Using Wedge Wire As an Architectural Feature of Buildings and Bridges

Architecture requires a great deal of work and processing. Developing any kind of structure, whether it be a building or a bridge, there are all kinds of requirements to be considered and thought out, including how the design of the structure in question works practically and aesthetically.

Bridges are used in different ways and so require different designs; a footbridge across a small river, for example, will be much less complex than a bridge crossing a large body of water. Larger bridges need to be able to support people and vehicles of varying sizes whilst consistently enabling safe passage; for example, if it rains it’s important that the bridge doesn’t become too wet, as it will become too slippery to cross safely.

It’s vital that manufacturers are able to work with clients to develop high quality structures and substructures for optimal safety, security and practicality. Carbis Filtration has worked on several projects using high strength and quality wedge wire screens as an architectural feature.

What is Wedge Wire?

Wedge Wire is a welded steel structure that is primarily used for filtration, separation and retention.

Wedge Wire is made up of surface profiles and support profiles. The surface profiles are usually v-shaped to allow for filtrate flow through, and are welded onto support profiles

For the purposes of proper filtration, Wedge Wire’s determines the direction of the flow through its design. This is determined specifically by the direction of the surface profiles in relation to the support profiles, and standard wedge wire screens either direct flow-out-to-in or flow-in-to-out, known as FOTI and FITO respectively.

Wedge wire filters have a lot of advantages from an architectural perspective. For one, the material is very strong, making it ideal for use in the construction. Wedge wire screens are self-supporting as each intersection has been welded,
The design of such screens also minimises clogging, which is ideal for bridges that have to deal with debris, rain, spillages and so on.

Who Develops Wedge Wire?

As well as selling process filtration equipment and vessel internals, manufacturers like Carbis Filtration have developed bespoke architectural wedgewire screens to be used in a number of high profile projects, including:
• Thompson Street Foot Bridge
• Dublin Airport
• Kings Cross Underground London
• Arsenal Emirates Stadium

Carbis’ engineers work with the client from concept to the end, helping them to develop the design and meet whatever requirements the client has. This level of flexibility makes them a popular choice of manufacturer as there is plenty of scope for adjustment to meet the various needs of different organisations. For example, their alloy welding service enables them to cut metal into whatever shape is required.

Carbis’ wedge wire screens are usually constructed in stainless steel for the purposes of durability, but the will produce them in other alloy metals is requested. The screens were developed to cope under the pressures of external forces, from the weather to the strain of pedestrians and traffic. What’s more, their products are manufactured in accordance with the BSEN ISO 9001 quality accreditation. If you’re in need of a manufacturer for a construction project, they’re easily one of the best around.

10 Key Steps for Safe, Effective Simulation Training

There are 10 key steps for creating realistic, scenario-based, decision-making simulations. They are:
1. Needs Assessment

2. Levels of Simulation

3. Creating the Simulation Format

4. Designing the Simulation

5. Training & Controlling Demonstrators

6. Providing the Training

7. Equipment & Safety Procedures

8. Creating Multidimensional Scenarios

9. Creating Multiple-Use Scenarios

10. Debrief

Step 1: Needs Assessment

Instructors must begin the development of a simulation-training program with a needs assessment. On what do their officers need to spend their simulation training time? Although shootouts with heavily armed bank robbers need to be addressed, officers must train for all use-of-force levels. In fact, in a recent series of statewide instructor updates conducted in Wisconsin, Bob Willis, a nationally recognized trainer, found the most glaring need of the 1,800 instructors was communication skills. Train for the needs of your officers – not just the high-risk fun stuff.

