Sewer manholes: overview of types, their sizes and classification + what to look for when choosing

Modern sewer manholes are elements of engineering systems that provide protection for both underground networks and users. They are installed above drainage, rotary, collector, inspection and storage wells. Used in the construction of all types of underground communication structures.

You will learn everything about the types of manholes for sewerage installations and the rules for selecting them for their intended purpose from the article we presented. We will talk about how to decide on a model depending on pedestrian and traffic load. Taking into account our recommendations, you will easily find the best option.

Hatch classification options

The main central and household communications for various purposes are located underground. For regular inspection, maintenance of proper order and scheduled repairs, they require convenient and safe access. It is provided by special wells with an external hatch.

By product purpose

The primary classification of hatches is carried out according to their intended purpose and directly depends on the type of pipes or cables that need protection.

There are four main groups in total:

• water supply network;
• storm drain;
• telecommunication complex;
• sewage drains.

The hatches of the first group carefully close individual fragments and components of the heating main and water supply system. The depth of inspection wells is 1-2 meters.

In the last century, only cast iron hatches were used to seal exit openings. Now they are being successfully replaced by lightweight structures made from modern polymer compounds and advanced composites.

In cable alarm well shafts, the hatch has not one, but two covers - a locking one and a protective one. The first is made of lightweight steel and is equipped with a reliable lock. The second serves as an external barrier for intruders to penetrate in order to steal an expensive cable.

For storm drainage, a hatch is necessary to protect the networks from outside penetration. Collector wells storm sewer sometimes the depth reaches 6 meters. The shaft contains metal reinforcement elements that pose a threat to a person or animal if they fall.

To reliably close the storm well opening, hatches with covers made of the same material as the main drainage line are used.

The telecommunications complex - electrical, telephony, broadband Internet - provides for the use of hatches to protect valuable equipment and protect the system from unauthorized entry by third parties.

Typically, such networks are equipped with lightweight plastic hatches, equipped with an advanced and reliable lid locking mechanism. Sewage pits are equipped with hatches with covers. For the most part, they are used in the private sector, where central sewerage is not available.

The hatch prevents the leakage of unpleasant odors from sewage accumulating in one place.Provides access to cesspool workers involved in pumping out cesspools. In such a situation, there is no point in spending money on an expensive cast-iron part. A budget plastic hatch will do the job quite well.

There is another type of model called an inspection hatch. It provides access to the main working nodes water supply systems and drainage. It is mainly located inside sanitary and hygienic premises under the bathtub or in a wall covered with plastic siding or plasterboard.

Hatches for various purposes are mainly produced in the form of a standard size circle. This option is the most convenient and affordable. Revision models have compact dimensions and a rectangular or square shape

To make it easier to recognize the purpose of hatches, they are marked with a letter abbreviation.

The designations are very easy to decipher:

• IN — plumbing module;
• G, PG — traditional/underground fire hydrant;
• TO — industrial or domestic sewerage;
• D — rainwater runoff;
• HS — local gas distribution network;
• GTS, MTS — city telephone complex;
• MG — main-type gas pipeline;
• T - telephone;
• TS — heating network.

On some hatch models, the purpose is reflected not in letters, but in a characteristic pattern.

Varieties by size

Manufacturers offer round and square shaped lids. Let's look at each of these groups in more detail.

Type #1 - round hatches

Round is a classic option for protecting sewer wells from external penetration. They look neat and compact, fit comfortably into the shaft and never fall inside, regardless of possible reversal.

The operating load is distributed evenly over such a cover and is not concentrated in individual areas.

With the installation of round hatches above sewer well There are no problems, since the product can not only be brought to the installation site, but also rolled up. This is especially important when the installation is not carried out by a team of workers, but by the owner of a personal site.

It is most profitable for the manufacturer to produce round sewer manholes. They require 40% less raw materials, and their functions are superior to square models in every way

Type #2 - square and original shape

Square hatches are not so widespread. Their price exceeds the cost of round analogues, because more raw materials are spent on creation.

Installing them alone is quite problematic, especially when it comes to super-heavy cast iron models. It is almost impossible to bring such a product to the installation site yourself due to too much weight.

Hatches of a specific shape are not widespread. Usually they are produced to order, taking into account the wishes of a specific client. First of all, they carry an aesthetic and design load, giving the territory a specific, original and memorable look

The main disadvantages of square hatches are their vulnerability to increased external pressure and the risk of falling inside the well when turned diagonally. It is this moment that seriously reduces the popularity of the product and makes it unsuitable for installation in areas of heavy traffic flow.

By weight and application areas

Domestic sewer manholes are divided by weight into heavy ("T" type) and lungs ("L" type). This factor determines the conditions and areas of their application.Models of the “T” type are installed on highways, highways, intracity roads and roadways in yards. Cast iron products in this category weigh 90-100 kg, composite ones - up to 45 kg.

