GUEST 6942-98 cast iron sewer pipes: substantive provisions
Standard 6942-98 applies to sewer communications made of cast iron and fittings for them, which are designed for internal systems. The document presents a range of products, their species, dimensions and designs, technical requirements, control methods, rules of admission, as well as requirements for transportation and storage of products. in addition, GUEST 6942 contains some instructions for operation and installation of cast iron pipes.
Cast iron pipes have been used for sewerage for decades, there are varieties of these products for indoor and outdoor systems
Properties of cast iron
Cast iron is an alloy of iron, which is characterized by a high content of carbon forms. The amount and shape of carbon (cementite, graphite) determine the production of different types of cast iron: gray, white, malleable, high-strength. Carbon bound in white cast iron, in gray - lamellar graphite, in high-strength - spherical graphite, malleable - flaky graphite.
In the standard 6942 the characteristics of pipes and fittings for sewerage are given, which are made of cast iron. This material is environmentally friendly and has excellent anti-corrosion properties. Spherical graphite is included in the cast iron for the production of pipeline parts. It significantly improves the anti-corrosion parameters and the degree of wear of structures, which saves a lot of resources and money.
Cast iron is characterized by low crystallization temperatures, excellent fluidity in molten form and low shrinkage. The most common method of producing pipes from this material is casting. This process ensures that the products have uniform wall thickness, savings in raw material consumption and the required material density.
Modern pipes have a smooth inner coating, which facilitates the easy passage of sewage through the pipeline
According to the GOST document 6942-98, cast iron sewer pipes are covered with an anti-corrosion layer, which makes their inner surface smoother and, so, reduces the coefficient of friction and leads to increased fluidity.
Technical characteristics of cast iron products
Cast iron has good technical performance, to which they belong:
- high strength;
- durability;
- corrosion resistance;
- sound insulation properties;
- pliability in molding and casting;
- low value of the coefficient of thermal expansion;
- non-flammability and fire safety;
- no release of toxic substances.
Production of cast iron sewer pipe (GUEST 6942-98) is made with different diameters, weight, wall thicknesses, length. There are nominal outer diameter and the value of the catch passage. The most important indicator is the nominal diameter, which is often guided when choosing and installing a sewer network. The rounded or conditional value of the inner diameter shows the conditional passage of the pipe.
pay attention! The choice of the appropriate product is influenced by the amount and load of wastewater.
The diameters of cast iron sewer pipes range from 5 to 15 div. The internal system can be built on communications from 5 to 10 cm, external - higher 10-15 div.
The greater the load on the system, the larger the diameter should be in the pipes used for installation
The internal system includes various types of plumbing, risers of pipelines. As the accumulation and increase of effluents, the diameter of the pipes increases to 50-120 div.
Classes of cast iron pipes
The applied load and pressure on the walls of the cast iron sewer pipe determines its assignment to a certain class. So, allocate class A, B and LA. Class A parameters are given in the table.
Table 1
| Conditional passage, cm | Meters in tons | The mass of the product, kg | Wall thickness, cm | Outer diameter, cm |
| 6,5 | 80,65 | 12,4 | 0,74 | 8,1 |
| 8,0 | 61,73 | 16,2 | 0,79 | 9,8 |
| 10,0 | 48,08 | 20,8 | 0,83 | 11,8 |
| 12,5 | 37,31 | 26,8 | 0,89 | 14,4 |
| 15,0 | 29,67 | 33,7 | 0,92 | 17,0 |
| 20,0 | 20,49 | 48,8 | 1,01 | 22,2 |
| 26,0 | 15,17 | 85,9 | 1,10 | 27,4 |
| 30,0 | 11,74 | 85,2 | 1,19 | 32,6 |
| 35,0 | 9,39 | 106,5 | 1,28 | 37,8 |
| 40,0 | 7,66 | 130,5 | 1,38 | 42,9 |
| 50,0 | 5,45 | 183,5 | 1,56 | 53,2 |
| 60,0 | 4,08 | 244,8 | 1,74 | 63,5 |
| 70,0 | 3,16 | 316,0 | 1,93 | 73,8 |
| 80,0 | 2,63 | 384,6 | 2,11 | 84,2 |
| 90,0 | 2,08 | 380,9 | 2,23 | 94,5 |
| 100,0 | 1,73 | 578,0 | 2,48 | 104,8 |
Such pipes can withstand the value of pressure in 100 kPa. They are used for the most important areas of internal or external sewerage.
