The Dangers of Manholes: Staying Safe Around Access Points

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Evan Mowbray

The Dangers of Manholes: Staying Safe Around Access Points

Utilities are an important aspect of modern infrastructure, maintaining systems that keep the world operational. Sanitary and storm sewers keep water flowing and protect from contamination. Electric and communication lines power our technology and connections to the world. Gas lines provide heat and fuel. Each utility system is connected through access points and utility vaults, often referred to as manholes.

There are estimated to be over 20 million manholes in the United States. Manholes house the connections often accessed by utility and construction workers for maintenance purposes. However, this accessibility means manholes can often present risks to the public that they might not be aware of. In this week’s blog post, I’ll go over some of the hazards involved with manholes and what our team at Trinity does to avoid these risks.

The most obvious risk associated with manholes is falls. There are a number of stories involving civilians falling into manholes, resulting in both injuries and deaths. These falls aren’t limited to faulty manholes either, as heavy rain or storms can result in shifts to the cover, which can increase the potential for these accidents. Inspecting manholes regularly (especially after a large storm) is important in making sure that people will be safe around them. Our team at Trinity is familiar with Cleverscan, a manhole scanning system used to photograph and map manhole walls for potential structural defects. Another lesser known danger occurs with potential electrocution. Workers should avoid touching live wires inside of a manhole. Burnt wires inside of manholes also have the potential to come into contact with the manhole lid, building a charge under the right conditions.

An image of a video pipe inspection crawler inside of an open manhole.

Other accidents occur with open manholes during maintenance and construction operations. An open manhole presents a dangerous risk if not guarded off properly with cones or a manhole guard, requiring increased surrounding awareness. Pinch points are also important to be aware of when opening a manhole. While they may look light, a manhole is often made of heavy iron, resulting in potential injuries resulting from pinching if you don’t open them properly. In other words, don’t use your hands to open a manhole. The easiest way to prevent these accidents is through increased safety awareness and precautions. Utilizing proper lifting techniques and tools, surrounding the manhole with a manhole guard, and harnesses if you need to enter a manhole are all great practices in construction safety.

An image of a manhole cover made for video pipe inspections next to the existing manhole. Evan Mowbray's boots can be seen in the bottom center of the image.

Notably, entering a manhole presents a confined space risk. Confined spaces are defined as having limited entrances and exits, but large enough for workers to enter for maintenance. Some of the risks often associated with confined spaces include flammable gas, lower levels of oxygen, and harmful atmospheres. Sewer manholes and wells can contain hydrogen sulfide, a flammable and potentially deadly gas if breathed in. Thankfully, there are ways to avoid entering a manhole for inspections. Our team utilizes a video pipe inspection system and other methods  to service utility manholes without entering them. Similar to the manhole scanner, this technology allows for a full range of motion in inspecting pipe systems and allows us to report on internal structures. Visit our website to find out more information about Trinity’s pipe inspection services.

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