November

2014

DIN 19704-2
D
ICS 93.140; 93.160 Supersedes
DIN 19704-2:1998-05

Hydraulic steel structures –

Part 2: Design and manufacturing,
English translation of DIN 19704-2:2014-11

Stahlwasserbauten –
Teil 2: Bauliche Durchbildung und Herstellung,
Englische Übersetzung von DIN 19704-2:2014-11
Constructions hydrauliques en acier –
Partie 2: Construction et fabrication,
Traduction anglaise de DIN 19704-2:2014-11
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Document comprises 38 pages

Translation by DIN-Sprachendienst.
In case of doubt, the German-language original shall be considered authoritative.

© No part of this translation may be reproduced without prior permission of

DIN Deutsches Institut für Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,
has the exclusive right of sale for German Standards (DIN-Normen).
www.din.de
www.beuth.de
!%|&M"
12.18 2890342
 DIN 19704-2:2014-11

A comma is used as the decimal marker.

Contents
Page

Foreword ......................................................................................................................................................... 5
1 Scope ................................................................................................................................................. 6
2 Normative references ....................................................................................................................... 6
3 General considerations for design, operation and maintenance ................................................ 8
3.1 General requirements ....................................................................................................................... 8
3.2 Accessibility ...................................................................................................................................... 8
3.3 Rooms for drive systems ................................................................................................................. 9
3.4 Locking mechanisms ....................................................................................................................... 9
3.5 Inspection gates................................................................................................................................ 9
3.6 Trash racks ........................................................................................................................................ 9
3.7 Covers ................................................................................................................................................ 9
3.8 Protection against ship impact ....................................................................................................... 9
4 Detailing of steel structures .......................................................................................................... 10
4.1 General ............................................................................................................................................. 10
4.2 Minimum thicknesses .................................................................................................................... 10
4.3 Bolted connections......................................................................................................................... 10
4.3.1 General ............................................................................................................................................. 10
4.3.2 Minimum diameter of bolts and rivets .......................................................................................... 11
4.3.3 Hole pitches for bolts and rivets ................................................................................................... 11
4.3.4 Securing of bolts............................................................................................................................. 11
4.4 Welded connections ....................................................................................................................... 12
4.4.1 Fillet welds....................................................................................................................................... 12
4.4.2 Butt welds ........................................................................................................................................ 12
4.4.3 Flange plates ................................................................................................................................... 12
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4.4.4 Welding of cold-worked components ........................................................................................... 12

4.4.5 Welding of load-bearing components .......................................................................................... 12
4.4.6 Protective measures ....................................................................................................................... 12
4.5 Axle supports .................................................................................................................................. 13
4.6 Cut-outs ........................................................................................................................................... 13
4.7 Filler plates ...................................................................................................................................... 13
5 Fabrication of steel structures ...................................................................................................... 13
5.1 Manufacturerʼs approval ................................................................................................................ 13
5.2 Tolerances ....................................................................................................................................... 13
5.2.1 General ............................................................................................................................................. 13
5.2.2 Tolerance classes ........................................................................................................................... 14
5.2.3 Tolerances for embedded elements ............................................................................................. 14
5.2.4 Tolerances for gates ....................................................................................................................... 14
5.3 Testing of welds .............................................................................................................................. 17
5.4 Testing of hollow structures .......................................................................................................... 17
5.5 Stainless steels ............................................................................................................................... 17
5.6 Combined use of structural steel and stainless steel................................................................. 18
5.7 Protection against corrosion ......................................................................................................... 18
5.7.1 Machining of edges and welds ...................................................................................................... 18
5.7.2 Coating ............................................................................................................................................. 18
5.7.3 Cathodic protection ........................................................................................................................ 18
6 Seals ................................................................................................................................................. 18
6.1 Material pairs ................................................................................................................................... 18

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6.2 Design ............................................................................................................................................... 19

6.3 Seal sliding faces and stop faces .................................................................................................. 19
6.4 Rubber seals .................................................................................................................................... 19
6.5 Sealing timber/stop rails ................................................................................................................. 20
6.6 Leakage ............................................................................................................................................ 21
7 Prevention of icing .......................................................................................................................... 21
7.1 Heating of sealing faces ................................................................................................................. 21
7.2 Water circulation ............................................................................................................................. 21
8 Embedded elements ........................................................................................................................ 22
8.1 Installation ........................................................................................................................................ 22
8.2 Concreting ........................................................................................................................................ 22
8.3 Joints ................................................................................................................................................ 22
8.4 Rails and guide rails ........................................................................................................................ 22
9 Design principles for machinery .................................................................................................... 23
9.1 Support and guidance of gates ...................................................................................................... 23
9.2 Drives ................................................................................................................................................ 23
9.2.1 Accessibility ..................................................................................................................................... 23
9.2.2 Speed of gate ................................................................................................................................... 23
9.2.3 Switch-off at end position............................................................................................................... 23
9.2.4 Synchronization monitoring and closed-loop control ................................................................. 23
9.2.5 Position-sensing systems .............................................................................................................. 24
9.2.6 Overload protection devices .......................................................................................................... 24
9.2.7 Manual drives ................................................................................................................................... 24
10 Design principles for special machine components ...................................................................24
10.1 Oil-hydraulic drives ......................................................................................................................... 24
10.1.1 General requirements for hydraulic cylinders ............................................................................. 24
10.1.2 Design and manufacture of hydraulic cylinders .......................................................................... 25
10.1.3 Passages of piston rods and linkages .......................................................................................... 26
10.1.4 Hydraulic components .................................................................................................................... 26
10.1.5 Hydraulic fluids ................................................................................................................................ 27
10.1.6 Hydraulic station ............................................................................................................................. 28
10.1.7 Pipework ........................................................................................................................................... 29
10.1.8 Changes in gate position ................................................................................................................ 30
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10.1.9 Manual and emergency drives ....................................................................................................... 30

10.1.10 Marking ............................................................................................................................................. 31
10.1.11 Protection against corrosion ......................................................................................................... 31
10.2 Electric lifting cylinders .................................................................................................................. 31
10.3 Brakes ............................................................................................................................................... 32
10.4 Couplings ......................................................................................................................................... 32
10.5 Shaft-to-hub connections ............................................................................................................... 32
10.6 Cylindrical and bevel gears ............................................................................................................ 32
10.7 Worm gears ...................................................................................................................................... 32
10.8 Drive assemblies ............................................................................................................................. 33
10.9 Plain bearings .................................................................................................................................. 33
10.10 Spherical plain bearings ................................................................................................................. 33
10.11 Rolling bearings .............................................................................................................................. 33
10.12 Bearings for slewing movements .................................................................................................. 33
10.13 Radial seals ...................................................................................................................................... 34
10.14 Bearing housings ............................................................................................................................ 34
10.15 Sprocket chains ............................................................................................................................... 34
10.16 Pinion racks and pinion chains ..................................................................................................... 35
10.17 Rope drives ...................................................................................................................................... 36
10.18 Wheels and guide rollers ................................................................................................................ 36
10.19 Sliding guideways ........................................................................................................................... 36
10.20 Axles and hinge pins....................................................................................................................... 36
10.21 Springs ............................................................................................................................................. 36

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10.22 Threads ............................................................................................................................................ 36

10.23 Fasteners ......................................................................................................................................... 37
10.23.1 Bolts and bolted connections ....................................................................................................... 37
10.23.2 Welds ............................................................................................................................................... 37
Bibliography ................................................................................................................................................. 38
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Foreword
This standard has been prepared by Working Committee NA 119-02-04 AA “Hydraulic steel constructions” of
DIN-Normenausschuss Wasserwesen (DIN Standards Committee Water Practice). DIN-Normenausschuss
Bauwesen (DIN Standards Committee Building and Civil Engineering) was also involved in the development
of this standard.

The DIN 19704 series of standards consists of the following parts under the general title Hydrolic steel
structures:

— Part 1: Criteria for design and calculation

— Part 2: Design and manufacturing

— Part 3: Electrical equipment

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. DIN [and/or DKE] shall not be held responsible for identifying any or all such patent rights.

Amendments

This standard differs from DIN 19704-2:1998-05 as follows:

a) the content has been revised to reflect new technological developments and experience in water
management, shipping, and dam management;

b) the standard has been brought into line with the new generation of standards for civil engineering,
DIN EN 1990 ff. (“EUROCODEs”);
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c) the standard has been editorially revised.

Previous editions

DIN 19704: 1958-06, 1963-12, 1976-09

DIN 19705: 1963-12, 1976-09
DIN 19704-2: 1998-05

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1 Scope
This standard covers the detailing and fabrication of hydraulic steel structures as specified in
DIN 19704-1:2014-11.

2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.