Class B parameters are shown in the table.
Table 2
| Conditional passage, cm | Meters in tons | Mass meters meters, kg | Wall thickness, cm | Outer diameter, cm |
| 6,5 | 75,19 | 13,3 | 0,80 | 8,1 |
| 8,0 | 57,14 | 17,5 | 0,86 | 9,8 |
| 10,0 | 44,84 | 22,3 | 0,90 | 11,8 |
| 12,5 | 34,36 | 29,1 | 0,95 | 14,4 |
| 15,0 | 27,47 | 36,4 | 1,00 | 17,0 |
| 20,0 | 18,90 | 52,9 | 1,10 | 22,2 |
| 26,0 | 13,97 | 71,6 | 1,20 | 27,4 |
| 30,0 | 10,79 | 92,7 | 1,30 | 32,6 |
| 35,0 | 8,61 | 116,1 | 1,40 | 37,8 |
| 40,0 | 7,07 | 141,4 | 1,50 | 42,9 |
| 50,0 | 5,02 | 199,4 | 1,70 | 53,2 |
| 60,0 | 3,75 | 266,6 | 1,90 | 63,5 |
| 70,0 | 2,92 | 342,9 | 2,10 | 73,8 |
| 80,0 | 2,33 | 429,0 | 2,30 | 84,2 |
| 90,0 | 1,91 | 523,9 | 2,50 | 94,5 |
| 100,0 | 1,59 | 627,9 | 2,70 | 104,8 |
Pipes of this class have the greatest wall thickness, have good strength, withstand the value of pressure in 100 kPa.
The characteristics of cast iron pipes of class LA are given in the table.
Table 3
| Conditional passage, cm | Meters in tons | The mass of the product, kg | Wall thickness, cm | Outer diameter, cm |
| 6,5 | 88,50 | 11,3 | 0,67 | 8,1 |
| 8,0 | 67,11 | 14,9 | 0,72 | 9,8 |
| 10,0 | 52,91 | 18,9 | 0,75 | 11,8 |
| 12,5 | 40,82 | 24,5 | 0,79 | 14,4 |
| 15,0 | 32,79 | 30,5 | 0,83 | 17,0 |
| 20,0 | 22,42 | 44,6 | 0,92 | 22,2 |
| 26,0 | 16,64 | 60,1 | 1,00 | 27,4 |
| 30,0 | 12,69 | 77,6 | 1,08 | 32,6 |
| 35,0 | 10,25 | 97,6 | 1,17 | 37,8 |
| 40,0 | 8,44 | 118,5 | 1,25 | 42,9 |
| 50,0 | 5,97 | 167,5 | 1,42 | 53,2 |
| 60,0 | 4,49 | 222,9 | 1,58 | 63,5 |
| 70,0 | 3,48 | 287,2 | 1,75 | 73,8 |
| 80,0 | 2,78 | 359,8 | 1,92 | 84,2 |
| 90,0 | 2,28 | 437,8 | 2,06 | 94,5 |
| 100,0 | 1,90 | 525,6 | 2,25 | 104,8 |
Disadvantages and advantages of products
The disadvantages of cast iron pipes, fittings for them can be attributed to their heavy weight, which requires considerable effort when laying the sewer pipeline.
One of the disadvantages of cast iron pipes is their high weight, therefore transportation and installation often require the involvement of equipment
The process of connecting such communications is also very labor-intensive. It takes more time to stack, than for a similar process with products made of other materials.
pay attention! The installation of external sewerage networks often requires the use of special equipment, that installation works were carried out in full compliance with rules and regulations.
However, cast iron products have many advantages. They have a fairly high strength due to the peculiarities of casting and alloying. Reliable operation is guaranteed for decades. The lowest service life of such communications - 40 years, highest - 80-100 years.
