Self-restrained dismantling joint FD type DN50-600 PN10-16

Minimal length

Assembly length

Max. length

Direction of the water →



Self-restrained dismantling joint FD type DN50-600 PN10-16

Type FD
Main features

The self-restrained dismantling joint FD type in ductile iron allows the installation or removal of equipment between two fixed flanges of a pipeline.

The sliding system can reach a 50 mm displacement to ease the removal of the equipment.

For this type of self-restrained dismantling joint the locking of the valve to the pipeline is made by the tie bars and the gland.

This piece is designed and manufactured in alimentary quality for potable water.

They have a mobile MALE PART and one fix FEMALE PART. Between these two parts there is an intermediate flange allowing a good closing and making a good seal in contact with seal joint.


The self-restrained dismantling joints FD type in ductile iron exist in a range from DN50 to 600, for pressure PN10 and PN16.

Material and coating






Fixed body

Ductile iron 500-7 according to EN1563

Blue epoxy powder 250 microns average thickness with a minimum of 200 microns, conforming to EN 14901-1 (PECB)



Ductile iron 500-7 according to EN1563


Sliding body

Ductile iron 500-7 according to EN1563



EPDM rubber


Tie bars

Carbon steel Class 8.8

Geomet 720+


The installation will be made using the tie rods. Tie rods must extend until the flange of the valve or of the piece connected to the dismantling joint.

Bolts used for the assembly must have the same metric and quantity of DN that flanges used.

Its length will have to be sufficient so that the ends of the nuts and bolts exceed at least of 1 centimeter of the external bolts.

Installation process:

Step 1: It is advised to check the length of final assembly of the dismantling joint, so that it is closest to its nominal measurement, to facilitate the assembly and the disassembling of this one.

Minimal length

Assembly length

Max. length

DNAssembly lengthTolerance of assembly ±
50 - 200193-21111,5 - 21,5
250 - 40028040

Step 2: The correct position for the assembly of the dismantling joint will be, water downstream from the female part and water upstream of the male part.

Direction of the water →

Note: for pipes with a water direction in the two sides (pipes of discharge), the dismantling joint will make the sealing in the two directions when the flow of water is contrary to the assembly indicated above, the pressure loss will be superior.

Step 3: To unscrew the bolts which tighten the intermediate flange as well as the internal bolts of the flanges of connection, to check that the male/female sliding is slowly made in order to avoid any stretching and/or scratch between the fixed and mobile parts (pyramidal joint, male and female).

Step 4:To place the dismantling joint in its final position, making sure that the position of the holes of the flange coincides with the position of the holes of the pieces to connect.

Note: The maximum tolerable angular deflections for the flanges (parallelism) of pieces to be connected will not exceed the following value of 0,25º X 1000/DN considering only the connection which is carried out with the tie rods does not enable a greater deflection than that caused by the tie rods with the holes of the flanges.

Step 5: To put the tightness seals on the flanges to be connected.

Note: When the joint is installed, it must be able to avoid small imperfections of the flange like:

- Non parallel flanges

- Deformation of the channels

- Corrugated Surface

- Notch in surface

- Other imperfections on surface

Step 6: To separate the end flanges of the dismantling joint until its position of contact with the flanges of the pieces to be connected.

Step 7:To start the assembly of the nuts and bolts by forming a circle with all the tie rods, (at least to make 100% of all the holes of the external flanges).

Note:Be careful to never use less threaded rods than those which are determined by the flange.

Step 8:The tightening of the bolts and nuts is done directly on the flange in diagonal by taking the values of table 3, like orientation of the maximum tightening torque.

Note: The best output of the bolts/stems is done in the elastic zone.

For the design of the unions systems of joint/screw/flange to see Codes ASME section.

Step 9:To tighten the bolts of the intermediate flange by taking the values of table 3, as maximum value of the tightening torque with 85% of the elastic tension of the nuts and bolts to be used.

Indications to be followed for tightening:

1. To manually tighten initially the bolts by leaving width, then to tighten manually uniformly.

2. To use the torque wrench, to turn all bolts up to a maximum of 30% of the total of the tightening torque. To check that the flange is placed uniformly on the joint.

3. To turn until a maximum of 60% of the total of the tightening torque.

4. To turn until the total of the tightening torque.

5. Final tightening up to the total tightening torque, clockwise on the adjacent bolts.

Example of installation in diagonal:

1º step: Position 1-5

2º step: Position 2-6

3º step: Position 3-7

4º step: Position 4-8

Step 10:Once the installation is start up and with the appropriate working pressure, to check that there are no water losses on the sealing joints, by carrying out convenient tightening of the nuts and bolts until eliminating these losses.


The pieces will be transported assembled with all the components, without fixing the length of assembly (if the tie rods of assembly are not included) and while preventing that the once assembled elements do not move.

The equipment will be packed perfectly to avoid possible damage which would deteriorate the quality of coating.

The pallet used will be European with a dimension 800x1200 mm.


These plates are on all the provided equipment. They show all the “register dated” and controls on the dismantling joint.

To order spare parts, it is necessary to refer to this identifying plate.

Packaging sticket

Product sticker


Each year it is necessary to check the seals, to see whether they are lubricated or to change them.

Every two years the coating should be controlled. In case of serious scratches, the coating must be repaired.

Every ten years, the seals should be replaced.

Spare parts: Pyramidal joint

Never re-use this joint taking into account its important deformation. Even if the joint seems to be in good report, it should not be re-used. The price of a new joint is quite lower than the cost of work of assembling and disassembling of the joint because of later problems due to the re-use of the joint.

Compliance to Standards

For the FD Joint: These pieces comply with the standard NFE 29220, especially concerning the flanges dimensions according to the NF EN 1092.

The stroke range is higher than those required in the NFE 29220.