Step 2: Levels of Simulation

All too often instructors go too fast, too soon in their simulation training. You can’t teach officers new skills and then, with little or no practice, expect them to do well in high-level, high-stress, decision-making scenarios. After introducing the new skills, instructors should use seven levels of simulation to prepare their officers for high-level, decision-making simulations. These levels include:

1. Shadow training

2. Prop training

3. Partner training

4. Dynamic movement training

5. Relative positioning training

6. Environmental-factors training

7. High-level simulations

Step 3: Creating the Simulation Format

Next, an instructor must work from a written simulation worksheet to provide the necessary documentation of what officers were trained to do. Besides the individual officer-evaluation form, these simulation worksheets should consist of a title page listing scenario type, objectives, overview and equipment; a page for student instructions; a page for role player instructions; and a page with a diagram of the scenario. These worksheets are essential for documenting training and can help you defend against failure-to-train allegations.

Step 4: Designing the Simulation

After the needs assessment, the instructor will begin designing the simulation, which consists of:

1. Developing the simulation

2. Choreographing the simulation

3. Rehearsing the simulation

4. Implementing the simulation

5. Debriefing the simulation

6. Evaluating the simulation

Carefully design, choreograph and rehearse your simulations, or they can lead to training injuries, the adoption of poor tactics and liability exposure.

Step 5: Training & Controlling Demonstrators

The most important component of successful, meaningful simulation training remains the development of well-trained, fully controlled demonstrators. Instructors must assign these demonstrators roles that are specific, limited and carefully supervised to prevent a deviation-from-role that can lead to poor training and injuries. Tell demonstrators specifically and in writing what they can do and, equally important, what they can’t do.

Remember: If you use officers for role players (and most of us do), they love to win. With adrenalin dumping, it’s hard for an untrained, unsupervised role player to remember that the ultimate goal of the demonstrator is eventually to lose (i.e., be controlled by the officer in the simulation). Yes, demonstrators need to be challenging and realistic, but if the trainee performs effective tactics, the demonstrator should give realistic responses and allow the technique to succeed.

Step 6: Providing the Training

Once the simulation is designed and practiced with demonstrators who understand their roles, the instructor can begin the simulation training. Follow this checklist:

1. Conduct an initial wellness check

2. Explain the training safety rules

3. Conduct a physical warm-up

4. Explain the simulation drill’s format

5. Conduct the simulation drill

6. Conduct a debriefing session

7. Conduct a current wellness check

Finally, instructors should make their training a positive learning experience. Properly explain what you expect of the student, conduct a fair, winnable scenario and properly debrief the student.

Step 7: Equipment & Safety Procedures

Although simulation training helps prepare our officers to survive and win encounters on the street, it must be conducted safely – there are no acceptable casualties in corrections, especially in corrections training. Wellness checks, training safety rules and safety procedures make this happen.

Simulation safety begins with the development of appropriate safety procedures, the development and use of safety officers, and the enforcement of stringent safety procedures. Many equipment manufacturers have developed safety procedures to use in conjunction with their equipment. Instructors should always follow these guidelines to prevent unnecessary liability.

Instructors must keep their officers safe from live-fire training accidents.

Step 8: Creating Multidimensional Scenarios

One of the most critical issues facing instructors of corrections tactics training is the difficulty in finding the time to focus on multi-dimensional scenarios that allow their officers to train for the full range of corrections responses. Most simulations now focus on using one of the use-of-force options (i.e., verbal, empty hand control, intermediate weapons or firearms). This creates two challenges: 1) Training officers to respond effectively to the approach, intervention and follow-through phases of any encounter, and 2) preventing officers from getting caught in a single force option loop, unable to move up or down the available force options.

To address the first issue, instruct officers to finish their simulation training with at least one full-length scenario that takes them from initial contact to debriefing the subject at the end of the incident. Address the second issue by teaching the officers transition drills that take them from verbal to empty hand tactics, empty hand to aerosol spray, baton to firearm, etc.

These multi-dimensional scenarios will assist officers in preventing the gridlock that often occurs when facing stressful situations because no bridges have been built between the multiple techniques and tactics officers are trained to use.