DIN 13-1, General purpose ISO metric screw threads — Part 1: Nominal sizes for coarse pitch threads;
nominal diameter from 1 mm to 68 mm

DIN 2523, Non-soldering compression fittings with cutting ring — Complete fittings and survey

DIN 15020-1, Lifting Appliances; Principles Relating to Rope Drives; Calculation and Construction

DIN 19703, Locks for waterways for inland navigation — Principles for dimensioning and equipment

DIN 19704-1:2014-11, Hydraulic steel structures — Part 1: Criteria for design and calculation

DIN 19704-3:2014-11, Hydraulic steel structures — Part 3: Electrical equipment

DIN 20066, Hydraulic fluid power — Hose assemblies — Dimensions, requirements

DIN 50969-2, Prevention of hydrogen-induced brittle fracture of high-strength steel building elements —
Part 2: Test methods

DIN 53504, Testing of rubber — Determination of tensile strength at break, tensile stress at yield, elongation
at break and stress values in a tensile test

DIN 53508, Testing of rubber — Accelerated ageing

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DIN 55670, Paints and varnishes — Method for testing paint coatings for pores and cracks using high-voltage

DIN 86076, Gasket sheets for ship building — Requirements and tests

DIN EN 350-2, Durability of wood and wood based products — Natural durability of solid wood — Part 2:
Guide to the natural durability and treatability of selected wood species of importance in Europe

DIN EN 1090-2:2011-10, Execution of steel structures and aluminium structures — Part 2: Technical
requirements for steel structures

DIN EN 1993-1-1, Eurocode 3: Design of steel structures — Part 1-1: General rules and rules for buildings

DIN EN 1993-1-8:2010-12, Eurocode 3: Design of steel structures — Part 1-8: Design of joints

DIN EN 1995-1-1, Eurocode 5: Design of timber structures — Part 1-1: General — Common rules and rules
for buildings

DIN EN 10025-1, Hot rolled products of structural steels — Part 1: General technical delivery conditions

DIN EN 10226-1, Pipe threads where pressure tight joints are made on the threads — Part 1: Taper external
threads and parallel internal threads — Dimensions, tolerances and designation

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DIN EN 10226-2, Pipe threads where pressure tight joints are made on the threads — Part 2: Taper external
threads and parallel internal threads — Dimensions, tolerances and designation

DIN EN 13411-4, Terminations for steel wire ropes — Safety — Part 4: Metal and resin socketing

DIN EN 14359, Gas-loaded accumulators for fluid power applications

DIN EN ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1:
Dimensions, tolerances and designation

DIN EN ISO 1183-1, Plastics — Methods for determining the density of non-cellular plastics — Part 1:
Immersion method, liquid pyknometer method and titration method

DIN EN ISO 4032, Hexagon regular nuts (style 1) — Product grades A and B

DIN EN ISO 4034, Hexagon regular nuts (style 1) — Product grade C

DIN EN ISO 4035, Hexagon thin nuts chamfered (style 0) — Product grades A and B

DIN EN ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections

DIN EN ISO 8434-1, Metallic tube connections for fluid power and general use — Part 1: 24° cone connectors

DIN EN ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests

DIN EN ISO 12944-1, Paints and varnishes — Corrosion protection of steel structures by protective coating
systems — Part 1: General introduction

DIN EN ISO 12944-4, Paints and varnishes — Corrosion protection of steel structures by protective coating
systems — Part 4: Types of surface and surface preparation

DIN EN ISO 12944-5, Paints and varnishes — Corrosion protection of steel structures by protective coating
systems — Part 5: Protective paint systems
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DIN EN ISO 17636-1, Non-destructive testing of welds — Radiographic testing — Part 1: X- and gamma-ray
techniques with film

DIN EN ISO 17636-2, Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray
techniques with digital detectors

DIN EN ISO 19232-3, Non-destructive testing of welds — Image quality of radiographs — Part 3: Image
quality classes

DIN ISO 34-1, Rubber, vulcanized or thermoplastic — Determination of tear strength — Part 1: Trouser, angle
and crescent test pieces

DIN ISO 815-1, Rubber, vulcanized or thermoplastic — Determination of compression set — Part 1: At
ambient or elevated temperatures

DIN ISO 1431-1, Rubber, vulcanized or thermoplastic — Resistance to ozone cracking — Part 1: Static and
dynamic strain testing

DIN ISO 1817, Rubber, vulcanized — Determination of the effect of liquids

DIN ISO 2285, Rubber, vulcanized or thermoplastic — Determination of tension set under constant
elongation, and of tension set, elongation and creep under constant tensile load

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DIN ISO 3302-1:1999-10, Rubber — Tolerances for products — Part 1: Dimensional tolerances

DIN ISO 4649:2006-11, Rubber, vulcanized or thermoplastic — Determination of abrasion resistance using a
rotating cylindrical drum device

DIN ISO 6022, Hydraulic fluid power — Mounting dimensions for single rod cylinders, 25 MPa (250 bar) series

DIN ISO 7619-1, Rubber, vulcanized or thermoplastic — Determination of indentation hardness — Part 1:
Durometer method (Shore hardness)

DIN CEN/TS 13001-3-2, Crane safety — General design — Part 3-2: Limit states and proof of competence of
wire ropes in reeving systems

AD 2000-Merkblatt (AD 2000 Code of practice) HP 5/3, Herstellung und Prüfung von Verbindungen —
Zerstörungsfreie Prüfung von Schweißverbindungen (Fabrication and testing of joints in pressure vessels —
Non-destructive testing of welds) 1)

DVS 0704, Empfehlungen zur Verwertung von Ultraschallbefunden an Schmelzschweißverbindungen nach

DIN 8563-3 (Recommendations for assessment of results of ultrasonic testing of fusion welds according to
DIN 8563-3)

Merkblatt 822, Die Verarbeitung von Edelstahl Rostfrei (Processing of high-grade stainless steel) 2)

3 General considerations for design, operation and maintenance

3.1 General requirements

To ensure their reliability, hydraulic steel structures shall be designed to be simple, robust and safe. For steel
structures, a service life of 70 years shall be assumed, for machine components and their electrical
equipment, 35 years. This does not apply to parts subject to wear. When designing the whole system, and in
particular the machinery and electrical systems, a risk analysis in accordance with the EU Machinery Directive
shall be carried out and the results implemented.

When designing the steel structure and the seals, due attention shall be paid to hydrodynamic effects.
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Any cavitation shall be prevented by taking suitable measures with regard to design features, venting, etc.

To facilitate control of the headwater level and for easy removal of ice and floating debris, these should be
able to pass over the top of the gates, whenever possible.

3.2 Accessibility

The design shall take into consideration the need for simple and efficient maintenance, also with regard to the
civil engineering aspects. This applies especially to ease of access, inspection and replacement of elements
and components.

Gates should be accessible. For this purpose, ladders, manholes, gratings and walkways may be provided. It
shall be possible to vent closed, accessible gates, and they shall be fitted with a sufficient number of access
openings of adequate size.

Ladders shall be designed along the lines of DIN 19703.

1) Obtainable from: Beuth Verlag GmbH, 10772 Berlin.

2) Obtainable from: Informationsstelle Edelstahl Rostfrei, 40237 Dusseldorf.

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3.3 Rooms for drive systems

Rooms for drive systems shall be kept free of water, vented and, where necessary, protected against
condensation. It shall be ensured that the machinery and electrical systems are kept sufficiently cool by
means of heat removal. If the driving machinery is not located above the maximum water level, the rooms for
drive systems and penetrations for cables and pipes shall be made proof against water exerting hydrostatic
pressure.

Drive motors and controls for gates which are used for flood water discharge or flood protection shall remain
accessible even at the design flood water level.

Rooms for drive systems shall be designed to prevent environmentally hazardous fluids from escaping into the
environment.

Auxiliary equipment for repair purposes shall be provided for all drives and each room.

Drives should be installed and removed as assemblies and be able to be conveyed to the surface.

3.4 Locking mechanisms

Gates shall be capable of being mechanically locked in the required positions as governed by the locking
system and operational safety requirements, and to facilitate erection and maintenance work.

3.5 Inspection gates

It shall be possible to inspect any submerged parts, usually by means of inspection gates.

Inspection gates should be designed for quick and simple installation and removal, even in flowing water if
required.

3.6 Trash racks

Intake trash racks shall be capable of being cleaned. It shall be possible to lift trash racks installed at a low
level.
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Trash racks should not be installed in front of deep sluices unless they can be cleaned. The absence of trash
racks shall be taken into account by a suitable design of gate and sluice.

3.7 Covers

Pits and channels shall have slip-proof covers. They shall be installed in tied frames, from which they should
be easily removable. They shall be fixed if there is a risk of uplift.

3.8 Protection against ship impact

Gates likely to be subjected to ship impact shall be protected by suitable means.

In the case of mitre gates, protective bars should be located approximately 100 mm behind the chamber wall
line when the gate is in the open position.

See DIN 19703 for the installation of impact protection installations.

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4 Detailing of steel structures

4.1 General

In general, DIN EN 1993-1-1 and DIN EN 1090-2 apply.

Supplementing and differing provisions are stated in the following.

The requirements of DIN EN 1090-2 apply to steel structures and rails, with the exception of other parts firmly
connected to the solid structure.

The decision as to which execution class is required is made by the client.

The class EXC 2 is required as a minimum. This remains the case when fatigue assessment to DIN 19704-1
is irrelevant or not required. If inspection gates are also to be considered not subjected to predominantly static
loading, this shall be specified accordingly by the client.

The design of steel structures shall aim to keep mechanical stresses (e.g. due to ice, flotsam or floating
debris) to a minimum.

The support conditions for gates shall not significantly change as a result of settling, deformation or wear.

The use of stainless steel shall be kept to a minimum.

NOTE 1 Minor mechanical stresses and corrosion tend to occur with even surfaces and less complex designs. See
DIN EN ISO 12944-3 for design principles that take into account corrosion protection.

NOTE 2 Design features to ensure constant support conditions for the gate include the selection of a gate of low
torsional stiffness, and means of adjusting bearings, rails and seals.