Polymer, rubber and plastic products are not presented here and are categorically not suitable for work under conditions of heavy mechanical load.

For more complex operating conditions, enterprises produce special high-strength and durable hatches weighing about 150 kg, capable of withstanding pressure of about 40 tons. They are marked with the abbreviation “TM” and are installed on busy highways or at airports

The “L” type of product is suitable for installation on sidewalks, pedestrian paths, park areas and other places inaccessible to cars and trucks.

In cast iron complexes, the weight of the lid ranges from 55-90 kg. For polymer-composite parts - 45 kg, for polymer parts - from 12 to 15 kg.

Types of hatches by material of manufacture

The following materials are suitable for the production of modern sewer manholes:

• high-strength gray cast iron;
• plastic;
• polymer-sand mixture;
• composite composition;
• rubber;
• concrete/reinforced concrete.

Products differ significantly from each other in many respects and are intended for different intended uses. The production and purpose of models are regulated by current SNiPs and GOSTs.

Features of cast iron hatches

For the manufacture of hatches, dense gray cast iron of class SCh20 is used. This composition is an alloy of carbon, iron and multi-structured graphite inclusions. It has good strength, is not afraid of mechanical damage, and can easily withstand intense global and local loads.

Until recently, cast iron hatches were installed in almost all wells, regardless of the type and variety of communications. Now the situation has changed and heavy cast iron is being actively replaced by polymer, composite and plastic models

The cast iron hatch has high performance and physical properties. During operation, it retains its original integrity and does not break or crack under the influence of an aggressive environment.

Among the most useful characteristics of heavy, high-quality models are the following:

• service period from 30 to 100 years;
• maintaining the integrity of the structure and rigidity of the structure throughout the entire service life;
• neutrality to temperature changes, corrosion, humidity and other climatic factors;
• record resistance to loads and the ability to withstand weight from 25 to 40 tons;
• a hinged locking mechanism that eliminates the possibility of the cover flying off while traffic is moving along the highway;
• The kit includes a rubber gasket to ensure absolute tightness of internal communication systems.

The models also have disadvantages. Cast iron hatches weigh a lot and this significantly complicates the process of transportation and subsequent installation. It is extremely problematic to cope with the installation of such a part alone.

You will have to spend a substantial amount on the purchase, several times higher than the cost of plastic and composite products.

A lock must be placed on the cast iron hatch cover. Otherwise, it may be stolen and sold for scrap. The communication network in such a situation will remain unprotected and will be a source of danger for people and animals

Cast iron hatches can be installed anywhere, but it is most effective and expedient to include such elements in communication systems located at docks and airports, on busy highways, and parking areas for heavy vehicles, tracked and other agricultural equipment.

In areas with medium or low loads, installing cast iron is completely optional. But if the owner still wants to do this, no one can stop him.

Why are plastic products interesting?

Plastic hatches are made by injection molding from polyvinyl chloride. To enhance the working properties, the composition is enriched with composite additives or equipped with fittings compatible with the products. Models are not afraid of pedestrian loads. Usually located where there is no traffic.

Plastic hatches are environmentally friendly. Made from recycled materials, they do not emit harmful substances or aggressive compounds into the atmosphere. This makes it possible to use them in close proximity to residential buildings

The main advantages of plastic hatches are light weight, intrinsic safety, independence from weather conditions and temperature, long service life and reasonable cost. They are usually placed above plastic wells. There is only one drawback - the impossibility of installation in an area of ​​heavy traffic.

Polymer-sand options

Sand-polymer models are produced by injection molding followed by hot pressing.

For their manufacture the following materials are used:

• mixed sand;
• thermoplastic polymer elements;
• durable industrial dyes.

The creation process is built on the basis of progressive technological solutions and makes it possible to produce visually attractive, wear-resistant and durable products with minimal financial costs.

Some models of hatches made of polymer-sand compositions are designed for the installation of a special locking device. This allows you to protect the block from unexpected opening under the influence of any external reasons

Polymer sand hatches are marked in the form of the letter “L”.

The standard size is determined by two indicators:

• 690x55 mm on the cover;
• 750x90 mm along the body;

The first number indicates the length, the second the height. These parameters are considered optimal for communication networks for various purposes.

Lightweight hatches made of sand-polymer mixture have the following advantages:

• minimum weight compared to other similar products;
• low cost, allowing significant savings in the process of arranging communication networks;
• long operational period, which, according to the manufacturer, is about 50 years;
• elementary transportation and a simple installation process that does not require additional labor or specific expensive equipment;
• resistance to aggressive manifestations of the external environment, temperature changes, peak heat/cold, direct sunlight, shock and other mechanical damage;
• neutrality in contact with alkalis, acids, alcohol compounds and technical oils;
• variety of shapes, shades, designs and external decor of lids.

Another undeniable advantage of polymer-sand parts is safety. A cast iron part can be stolen at any time and sold for scrap.