No sharp temperature jumps, nor its highest values do not worsen the parameters of cast iron pipes. The anticorrosive covering reliably protects products from aggressive influences of drains, formation of rust and plaque. They have high fire safety and relatively low cost.
Requirements for pipes and fittings
Cast iron sewer communications and fittings to them must be free of defects, which can worsen their installation performance: growths, inflow, drops of metal, layers on the inner and outer surfaces. If there are minor defects, which are due to the method of production and do not reduce the quality of the product, then their elimination is allowed.
Cast iron pipe should not have a bleach depth of more 1 mm over the entire outer surface. On shaped elements in places of sockets of forms (foundries), on the length 6 cm from the end, on the outside of the smooth ends of the products and the ends - more depth 2 mm Bleaching is a defect of the casting in the form of hard and difficult to machine machined places.
pay attention! Permissible deviation of the construction length of the document 6942 is 0,9%.
For nominal values of internal diameters of bells of shaped elements and pipes, as well as the outer diameters of the smooth ends of the products and the shanks of the shaped elements, the permissible deviation is 2 mm.
Production of pipes is carried out according to GOST and ready pipes check for compliance with various parameters, specified in this document
Smooth ends of pipes on a segment up to 15 cm and shanks of shaped elements on a segment up to 7 cm from the ends can be thickened no more, than on 2 mm. At the same time in such places the internal diameter of products has to be reduced.
When calculating the mass of cast iron sewer pipes (GUEST 6942-98 )accepted density of cast iron 7,1 g / cm3. If the product meets all the quality characteristics of the Guest, but its mass exceeds the maximum, then it is considered suitable. For pipes with conditional passage 10 and 15 cm deviation from straightness should be less 2 mm per meter of length, and with the passage 5 cm - 5 mm per meter of length. After applying the anti-corrosion coating on the outer and inner sides of pipes and fittings, they must withstand the value of hydraulic pressure not less 100 kPa.
Rules of acceptance and labeling of products
The raw material for the manufacture of pipes and fittings is gray cast iron with the addition of lamellar graphite, corresponding to GOST 1412. The fork is carried out according to GOST 26358. Products must be covered with anti-corrosion coating on the inside and outside, which have a softening temperature of at least 60 ° C (333 TO).
Marking of pipes and fittings is applied with indelible paint. It includes:
- trademark of the manufacturer or his name;
- symbol of products;
- performance standard.
The products are tested for compliance with such requirements:
- In terms of presence bleached: half a percent of products from the total batch.
- 100% the products of the batch must not have defects and have the appropriate appearance of anti-corrosion coating.
- In terms of deviations from size (nominal), wall thickness, tables, straightforwardness, endurance of pressure and stickiness of an anticorrosive covering: no less 2% products from the whole batch.
The manufacturer applies markings to the pipes, which contains data on the characteristics of the pipe
The composition should be applied solid, smooth, nelipkim, strong layer, without bubbles and cracks.
Mechanisms for product inspections
Determination of the value of nonlinearity of cast iron sewer pipe (GUEST 6942-98) is carried out by means of a shtangenreismas, that corresponds to GOST 164, control horizontal plate and two steel prismatic supports of the same height.
Prismatic supports are installed parallel to each other on the control horizontal plate. The distance between them should be more than half the length of the product, which is subject to verification. A pipe is laid on the support by bending down. The distance from the plane of the plate to the lower point of the cast iron pipe is measured with the help of a barbell with an accuracy of one tenth of a millimeter in that place, where the largest deflection.
Deviation from the straightness of the product on 1 meter of its length (?) calculated by the formula:
?=(b-c)/d
In expression b is the height of the support in millimeters; c is the distance from the plane of the plate to the bottom of the pipe in millimeters; d is the distance between the supports (in m).
The softening temperature of the anti-corrosion layer is checked according to GOST 11506. Its strength of adhesion to the metal of the pipe is checked by applying to the coating incisions in the form of a grid with a knife blade. The distance between the grid lines is not less 40 mm.
pay attention! At qualitatively put covering at cuts there will be no exfoliation.