4.2 Minimum thicknesses

With the exception of filler plates and equipment such as heating pipes, air bubbler system pipes and lubricant
pipes, the following minimum thicknesses shall be observed for elements made from unalloyed structural
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steel:

— upstream-facing plates for lock gates, barrage gates and safety gates: 12 mm;

— upstream-facing plates for other gates and inspection gates: 10 mm;

— steel plates, flats and wide flats: 8 mm;

— steel bars and sections, and walls of hollow sections and tubes: 6 mm;

— embedded steel elements: 10 mm.

Minimum thicknesses of elements made from stainless steel shall be specified by the client.

4.3 Bolted connections

4.3.1 General

Bolted connections intended to withstand shear and bearing pressure or ensure positional stability shall be
designed as fitted shear bolt connections.

There shall be no bolted joints on upstream faces unless they are required, for example, to enable the
subsequent removal of such plates or the assembly and disassembly of gates consisting of several parts.

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Friction-grip connections are not permitted owing to the risk of corrosion on submerged friction interfaces.

The use of stainless steel screws is generally to be avoided. If stainless steel screws are used for connections
where the screws are removable, adjustable or replaceable, the tightening torque and pre-stressing forces
given in Table 1 shall not be exceeded.

The pre-stressing loads and tightening torques of other property classes shall be converted relative to their
yield stresses.

Table 1 — Maximum permissible pre-stressing loads and tightening torques for stainless steel bolts of
property class 70

Thread size Pre-stressing load Tightening torque

in kN in Nm
M 16 45 150
M 20 56 275
M 24 69 285
M 27 72 400
M 30 88 550

4.3.2 Minimum diameter of bolts and rivets

The nominal diameter of bolts and rivets shall be at least 16 mm.

4.3.3 Hole pitches for bolts and rivets

The following table partially replaces DIN EN 1993-1-8:2010-12, Table 3.3, with t being the thickness of the
thinnest of the external parts of the connection and dL being the hole diameter.

The smaller value shall be taken in each case.

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Table 2 — Maximum edge distances and hole pitches

Type of connection Maximum edge Maximum pitch

distance
Sealing joints max. 2.5 dL or 5 t max. 3 dL
Other joints and connections max. 3 dL or 6 t max. 6 dL or 12 t
Mountings of elastomer seals — max. 12 t

4.3.4 Securing of bolts

Adhesives, locking nuts according to DIN EN ISO 4032, DIN EN ISO 4034 and DIN EN ISO 4035 or other
suitable locking systems may be used to secure bolts.

Pre-stressed bolts do not require additional securing.

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4.4 Welded connections

4.4.1 Fillet welds

Interrupted welds are only permitted on elements embedded in concrete, with the distance of the free concrete
surface to the fillet weld interruption being at least 100 mm (see Figure 1).

Figure 1 — Interrupted fillet welds

The minimum throat thickness a shall be 3 mm.

Single-sided fillet welds are only permitted for closed profiles (e.g. hollow stiffeners) and elements embedded
in concrete.

4.4.2 Butt welds

The following applies to butt welds for plates differing in thickness perpendicular to the line of force:

— edges abutting by more than 3 mm are to be bevelled to a slope of 1:4 or less;

— backing strips made from steel on the root side of butt welds are to be welded on both sides unless they
are located in sealed hollow structures.
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4.4.3 Flange plates

In the case of flange plates, the slope of the face fillet weld shall be bevelled to 1:2 or less, and the slope of
additional flange plates to 1:4 or less.

4.4.4 Welding of cold-worked components

Welding of cold-worked components that are made from unalloyed structural steel according to
DIN EN 10025-1 and are not subjected to predominantly static loading shall be subject to the clientʼs consent
in each particular case.

4.4.5 Welding of load-bearing components

The requirements for welds of components that are not subjected to predominantly static loading stem from
the execution class of the component. Welds subjected to predominantly static loading shall meet at least the
requirements of quality level C according to DIN EN ISO 5817.

4.4.6 Protective measures

Welding at low temperatures shall be permitted only with the consent of the client and on condition that
special precautions are taken.

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4.5 Axle supports

Axle support plates and hubs shall consist of a single unit, considered in the direction of their depth.

If, for the support of axles, etc., reinforcement plates are used instead of hubs, they shall be of circular form
and welded on along their external and internal diameter (see Figure 2).

Figure 2 — Welding of reinforcement plates

4.6 Cut-outs

The radius of cut-outs should be as great as possible, but not less than r = 40 mm.

4.7 Filler plates

Using stainless steel filler plates in conjunction with unalloyed steel shall be avoided. Filler plates not
submerged in water shall be designed according to DIN EN 1993-1-8:2010-12, 3.6. Filler plates up to 5 mm
thick that are sometimes or permanently submerged shall be made from a single layer of stainless steel and
5 mm smaller than the connecting flange plate; they shall be continuously welded on on one side using fillet
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welds. Thicker filler plates may be constructed from unalloyed steel and are also to be welded on using
continuous fillet welds.

Deviations require approval from the client.

5 Fabrication of steel structures

5.1 Manufacturerʼs approval

Companies that manufacture hydraulic steel structures shall meet the requirements of the relevant design
execution class (see DIN EN 1090-2:2011-10, Table A.3).

5.2 Tolerances

5.2.1 General

For embedded elements of wheel gates and sliding gates, radial lock gates, flap gates and mitre gates, the
inevitable fabrication and erection inaccuracies should not exceed the tolerances given in Tables 3 to 6.

For inspection and other gates, as well as for special cases (e.g. installation of fixed elements under water),
the tolerances shall be specified by the client.

The tolerances given are applicable for cases where water pressure is not to be taken into account.

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5.2.2 Tolerance classes

See Tables 3 to 6 for tolerance classes 1 and 2.

As a rule, tolerance class 1 shall apply, with tolerance class 2 covering any special requirements specified by
the client.

5.2.3 Tolerances for embedded elements

All the dimensions in Tables 3 to 6 refer to the nominal position of the elements concerned.

Tolerances covering the distance of rails positioned opposite each other in the direction of flow shall be
specified as a function of the type of rear guide roller and any seal. For gates that create a seal on both sides
and for guided gates, tolerance class 2 shall always be applied for ∆x. Furthermore, it shall always be ensured
that the seal is sufficiently pre-stressed.

For repair works to existing elements the tolerances to be adhered to shall be specified by the client.

5.2.4 Tolerances for gates

Tolerances for gates shall be harmonized with those for embedded elements, if this is required for functional
reasons.

If no tolerances are specified by the client, DIN EN 1090-2:2011-10, Annex D shall be applied.

The deviation from parallelism of the axles of gates with fixed wheels shall not exceed the value
tan α = 0,000 5.

If the gates are not fully assembled or preassembled in the workshop, suitable means for their adjustment
during erection shall be provided in their design.

If sealing faces are situated on the gate body, the tolerances from 5.2.2 shall apply by analogy.
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Table 3 — Tolerances for embedded elements for fixed-wheel gates and sliding gates

No. Elements Tolerance class 1 Tolerance class 2

1 Rails, L < 5 000 mm ∆y = 2 mm ∆y = 1 mm
straightness at right angles to
2 L > 25 000 mm ∆y = 4 mm ∆y = 2 mm
direction of flow for
3 L < 5 000 mm ∆L1 = ± 2 mm ∆L1 = ± 1 mm

4 L > 25 000 mm ∆L1 = ± 4 mm ∆L1 = ± 2 mm

Intermediate values may be obtained by linear interpolation.
5 Rails, ∆x = 2 mm ∆x = 1 mm
straightness in direction of flow
6 Rails, ∆x = 1 mm ∆x = 0,5 mm
straightness over length of 2 000 mm
7 Machined rails, tan α = 0,002 tan α = 0,002
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cross fall
8 The sealing faces shall be toleranced in relation to the rails.
9 Ground sill, L < 5 000 mm ∆z = 1 mm ∆z = 1 mm
straightness over entire length
for
10 L > 25 000 mm ∆z = 3 mm ∆z = 2 mm
Intermediate values may be obtained by linear interpolation.
11 Ground sill, ∆z = 1 mm ∆z = 1 mm
straightness over length of 1 000 mm
a Clearance

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 DIN 19704-2:2014-11

Table 4 — Tolerances for embedded elements for radial lock gates

No. Elements Tolerance class 1 Tolerance class 2

1 Straightness tolerance for L < 5 000 mm ∆y = 2 mm ∆y = 1 mm
lateral guide rolls and seals
2 L > 25 000 mm ∆y = 4 mm ∆y = 2 mm
Intermediate values may be obtained by linear interpolation.
3 Straightness over length = 1 000 mm for ∆y = 2 mm ∆y = 1 mm
lateral guide rollers and seals
4 Pivot bearings/axial L < 5 000 mm ∆x = ∆z ∆x = ∆z
misalignment = 1,5 mm = 1 mm
5 L > 25 000 mm ∆x = ∆z ∆x = ∆z
= 3 mm = 2 mm
Intermediate values may be obtained by linear interpolation.
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6 Pivot bearings/parallelism of axes tan α = 0,002

7 Ground sill, L < 5 000 mm ∆z = 1 mm ∆z = 1 mm
straightness over entire length,
for
8 L > 25 000 mm ∆z = 3 mm ∆z = 2 mm
Intermediate values may be obtained by linear interpolation.
9 Ground sill, ∆z = 1 mm ∆z = 1 mm
straightness tolerance over length of 1 000 mm
a) Clearance
b) ∆x or ∆z
c) Notional axis

