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Do you need a trench shield?

Posted 21st February 2020

Do you need a trench shield

Before we begin probing into the finer details of trenching and using trench shields, let’s ask ourselves a question.

How fast can you sprint?

20kph? 30kph? 40kph?

The fastest man on earth, as we all know, is Usain Bolt. He’s reached a top speed of 43.45kph, which is 12.07 metres per second. The average man can sprint up to 32kph, which is 8.89 metres per second.

Back to trenching. You’re working in a 2.0m deep trench. You’re in a hurry and have climbed into the trench without a shield, as the job’s only “going to take a few minutes”. The job is nearly finished when you notice that there are some small cracks appearing in the trench walls. Maybe you should get out….

Dark. All is dark. You’re struggling to breath, as if someone was standing on your chest. Your legs feel strange and you can’t seem to move.

What’s happened is that the trench walls have collapsed onto you. The walls of a trench can collapse in less than 1/10 of a second. Even Usain Bolt couldn’t sprint away from a trench that’s caving in.

Then there’s the weight. Each cubic metre of dirt can weigh over 1,500kg. Try breathing with that weight on your body.

It’s not nice. And not safe. But read on – we’ve got it sorted!

Let us explore the basics. An excavation is classified as any cut or hole in the ground. A trench is a cut in which the depth is greater, or deeper than the trench is wide. We will be looking at trenches specifically today.

New Zealand’s laws specify you must use trenching protection when working in a trench 1.5m or deeper. This is all very well if you’re standing up in the trench and the soil conditions are perfect. However, if you’re bending or kneeling whilst working on a pipe or cables, or the soils is wet, sandy, or loose you’re at risk. As a rule of thumb – If your head is below ground level when you are working, or there is any doubt at all about the ground conditions, you need a shield! To find out the regulations you need to meet, check out New Zealand’s safety regulations on NZTA https://worksafe.govt.nz/topic-and-industry/excavation/excavation-safety-gpg/

The good news is we are here to help! We have many options ranging from the humble but efficient soldier trench shield to the large drag shield. Each option has many benefits, of which the first is to protect you and your workers from unforeseeable trench collapses. In fact, several of our trench shields can be widened whilst in the trench, creating positive ground pressure. This decreases the chances of collapses dramatically and prevents the ground from cracking and crumbling. Some shields can be stacked, giving you greater working depth. Some can even be configured in several different ways with the same components, giving you more flexibility in any job.

You’re unique and so are your projects. We understand that different projects have different requirements and we can help you create a custom shoring system that meets your requirements, and all legal trench shoring regulations. We offer customised shields with trench widths to suit your trench designs and use different material such as lightweight alloy or heavy-duty steel plating. Our modular system is versatile, with over 68 different configurations and increasing, to suit every project. From open-ended shields to 3-sided and closed box configurations, we have it all sorted. If you need completely customised components designed and created to help you get your job done faster and efficiently, we can help solve your problem. 

Click here to see our range of Trench Shields

Or to find more about what shields we can offer and how we can help, simply phone 0508 31 31 31 or email sales@transquip.co.nz.