Exploring The Primary Causes Of Manhole Leaks & Manhole Rehabilitation Solution

By Author: Danniel Kollen
Total Articles: 24
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Manhole covers are a common sight for pedestrians. Despite its occurrence after every few steps, it’s no less important. It provides easy access to pipework, sewage pipes, electric supply, telephone lines, and miscellaneous underground assets. Much like every other public property, manholes need maintenance as it’s prone to harsh weather conditions, like erosion, water runoff and road traffic. Sometimes, internal problems also occur, causing the underground pipes to leak. During such instances, the water breaks open the cover, causing surface water flooding. The article today shall elaborate on these problems and discuss manhole rehabilitation solutions practised in Ireland.

What Triggers Manhole Leaks?

A number of both internal and external factors cause infiltration in manholes. A few to name would be:

1. Use of poor materials and methods for manhole construction.
2. Pressure from the traffic above with the load falling directly over the casting.
3. Movements at the ground level.
4. The appearance of cracks on concrete.
...
... 5. Temperature fluctuations.
6. Faults in valves. This shows up with time.
7. Faulty sealing of water-tight joints.
8. Newly cemented joints with the underlying old cement refusing to blend, thereby creating a void. Usually, water collects in them.
9. Worn out manhole covers that have been improperly sealed.
10. Cracks, corrosion and damages in pipes underground.

To elaborate a little, sometimes cracks are already present on pipelines. Adverse weather conditions worsen them, causing the cracks to widen. Prolonged periods of storm or flooding further triggers the manholes, and ultimately, the water overflows, posing a threat to pedestrians and highway agencies.

Manhole Rehabilitation Method

The most popular method widely practised across Ireland is the sealing of manholes with localised gel injection. People opt for this practice primarily because it’s cost-effective. The repair work starts with experts closely inspecting manholes for leaks and infiltration. On detecting the vulnerabilities, they inject gel into the affected region. Typically, it’s a hydroscopic polyurethane resin with activated water that takes little time to get soaked into the pipe penetrations and mortar joints. Ultimately, it surrounds itself like an impenetrable gel and seals up the identified leaks.

Benefits of Permeation Grouting
The method discussed above is permeation grouting, a process with the following two benefits:

1. It improves the load-bearing capacity of the region where it is injected.
2. The watertight foam permanently seals the leakages, eliminating the issue once and for all.

Types of Resins used up in Permeation Grouting

Typically, two main types of prime resins are used in the process.

1. HydroGel SX
Composed of 15 or 8 parts of water, the polyurethane gel creates a flexible water-tight foam, well capable of sealing all types of structures, including joints and manholes. Experts usually call this method of injecting hydrogel as ‘twin streaming’. Typically, a two-component pump blends the product for sealing the walls.

2. Prime Flex 910
Composed of rigid hydrophobic foam, this chemical works wonders for sand and soil, congealing the loose particles. Injecting it into the ground, resists water flow under the ground, thereby permanently sealing the leaks for the better.

Of the two resins, prime flex 910 is the most preferred one for sealing voids, eliminating leaks and reinforcing granular soil.

Whom to Approach for Rehabilitating Manholes in Ireland?

You can approach anyone who has insights and years of experience in manhole benching, structural relining, re-benching, chemical injection and ironworks replacement. USA Ltd ticks all the criteria with the right certification, training and 25 years of experience in this field. You may consider them for repair works now. The professional also offers a complete pipeline solution and works underground for ensuring a better environment. The team’s portfolio provides a clear insight into the efforts put in by them all across Ireland.

Author Bio:
The author writes articles on manhole benching, CCTV surveys, sewer cleaning, manhole integrity testing, and similar such civil engineering works. Her write-ups provide an insight into the concepts for better understanding of the jargons.