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 DIN 19704-2:2014-11

Table 5 — Tolerances for embedded elements for flap gates

No. Elements Tolerance class 1 Tolerance class 2

1 Side plating,
∆y = 4 mm ∆y = 2 mm
flatness over entire surface
2 Side plating,
∆y = 3 mm ∆y = 1,5 mm
flatness over length of 1000 mm
3 Pivot bearing,
∆x = ∆z = 0,5 mm ∆x = ∆z = 0,5 mm
axial misalignment with more than 2 bearings

Table 6 — Tolerances for embedded elements for mitre gates

No. Elements Tolerance class 1 Tolerance class 2

1 Gudgeons and pintle bearings, ∆x = ∆y = 2 mm ∆x = ∆y = 1 mm
misalignment
2 Wall plates and quoin posts, ∆y = 2 mm ∆y = 1 mm
misalignment
3 Mitre brackets of quoin and mitre posts, a a
maximum gap width (with gate in closed position s= s=
10 000 10 000
and under water load)
where a = the shorter distance between two
adjacent brackets (from centre to centre), in
mm

5.3 Testing of welds

Radiographic examination of welded connections by X- or gamma rays shall be as specified in

DIN EN ISO 17636-1 or DIN EN ISO 17636-2. Radiographic film images shall comply with image quality class
B as in DIN EN ISO 19232-3. The test requirements shall be in accordance with class B as in
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DIN EN ISO 17636-1 or DIN EN ISO 17636-2.

Ultrasonic testing shall be carried out by a qualified materials tester in line with AD 2000-Merkblatt HP 5/3.
The requirements relating to class B (as above) shall be applicable. The results shall be converted into quality
levels as in DIN EN ISO 5817 using the procedure specified in DVS-Merkblatt 0704.

5.4 Testing of hollow structures

The tightness of hollow structures such as flotation chambers or heating pockets shall be verified by means of
pressure testing using a proof pressure of 0,3 bar over a minimum duration of 6 h.

5.5 Stainless steels

Elements and components made from stainless steel shall be handled carefully at the location of their
fabrication and on site. In particular, they shall be protected against soiling and damage (e.g. from grinding
and welding spatter).

After completion of all work, stainless steel surfaces shall be cleaned using rotating stainless steel brushes or
fine sanders or polishers made from a suitable material, or by equivalent means. They shall then be rinsed
thoroughly in clean water. Any tarnish on surfaces not embedded in concrete shall be removed.

Merkblatt 822 shall be complied with.

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 DIN 19704-2:2014-11

Stainless steel and unalloyed structural steel shall be stored separately, both at the manufacturer’s location
and at the construction site.

5.6 Combined use of structural steel and stainless steel

The risk of electrolytic corrosion shall be taken into account when stainless steel is used in conjunction with
unalloyed structural steel, the degree of such corrosion being a function of the potential difference, the ratio of
areas of the conducting metals in contact with each other, and the conductivity of the electrolyte (see
DIN EN ISO 12944-3).

If elements made from stainless steel are embedded in concrete, the ties and stiffeners in the concrete may
be of unalloyed structural steel provided the concrete cover is 60 mm thick or more.

5.7 Protection against corrosion

5.7.1 Machining of edges and welds

To ensure corrosion protection, all external machined edges shall be prepared in accordance with preparation
grade P3 as given in DIN EN ISO 8501-3.

5.7.2 Coating

Since hydraulic steel structures are exposed to severe corrosion attack, frequently in conjunction with
mechanical and biological stresses, importance shall be attached to passive corrosion protection in the form of
thick-layer, abrasion-resistant paint systems (see DIN EN ISO 12944-5).

Surfaces of bolted and riveted connections in direct contact shall be provided with the required coating prior to
assembly.

5.7.3 Cathodic protection

To prevent corrosion of gates and other structures which are permanently in contact with water (e.g. canal
bridge troughs), the additional installation of cathodic protection systems can be useful (active protection).
These can take the form of electroplating or impressed-current systems. Thorough preliminary investigations
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(water analyses, supply measurements, etc.) are required prior to their rating and installation. Adequate
preparation for cathodic protection systems (i.e. for accommodation of anodes, cables and guard circuits)
shall be made as early as the design stage.

NOTE See also BAW MKKS (BAW Code of Practice on cathodic corrosion protection in hydraulic steel structures).

6 Seals

6.1 Material pairs

Seals may consist of the following material pairs:

a) elastomer and granite;

b) elastomer and plastic;

c) elastomer and metal;

d) plastics (e.g. PA, PE) and metal;

e) wood and metal;

f) metal and metal.

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 DIN 19704-2:2014-11

6.2 Design

Seals shall be easily replaceable and accessible.

Deformation of the gate shall be taken into account when engineering the sealing system.

Adjustable seals shall be selected if the deformation of the gate and the wear of the seals are likely to equal
the seal clearance.

In the case of bottom seals, the rubber elements (uncompressed) should protrude by about 5 mm in order to
compensate for unevenness in the sealing face. If the tightness is nevertheless unsatisfactory, additional
adjustments will be required (e.g. by re-tightening seal bolts).

Weld-on steel stud bolts are not permitted for fixing seals.

The use of weld-on nuts, cap nuts and screws is not recommended.

6.3 Seal sliding faces and stop faces

Sliding faces in contact with rubber seals shall be made from either plastic/granite, stainless steel or coated
structural steel.

Where there are large sliding faces (e.g. for lateral seals of radial or lap gates) and high water conductivity (as
in the case of seawater, brackish water and heavily contaminated river water), the use of coated structural
steel is to be given preference. Coatings shall meet stringent requirements with regard to adhesion, hardness,
evenness, smoothness and resistance to elevated temperatures.

For the surface roughness, an arithmetic mean deviation of the profile of Ra = 3,2 μm shall not be exceeded.
The coating shall be designed to withstand severe mechanical stress as defined in DIN EN ISO 12944-1.

If seals are designed to lose contact with the sliding face while the gate is in motion, transitions shall be
flattened.

Taking into account the deformation and the play when the gate is in motion, the width of stop faces or sliding
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faces shall be designed so that the faces protrude by at least 25 mm on either side.

6.4 Rubber seals

It shall be possible to adjust adjustable seals within small ranges, even after any coating has been applied.
Adjusting devices shall be made from stainless material.

Seals shall compensate for any unevenness of the sliding faces by being appropriately pre-stressed and of
suitable elasticity, even in the absence of water pressure, and shall retain their sealing function throughout.

Moulded corner pieces shall be used for perimeter seals having the same or similar cross sections.

Jointing of seals shall be by vulcanizing using a joint mould or an equally effective method.

DIN ISO 3302-1 shall apply with regard to seal tolerances.

The seal materials shall comply with the specifications of Table 7 as a minimum.

Clamping and spacer strips shall be rounded or chamfered on the seal side.

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 DIN 19704-2:2014-11

Table 7 — Material characteristics for rubber seals

Properties Testing as in Requirement

Shore A hardness DIN ISO 7619-1 65 ± 5 a
Tear strength DIN 53504 (testing rod S2) ≥ 15 MPa
Elongation at break DIN 53504 (testing rod S2) ≥ 300 %
Compression set DIN ISO 815-1
168 h/23 °C (test piece type B) ≤ 20 %
24 h/70 °C ≤ 25 %
Tear propagation resistance DIN ISO 34-1 (Method A, trouser test piece) ≥ 8 N/mm
Heat ageing 7 d/70 °C DIN 53508
Change in Shore A hardness DIN ISO 7619-1 ≤+8
Tear strength DIN 53504 (testing rod S2) ≥ 10 MPa
Elongation at break DIN 53504 (testing rod S2) ≥ 300 %
Low-temperature behaviour DIN ISO 7619-1 ≤ 90
24 h/–20 °C
Shore A hardness
Behaviour after ozone ageing DIN ISO 1431-1
48 h, 40 °C, 50 pphm Procedure A no cracks
Tension set DIN ISO 2285
24 h, 70 °C, 100 % elongation (Strip test piece *), RT measurement, 30 min ≤ 20 %
after load is removed)
Abrasion DIN ISO 4649 (with 5 N) ≤ 120 mm3
Density DIN EN ISO 1183-1 Nominal value as given
by manufacturer
± 0,02 g/cm3
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Resistance to seawater b DIN 86076

28 d, 50 °C
Change in Shore A hardness DIN ISO 7619-1 ≤5
Change in volume DIN ISO 1817 ≤ 10 %
Tear strength DIN 53504 (testing rod S2) ≥ 10 MPa
Elongation at break DIN 53504 (testing rod S2) ≥ 300 %
a A different hardness can be specified if a justifiable reason is given.
b For seals exposed to sea or brackish water.

6.5 Sealing timber/stop rails

Rails that create a seal are preferably to be made from PE-UHMW. If, in certain cases, wood is used, the
specifications of DIN EN 1995-1-1 apply.

The wood selected shall be of resistance class 1 or 2 as in DIN EN 350-2.

*) Translatorʼs note. Term used in DIN ISO 2285. “Trouser test piece” is the more frequently used term.

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 DIN 19704-2:2014-11

6.6 Leakage

Unless otherwise specified by the client, leakage for operational gates shall be limited to 0,05 l/m ∙ s.

