How to fix a polymer sewer manhole

To access underground utilities through inspection wells, various types of hatches are used. Outwardly, they differ little from each other, although they pursue one goal - to protect passers-by from falling into the sewers. To understand which products should be installed, you need to understand the materials and methods of closure, as well as the size and shape of the closure structures.

Scope of application of sewer hatches

The manhole cover has a double function - it protects people from falling into underground sewer labyrinths, and also prevents the mine from clogging up with debris and foreign objects.

Products are used wherever it is necessary to close access to inspection wells:

• storm sewer;
• domestic waste water;
• electrical cable;
• phone line;
• gas pipes;
• heating main;
• water pipes.

Depending on the expected load, the material and the opening method are selected. In private territories, locks that are easier to use are installed, since the likelihood that the device will be removed is small. On your own site, you can install a less durable structure of the sewer hatch, since the potential load on it will be small.

On the roadway, you need durable products, for example, cast iron, which can withstand the constant load of passing cars.

Well construction

A sewer hatch is a product consisting of a body and a cover. Both are made from the same material.

Lockable and non-lockable structures are produced. The former are installed where there is access to various expensive equipment inside the mine and there is a high probability of deliberate damage or theft.

Wells can be round, rectangular or square in shape. In most cases, round sewer manholes are used, since they are the most practical and economical.

The cover has a hole. It is used for opening with special hooks or for monitoring, for example, gas leaks in a gas pipeline.

The lid itself is made slightly convex so that water does not accumulate in it and does not freeze in winter. The relief is necessary so that the wheels of cars or passers-by do not slip on the metal.

There is a special marking to determine the communications to which it leads:

• TS - heating main;
• T - telephone cable, varieties - GTS and MTS;
• MG - pipes of the main gas pipeline;
• ГС - gas network;
• PG or G - fire hydrant;
• K - domestic wastewater (sewerage);
• B - water supply;
• D - drainage or rainwater drainage.

The hatches are marked on top with letters or drawings. For example, access to an electrical cable can be indicated by a lightning bolt.

Sizes of manholes and diameters of covers

Sewer hatches are distinguished by load class:

• For pedestrian areas of a private territory, light small-sized hatches are suitable. Marking according to EN-124 - LM (A15). Load at least 15 kilonewtons (1 ton = 10 kilonewtons). Product weight 45 kg.
• In the pedestrian zones of public places, light, but more massive products weighing up to 60 kg are installed. The rated load is also 15 kN. Marking - A15 L.
• The middle hatch has a safety factor of up to 125 kN and weighs 95 kg. Recommended for parking lots, sidewalks, park areas.Marking C (B125).
• Heavy manholes are used on highways with heavy light traffic. The hatch weight is 120 kg, and the rated load is 250 kN. Designation - T (C250).
• Heavy main hatches withstand a load of 400 kN, with a weight of 140 kg. They are used on intercity highways, where, in addition to passenger cars, cargo trucks and buses run. TM marking (D400).
• Superheavy manholes are used in the construction of airfields and docks, where the weight of vehicles exceeds 100-200 tons. Loads over 600 kN with a product weight of 155 kg. Marking - ST (E600).

In the designs of heavy and super-heavy products, elements that cause a concentration of load at one point and provoke a break in the metal are excluded. Such hatches are made on machines with numerical software, which ensures a tight fit of the cover to the body, eliminating uneven loads during collision.

The dimensions of the body and lids are the larger, the more load the product can withstand.

These dimensions refer to standard cast iron designs. Although the industry produces hatches of various sizes. You can find very small - 38 cm in diameter - cast iron, and polymer 1 m in size.

Cover locks

Locks are designed to prevent unauthorized entry into the system and theft of expensive equipment or cables, which are usually made of non-ferrous metals. Such waste is resold to scrap metal collection points.

The locks prevent the cover from sliding, which can collapse under constant load. On the freeway, this leads to an accident, as the car's wheel gets caught in the sunroof and the suspension breaks.

In pedestrian areas, two covers are usually installed - a locking one and a protective one. The closing cover is located below and has a secret lock, which is available in four versions:

• Spacer mechanism.
• Crab (or ray).
• The body and cover are connected by means of a thread.
• A lock in the form of a flag between the body and the lid.

The most reliable are the spacer and crab lock mechanisms.

Varieties by material of manufacture

Sewer hatches are made of the following materials:

• gray cast iron;
• high-strength cast iron, which at rated load is 4 - 5 times higher than gray;
• polymer sand mixture;
• plastic;
• composites;
• durable rubber;
• reinforced concrete or concrete.

Each material has its own advantages and disadvantages.

Cast iron products

Gray cast iron is an alloy of iron with carbon. It is characterized by low shrinkage, that is, it does not shrink or expand under the influence of temperatures. It is widely used in industry, since the cost of its production is relatively low, and its characteristics are not inferior to more expensive alloys and metals.

Advantages when using cast iron hatches:

• durability;
• withstanding heavy loads;
• resistance to sudden changes in temperature.

