Houghto Riser Tension Fluid

A solution for Direct Acting Riser Tensioners

Houghto-Safe NL1 has been designed to cope with the

PRODUCT DATA

demanding conditions, seen, particularly in direct acting tensioner systems.

This is largely due to its high levels of mixed hydrodynamic and boundary lubrication properties, validated in long-term cylinder tests - with results indicating that it has superior properties compared to other currently available water-glycol fluids—in terms of wear on the rod coating and the seal configuration.

Houghto-Safe NL1 has been given an OCNS rating of “D” by Cefas and is registered on the NEMs database for Norway with much reduced “red” content, the remainder being yellow/green. Existing fluids are currently rated B with Cefas so this is a 2 step improvement.

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For nearest Houghton location and contact information go to: www.houghton-offshore.com

This document contains information based on data that is believed to be correct.

However, the product may not be applicable to all uses and operating environments.

No warranty or guarantee is expressed or implied.

Earlier generations of piston rod design in riser tensioner systems exploited the application of very “hard” thermally sprayed coatings which can have some surface porosity and encourage the hydraulic fluid to be retained in the coating surface profile. This promotes hydrodynamic lubrication of seals and guide bands during short/slow rod movements in certain ocean conditions (deepwater, long wavelength and high ambient temperature).

PRODUCT DATA

Later generations of DAT/N-Line piston rods are made from carbon steel coated with either a solid super duplex stainless steel (UNS S32750) or an overlay welded cobalt based alloy (typical UNS R31233). These have very good corrosion resistance properties in seawater and marine environments but have reduced surface hardness. The latter can lead to polishing, of the rod surface, particularly around the mid-stroke (main working) area. Some work-hardening may be experienced and some wear marks are often observed if the system is not cleaned regularly.

Short piston rod movements combined with mid-section polished surfaces indicate that surface retention of hydraulic fluid has been reduced. This leads to boundary lubrication rather than hydrodynamic lubrication. Boundary lubrication is less likely to promote sufficient exchange or flow of hydraulic fluid in “gaps” between seals and guide bands inside tensioner cylinders. At lower velocities, a thinner lubricating fluid film is generated that may lead to higher friction. This friction creates heat which raises the temperature in the system.

Degradation of hydraulic fluid (evidenced by accelerated reduction in pH) has been observed in some DAT/N-Line systems. Such degradation includes the formation of sticky, high viscosity, black residues that contain metal fines. Metal fines have been shown to react with organic acidic additives in the fluid— under certain conditions, this can result in the observed black residues. These residues are of concern as they may deposit around sealing elements. It is also of concern that deposits might reach the interiors of anti-recoil valves and cause the system to fail.

In addition to the above, the cylinder bore surface is often uncoated, untreated lowalloy carbon steel that has reduced corrosion and corrosive wear resistance under lower pH conditions.

See overleaf for technical data on Houghto-Safe NL1 2

For nearest Houghton location and contact information go to: www.houghton-offshore.com

This document contains information based on data that is believed to be correct.

However, the product may not be applicable to all uses and operating environments.

No warranty or guarantee is expressed or implied.

Technical Data Property Environmental Rating

UK North Sea

Unit Cefas

Environmental Rating

Norway

NEMs

H’Safe NL1 D 98.5% yellow/green

PRODUCT DATA

Appearance Specific Gravity @15.6°C pH Viscosity @ -20°C

Visual

cSt

Clear, Pink 1.080 9.60 800

Viscosity @ 0°C

cSt

270

Viscosity @ 20°C

cSt

85

Viscosity @ 40°C Viscosity @ 60°C Pour Point

cSt cSt °C

40 20 -40

Flash Point Water Content

°C %

None 35

J/hr/m/°C /°C /atm kJ/Kg/°C mg loss mg loss mm scar

1.60 7.0 x 10-4 3.3 x 104 3.4 5 6 0.52

Ratio

40:1

Thermal Conductivity Thermal Expansion coefficient (Volume) Bulk Modulus @20°C Specific Heat Capacity @ 25°C Vickers V104 Vane pump 200hrs @ 1500psi Vickers V104 Vane pump 200hrs @ 2000psi 4 Ball test, 40Kg, 60 mins Compression Ignition (Def Stan 91-110 Annex D ) Corrosion - Liquid-phase ASTM D665B Corrosion- Vapour-Phase EN10025, 60°C, 16hrs