Checking the stickiness of the anti-corrosion layer is performed at temperature 15-30 ° C by pressing a blank sheet of paper (writing) to a covering of a pipe in accordance with GOST 18510. The layer is considered non-sticky, if there are no traces of coating on the paper after it is removed. Such inspection is carried out not earlier than in a day after drawing an anticorrosive layer on a product.
Exterior colored pipe coating is corrosion protection, the protection layer is also checked for damage
Carrying out tightness testing of products
To check the tightness of shaped elements and pipes according to the document 6942-98 need a stand, pump and plugs (with a branch pipe and deaf). The stand is equipped with a manometer, the division price of which is not rougher 10 kPa. The pump must create a hydraulic pressure level 0,2 MPa.
Shaped elements and sewer pipes are located on the stand. To the hole, which is closest to the pump, the cap with a branch pipe is established, which provides a connection to it. A plug with a nozzle is installed on the other hole to drain the water. If there are other openings - deaf plugs are installed on them.
Using a pump, the inspected area is filled with water, is blocked by a valve or other shut-off mechanism pipe for draining water and it creates a pressure of at least 100 kPa. Maintaining such pressure lasts at least 15 With. during this time, the pipeline connections are inspected.
If no water leaks through the pipe connections and pipe walls, as well as fogging of the outer surfaces of shaped elements and pipes, then the plot, which is being tested, is considered airtight.
Dimensions of cast iron pipe and bell
GUEST 6942-98 determines the design and dimensions of cast iron sewer pipe. The document assumes the production of products without bells with their delivery with couplings, if agreed between the manufacturer and the consumer. The length of such a pipe may not correspond to that given in GOST 6942. Dimensions and products are listed in the table (the values of the linear parameters are given in centimeters).
Table 5
| Conditional passage | Wall thickness | Mass without anti-corrosion coating, kg | Construction length | The length of the bell |
| Five | 0,4 | 4,5 | Seventy five | Five |
| 5,8 | A table | |||
| 11,0 | Two hundred | |||
| Ten | 0,45 | 10,5 | Seventy | 5,5 |
| 13,9 | A table | |||
| 16,1 | One hundred twenty | |||
| 24,9 | Two hundred | |||
| 26,0 | Two hundred | |||
| 27,1 | Two hundred | |||
| Fifteen | 0,5 | 15,7 | Seventy | Six |
| 20,7 | A table | |||
| 39,6 | Two hundred | |||
| 41,5 | Two hundred and ten | |||
| 43,4 | Two hundred and twenty |
GUEST 6942-98 highlights 4 types of bells shaped parts. Sizes of shafts of shaped elements (in centimeters) are given in the table.
Table 6
| Conditional passage | 5,0 | 10,0 | 15,0 |
| Width taking into account the thickness of the walls | 5,8 | 10,9 | 16,0 |
| Overall width | 6,2 | 11,4 | 16,4 |
| Wall thickness | 0,4 | 0,45 | 0,5 |
The sizes of branch pipes
The branch pipe is a shaped element of the pig-iron pipeline, which is required to change the connection type. This detail is used to compare systems, made of different materials.
Pipes are used to connect cast iron pipes, which are available in a variety of shapes and sizes
GOST allocates transitional and compensating branch pipes. They are used in sewage systems and public sewage, industrial and residential buildings.
pay attention! The compensation pipe is used when several sewer systems need to be connected, differing in their structure.
The sizes of branch pipes according to the document 6942-98 are given in the table. Linear dimensions are given in centimeters.
Table 7
| Conditional passage | Mass without anti-corrosion coating, kg | Construction length |
| 5,0 | 2,0 | Twenty five |
| 2,5 | Thirty-five | |
| 2,8 | Fourty | |
| 10,0 | 3,8 | twenty |
| 4,4 | Twenty five | |
| 5,7 | Thirty-five | |
| 15,0 | 8,8 | Fourty |
A feature of the compensation pipe is an elongated bell. Parameters of such a branch pipe according to GOST 6942 must match the table. Linear dimensions are given in centimeters.