Step 9: Creating Multiple-Use Scenarios

Another challenge facing trainers: Over time, their scenarios are soon burned by their officers letting other officers know the scenario prior to taking the class. To combat this, create scenarios with multiple outcomes. Of course, over time even a scenario with a couple of different outcomes can be compromised.

To limit the number of scenarios needed to keep your officers honest, develop a subject-resistance matrix that gives all role players five separate roles, including:

1. Compliant

2. Shell-shocked

3. Physically resisting

4. Presenting a deadly threat

5. Fleeing

Once you define each one of the roles, you can easily change scenarios by switching the role player’s role. This effectively gives you five versions of each scenario when using one role player.

It gets even more fun when you add a second role player, which allows 25 separate scenario versions. This adds an exciting, time-saving dimension to your scenario training because now, instead of creating a whole series of scenarios on a certain topic (e.g., domestic disturbances), you can create one scenario with 25 separate responses. So what if the officers know we are working on domestic disturbances? They don’t know what version they will have to respond to.

Even more important, they will start to place the subjects that they deal with in these five separate categories and learn preplanned tactics for dealing with them more effectively. As an added bonus, officers start transferring these multiple lessons-learned in training scenarios to the real world. They begin to think about multiple endings for those routine dispatches and start to ask, “What’s different this time?”

Step 10: The Debrief

The last step consists of debriefing the officer’s responses in these decision- making, scenario-based simulations. Debriefing is a critical tool in changing and improving an officer’s future performance, but it’s often not done or done badly.

Debrief in a positive manner. The old way of reading the officer the riot act, telling them everything they did wrong and putting them back into line is both destructive and counterproductive. Instead, conduct debriefing in a team-building atmosphere that includes the following components:

• Are you OK?

• How do you think you did?

• Positive comment, if possible

• What would you do differently?

• Role player, and/or peer jury comments

• Instructor summation

In addition to this team debriefing or as a part of it, review a videotape of the incident. Because articulation (having the officer explain why they did the right thing) is an important part of the training process, include it at this point. Many training facilities add report writing and even courtroom testimony to this section.

Take officers out of the scenario and, prior to debriefing, instruct them to make an immediate verbal report to their supervisor – kind of like the real world. Finally, if the officer did not complete the scenario in a satisfactory manner, provide remedial training to bring them up to a satisfactory performance level. Document this remedial training.

Go beyond merely asking your officers what they did; ask why they did it. Make sure you listen to your officers’ perceptions and reasons for responding as they did prior to telling them what you think they should have done.

Several years ago, we designed a scenario that tested officers’ ability to use their firearm to stop a threat. Two officers responded to a domestic disturbance involving two brothers fighting. Upon the officers’ arrival, one brother was straddling the other on the floor while hitting him on the head multiple times with a steel pipe. The assaultive brother refused to stop. We interpreted this scenario as a clear shoot situation, but we were shocked that less than 20 percent of the officers fired their firearms. They used a whole range of other force options.

When we asked them why they didn’t shoot the assaultive brother, we received numerous answers, including:

• The subject wasn’t attacking them

• This was a domestic

• They weren’t sure what was going on

• They could have unintentionally shot the apparent victim

• The subject was turned away from them

• The baton was in the their hand

• Liability concerns

Some of their perceptions and tactical responses were very enlightening. Several ways they stopped the threat were especially interesting, including striking the assaultive brother on the back of the neck with a baton, which we thought was an innovative way to end the assault without potentially shooting the brother on the ground. This led us to ask officers in future classes what they saw and why they responded the way they did before giving our “right” answer to the scenario.


Document your scenarios and evaluations of the officers’ performance in the training, along with any remedial training given to each officer as a result.

Conduct safe simulation training. Ask yourself this question before an investigator puts it to you during a formal inquiry: “What would other well-trained, experienced instructors have done to keep themselves and their officers safe in this type of training simulation?”

What’s the difference between a tragedy and negligence?


Too many repetitions of needless, preventable training injuries and death have occurred. A developing standard-of-care exists and, as a trainer, you will be held accountable.

