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Internaldiameter

d1

Externaldiameter

d2

Materialthickness

h1

Height overprotrusions

h2

Height ofprotrusions

h3

Protrusiontangentialdiameter

d3

Protrusioninternaldiameter

d4

min. max. min. min. max. min. max. min.max.

For use withbolts of

designation

EN14399-9 Dimensions of compressible washer-type direct tension indicator

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M12 12.75 12.85 26.00 32.50 2.50 5.50 0.80 20.00 13.85

M16 16.75 16.85 35.00 36.80 3.00 6.00 0.80 25.00 17.85

M20 20.95 21.05 41.00 46.00 3.50 6.50 0.80 29.00 22.05

M22 23.05 23.15 46.50 50.60 4.00 7.00 0.80 33.00 24.15

M24 25.15 25.25 50.00 55.20 4.00 7.00 0.80 38.00 26.25

M27 28.30 28.40 54.00 62.10 4.00 7.00 0.80 43.00 29.40

M30 31.45 31.55 59.00 69.00 4.00 7.00 0.80 46.50 32.55

M36 37.75 37.85 78.00 83.00 4.00 7.50 0.80 56.00 38.85

Product OverviewThe purpose of the direct tension indicators is to show thata defined preload is achieved in the bolt. The direct tensionindicator can be used alone or with bolt face washers or nutface washers conforming to BS EN 14399-9. In either case itis essential that the direct tension indicators are used aspart of an assembly in accordance with BS EN 14399-1.

To comply with BS EN 14399-1, it is essential that theassemblies are supplied by one manufacturer and includebolts, nuts, washers and direct tension indicators.

Important notePreloaded bolted assemblies are very sensitive to differences inmanufacture and lubrication. Therefore it is important that the assemblyis supplied by one manufacturer who is always responsible for thefunction of the assembly.

For the same reason, it is important that the coating of the assembly isunder the control of one manufacturer.

Beside the mechanical properties of the components, the functionalityof the assembly requires that the specified preload can be achievedwhen the average gap remaining after tightening (compressedprotrusions) is less than the specified values in the standard, if theassembly is tightened with a suitable procedure. The test method givenin the standard has been developed to demonstrate the suitability of thecomponents for preloading.

General requirements EN14399-1

Bolt/nut assembly EN14399-3 or EN14399-7 EN14399-4 or EN14399-8

Marking HR HV

Property classes 8.8/8 or 8.8/10 10.9/10 10.9/10

Washers EN14399-5 or EN14399-6 EN14399-5 or EN14399-6

Marking H H

Direct tension indicator EN14399-9

Marking HB H10 H10

Bolt/nut face washer EN14399-9

Marking HB/HN HB/HN

Suitability test forpreloading EN14399-2 EN14399-2

System HRSystem of bolt/nut/washerassemblies System HV

Systems of bolt/nut/washer assemblies

Direct Tension Indicator WashersEN 14399 - 9 System HR or HV

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Characteristic Standard

Material Steel

General Requirements EN 14399-1

Maximum hardness 380HV

Self Colour as processedc

Hot Dip Galvanised EN ISO 1461

Others to be agreed

Associated washers EN 14399-5 or EN 14399-6

SurfaceFinisha

a The direct tension indicators shall not be electroplated or subjected to any process thatcould result in hydrogen embrittlement.

b Sherardising is considered to provide corrosion protection equivalent to hot dip galvanising.c “As processed” means the normal finish resulting from manufacture with a light coating of oil.d Other coatings may be negotiated between the purchaser and the manufacturer provided

they do not impair the mechanical properties or the functional characteristics. Coatings ofcadmium or cadmium alloy are not permitted.

e For acceptance criteria use 0,65 AQL, Ac No 0; see EN ISO 3269:2000, Tables 5 and 6.

Specification and reference standard Indicator compression loads at appropriate gap

Heat treatment hardened and tempered or controlledrolled and tempered

Acceptibility

EN 14399-3, EN 14399-4, EN 14399-7 orEN 14399-8Associated bolts and nuts

For acceptance procedure,see EN ISO 3269:2000e

M12 47.00 56.00 59.00 71.00

M16 88.00 106.00 110.00 132.00

M20 137.00 164.00 172.00 206.00

M22 170.00 204.00 212.00 254.00

M24 198.00 238.00 247.00 296.00

M27 257.00 308.00 321.00 385.00

M30 314.00 377.00 393.00 472.00

M36 458.00 550.00 572.00 688.00

For use withbolts of

designation

Compressed load

Designation H8

min. max. min. max.

Designation H10

Dimensions of nut face washers

M12 12.10 12.35 22.70 24.00 2.70 4.30

M16 16.10 16.32 27.70 29.00 3.70 4.30

M20 20.10 20.40 34.40 36.00 3.70 4.30

M22 22.30 22.60 37.40 39.00 3.70 4.30

M24 24.20 24.50 41.40 43.00 3.70 4.30

M27 27.20 27.55 46.40 48.00 4.40 5.60

M30 30.20 30.55 50.10 52.00 4.40 5.60

M36 36.20 36.55 60.10 62.00 5.40 6.60

For use withbolts of

designation

Internal diameterd1

External diameterd2

Thicknessh

min. max. min. max. min. max.