7 Prevention of icing

7.1 Heating of sealing faces

It shall be the responsibility of the client to specify the surfaces to be heated. Seal heaters shall be designed
to prevent the formation of ice at air temperatures down to –20 °C.

Heated surfaces should be warmed just enough to keep their temperature above freezing point.

Surfaces are to be conventionally warmed:

a) by heating elements positioned in cavities;

b) by electrical heating elements (strip or grid) fixed to the surfaces.

Heating elements shall be installed with adequate protection against environmental influences, and shall be
removable. Thermal conduction can be improved by filling existing cavities with an appropriate frost-proof and
environmentally friendly heat transfer fluid whose level shall be capable of being monitored and maintained.
Temperature-related fluctuations in the volume of the fluid shall be taken into account. In general, the
temperature of the heating system should be adjustable.

7.2 Water circulation

Water circulation enables the heat stored in deeper water to be used to prevent the formation of ice on the
gate.

For this purpose, the following systems may be used:

a) pressurized water systems;

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b) air bubbler systems;

c) mechanical circulating systems (e.g. mixer plant).

Pipes for pressurized water and air bubbler systems shall be made from plastic. It shall be possible to flush
liquid or blow air through them for cleaning purposes.

The outlets should be located as deep as possible in the water and fitted with screw nozzles.

Compressors for air bubbler systems shall be equipped with a downstream filter system that prevents the
concentration of residual oil exceeding 0,01 mg/m3 at 20 °C.

The output of the system should be at least 1 l/s per metre of pipe length in the air outlet zone.

If there are several gates, it should be possible to operate air bubble pipes separately.

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8 Embedded elements

8.1 Installation

Embedded elements whose accuracy to gauge is a major factor, such as bottom seal contact faces, guide
rails, seal sliding faces and stop frames, should generally be installed in duly prepared recesses, after which
they shall be aligned and grouted.

The recesses shall be large enough to enable the trouble-free placing of second-stage concrete and
compaction by internal vibrators. Steel ties should be fitted in the recesses to which the elements to be
embedded can be fastened for alignment purposes.

Ingress of water in joints between concrete and steel elements shall be prevented. Care shall be taken to
ensure proper adhesion between first-stage and second-stage concrete (e.g. by the use of ties or projecting
reinforcement, application of tack coats, sandblasting of the first-stage concrete, or other suitable measures).

Embedded elements shall be tied so as to enable their easy installation and grouting, and to ensure
satisfactory transmission of loads. Any ties affecting the load-bearing function shall grip into both the second-
stage and first-stage concrete.

However, if elements are to be embedded without being tied, suitable measures shall be taken to keep them
in the correct form and position during the concreting operations and until the concrete has sufficiently set.

If a cathodic protection system is foreseen, the gate, including any embedded steel elements, and the
conductive parts of the solid structure (i.e. reinforcement and sheet piles) shall be kept electrically isolated.

8.2 Concreting

Loads occurring as a result of concrete pressure on the formwork shall not be transmitted to the embedded
elements.

These shall be checked for their correct position before and after grouting. This process shall be documented.

8.3 Joints
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If embedded elements cross construction or movement joints in the concrete, special structural measures are
generally required (e.g. interruption of bottom seal contact face).

8.4 Rails and guide rails

Rails, including guide rails, of frequently operated gates (e.g. lock gates) shall be replaceable on the basis of
the anticipated wear.

Countersunk bolts shall not be fitted in the crown of rails.

There shall be no joints in rails at points of high wheel pressure. Where unavoidable, joints should be mitred at
an angle of 45°.

Any differences in height of rails shall be levelled out.

Rails and sleepers shall be frictionally connected to enable direct load transmission.

For rails made from unalloyed structural steel as the base material and with a stainless steel crown (e.g.
applied by deposit welding or explosive cladding), the minimum thickness of the crown after mechanical
machining should still be 6 mm or equal to the half-axis measurement b of the ellipsis; the greater of these two
values shall be used. 7.7.4 and 10.22 of DIN 19704-1:2014-11 shall be observed. Deposit welding shall be
with at least three runs.

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9 Design principles for machinery

9.1 Support and guidance of gates

Fixed-wheel gates shall be provided with lateral guide rollers. In the case of fixed axles, this shall be by means
of single-flanged wheels or by means of lateral guide rollers, and in the case of roller trains, by means of
double-flange wheels and lateral guide rollers.

Lateral guide rollers or skids shall either be spring-mounted or have reasonable clearance. Care shall be
taken to ensure the unhindered interaction of lateral seals and lateral guide rollers. If the gate is centrally
suspended, each side shall be guided at a minimum of two points.

Radial lock gates should also be equipped with lateral guide rollers.

For gates with double-acting drive, whose wheels will alternately contact two rails on opposite sides, additional
spring-preloaded rear guide rollers should be provided.

9.2 Drives

9.2.1 Accessibility

Mechanical or hydraulic drives shall be easily accessible. Components that require adjustment and/or regular
servicing (e.g. limit switches, lubrication points, hydraulic filters) shall be easily accessible. Hydraulic
components should be clearly positioned on the power units.

9.2.2 Speed of gate

Gates shall be accelerated and decelerated within a reasonable time as a function of the design type, mass
and travel time.

Gates shall approach the end position at a speed not exceeding 0,1 m/min to 1,0 m/min, depending on their
type and mass.

9.2.3 Switch-off at end position

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Preferably, drives should be switched off at their end position by limit switches that are automatically actuated
when the gate reaches a certain position. If, for operating reasons (e.g. closing pressure), drives are to be
switched off as a function of load or pressure, position-actuated limit switches shall be used to control the
movement of the gate to end position (see DIN 19704-3:2014-11, 4.6 and 5.1).

9.2.4 Synchronization monitoring and closed-loop control

The synchronous operation of gates with double-acting drives shall be monitored, except for drives of gates of
large torsional stiffness such as radial or flap gates, or drives with a shaft.

In order to ensure the synchronous operation of drives, mechanical, electrical, electronic, electronically
programmable or hydraulic synchronization closed-loop control systems may be used, as well as
combinations thereof.

Synchronization monitoring and closed-loop control systems shall operate as a function of the position.

A position-sensing system is required on either drive side. The local control cabinet shall be fitted with a digital
position indicator.

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9.2.5 Position-sensing systems

Gates which can be operated to stop at any pre-selected position in addition to the end positions shall be fitted
with a position-sensing system. It shall be the responsibility of the client to specify the type of display (i.e.
digital, analogue, or mechanical) to be used.

Position-sensing systems shall be designed to rule out any risk of icing or blocking.

For hydraulic drives, position-sensing systems located in the cylinder shall be removable without the cylinder
having to be emptied.

Position-sensing systems that take absolute measurements are to be preferred over incremental
measurement systems. If non-absolute measurement systems are used, suitable means shall ensure that, in
the event of a power loss, the gate position is saved and the gate can be repositioned in accordance with the
correct measurement value. Such means are, for example, a system that guarantees the uninterrupted
provision of electrical energy; or a measuring system can be easily recalibrated and reintegrated to restore
normal operation.

9.2.6 Overload protection devices

Drives shall normally be fitted with an electrical overload protection device, which shall be designed in line
with the specifications of DIN 19704-3:2014-11, 4.7.

Protective equipment in the form of couplings with an electrical switch-off device shall be arranged so that
they do not hold the load while the drive is at rest.

Seals of overload protection devices shall not be broken when the gate is in operation.

9.2.7 Manual drives

Mechanical drives shall be equipped with manual drives for adjustment and maintenance work. Once the
manual drive is activated, the main drive shall be automatically disconnected from power or disengaged. In
the case of double-acting drives, this applies to both drive units.
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Manual drives shall be automatically made inoperative when the gate is operated electrically. The brake of the
main drive shall be capable of being released only after the manual drive has been engaged. Equally, it must
be applied again before the manual drive can become disengaged. This is an essential process.

Manual drives shall be fitted with an automatic friction disc brake (which shall act in both directions, where
required) or be designed with a self-locking mechanism. See 10.1.9 for manual hydraulic drives.

10 Design principles for special machine components

10.1 Oil-hydraulic drives

10.1.1 General requirements for hydraulic cylinders

Hydraulic cylinders should be positioned to prevent the piston rod being submerged in flowing water, thus
preventing damage from flotsam and ice. If this is not possible, protective measures shall be provided. The
use of bellows is not permitted.

Hydraulic cylinders shall be hinged at both ends on bearings to allow them to move freely to all sides, unless
bending is precluded owing to restraint. Flanged cylinders (except for locking cylinders) may be used in cases
where the cylinders are arranged vertically and their correct guidance is ensured, and the play in the gate
movement can be minimized.

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 DIN 19704-2:2014-11

Any additional support of hydraulic cylinders (i.e. three-point support) may only become effective when the
cylinder is depressurized.

At the end positions of gates, hydraulic cylinders shall have sufficient internal clearance between the piston
and the covers, unless a stop is provided in the design.

Unless a more precise verification is required, for cylinders in compression, the piston rod and front bearing
head of the cylinder barrel shall have an overlap equal to at least 1,5 D as the centre distance between
guides (D being the internal barrel diameter).

Cylinders which are temporarily or permanently pressurized at system pressure shall be isolated so as to be
leak-tight in the direction of loading by being flanged-mounted on shut-off or control manifolds. Control
manifolds shall be equipped with manually operated stop valves between the cylinder and the shut-off valve.

