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Cribbing: Soft, Hard, or Plastic?
A Posting from Forum Moderator Ron Moore
When asked about my thoughts on vehicle rescue cribbing, I see two ways of approaching the subject. Soft or hard wood?. Plastic is completely out of the question in my opinion for any type of individual pieces of cribbing other than the pre-formed plastic stepchocks. In my opinion, individual pieces of plastic cribbing should be illegal for fire departments to use at a crash scene! They should be banned from existence.
FEMA recommends that crews doing structural shoring use soft wood, construction-grade lumber for their building collapse rescue. Soft wood allows the heavy loads of a crushed building to sink in as it compresses. You'll hear the creaking and cracking as the wood takes on the load. Soft wood is cheap so if the wood cracks or get contaminated at a scene, you just throw it away.
A box crib of 4x4 dimensional pine lumber, either regular pine or pressure-treated, can support a <br />load of 24,000lbs if constructed properly. Put three pieces parallel on each layer and it will support more than double that.
The smallest building collapse cribbing is generally 24 inches in length and is sized as 2x4, 4x4, 6x6 and even larger.
For extrication, the recommendation I make is hard wood. This is the strongest material under all <br />situations. Plano Fire Rescue bought "cribbing paks" from Frank Maltese, of the Branch <br />Corporation <[email protected]>. His wood is true dimension hard wood maple. 1x4, 2x4, 4x4 and <br />wedges with rope handles. These are very durable and are well liked by our crews. Kind of a once <br />in a lifetime investment because the wood holds up so well.
I believe that vehicle rescue cribbing should be a maximum of 18 inches in length. We tried 24 inch stuff but it is too long for most car crash operations.
For a department just starting out, wondering what cribbing they should invest in, I'd try this. If you can get hard wood fine. Go with it. If not, purchase regular construction-grade wood at a Home Depot-type place and cut it into 18" lengths. Secure strap handles (such as pieces of old seatbelts) onto the ends and bundle it into a carry bag. See how the guys like it. If it holds up OK, you're a hero. If the wood continues to crack or fail, or is to soft for your use, transition over to hard wood.
A note on building wedges. If you want to build a wedge, start with a 4x4 block that is 22 inches long. Measure 4 inches in from each end and mark it. Cut on a diagonal between the 4 inch marks at each end. Leaving 4 inches solid at the thick end of a wedge makes a very strong wedge with a good <br />angle. You can do the same to create a 2x4 wedge.
Two pair of stepchocks will also be very valuable. These can be the plastic manufactured material or you can build them yourself out of wood.
Quantities of cribbing and how many of each size you carry is your decision. Consider space on your response vehicles, your most common crash scenario, and the types of vehicles that you generally encounter. At least have enough on-hand to get you through your bread and butter rescue calls.
Any other suggestions, comments, things you're doing to make your own cribbing, lessons learned, training tips, or hidden secrets you want to share????
When asked about my thoughts on vehicle rescue cribbing, I see two ways of approaching the subject. Soft or hard wood?. Plastic is completely out of the question in my opinion for any type of individual pieces of cribbing other than the pre-formed plastic stepchocks. In my opinion, individual pieces of plastic cribbing should be illegal for fire departments to use at a crash scene! They should be banned from existence.
FEMA recommends that crews doing structural shoring use soft wood, construction-grade lumber for their building collapse rescue. Soft wood allows the heavy loads of a crushed building to sink in as it compresses. You'll hear the creaking and cracking as the wood takes on the load. Soft wood is cheap so if the wood cracks or get contaminated at a scene, you just throw it away.
A box crib of 4x4 dimensional pine lumber, either regular pine or pressure-treated, can support a <br />load of 24,000lbs if constructed properly. Put three pieces parallel on each layer and it will support more than double that.
The smallest building collapse cribbing is generally 24 inches in length and is sized as 2x4, 4x4, 6x6 and even larger.
For extrication, the recommendation I make is hard wood. This is the strongest material under all <br />situations. Plano Fire Rescue bought "cribbing paks" from Frank Maltese, of the Branch <br />Corporation <[email protected]>. His wood is true dimension hard wood maple. 1x4, 2x4, 4x4 and <br />wedges with rope handles. These are very durable and are well liked by our crews. Kind of a once <br />in a lifetime investment because the wood holds up so well.
I believe that vehicle rescue cribbing should be a maximum of 18 inches in length. We tried 24 inch stuff but it is too long for most car crash operations.
For a department just starting out, wondering what cribbing they should invest in, I'd try this. If you can get hard wood fine. Go with it. If not, purchase regular construction-grade wood at a Home Depot-type place and cut it into 18" lengths. Secure strap handles (such as pieces of old seatbelts) onto the ends and bundle it into a carry bag. See how the guys like it. If it holds up OK, you're a hero. If the wood continues to crack or fail, or is to soft for your use, transition over to hard wood.
A note on building wedges. If you want to build a wedge, start with a 4x4 block that is 22 inches long. Measure 4 inches in from each end and mark it. Cut on a diagonal between the 4 inch marks at each end. Leaving 4 inches solid at the thick end of a wedge makes a very strong wedge with a good <br />angle. You can do the same to create a 2x4 wedge.
Two pair of stepchocks will also be very valuable. These can be the plastic manufactured material or you can build them yourself out of wood.
Quantities of cribbing and how many of each size you carry is your decision. Consider space on your response vehicles, your most common crash scenario, and the types of vehicles that you generally encounter. At least have enough on-hand to get you through your bread and butter rescue calls.
Any other suggestions, comments, things you're doing to make your own cribbing, lessons learned, training tips, or hidden secrets you want to share????
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