CRIBBING BASIC’S

Definitions

• Cribbing - Specially cut and/or pre cut pieces of wood/polyethylene used to support raised objects, or bases to place tools that are working, and as blocks which chains and cables pass over while moving.
• Box Crib - An arrangement of cribbing that is typically stacked at right angles to the parallel pair immediately below.
• Stabilize - Brace, support or hold steady and make stable in a solid fixed manner.

Definitions cont.

• Foot Print
• Width of the bottom of the stack.
• Gives you a basis on how tall your stack can be.
• Contact Point
• Points on the stack that the weight of the load is transferred to the ground.
• Estimate 6000lbs per contact point when using 4x4’s.
• Estimate 15,000lbs per contact point when using 6x6’s.

Definitions cont.

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• Over lap distance
• Four inches is the minimum that cribbing should overlap.

Safety

• PPE (Incident Dependent)
• Leather work gloves or structural gloves
• Helmet
• Turn out coat and bunker pants with boots
• Reflective vest (incident dependant)
• Radio

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Safety Cont.

Safety concerns to think about:

• Add appropriate cribbing as you lift. Note: The term “lift an inch/crib an inch” is not feasible due to our cribbing thickness.
• Use another piece of cribbing or tool to place cribbing, keeping your hands/body out of the fall area.
• Have a stabilization plan and make sure everyone is on the same page. Think “cause and effect”
• Never pull cribbing out from a supported load all at once. Have a plan in place before removing.
• Do you know what kind of surface your working on? Concrete or paved roadway, swamp lands, grass, snow or ice covered, steep or shallow angle.

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Safety Cont.

Safety concerns to think about cont:

• Do I have enough cribbing or the right materials to get the job done safely and efficiently?
• Never place cribbing on top of an air bag.
• On larger more complex stabilization incidents consider assigning a safety officer to that specific operation.
• When stabilization is complete do a walk around and make sure all your points where cribbing stacks are located are touching/supporting object being stabilized.

Safety Cont.

• FREEZE!! Use this term to stop operations when necessary for safety.
• Never stack cribbing more than two pieces high on same course.

Good

Bad

Incidents that may use cribbing for stabilization

• MVA’s
• Chocking wheels
• Vehicle on its side or top
• Requiring extrication
• Under-ride accidents
• Vehicle into a building
• Industrial accidents
• Vehicle fires
• Structural collapse
• Trench collapse

Cribbing used by �Camas Fire & Rescue

• Soft Wood 4x4

True Dimensions

• Width: 3 1/2 inches
• Height: 3 1/2 inches
• Length: 20 inches
• 1 inch web used for handle

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• Soft Wood 2x4

True Dimensions

• Width: 3 1/2 inches
• Height: 1 1/2 inches
• Length: 20 inches
• 1 inch web used for handle

Cribbing used by �Camas Fire & Rescue cont.

• Soft Wood Wedges

Dimensions

• Width: 3 1/2 inches
• Height: 0 - 3 1/2 inches
• Length: 20 inches

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• Polyethylene Wedges

Dimensions

• Width: 6 & 3 inches
• Height: 0 - 3 inches
• Length: 8 3/4 inches

Cribbing used by �Camas Fire & Rescue cont.

• Polyethylene Step Chock

Dimensions

• Width: 3 1/2 inches
• Height: 10 1/2 inches
• Length: 20 inches
• 5 Step increments, at 2 1/4 - 2 1/2 inches up per step

Equipment that may be used in conjunction with cribbing

Hydraulic Rescue Tools

Lifting Bags

Hand Tools

Rescue 42’s

Box cribbing

A box crib is the most common method of cribbing and is constructed by arranging pairs of wood in a regular log cabin style to form a rising rectangular frame.

Basic box cribbing principles

• Have a solid foot print.
• Ends of cribbing should over lap each other by four inches.
• The higher number of contact points between two courses will increase the stacks strength.
• Rule of thumb: Box crib stack should not exceed three times the foot print height. (example with a 12” foot print your stack should not exceed 36” high)
• Stack is most efficient when weight is directed straight down the stack at all contact points.

Box cribbing designs

2x2 Box Crib

• Typically made out of 4x4’s, but can be made of any dimension lumber.
• A 2x2 box crib made of 4x4’s can support 24,000lbs with all contact points covered.
• A 2x2 box crib made of 6x6’s can support 60,000lbs with all contact points covered.
• Weight bearing capacity and height go down when less than four contact points are touching.

Box cribbing designs cont.

3x3 Box Crib

• Typically made out of 4x4’s, but can be made of any dimension lumber.
• A 3x3 box crib made of 4x4’s can support 48,000lbs with all contact points covered.
• A 3x3 box crib made of 6x6’s can support 120,000lbs with all contact points covered.
• Weight bearing capacity and height go down when less than nine contact points are touching.

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Box cribbing designs cont.

Crosstie Platform

• Will provide greater capacity.
• Down fall is the stack uses large amount of cribbing.
• Is a great platform when air bags need to be elevated for a lift.

Box cribbing designs cont.

Sloped Stack Crib

• Wedges can be used to transfer a sloped load into the vertical supporting column of the stack.

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Box cribbing designs cont.

• Situations will exist where you will not be able to do a perfect box.
• Your foot print will be smaller on sets like these, so watch the height of the stack. (1:1 is a safe rule when not building a perfect box)

Box cribbing designs cont.

• Improper box crib stack.
• Weight is limited to how much the timber can hold across a span.

Resources available with larger amounts of cribbing

• Mutual Aid Engines
• Heavy Rescue 5 (Cribbing up to 8ft long, plywood, Air shores, Air Bags)
• TR61 USAR Trailer (Cribbing up to 8ft, Tele-cribs, Air Bags)
• Home Depot @ 192nd Ave & SE 1st street
• Lowe’s @ 192nd Ave and Mill Plain
• Washougal Lumber Co @ 2820 E street

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Inspections and cleaning

Inspections

• Check for cracks that may be forming.
• Make sure webbing handles are intact.

Cleaning

• Sweep or rinse clean.
• May use a mild soap solution if needed.
• Let dry before placing in cabinet.

FEMA Cribbing Guide

FEMA Cribbing Guide Cont.

FEMA Cribbing Guide Cont.