It shall be the responsibility of the client to specify details of monitoring leakage where cylinders are
submerged temporarily or over prolonged periods.

Both cylinder chambers shall be permanently filled with oil. If the gate is lowered without the pumps running, it
shall be ensured that the unpressurized chamber is filled with oil.

To enable proper bleeding of cylinders, pressure tappings shall be provided at suitable locations. If required,
suitable procedures shall be specified for assembly and filling of cylinders.

10.1.2 Design and manufacture of hydraulic cylinders

10.1.2.1 Cylinder barrels

Cylinder barrels shall be manufactured from seamless steel tubes, where possible without joints, and shall
normally be designed to enable flanges to be connected at both ends.

The cylinder bore shall be finished to a surface roughness Ra < 0,4 μm.

If bracing rings are welded to the barrel, this shall be finished after welding.
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10.1.2.2 Piston rods

Piston rods, including those for hydraulic cylinders designed as specified in DIN 19704-1, 10.2, shall be
fabricated either from

a) stainless steel with a chromium content of not less than 15,5 % (mass fraction) and a multilayer hard
chromium plating with an overall thickness of not less than 50 µm, or

b) unalloyed steel with an oxide ceramic coating.

It shall be the responsibility of the client to specify constructional details.

Surfaces should be finished so that in both cases the arithmetic mean deviation of the profile is Ra < 0,3 μm.

Oxide ceramic coatings shall be designed to rule out corrosion of the substrate. It should be homogeneous,
scratch-resistant, free of cracks and non-conductive, and shall have a thickness of at least 150 µm and a
surface hardness of 800 HV 0,3.

Subsequent sealing of pores is not permitted.

The corrosion resistance of oxide ceramic coatings shall meet the requirements for the DIN EN ISO 9227 test
over an exposure period of 1 000 hours.

Piston rods shall be fabricated as single units unless otherwise justified.

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10.1.2.3 Mountings and connections

Piston rods with piston rod heads, which are fitted with spherical plain radial bearings, shall generally be
connected to the gate or the supporting structure.

The connection of the rod to the rod head should be designed with male thread on the rod.

The thread of the rod heads and spherical plain radial bearings shall be sealed against the ingress of water.
Any holes for securing safety equipment shall not be drilled into the thread, and shall be sealed.

If cylinders are mounted by means of clevises, these should be fabricated as single units. Welds in clevises in
tension shall be butt welds.

Where there is journal or cardanic bearing of the cylinders, all bearings shall be self-lubricating. Contact faces
of bearing pins shall be made from stainless steel.

10.1.2.4 Guides and seals

Guides for pistons and piston rods shall generally be made from copper alloys. The use of plastic guides is
also permitted.

Only multi-lip systems shall be used for sealing. Any build-up of drag flow pressure shall be precluded.

The seals used between components without counter-movements (such as between cylinder head and barrel)
shall be O-ring seals. O-ring seals with diameters ≥ 125 mm shall be fitted with additional back-up rings.

Where piston rods pass through the cylinder head, the latter shall be fitted with dirt wipers, and with serrated
ice scrapers if there is a risk of ice formation. The wipers/scrapers shall be secured by positive locking.

Where cylinders are designed to be used under water, additional seals within a corrosion-resistant housing
shall be provided to prevent water being sucked in.

10.1.3 Passages of piston rods and linkages

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Seals for sealing the piston rods and linkages against the water pressure present in the gate shaft shall be
accommodated in housings mounted on the cover.

Housings shall be equipped with guide bushes, dirt wipers and at least one multi-lip seal. A lubrication point
shall be provided for frequently moved rods. There shall be sufficient clearance between seal housing and
cylinder head to ensure adequate accessibility for servicing. The piston rods shall be able to move without
restraint.

10.1.4 Hydraulic components

10.1.4.1 General

Pressure shall be generated by positive displacement pumps with a constant or continuously variable output.

Pumps with a widely variable output are recommended for systems involving heavily fluctuating flows.

Motors shall be mounted in a way that limits vibration.

Where possible, all the equipment required for the control of the hydraulic system, such as flow control valves,
pressure relief valves, etc., shall be clearly arranged on the same control panel. The actuator ports shall be
directly connected to the manifolds.

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 DIN 19704-2:2014-11

For electrically operated valves, DC wet-pin solenoid valves should be used wherever possible. Such valves
shall be fitted with an easily accessible manual override with a detent facility.

Pilot-controlled flow control valves shall be provided with facilities for smooth adjustment of the devices
associated with the main piston.

The functions of the solenoid valves shall be indicated by LEDs, except for proportional valves and servo-
valves.

The electrical connection for any electrically actuated components such as valves, pressure switches and float
switches shall be made via plug connections.

Depending on the system size, pressure gauges (manometers) shall be provided in a sufficient number and in
general with a diameter of 100 mm. They shall be provided with glycerine fill and a manual stop valve.
Electronic measuring devices may also be used.

10.1.4.2 Pressure relief valves

The following pressure relief valves shall be provided as a minimum for protecting the system (see
DIN 19704-1:2014-11, 8.5 and Figure 5):

a) valve to release pressure in the hydraulic cylinder during motion (DV1);

b) valve to release pressure in the hydraulic cylinder for accidental load case combination 3 (DV3);

c) valve to release pressure in the hydraulic system, generally at the pump outlet (DV2).

Valves of types DV1 and DV3 shall be direct operating, and shall be located together with the shut-off valves
directly at the cylinder. All pressure relief valves shall be sealed after trial operation.

10.1.4.3 Hydraulic oil filters

Hydraulic stations shall be fitted with at least one return line filter of 10 µm maximum pore size, with one-way
filter elements. The use of paper filters is not permitted. The filter system shall be suited to the components
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used and shall include connections for a bypass filter.

The nominal flow of the filter should be at least four times the maximum flow. All filters shall be provided with a
visual clogging indicator, with an electrical connection and a bypass valve having an opening pressure of
3 bar.

10.1.4.4 Hydraulic accumulator systems

Bladder-type or piston-type accumulators with or without downstream gas vessel and gas precharging are to
be used as hydraulic accumulators.

The design of and acceptance procedure for hydraulic accumulator systems shall be as specified in
DIN EN 14359.

10.1.5 Hydraulic fluids

If any leakage in the hydraulic system is likely to cause the hydraulic fluid to come into contact with the water
(e.g. in the case of an accident), the use of biodegradable hydraulic fluids should be given preference over
those based on mineral oils. Where synthetic esters or polyglycols are used, due attention should be paid at
the design stage and when handling the fluids during maintenance and operation (e.g. by appropriate choice
of materials and monitoring).

Triglycerides (plant or animal-based oils) are not suitable for use together with hydraulic steel structures owing
to their ageing behaviour. It shall be the responsibility of the client to specify the type of fluid to be used.

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It should be noted, however, that the use of biodegradable fluids does not confer immunity from the obligation
to prevent any leakage of these fluids.

Hydraulic fluids will generally be suitable for use at temperatures from –25 °C to +60 °C.

Filling of the system and subsequent topping up may only be by means of filters with a pore size that meets
the requirements specified in 10.1.4.3.

10.1.6 Hydraulic station

It shall be the responsibility of the client to specify the design of the hydraulic station to suit the operating
conditions, scope of the task and standardization conditions.

The station may be an assembly (e.g. oil reservoir with mounted motor/pump units and control unit) or consist
of individual units (e.g. oil reservoir, pumping station, valve assembly, and accumulator station, if any).

Oil reservoirs shall be designed so as to accommodate three times the volume of the maximum flow supplied
by the pump(s) in one minute, plus the differential volume of all connected cylinders, plus the contents of the
piston rod chamber of the largest connected cylinder plus the contents of the associated pipework.

The distance between the ends of suction and return lines shall be as large as possible.

The inlet of the suction pipe shall be designed for optimum flow (i.e. at least with the end cut at an angle).

The upper and lower edges of suction pipe inlets shall be at a reasonable distance from the reservoir bottom
and be located sufficiently deep below the lowest fluid level (i.e. the level where the float switch responds).

Reservoirs shall be designed to have a sloping bottom, drain valve, access openings, permanent oil level
indicator and float switch (the latter being removable without this requiring the removal of other components).

Fillet welding shall be double-sided whenever possible.

The reservoir may be ventilated by means of either

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a) a humidity absorber with transparent container. Any air escaping as the oil level rises shall not pass
through the adsorber; or

b) a humidity adsorber with carbon filter. In this case, air escaping may pass through the granulate; or

c) a hydro-compensator.

Openings in the reservoir shall be plugged airtight.

There should be no fittings and valves within the fluid reservoir.

If the rooms for drive systems cannot be designed as specified in 3.3, the fluid reservoir shall be installed in a
sheet steel tray with a capacity equal to 10 % of the nominal reservoir capacity.

Hydraulic variable displacement pumps should be installed next to the reservoir in a manner enabling their
convenient maintenance. Suction lines shall be equipped with a manually operated shut-off valve provided
with a limit switch.

The required total flow should be shared by at least 2 motor/pump units.

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10.1.7 Pipework

10.1.7.1 General

When determining the routing of pipes, attention should be given to good accessibility. Pipes shall be spaced
to ensure easy mounting of fittings and flanges, and should not be laid on top of one another.