We need to conduct decision-making scenario training, but we must do it right.

Touring Caravan Tyre Pressures and Loading Weights

The unfortunate truth is caravan tires are not often at the top of our priorities when we are loading up for a holiday. Even if pressures are checked, do you really know what they should be? Your car tyres are easy in this respect as there is usually a sticker somewhere on the car telling you what the correct pressures are, or you can refer to the manual.

Your caravan is not that easy because the weight can vary so much depending upon how much it is carrying. Two people popping off for a long weekend away are likely to be carrying far less than a family of four taking the same caravan for two weeks in France. The tyre pressures will need to be different in both cases, but how do you find out what they should be?

Tyre Sidewall Codes

Here is a typical tyre size code:

P205/65 R16 80 V

The ’80′ is the Load Index for the tyre. This will typically range from 60 to 130 and represent a maximum load of between 250 and 1900kg for that tyre.

Obviously the first thing to be sure of is that the tires are capable of carrying the total weight of your caravan.

There should also be markings on the tyre giving the maximum pressure it can be inflated to.

Calculating Total Weight of Your Caravan

It can come as quite a shock the first time you work out the true weight of the thing you are happily towing around behind you because it will probably be much higher than you realise.

The VIN plate will contain various details relating to weight. The one you need for this exercise will probably be marked as the MTPLM which stands for Maximum Technically Permissable Laden Mass, or more simply, the total weight of the caravan and all of the stuff you packed into it before you set off.

There are two ways to find out what this is. The most accurate and quickest way is to load up and take the thing to a weigh bridge. The other way is to get a set of those scales we use to weigh our luggage before getting on a plane these days and weigh every single item you carry aboard the caravan. Add the total figure to the basic unladen weight of the caravan which should also be recorded on the VIN plate.

However you work it out the figure should be no more than the MTPLM. It’s worth noting here that the manufacturer of your towing vehicle will usually state that the figure you have just worked out should be no more than 85% of the kerb weight of the towing vehicle.

There are a couple of things that can catch you out if you are getting close to that MTPLM. If you weigh each item rather than use a weigh bridge, do not forget that anything you have attached to or built into the caravan, like an awning attached permanently to side or perhaps a television and associated satellite equipment must also be added to the factory-fresh weight recorded on the VIN plate.

Secondly, if the cupboards are full of crockery or the fridge is full of food these also need to be accounted for. It’s amazing how things like this add up, so it’s probably better to take the van to a weigh bridge to get an accurate check.

Once you know what the weight really is, divide it by the number of wheels on the caravan and confirm from the above table that this is within the allowable weight for the tyres.

Finding the Correct Tyre Pressure

Once you have sorted out the total weight of your caravan, have confirmed that it is within the safe limit of the tyres and have found the maximum permitted pressure from the markings on the tyre, usually near the wheel rim, we can work out the correct tyre pressure.

Take the figure for the max. pressure and divide it by the max. weight from the above table, then multiply by the actual load on each tyre. This will give the correct pressure.

For example, if the tire is marked with, say, 64psi for the max. pressure and the max. weight is 950kg, with the actual weight on each tyre worked out from the table above at 450kg, use your calculator to do the following:

64 divided by 950, then multiplied by 450

and you should end up with 30 as the recommended tyre pressure. Substitute your own values to get your correct tyre pressure.

Confidence Check

A good way to check this is to inflate the cold tyres to the pressure you have just worked out and take the caravan for a drive. You need to cover about 50 miles, preferably on a motorway, to ensure they reach their working temperature. Pull off the motorway and park up as soon as you can. Check the pressures while the tyres are hot.

The hot pressure should be around 4psi more than they were when cold.

If there is more than 4psi difference the cold pressure was too low.

If there is less than 4psi difference then the cold pressure was too high.

Make the necessary changes and try again.

This may seem a bit long-winded, but it’s much better than a blow out!