compressed cylinder contains about 250
  Cu. Ft. of Oxygen

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Liquid Oxygen - Dewar
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Compressed Oxygen Trailer

• Used when a large Demand is needed
• A tube style Trailer Cannot be easily moved
  around a site
• May not be readily available

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Oxy Acetylene Equipment
Acetylene Regulator Oxygen Regulator
Do not operate above 15 PSIG

• Regulates gas down to its working pressure
• Stand off to side when opening cylinder
• Regulator screw should be backed out and turn
  freely before opening cylinder

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Flashback Arrestors
Flashback Arrestor prevents a fire from burning
back to the cylinder
Check valves
Check valve allows gas to flow in one
direction A quick connect acts as a check valve
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Hoses are Color CodedAlso threaded differently
depending on application

• Oxygen is Green with Right-Hand threads
• Fuel Gas is Red with Left-Hand threads
• All fuel gas equipment has a groove on the
  fitting to indicate Left-Hand threads

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Hoses Get Abused in Debris PileAre exposed to
sharp edges, etc.Inspect for cracks/burns
other wear

• Make sure hoses are rated for the fuel and proper
  tip size
• Keep clean from grease/oil other oxidizers

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Torches

• Various lengths/styles and head angles
• Some are made for welding and have a cutting
  attachment
• The size of the tip not the torch length
  determines the thickness of the cut

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Torch Tips
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Tip Selection Chart
A 145 cu. ft. cylinder should not have a
withdrawal rate of more than 21 SCFH Refer to the
chart above for safe tip size
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Oxy-Gasoline - Petrogen
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Oxy-Gasoline - Petrogen

• Advantages
• Can cut steel that is up to 14 in. thick
• Will cut through various sized air gaps
• Less likely to fuse itself back together
• Not limited by the fuel cylinder size

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Oxy-Gasoline - Petrogen

• Disadvantages
• Equipment is not available locally
• Rescuers must understand that the Petrogen torch
  setup, tuning and usage is different than the
  oxy-acetylene setup
• Failing to understand the differences will
  produce poor cutting results

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Petrogen Safety Practices

• Always perform a check for leaks
• When checking for a fuel leak look for liquid
  fuel on the ground and couplings
• Secure fuel tank in the upright position Fuel
  cannot flow with tank on its side

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Petrogen Safety Practices

• A flashback arrestor should be used on the oxygen
  line.
• One is not required for the fuel line
• Do not operate fuel tank below 10 psi

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Petrogen Equipment Fuel Tank

• Holds 2.5 gallons of fuel
• Equal to a 250 cu.ft. acetylene cylinder
• Has a pressure relief on the filler cap
• Has a safety valve on the pressure gauge fuel
  valve
• Use the freshest fuel available

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Petrogen Equipment - Torches

• Various lengths/styles and head angles
• The size of the tip not the torch length
  determines the thickness of the cut

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Petrogen Equipment Torch Tips

• Tip has two pieces
• Fuel enters the tip as a mist /atomized gasoline
  oxygen mixture
• Has oxygen and pre heat ports similar to
  Oxy-Acetylene
• If tuned properly, fuel entering tip should keep
  tip cool as it vaporizes

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Petrogen Equipment Tip Chart

• Serves as a basic starting point
• Settings will depend on operator experience
• You are not limited by the 1/7 per hour rule
• Tip does not need to be as clean a for
  oxy-acetylene tip

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Petrogen Equipment
A big advantage of the Petrogen is that is can be
fully broken down and repaired in field with a
spare parts kit.
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Petrogen Equipment - Poor Practice

• Operator Error caused this overheated equipment
• Typically caused by too close of a coupling
  distance or tuning the torch too lean
• A coupling distance of ½ is a good safe starting
  point

Heat transferred from Tip overheated mixer
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Exothermic Torch
Exothermic uses a consumable rod with oxygen
pushing through the rod. Its primary Function is
to melt the material
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Exothermic Torch