Movable elements and connections and movement joints shall be fitted with flexible hydraulic hoses. Only
hoses conforming to DIN 20066, used in conjunction with corrosion-protected fittings, are permitted. The fitting
shall be galvanized on the inside and outside, and made from stainless steel in areas intermittently or
permanently under water. The installation instructions specified in DIN 20066 shall be observed. The use of
rotary joints is permitted.

If the laying of pipes or hose in flowing water or in its immediate vicinity cannot be avoided, protective
measures against flotsam shall be provided.

Pipes shall be fitted with manually operated shut-off valves for partial shutdowns, at least at the ports of the
hydraulic station and at the ports of hydraulic cylinders and hydraulic motors. It shall be the responsibility of
the client to specify the provision of any additional shut-off valves (e.g. on hoses).

It shall be possible to depressurize the whole system (or separate compartments, if required).

Manually operated shut-off valves outside the rooms for drive systems shall have a galvanized body and
stainless steel internal components. The material used for the shut-off valves shall be the same as the
material used for the pipes.

Proper bleeding of the piping system shall be ensured, with pressure tappings recommended for this purpose.

10.1.7.2 Flow rates

The design of hydraulic pipework shall be based on the following guideline values for the maximum flow:

pressure lines (supply and return) DN < 40 : 3,0 m/s

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DN ≥ 40 : 5,0 m/s

pilot oil return and leakage lines DN < 40 : 1,0 m/s

DN ≥ 40 : 1,5 m/s

pump suction lines : 0,6 m/s

10.1.7.3 Pipes and fittings

It shall be the responsibility of the client to make a selection among the following combinations of connections.

1) Pipes of size DN < 40 located inside the rooms for drive systems and the hydraulic station:

a) precision tubes made from unalloyed steel and pipe joints using unalloyed steel compression
couplings;

b) precision tubes made from unalloyed steel and pipe joints using unalloyed steel weld-on nipples with
O-ring seal;

c) precision tubes made from unalloyed steel and positive-locking pipe joints, made using cold forming
with soft seals; pipe supports and union nuts shall be in accordance with DIN 2353 and
DIN EN ISO 8434-1;

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 DIN 19704-2:2014-11

d) precision tubes made from stainless steel and pipe joints using stainless steel weld-on nipples with
O-ring seal;

e) precision tubes made from stainless steel and positive-locking pipe joints, made using cold forming
with soft seals; pipe supports and union nuts shall be in accordance with DIN 2353 and
DIN EN ISO 8434-1;

2) Pipes of size DN < 40 located outside the rooms for drive systems:

f) precision tubes made from stainless steel and pipe joints using stainless steel weld-on nipples with
O-ring seal;

g) precision tubes made from stainless steel and pipe joints using stainless steel flared fittings with
double cone with O-ring seal;

3) Pipes of size DN ≥ 40:

h) pipes made from unalloyed steel, of 6 mm minimum wall thickness, and pipe joints using unalloyed
steel weld-on flanges;

i) pipes made from stainless steel and pipe joints using stainless steel weld-on flanges.

The external diameter of pipes downstream of the hydraulic station should be at least 16 mm.

Changes in direction of the pipe run should preferably be made by bending the tubes, without this leading,
however, to significant changes in their cross section.

Pipes should be fixed to or supported on plastic pipe brackets arranged on a zinc-plated supporting structure.
The minimum distance of pipes from the wall or floor shall be equal to about 2 DN. It shall be the responsibility
of the client to indicate whether the bearing structure and fasteners are to be made from stainless steel (e.g. in
coastal areas). The specifications of DIN ISO 6022 apply.

For weld-on cones and flanges, welds shall be dressed internally. Pipes made from unalloyed or low-alloy
structural steel shall be pickled on the inside and protected against corrosion until installation. The pipework
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shall be cleaned before installation. The entire pipework shall be flushed before commissioning.

10.1.7.4 Pipe failure monitoring

The hydraulic pipework shall be equipped with monitoring devices designed to cut off the drives electrically in
the event of pipe or hose failure. The use of automatic shut-off valves that switch off the drive as a function of
the flow is not permitted.

10.1.8 Changes in gate position

Changes in the position of the gate as a result of unavoidable, internal leakage and changes in the volume as
a result of changes in temperature of the hydraulic system shall be taken into account, monitored and
automatically adjusted, if required.

10.1.9 Manual and emergency drives

Hand pumps shall be provided for adjustment and servicing work. For systems equipped with pilot-operated
valves, separate manually operated valves or separate supply systems to the connected pressure and pilot
lines are to be provided. The latter may be connected to the hand pump via a flexible pressure hose fitted to a
quick-release coupling.

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In order to ensure minimum operability of the system at all times, emergency pump power units may be used
which are either firmly installed or can be connected via quick-release couplings and are powered by external
energy sources (e.g. internal combustion engines, battery-operated DC motors).

It shall be the responsibility of the client to specify the type of emergency drive to be used.

10.1.10 Marking

All hydraulic components shall be identified by the item number given on the hydraulic circuit diagram. For
electrically operated components, the entries from the electrical circuit diagram shall also be included. All pipe
fittings also require identification. It shall be the responsibility of the client to specify any further markings or
labels.

10.1.11 Protection against corrosion

Welded structures made from unalloyed structural steel (e.g. oil reservoirs, supporting frames and valve
consoles) shall be derusted to preparation grade Sa 2½ prior to application of the corrosion protection (as in
DIN EN ISO 12944-4).

The corrosion protection system used for the hydraulic system shall be compatible with the fluid used.

10.2 Electric lifting cylinders

Electric lifting cylinders shall be sealed on the inside and outside. All elements of the cylinders, including the
required transmission and drive motor, shall be designed in accordance with protection code IP 65. If a higher
level of protection is required, this shall be specified by the client.

Electric lifting cylinders shall be equipped with a spring assembly to absorb axial impact loads that occur
during operation.

A torque rod shall be used to prevent twisting of the piston rod.

Axial forces shall not be transferred to the gear motor.

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Biodegradable grease of water hazard class 1 shall be used as a lubricant.

The installation area of the seals (piston rod guide) shall be protected against corrosion using suitable means.

S 355 SR or N shall be used as the base material for the piston rod.

The piston rod shall be coated in a nickel-based substance protecting against corrosion and an oxide ceramic
coating. The total thickness shall be at least 400 µm. The corrosion protection coating thickness shall be at
least 150 µm and the oxide ceramic layer at least 250 µm.

The oxide ceramic coating shall be homogeneous, scratch-resistant, tear-resistant and pore-free. It shall not
conduct electricity and shall have a minimum hardness of 800 HV 0,3.

The corrosion resistance of the coatings shall be tested using salt spray tests according to DIN EN ISO 9227:

— with fresh water for at least 500 h;

— with salt water for at least 1 000 h.

Particularly when used in sea water or brackish water atmospheres, pore-free coatings shall be used for oxide
ceramic-coated piston rods made from unalloyed steel. Verification that the coating is pore-free and tear-free
shall be conducted in accordance with DIN 55670. Sealing pores is not permitted once the coating has been
applied.

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Seals shall be used that are made of material suitable for operation with the grease specified by the
manufacturer (grease with low hazard risk to water) and the ceramic coating. Suitability for use shall be
confirmed by the seal manufacturer or based on values previously recorded.

10.3 Brakes

The brakes used should be external double-shoe drum brakes with powered release system, or disc brakes.

In the case of frequently operated gates (e.g. lock gates), a means of automatic brake adjustment is
recommended.

10.4 Couplings

Couplings that transmit torque even once the overload protection device has responded (see 9.2.6) shall be
protected against current breakdown. For flexible couplings, transmission of loads shall be unimpeded even in
cases of failure or destruction of all flexible components of the coupling.

10.5 Shaft-to-hub connections

Keyed connections are only to be used for low-speed (circumferential speed < 0,8 m/s), open gears or chain
sprockets and pinions.

10.6 Cylindrical and bevel gears

Cylindrical and bevel gears shall preferably be accommodated in closed boxes that are oil-tight and rigid. For
larger gear boxes in tension, a construction made from spheroidal cast iron or a welded construction is
recommended.

The two output stages of toothed gears may be open.

For toothed gear strips, interference fits are not allowed.

Closed gearboxes shall be oil-lubricated. Care shall be taken, even after longer downtimes, that meshed teeth
are immediately lubricated on start-up. Oil sight glasses shall be provided at suitable, clearly visible places for
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checking the oil level. Oil drains shall be easily accessible and fitted with drain valves and plugs. These should
be fitted directly at the boxes. Pans shall be installed at points where there is a risk of leakage. If possible, the
oil filling connection shall be equipped with a filter screen.

Lubrication with semi-fluid grease is permitted for low-speed, closed gears.

Open gear stages shall be lubricated with grease. Drips of grease shall be collected in accessible pans.

Gearboxes and oil and grease pans shall be provided with a means of corrosion protection that is lubricant-
compatible.

See DIN 19704-1:2014-11, 10.10, for toothing parameters.

10.7 Worm gears

In the case of worm gears, the worm shall be equipped with one fixed and one floating bearing. The housing
design shall ensure that in the case of oil-bath lubrication, the worm is permanently submerged in the oil.

The specifications of 10.6 shall apply by analogy.

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10.8 Drive assemblies

Grease lubrication in the gear chamber is permitted for drive assemblies.

NOTE Drive assemblies (e.g. multiturn actuators) combine an electric motor, gearing, and switchgear and
controlgear in one box.