Table 8
| Conditional passage | Mass without anti-corrosion coating, kg | Shank length | The length of the bell |
| Ten | 4,5 | Eight | Thirteen |
| Ten | 8,4 | Eight | Thirty seven |
| Fifteen | 6,5 | Eight | Thirteen |
| Fifteen | 12,8 | Eight | Thirty eight |
Linear dimensions (in centimeters) and the mass of the cast iron adapter are shown in the table.
Table 9
| Conditional passage | Weight without anticorrosive coating in kg | |
| two | two | |
| 10,0 | Five | 1,85 |
| 15,0 | Ten | 3,2 |
Cast iron knee and its characteristics
When installing sewer pipes, there is often a problem of inability to properly lay the pipeline. If there are any obstacles along the way, then the use of a cast iron knee is recommended. It helps to solve such difficulties effectively and quickly.
If a turn is planned in the highway, then for its implementation use a knee of appropriate diameter
There are several varieties of this detail. There are flanged and bell-shaped knees. The installation option depends on the type of obstacle, which needs to be addressed.
Document 6942-98 defines the following parameters for the knees. Linear dimensions are given in centimeters.
Table 10
| Conditional passage | The distance from the point of bending to the shank | Mass without anti-corrosion coating, kg | The distance from the bending point to the bell |
| 5,0 | Thirteen | 2,0 | 5,7 |
| 10,0 | Fifteen | 4,9 | 8,5 |
| 15,0 | Eighteen | 7,5 | 12,5 |
Low knee weight by standard 6942-98 is 3,4 kg, distance from the point of bending to the shank - 24 cm, to the bell - 55 div.
Branches and indentations: their parameters
Taps are used to rotate the pipeline during installation. No communication system can do without them. GOST emits taps at 110 °, 120°, 135°, 150°. Their parameters are shown in the table. Linear dimensions are given in centimeters.
Instrument taps are made in the left and right versions. Their mass according to the document 6942-98 is 7 kg.
Cast iron indentation is used in non-pressure sewer networks for sewage and sewage. It is connected to the pipes by a bell connection.
pay attention! The retreat has good technical and operational parameters, low cost and long service life.
Such a connecting element, as a diversion, can be found in almost every sewer system
Characteristics of cast iron indentations according to the standard 6942-98 are given in the table. Linear dimensions are given in centimeters.
Table 11
| Conditional passage | Mass without anti-corrosion coating, kg | Bending radius | Length to the bell |
| Five | 2,1 | 6,0 | Twenty one |
| Ten | 5,0 | 8,5 | Twenty five |
| Fifteen | 8,0 | 9,0 | Twenty five |
Features of cast iron tee
Cast iron tee is used in the creation of sewer and plumbing systems. Flange products are widely used to separate the flow of water - and gas supply, providing heating. The advantage of tees is the ability to independently shut off streams. Structurally, they consist of three nozzles.
Standard 6942 determines the following parameters of tees. Linear dimensions are given in centimeters.
Table 12
| Conditional passage: Du / dy | 5/5 | 10/5 | 10/10 | 10/10D | 15/5 | 15,0/10,0 | 15,0/15,0 |
| Mass without anti-corrosion coating, kg | 2,4 | 4,2 | 6,0 | 8,3 | 6,0 | 7,5 | 10,0 |
| The distance from the main axis of the tee to the socket of the branch pipe | 4,0 | 4,0 | 7,0 | 9,5 | 4,0 | 7,0 | 9,5 |
| The distance from the axis of the branch pipe to the bell | 12,0 | 12,0 | 14,5 | 22,0 | 12,5 | 15,5 | 17,0 |
| The distance from the axis of the branch pipe to the shank | 4,0 | 6,5 | 7,0 | 15,0 | 9,0 | 9,5 | 9,5 |
The branch outlet angle is 87 ° 30? with a tolerance of 1 ° 30?.
The mass of the low straight tee is 5,8 kg, The distance from the axis of the branch pipe to the bell is 7 cm, to the shank - 24 cm; the distance from the main axis of the tee to the socket of the branch pipe - 5,5 div.
The mass of the transitional straight tee is 6,8 kg The distance from the axis of the branch pipe to the bell is 7 cm, to the shank - 14 cm; the distance from the main axis of the tee to the socket of the branch pipe - 7 div.