The polymer hatch is not in demand in this regard and will always remain in place even in a remote unguarded area that lies outside the control of private or government video surveillance.

A rich palette of colors makes it possible to choose a model in accordance with the surrounding landscape and landscape design of the local, urban or park area

Polymer-sand models can easily withstand loads of up to 3 tons. Placed in areas with medium or low traffic intensity. They are installed in pedestrian and green areas, in internal parking lots for passenger vehicles, parks, squares and areas located near apartment buildings and private cottages.

Nuances of composite modules

Composite is a new innovative material. It is thermoactive and contains fiberglass, polyester resins, calcite and other specific additives. At a temperature of 100 degrees it is subjected to hot pressing. As it cools, it hardens and acquires good strength characteristics.

The design of a composite hatch differs from analogues made from other materials. In the area of ​​the lid there are drainage channels. During intense rainfalls, they cut off the flow of rainwater and prevent it from penetrating into the well shaft

Composite hatches can withstand different loads, which depend on the class of the product: L - up to 1.5 t, S - up to 12.5 t, T - up to 25 t, TM - up to 40 t. They also serve reliably for 20 years or more . At the end of the operational period they are subject to recycling.

The advantage of composite hatches is expressed in the following positions:

• optimal weight of the finished product;
• practical structural device;
• rich color palette;
• resistance to fading, temperature changes, severe frosts, heat, ultraviolet radiation and chemical attack;
• flame retardant.

Composite elements last a long time and hardly wear out. They can withstand mechanical loads of up to 40 tons, but cost significantly less than their cast iron counterparts. When exposed to extreme heat, they lose their rigidity and become viscous. At such a moment, marks from heels may remain on the hatches.

Specifics of rubber compound products

Rubber sewer manholes perform the same functions as other products made from other materials. But they have their own specific qualities and characteristics.

They are made from rubber, plasticizers, fillers, stabilizers and additional substances. After volcanic treatment, this mixture turns into a durable hatch that is resistant to wear and easily tolerates contact with oils, acids and alkalis.

Rubber hatches can easily withstand mechanical loads of up to 12.5 tons, withstand aggressive climatic conditions and retain basic physical properties in temperatures from −40 °C to +50 °C

Among the main advantages of products made from rubber compounds:

• light weight;
• immunity to corrosion;
• crack resistance;
• convenient transportation;
• simplified installation process;
• possibility of installation directly into hot asphalt;
• more reasonable price compared to cast iron analogues.

Rubber hatches are suitable for installation above plastic wellslocated in parks and green areas, sports fields, parking lots, sidewalks and roads with low traffic.

Concrete covers

Reinforced concrete manholes for sewer networks are used extremely rarely due to their excessively large mass and problematic installation.

The main advantages of concrete models:

• uniform density;
• strength and durability;
• resistance to destructive processes.

Most often, such products are used where the outlet well neck has non-standard dimensions.

Heavy concrete sewer cover structures are often installed in areas where cast iron manholes are regularly stolen. Such a product is of no interest - it is not needed at a scrap metal collection point

Rules for choosing sewer manholes

When choosing a hatch for drainage, storage and sewer inspection wells, first of all you need to pay attention to the form. If the outlet neck of the communication system is made in the form of a circle, it will need a round part. It is better to close a square or rectangular hole with an element of the same shape.

Modern industry offers sewer manholes with an original design on the lid. They not only perform the function of protecting internal communications, but also act as an original design element

When you plan to install the hatch in a place subject to serious mechanical stress, you should choose a cast iron model. It will cost more than composites and polymers, but will last longer and withstand the constant pressure of passing heavy trucks.

For private households, it is not necessary to spend money on such a hatch, even if the owners have a heavy vehicle. Both composite and polymer analogues can easily endure one-time trips.

In the immediate vicinity of residential buildings with low traffic intensity, it is better to install composite or polymer hatches. They have noise-insulating properties and do not make harsh sounds when a car passes over them.

For installation in an open area, it is better to choose models equipped with a locking element. Which is able to protect the cast iron hatch from theft for the purpose of subsequent sale for recyclable materials.

Polymer and composite parts cannot be sold for profit, but they can be carried away by hooligans or teenagers. Therefore, such models would also benefit from a reliable lock or latch.

Conclusions and useful video on the topic

Video #1. How to install a sewer hatch on your site with your own hands:

Video #2. Strength testing of polymer and cast iron sewer manholes:

Video #3. What dangers do foreign-made sewer manholes pose:

When choosing a suitable hatch, it is necessary to take into account its future location, the level of potential load and the climatic conditions in which the operation will take place.

Ignoring any of these important parameters will negatively affect the purchase and it will not bring the desired results. A model that does not meet the general criteria will not cope with the task and will quickly fail. Owners will have to spend money again to purchase a more suitable product.

Please write comments, ask questions, and post photos related to the topic of the article in the block below. Tell us about how you bought a manhole to install a sewer system on a suburban area. Share your own criteria based on which you made your choice.