No rust No rust

Accelerated Ageing, pH after 60 days @ 80°C Nitrogen

9.6

Air 3

8.6 For nearest Houghton location and contact information go to: www.houghton-offshore.com

This document contains information based on data that is believed to be correct.

However, the product may not be applicable to all uses and operating environments.

No warranty or guarantee is expressed or implied.

COMPATIBILITY WITH SYSTEM COMPONENTS When considering fire resistant hydraulic fluids, either in the design or installation stage it is essential to have in mind their degree of compatibility with materials normally encountered in hydraulic systems. The following table describes in general terms the compatibility of Houghto-Safe NL1 with a variety of materials and is intended as a useful guide. It is advisable, however, finally to check compatibility at least with the material supplier. Houghton has specific testing in progress at the moment to confirm in more detail.

PRODUCT DATA

C NC LC

= = =

Compatible Not Compatible Limited Compatibility

Metals Ferrous Copper and Brass Bronze Cadmium and Zinc Lead Aluminum Magnesium Tin and Nickel

C C LC < 20% Lead.

NC NC LC - Anodized NC C

Paints and Finishes Common Industrial Oil Resistant Epoxy and Phenolic Vitreous Enamel

NC C C

Plastics Acrylic (includes Perspex) Styrene Epoxy Phenolic P.V.C. Nylon Polypropylene P.T.F.E.

C C C C C C C C

Rubbers (Elastomers Seal Materials) NBR Butyl High Mol Wt Polyethylene Ethylene Propylene Polyurethane Silicone Fluorocarbon (eg Viton)

C C C C NC .

C NC

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â&#x20AC;&#x201C; unless specific testing confirms otherwise.

For nearest Houghton location and contact information go to: www.houghton-offshore.com

This document contains information based on data that is believed to be correct.

However, the product may not be applicable to all uses and operating environments.

No warranty or guarantee is expressed or implied.

CLEANLINESS LEVEL Houghto-Safe NL1 is filtered during production to provide NAS1638 Class 6 in the container.

COMPRESSION IGNITION Sudden high compressions in compensator systems could raise the temperature sufficiently to constitute a fire or explosive risk. This establishes the need for a water based fluid to eliminate the possibility of auto-ignition and/or compression ignition.

The DEF Stan 91-110 Annex D compression ignition test is a modified version of a CFR cetane rating engine which has been designed for testing fire-resistant aqueous hydraulic fluid, for shipboard hydraulic systems .

Compression rate is reduced from a starting position of 50:1, in steps of 1 CR increment and evidence of ignition is based on pressure rise (> 2 bar)

PRODUCT DATA

Filter Media Cellulose Phenolic Resin Treated Metallic Earth Type

C C NC

CORROSION RESISTANCE Houghto-Safe NL1 is non-corrosive to ferrous and non-ferrous metals and readily passes Test Method IPA 135B / ASTM D665B. The Vapor Phase inhibitor also provides protection to metal surfaces above the fluid level.

WARRANTY The information given here is considered to be correct and is offered for your consideration, investigation and verification. No warranties are expressed or implied, since the use of our products is beyond our control. Statements concerning the use of Houghton products are not to be construed as recommending the infringement of any patent.

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For nearest Houghton location and contact information go to: www.houghton-offshore.com

This document contains information based on data that is believed to be correct.

However, the product may not be applicable to all uses and operating environments.

No warranty or guarantee is expressed or implied.