10.9 Plain bearings

Bushes made from non-ferrous casting alloys shall be fabricated applying the centrifugal casting or direct-chill
casting process.

The bearing liner backing of wrapped bushes made from composite material that are temporarily or
permanently exposed to water shall be made from corrosion-resistant material.

The thickness of the sintered metal coatings of plain bearings made from composite material shall be at least
as great as the wear anticipated over the entire friction path, but not less than 1 mm.

In plain bearings with solid lubricant inserts, the area of inserts should be approximately one third of the sliding
face areas, with the inserts located so that the sliding face is continuously supplied with lubricant.

The plain bearing length should be 0,75 to 1,25 times the bore diameter. This does not apply to plain bearings
used as guides for piston rods and in chain plates.

10.10 Spherical plain bearings

Spherical plain bearings should be maintenance-free or self-lubricating. A combination of steel and PTFE shall
not be used for sliding faces subject to sudden load reversals. The bearing combination steel/steel may only
be used for elastic alignment cases to prevent restraint, if load only occurs in one direction.

Even if made from corrosion-resistant material, bearings shall be provided with a double seal and have
lubrication points for pressing out dirt.

Bearings with PTFE sliding faces shall not be lubricated and thus require to be provided with a double seal
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and intermediate grease chamber.

10.11 Rolling bearings

Wheels and guide rollers of frequently operated gates (e.g. lock gates) shall generally be equipped with rolling
bearings, which are to be sealed on both sides and capable of being lubricated.

Rolling bearings shall generally be self-lubricating and shall be sealed if there is a risk of soiling. Lubrication
points shall be provided for pressing out dirt and abraded elements.

10.12 Bearings for slewing movements

Bearings for slewing movements shall be plain bearings. Where these are lubricated, the lubricant shall be
supplied to the part of the sliding face under load.

It shall be ensured that pintle bearings and gudgeons of mitre and swing gates do not transmit thrust in the
closed position. Pintle bearings shall be protected against soiling. Anchor bars for gudgeons shall be hinged
on both ends so as to allow movement to all sides.

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10.13 Radial seals

Radial seals for use outside dry rooms for drive systems shall be fitted with rubber-sheathed stainless steel
springs.

If required, the housings of radial seals shall also be made from stainless steel.

10.14 Bearing housings

Housings of bearings in tension shall not be made from grey cast iron. Instead, bearings made from nodular
cast iron or cast steel, or welded constructions are to be given preference.

10.15 Sprocket chains

Sprocket chains in hydraulic steel structures are usually duplex chains, i.e. supported on three pinions.

Multiple direction changes of such chains under load should be prevented.

The following design combinations are permissible. It shall be the responsibility of the client to specify the
design.

a) chains with moving pins (without anti-twisting safety mechanism):

— pins made from stainless steel

— plates made from stainless steel

— inner and outer plates with self-lubricating bushes

b) chains with fixed pins:

— pins made from stainless steel

— plates made from stainless steel

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— inner plates with self-lubricating bushes

Unalloyed pins and plates with lubrication of inner plates should only be used for rarely operated gates (e.g.
safety gates) where the drive chains are above water.

Chains shall allow easy disassembly for maintenance purposes.

Grooves to receive corrosion-resistant circlips shall be deep enough to prevent the circlips being subjected to
stress when fitted.

Washers between moving plates of a chain link shall be made from stainless steel.

The specifications of DIN 19704-1, 10.12 and 10.13, shall apply with regard to bush materials.

5.5 shall apply with regard to the treatment of stainless steel, and 5.6 shall apply by analogy when used in
combination with unalloyed steel elements.

The bush manufacturerʼs recommendations shall be followed to determine the fits for plate holes, bush outer
diameters, bush holes and pins.

Plate holes and pins should be manufactured to tolerance class 7; holes of bushes after fitting should comply
with the requirements for tolerance class 8.

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For plates, dimension x as in Figure 3 (holes in the plate without bushes) shall be manufactured to the
following tolerances:

— for holes of diameter D < 60 mm: + 00,03 mm;

— for holes of diameter D ≥ 60 mm: + 00,04 mm.

This does not apply to connecting links or end plates.

The number of teeth for pinions shall be at least z = 7.

Guides of appropriate size shall be provided at the pinions where the chain meshes to ensure the safe
guidance of the chain.

Below the pinion, guards shall be provided between the chain wheels.

The stainless steel used shall have a notch impact energy value of at least 27 J at –20 °C.

Figure 3 — Chain plate

10.16 Pinion racks and pinion chains

Pinion chains are normally designed as simple chains with a single pinion. It shall be the responsibility of the
client to specify the material combinations for chain elements, as follows:
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a) plates and pins (fixed and moving) made of stainless steel, or

b) plates and fixed pins made of unalloyed steel; moving pins of stainless steel.

Care shall be taken to use bolts with similar wear characteristics.

Fixed pins shall be welded into the plates.

Unless pins are secured to the plates to prevent torsion, these shall be fitted with self-lubricating bushes.

Guide rollers should be fitted with self-lubricating bushes.

Pinion chains shall have minimum clearance at the point where they mesh. Guides shall be designed so that
any deformation as a result of radial load is inconsequential.

+ 0,01
The pitch shall be accurate to within 0 .

The number of teeth for pinions shall be at least z = 9.

The specifications of 10.16 apply by analogy to pinion racks in the form of gear racks or gear segments.

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10.17 Rope drives

Rope drives shall be designed in accordance with DIN CEN/TS 13001-3-2. Torsion-free or low-torsion ropes
shall be used for ropes whose strands are at risk of unwinding due to the lifting height or insufficient tension
(single rope with free-moving load).

To compensate for differences in rope length where two ropes are used (e.g. in combination with
counterweights), the two ropes can be connected via helical springs instead of using a balance beam
construction.

Rope drives for frequently operated gates (e.g. lock gates) shall be provided with plastic lining. Welded rope
pulleys (without a lining) should be provided with hardened grooves.

DIN EN 13411-4 shall apply with regard to socketing of wire ropes.

Rope wedges in the drum are not permitted for fixing the rope to the rope drum. Where rope clamps are used,
three clamps shall be arranged over half the circumference, and a further 1½ windings shall be provided.

10.18 Wheels and guide rollers

For gates with embedded axles, wheels with a crowned surface shall be used.

Cylindrical rollers may be used if they are supported on roller trains, and if rocker bars and rocker strips are
arranged between the gate and the train (e.g. for wide-span gates).

The specifications of 8.4 shall apply by analogy for wheels with a facing applied by deposit welding.

10.19 Sliding guideways

Sliding guideways shall be made from materials with a low friction coefficient and high resistance to wear.
Ultrahigh-molecular-weight polyethylene (PE-UHMW) and cast polyamide (types PA 6 G and PE) are
recommended (see DIN 19704-1:2014-11, Table 3).

10.20 Axles and hinge pins

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Axles for wheels and rollers, for pivot bearings and for hinge and connecting pins shall be made of stainless
steel or be provided with a stainless steel facing applied by deposit welding. Axles with a diameter ≥ 300 mm
may be made of unalloyed steel with multilayer hard-chromium plating.

10.21 Springs

Springs may be made from rubber or be helical springs or disc springs, taking into account the resistance of
spring steel to hydrogen embrittlement (testing as in DIN 50969-2). The use under water of stainless steel disc
springs shall be avoided.

With rubber springs, resistance to hydrolysis and UV rays shall be taken into consideration when selecting the
rubber quality and related installation situation. The swelling behaviour shall be considered if installed under
water. Because of the volume incompressibility of rubber, sufficient capsule size shall be ensured if installation
takes place in capsules, so that the spring can deform freely. Spring characteristics shall be included in the
technical documentation.

10.22 Threads

For threads of loadbearing elements which can be loosened, except for threads of bolts and pipe threads (e.g.
threads of piston rods, anchor bars for gudgeons), the pitch shall not be smaller than the values given in
Table 8.

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Table 8 — Pitch for threads on loadbearing components

Nominal diameter of thread Pitch

mm mm

14 to 22 1,5
24 to 34 2
36 to 52 3
56 to 150 4
160 to 306 6

10.23 Fasteners

10.23.1 Bolts and bolted connections

For bolted connections, only metric threads according to DIN 13-1 are permitted, with the exception of pipe
threads according to DIN EN ISO 228-1, DIN EN 10226-1 and DIN EN 10226-2 for pipes, pipe fittings and
compression couplings. If components are intended to be re-used, pre-stressing of bolts in components with
threaded holes shall be limited to 60 % of the yield stress of the bolt material.

The edge distances for bolts in tension shall be not less than the thread nominal diameter.

10.23.2 Welds

It shall be the responsibility of the client to specify the type and scope of weld testing on machine components.
For hydraulic piping, 10 % of the welds made in the workshop and on site shall be radiographically examined
unless otherwise specified.

Welds for fixing flanges and weld-on nipples to cylinder barrels and hydraulic pipes shall be penetration
welded.
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Bibliography

DIN EN ISO 12944-3, Paints and varnishes — Corrosion protection of steel structures by protective coating
systems — Part 3: Design considerations

BAW MKKS, Merkblatt Kathodischer Korrosionsschutz im Stahlwasserbau 3) (Cathodic corrosion protection in

hydraulic steel engineering)
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3) Obtainable from: Bundesanstalt für Wasserbau (Federal Waterways Engineering and Research Institute).

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