• Advantages
• Can burn through almost anything
• Disadvantages
• Operator must wear full PPE
• Large spark showers of molten metal
• Area of work must be free of combustibles

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Oxygen Lance

• Uses exothermic technology but uses a much
  thicker and longer consumable rod
• This allows the operator to be at a safer
  distance away from the material being cut

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Plasma Arc - Electric arc Compressed air

• Advantages
• Can cut ferrous
• non ferrous metal
• Burns clean
• Low slag sparks
• Disadvantages
• Systems that can burn thicker material are large
  heavy
• Also require 220v to operate

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Basic Torch Handling Skills

• Make yourself as comfortable as possible
• Try to work the torch like a pool cue or pivot
  using your hand or material/debris as a pivot
  point

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Estimating Steel Weight - Area Method
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• Steel weighs 490 lbs per cubic ft
• Steel 1 thick weighs 490pcf / 12 40.8 psf
• For steel weight per square foot use
• 1 thick Use 40 lbs
• ¾ Use 30 lbs
• ½ Use 20 lbs
• ¼ Use 10 lbs

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1
12
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Area Method Examples 1 2
36x 2
Example 1
12x 2
36x 2
Example 2
Flanges 24x 5
Web 12x 3.5 inches
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Area Method Example - 1

• What is weight of this 36ft long steel section?
• 2 Steel 2 x 40 psf 80 psf
• Area per ft 2 x 3 sq ft 2 x 1 sq ft 8 sq ft
• Weight per ft 8 x 80 640 plf
• Total weight 640 x 36 23,040 lbs
• Exact weight 652.8 plf (only 2 off)

Pl 36" x 2"
Pl 12" x 2" ea end
Pl 36" x 2"
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Area Method Example - 2

• What is weight of this 20ft long steel section?
• 2 Flanges 40 psf x 5 x 2 ft x 2 800 plf
• Web 40psf x 3.5 140
• Weight per ft 800 140 940 plf
• Total weight 940 x 20 18,800 lbs
• Exact weight 958.8 plf (only 2 off)

Pl 24" x 5"
Pl 12" x 3.5
Pl 24" x 5"
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Area Method Round Tube Shapes

• Get area by Circumference x Length
• Either Measure distance around w/ tape or
• Multiply Diameter x 3 (exact is 3.14)
• Think - cut unfold tube

• Weight per ft is 3 x Diameter x Wt, per sq ft

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Area Method - Pipe Tube Example

• What is weight of this 16ft long steel pipe?
• 12 Diameter x ½ thick
• ½ Steel 20 psf Area per ft 3 x 1 3 sq
  ft
• Weight per ft 3 sf x 20 60 plf, Total 960
  lb
• Exact weight 61.4 plf (only 2 off)
• For Sq Tube use 4 x Size x Wt per sq ft
• For 8 Sq. x ¼ thick x 16ft (10psf for ¼)
• Wt per ft 4 x 8/12x 10psf 26.7 plf, 427lb
• From AISC Hbk 25.8 plf (only 4 off)

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Other clues for Steel Weight

• Numbers painted on steel at the Mill / Shop
• First number is Depth in Inches
• Second is Weight Per Foot in Pounds
• Third is Length in Feet
• Usually located near the end
• May be covered with other paint

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Shipping Storage Methods

• All torches hoses purged of combustible fuel
• Remove quick disconnects if used to completely
  remove fuel
• Store Petrogen torches, hoses fuel tanks in a
  ventilated shipping box
• Regulators are fragile and should be stored in
  protective oil free hard case
• Refer to IATA and local guidelines for shipping
  compressed gases
• Acetylene torches can be stored in a oil free
  hard case

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Review Unit Objectives

• The student will understand the capabilities and
  limitations of all the types of metal burning
  that can be used in USR operations
• Understand how to efficiently and safely cut and
  remove multiple pieces of steel from a debris
  pile