NOTE: The washers are intended to fit over the threaded portion of the shankonly. In some cases the washer diameter, d1, is less than the bolt shankmaximum diameter specified in EN 14399-3 and EN 14399-4.

Nut face washers and bolt face washersCharacteristic Standard

Material Steel

General Requirements EN 14399-1

Heat treatment hardened and tempered

Rockwell hardness 38 HRC to 45 HRC

Standard EN ISO 6508-1

Vickers hardness 372 HV30 to 448 HV30

Standard EN ISO 6507-1

Product grade Cb

Standard EN ISO 4759-3

Normal as processedd

Sherardised EN 13811

Others to be agreede

Associated washers EN 14399-5 or EN 14399-6

SurfaceFinisha

a In case of dispute, Vickers hardness test shall be the referee test method.b Except as otherwise specified in dimensional tables.c These washers shall not be electroplated or subjected to any process that could result in

hydrogen embrittlement.d “As processed” means the normal finish resulting from manufacture with a light coating of oil.e Other coatings may be negotiated between the purchaser and the manufacturer provided

they do not impair the mechanical properties or the functional characteristics. Coatings ofcadmium or cadmium alloy are not permitted.

Specification and reference standard

Acceptibility For acceptance procedure,see EN ISO 3269.

Hardnessalternativesa

Tolerances

Associated bolts and nuts EN 14399-3, EN 14399-4, EN 14399-7 orEN 14399-8

Direct Tension Indicator WashersEN 14399 - 9 System HR or HV

These minimum values are equal to 0.7 ƒub x As in accordance with EN1993-1-1:2005.Load in kN.

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Dimensions of bolt face washers

M12 13.00 13.27 23.48 24.00 2.70 4.30 1.6 1.9 0.50 1.00

M16 17.00 17.27 29.48 30.00 3.70 4.30 1.6 1.9 0.75 1.50

M20 21.00 21.33 36.38 37.00 3.70 4.30 2.0 2.5 0.75 1.50

M22 23.00 23.33 38.38 39.00 3.70 4.30 2.0 2.5 0.75 1.50

M24 25.00 25.33 43.38 44.00 3.70 4.30 2.0 2.5 0.75 1.50

M27 28.00 28.52 49.00 50.00 4.40 5.60 2.5 3.0 1.00 2.00

M30 31.00 31.62 54.80 56.00 4.40 5.60 2.5 3.0 1.00 2.00

M36 37.00 37.62 64.80 66.00 5.40 6.60 2.5 3.0 1.25 2.50

For use withbolts of

designation

Internal diameterd1

External diameterd2

Thicknessh

Inside chamferc

Outside chamfere

min. max. min. max. min. max. min. max. min. max.

AssembliesBolt and nut assemblies consist or bolts and nuts which shall meet all the requirements ofEN 14399-3, EN 14399-4, EN 14399-7 or EN 14399-8.

The functional characteristics of the bolt/nut/washer(s) assembly shall be achieved whentested together with direct tension indicators; the assembly may include washers accordingto EN 14399-6 or EN14399-5 (under the nut only) and/or nut face or bolt face washers.

under bolt head fitting

1. Direct tension indicator2. Bolt face washer

(not required for property class 8.8)3. Gap4. Washer according to EN14399-5 or 6.

under nut fitting

1. Direct tension indicator2. Nut face washer3. Gap4. Washer according to EN14399-5 or 6

(not required for property class 8.8).

under nut fitting

1. Direct tension indicator2. Nut face washer3. Gap4. Washer according to EN14399-6.

under bolt head fitting

1. Direct tension indicator2. Bolt face washer3. Gap4. Washer according to EN14399-5 or 6

(not required for property class 8.8).

Checking the indicator gap

Direct tensionindicator positions

Under bolt head, whennut is rotated

Under nut, whenbolt is rotated

Under nut, whennut is rotated

Designation H8 and H10Thickness of feeler gauge

0.40

Nut face washers and bolt face washers (concluded)

Example with six protrusions

Functional characteristics of thedirect tension indicator washerin the assemblyA specified feeler gauge, see below, shall be usedto determine that the required bolt preload hasbeen achieved by the assembly.

NOTE: Tests have shown the need for a smallergap when the direct tension indicator is used underthe rotated component. Direct tension indicatorsfitted as specified will result in the same loadsbeing attained when the bolts are tightened to thespecified gaps.

The average specified indicator gap shall bedetermined using the following measurementprocedure; the feeler gauge shall be used as a "nogo" inspection tool. The feeler gauge shall bepointed at the centre of the bolt (see illustrationbelow) and shall refuse to enter the number ofrefusal spaces specified in table below.

Under bolt head, whenbolt is rotated

0.25

Direct Tension Indicator WashersEN 14399 - 9 System HR or HV

Tightening of the assembly by rotation of the nut

Tightening of the assembly by rotation of the bolt head