Low Pressure Air Bags

Low Pressure Air Bags

• Reinforced straps run from top to bottom plate to prevent bulging and lateral movement
• Comparable in size and capacity to medium pressure systems
• Used for lifting or stabilizing overturned vehicles, especially with thin metal walls
• Provide a large footprint to minimize punch-through
• Can be used to fill voids in trench rescue operations
• Reach maximum stability at full inflation
• Operate at 0.5 bar or 7-8 psi
• Require same components as medium pressure bags: air source, pressure regulator, controller, relief valves, and hoses

Fluids and Pressure

• Fluids can be categorized as compressible (gases) or incompressible (liquids)
• Compressible fluids: density significantly changes with pressure, volume decreases as pressure increases
• Incompressible fluids: density does not significantly change with pressure, volume remains constant

Pressure and Pascal's Law

• Pressure: force per unit area applied perpendicular to a surface
• Measured in pascals (Pa) or pounds per square inch (psi)
• Affected by changes in force or area
• Pascal's Law: a change in pressure in a confined fluid results in an equal change in pressure throughout the fluid and container

Medium Pressure Air Bags

• Used for lifting or stabilizing overturned vehicles with thin metal walls
• Provide a large footprint to minimize punch-through
• Used to fill voids in trench rescue operations
• Operate at 1 bar/14.5 psi
• Reach maximum stability at full inflation
• Require air source, air pressure regulator, controller with relief valves, and hoses

Preparing for Lifting Operations

• Identify potential danger areas and keep personnel and equipment clear of those areas
• Maintain a safe stance allowing for rapid egress in case of load shift or fall
• Keep unused equipment in a centralized, safe zone to minimize trip hazards
• Work on a flat surface to avoid slippage and shifting of air bags and loads

Cribbing

• Cribbing material is required to support the load when lifted from the ground
• Cribbing is used to support the load and the air bags
• The "lift an inch, crib an inch" rule is critical to prevent the load from traveling unsupported
• Cribbing helps maintain surface contact between the air bag and the ground, ensuring stability and strength

Supporting the Load

• Air bags must be as close to the load as possible to maximize lifting height
• Place uninflated bags just barely touching the load with no large space in between
• Locate a solid surface under the load and use it as the lifting point, cribbing on both sides of the bags
• The "lift an inch, crib an inch" rule applies here as well

Air Bag Placement and Control

• Place air bags as close to the load as possible to maximize lifting height
• Nipples on the bags can be stacked or staggered for easier hose management
• In-line relief valves can be placed at the controller or the bag
• The controller should be positioned in a safe zone with a full view of the lift

Lift Operations

• One person operates the controller, while another directs the rescuer at the controller
• Communications should be limited to "Up", "Down", and "Stop" commands with the color of the air hose
• Air hoses tend to develop a "memory" and should be stored properly to maintain full surface contact with the air bag

Box Crib Construction

• A minimum of 3-by-3 crib layout should be used to maintain full surface contact with the air bag
• A solid layer of cribbing is necessary on top and bottom when working on soft ground

Stacking Air Bags

• High-pressure air bags can be stacked up to two bags to increase lifting height
• The larger bag should be placed on the bottom, and the smaller bag on top
• The total lift height is the sum of the individual bag heights
• The smaller bag's capacity dictates the total lifting capacity when stacked

Air Bag Lifting Principles

• Air bags can be used in tandem to lift a load that exceeds the capacity of a single bag.
• Each bag must only see its rated capacity, and not be overloaded.

Tandem Lifting

• Two bags of the same capacity can be used in tandem to lift a load, with each bag lifting half of the load.
• The maximum tandem lifting capacity is achieved only at 1 inch of lift.

Lifting Considerations

• When lifting a load, especially if it is resting on a patient, every action has an equal and opposite reaction.
• Cribbing is necessary to provide a hinge point for the load and prevent sway, which could cause further harm to the individual.
• Bags should be inflated slowly to maintain control and prevent the load from shifting.
• If more than one bag is used, inflate one bag at a time to maintain control.

Cribbing

• Cribbing material is necessary to support the load and air bags when lifting.
• The "Lift an inch, crib an inch" rule is critical to prevent the load from traveling unsupported.
• Supporting the air bags with cribbing is necessary to prevent loss of surface contact with the ground.

Air Bag Maintenance

• Routine maintenance of air bags is necessary to keep them operating at peak efficiency.
• Keep the surface of the tools clean and free of dirt, grease, etc.
• Clean the retainer assembly with dry cleaning solvent and lubricate with air tool oil after use.

Air Bag Safety Precautions

• Always pay attention to the load and maintain a stance that allows for rapid egress from the danger area.
• Identify the area that might be affected if the load was to fall or shift and keep personnel and equipment clear.
• Maintain all equipment not being utilized in a centralized area, in the safe zone.
• Work on a flat surface to avoid slippage and shifting of the air bags and or the load.