The disadvantage is the large weight of the products, as well as the possibility of a spark, which is unacceptable in some areas. For example, when installed on a gas pipeline, an explosion may occur. Cast iron products often become objects of theft, therefore additional protection against opening locks is required.

Ductile iron is distinguished by the presence of graphite in the alloy. It is used in places with heavy traffic and rated loads exceeding 250 kN.

Plastic hatches

One of the advantages of plastic manholes is their low cost, since they can be made from recycled materials.Every year the industry offers more and more durable models that are not inferior to metal ones.

The plastic can be given any color by adding pigment at the melting stage. Plastic models are especially popular in private septic tanks and storm sewers. Install polymer hatches in pedestrian areas without fear of being stolen - plastic is of no value to burglars.

Synthetic materials are not affected by temperatures and do not fade under the influence of ultraviolet radiation. The appearance of the site will remain for a long time. If you do not exceed the load, then the plastic will last a long time.

The only drawback is that such materials are not suitable for highways with a lot of traffic, as they quickly deteriorate.

Polymer sand mixture

It is a combination of sand - 70% and plastic waste - 30%. The quality of the finished mixture depends on the purity of the raw material - the absence of technical oils in it. After grinding and melting the components from the mixture, you can cast a product of any shape. After solidification, it acquires the following characteristics:

• not exposed to corrosive liquids, therefore it can be used in wells with household and industrial waste;
• resistant to low and high temperatures;
• weighs little;
• does not generate a spark, therefore the product is safe.

The hatches are of no material value compared to cast iron or iron.

Due to the fragile component in the composition - sand - sewer manholes made of polymer sand mixtures do not withstand heavy loads. They are used in private septic tanks, green areas and pedestrian areas.

Composite hatches

Premix composite material is popular. The production is based on the use of nanomaterials, which allow the components to be well mixed in the composition of the composite.

The premix contains:

• fiberglass;
• calcite;
• polyester resins;
• other additives.

The material is obtained by heating to 100 degrees, after which products of the desired shape are cast from it. Composite manholes can withstand loads of up to 40 tons, are lightweight and have excellent durability. They are of no value to robbers, so they last longer.

The price of a composite manhole is quite high - this is the only drawback.

Rubber manholes

Cast iron structures can be easily replaced with high-strength reinforced rubber. Such material does not rust, does not crack. Specially prepared rubber is resistant to high and low temperatures, aggressive liquids.

Rubber covers are used in various systems - fire extinguishing, water supply and drainage in the private and industrial sectors. The robbers do not touch them, so it is safe to install such models in public places.

For a high-quality installation, it is necessary to prepare the base - fill it with concrete. The cover is mounted flush with the asphalt or ground.

Concrete and reinforced concrete

For the manufacture of concrete and reinforced concrete hatches, high-quality cement is used - it is resistant to moisture and mechanical stress. To be used in combination with concrete rings: after installing the top slab with a hatch hole. For convenience, metal handles are poured into the concrete.

Advantage:

• low cost;
• weight - it is almost impossible for children or adolescents to lift a heavy plate;
• durability.

Disadvantages lie in the appearance of the product - it will not work to give a certain color to concrete due to poor adhesion with dyes.

Installation and securing

Lightweight polymer or polymer sand hatches can be installed by yourself. Heavy cast iron or concrete structures will require the help of other people or technology. On footpaths, the covers should be flush with the pavement.If the hatch is located on a flower bed, it is better to raise it slightly above ground level so that dirt does not fall into the well.

DIY installation steps:

1. First, the support ring is installed on a solid foundation - the formwork. For accuracy, you must use a level. If the installation is carried out at a slope, then the structure will eventually become unusable and collapse. A cement mortar is used to connect the concrete rings to the support ring of the hatch. When it is completely solidified, work can be continued.
2. The cover is mounted. How to do this depends on the model.
3. The final stage is filling the blind area. It is done at a distance of 1.5 m from the center of the hatch. A cement solution is used. To make the blind area neat, the edges are fenced off with bricks or bending metal, the bottom is covered with sand and poured with concrete. When it hardens, the devices are removed.

After installing a sewer hatch, it can be decorated with artificial stone or covered with a layer of synthetic grass. Flower beds are sometimes arranged in the covers so that the vegetation hides the presence of a septic tank on the site.

It must be remembered that maintenance of the well may be necessary at any time, so the top of the cover must not be heavily obstructed.

Prices for various types of hatches

The cheapest products will be products that cannot be heavily loaded. These are manholes made of plastic or polymer sand mixtures. Low cost, but higher performance rubber differs. If we are talking about installation in a summer cottage or near a private house, then there is no need to overpay for cast iron products.

Composite materials and ductile iron are more expensive. These materials are chosen if pressure is applied to the hatch every day, for example, a sewer well is located in the area of ​​vehicle movement. The price of a cast-iron manhole is comparable to the cost of a synthetic material.

The cost of products also depends on the size - diameter and height of the lid.