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Tips for Using Trench Boxes Safely

Trenches are a pretty common sight in many engineering or construction sites. They are meant for laying pipes, phone lines as well as lots of other constructions. While some are extremely shallow, others can be quite deep. Based on the soil’s quality, trench walls support themselves for a short time. An aluminum or steel trench box secures the trench walls to make it safe to work there without the risk of walls collapsing on people or equipment. Other names for trench boxes are manhole boxes, sewer boxes, tap boxes, or trench shields.


Before excavation commences, the site must go through a complete risk assessment to check for any potential risks, the employees needed and the equipment needed. The necessity of additional access is also assessed.
What I Can Teach You About Trenching

Then the trench needs to be looked at. How deep is it supposed to be? How big should it be? Trenches of more than 5 feet require support either from shoring, sloping, or trench box. But if it’s more than 20 feet deep, a registered engineer is required to design the trench’s support. How will people access the trench? Is it via a ramp, ladders or steps? The trench should always have safe access for workers within 25 feet , in case of emergency. The atmosphere inside the trench may also need to be tested for toxic gases or low oxygen levels. Trench boxes are designed to allow for simple installation but it’s not safe to stack these boxes over each other.
What I Can Teach You About Trenching

Tending to the trench

Check for any signs of movement or damage by inspecting the trench box/trench support daily.

All staff must put on protective gear, steel-toed boots, high visibility clothing, hard hats and so on.

Ensure that all heavy tools as well as equipment are kept far from the trench’s edge.


It is probably more difficult to extract a trench box than install it because of the earth’s movement around the trench. It’s recommended that a chain sling be used for extraction, using any of these 3 methods.

Straight pull–a sling is just attached to the two lifting or extraction points and lifted out.

Half pull–a sling is attached to one side of a trench box, lifted as high as possible, then the sling is switched to the opposite side and the action repeated till the trench support is removed.

Single pull–a single chain sling leg is connected to a point of extraction or lifting and the panel corners are lifted in turns; when the manhole box moves freely, it’s removed with the straight pull.

To sum up, trenches do save lives. It’s a legal requirement to use them and they need to be planned for. Provided they’re well maintained and used, they do make work so much safer and easier.