Tees are used to branch the sewer system
The mass of the transitional straight low tee is 4,7 kg The distance from the axis of the branch pipe to the bell is 5,5 cm, to the shank - 24 cm; the distance from the main axis of the tee to the socket of the branch pipe - 5,5 div.
The parameters of oblique tees are also given in the standard 6942.
Characteristics of crosses
When installing communication systems, it is important to consider the factor of pipe branching. Using a crosspiece for these purposes saves space and uses the material most efficiently. Branching occurs in two planes. Document 6942 contains the characteristics of crosses. The angle between the primary and secondary axes is 87 ° 30? with a tolerance of 1 ° 30?.
pay attention! The mass of straight crosses with a shifted axis of diversion is 7,6 kg. The displacement of the axis occurs on 25 mm.
Characteristics of oblique crosses at 60 ° with a tolerance of 1 ° 30? are given in the table. Linear dimensions are given in centimeters.
Table 13
| Conditional passage: main / taps | 5/5 | 10/5,0 | 10/10 | 15/5 | 15/10 |
| The distance from the branch point to the bell | 6,2 | Eight | 11,0 | 9,2 | 12,2 |
| The distance from the branch point to the shank | 10,8 | 9,5 | 12,5 | Eight | 10,8 |
| The distance from the branch point to the drain pipe | 6,2 | Nine | 11,0 | 12,0 | 13,5 |
| Mass without anti-corrosion coating, kg | 3,0 | 5,8 | 5,8 | 7,0 | 10,0 |
Characteristics of oblique crosses at 45 ° with a tolerance of 1 ° 30? are given in the table. Linear dimensions are given in centimeters.
Table 14
| Conditional passage: main / taps | 5/5 | 10/5,0 | 10/10 | 15/5 | 15/10 |
| The distance from the branch point to the bell | 9,0 | 11,5 | Fifteen | 14,0 | 18,0 |
| The distance from the branch point to the shank | Ten | 7,5 | Eleven | 8,5 | 8,5 |
| The distance from the branch point to the drain pipe | 9,0 | 12,5 | Fifteen | 16,0 | 18,8 |
| Mass without anti-corrosion coating, kg | 4,0 | 6,9 | 10,5 | 7,3 | 10,5 |
Two-plane crosspieces according to GOST 6942 happen in the left and right execution.
Couplings and other elements of the standard 6942 and their parameters
In the event of minor damage to the pipeline section (not more than three meters) it is not advisable to completely change the pipe or cut it. In this case, it is better to continue the loop with a new segment. When performing repair work on the existing pipeline, a sliding coupling is used.
Couplings are used as connecting elements in the installation and repair of highways
Because it has no internal partitions, ie the possibility of its movement on the product. This shortens the repair time, and accelerates the commissioning of communications. The sliding coupling is applicable at installation of shaped elements in a design of the pipeline.
Coupling parameters according to GOST 6942 are given in the table.
Table 15
| Conditional passage in cm | Mass without anti-corrosion coating, kg |
| Five | 1,3 |
| Ten | 2,7 |
| Fifteen | 5,0 |
Sliding couplings have parameters, are given in the table. Linear dimensions are given in centimeters.
Table 16
| Conditional passage | The distance between the bells | Mass, kg |
| Five | Eight | 1,8 |
| Ten | Ten | 3,8 |
| Fifteen | Twelve | 6,2 |
Cast iron plug is used to cut off part of the pipeline in case of failure or termination of further use. With its help you can block the flow of water or other working medium. The cap is a circle with several holes for mounting. The choice of the required product is made taking into account the diameter of the pipe, material and working pressure. Rubber plugs can also be used for cast iron pipes.
If in the future it is planned to branch the sewer, it makes sense to immediately install a tee and temporarily unused hole to close the cap
Audits provide access to the sewer pipeline for cleaning. The design of the cast iron revision is bell-shaped. The main difference is in diameter and dimensions.
So, according to the GOST document 6942-98 cast iron sewer pipe is the most reliable and durable for drainage systems. The advantages and relevance of their use is determined by resistance to various hydraulic pressures, temperature differences, loads and environmental safety.
