Technical Data

Steelmaster - 70WB Intumescent

Steelmaster 70WB

Steelmaster 70WB is a specially formulated Halogen-Free water based Intumescent coating for the fire

protection of structural steel in dry internal environments.

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Product features

• Suitable for dry internal “C1” environments
• Low odour/1998 EPA Compliant
• Accepted for “on-site” application
• Excellent application characteristics and aesthetic appearance
• Can be applied by spray, brush or roller
• Complements CDM regulations
• Manufactured to BS EN ISO 9001:2000
• Tested to BS 476 Part 21
• No Sealercoat required for C1 environments

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General information

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Technical information

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Loading requirement

In order to establish the DFT required for the specified period of fir e resistance, it is necessary to first

calculate the Hp/A values (also known as A/V values). The DFT can then be calculated from the Steelmaster

70WB loading tables.

* Achievable by airless spray only. For DFT above 800 micr ons, a minimum of two coats will normally be

   required by airless spray.

The maximum achievable in a single coat by br ush is 571 microns wet/400 microns dry.

The maximum achievable in a single coat by r oller is 357 microns wet/250 microns dry.

Exceeding the maximum film thicknesses indicated could r esult in cracking on drying.

DFT = Dry Film Thickness WFT = Wet Film Thickness

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Primers

When applied over other manufacturers primers, compatibility should be checked. Consult Jotun’s Technical

Department for recommendations. Compatible primer should be applied and over coated in accordance with

the manufacturers instructions. For optimum results, mean thickness of the primer should not exceed 150

microns.

Suitable Jotun primers include Penguard Primer, Penguard Special and Pilot Industry Primer.

Certain types of primers must be avoided as they could cause adhesion problems. These include thermoplastic

materials such as Chlorinated Rubber and bituminous primers. Certain “mastic” products and primer / finish

products may also prove to be unsuitable for a number of reasons, including short overcoating times.

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Surface preparation

Prior to application of a compatible primer, the substrate must be abrasive blast-cleaned in accor dance

with standard ISO 8501-1:1988. Cleanliness Sa2.5. Roughness 50 to 85 microns Ry5. Coating should occur

before degradation of the surface takes place (normally within 4 hours). If oxidation takes place, the steel

must be re-prepared. The surface must be dry and free of dust, salts, grease and any other contaminants

immediately before coating.

Compatible primer should be applied and over coated in accordance with the manufacturers instructions.

Certain types of primers must be avoided as they can cause adhesion problems. These include chlorinated

rubbers and bituminous primers.

If a zinc-rich primer has been used or is to be used, it is advisable to seal with a suitable tie-coat prior to

delivery to site. Jotun do not recommend the use of Steelmaster 70WB dir ectly over zinc-rich type

products.

Consult Jotun’s Technical Department for advice on compatible primers.

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Site conditions during steelmaster application

The steelwork should be protected from rain or condensation during the application and drying of

Steelmaster 70WB. If Steelmaster 70WB is allowed to get wet, defects may occur . The surface must be dry

and free of dust, salts, grease and any other contaminants immediately before coating

Steelmaster 70WB can only be applied when the air and steel temperature is above 5 C but below 40 C.

Relative humidity should be below 80% for successful application. The temperature of the substrate must

also be at least 5 C above the dew-point on a rising thermometer.

Application methods

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Recoat times in hours

Indications of approximate recoat times (ie overcoating Steelmaster 70WB with itself) taking into account

the following loadings:

Hours per brush application @ 571 microns wet

(approximately 742 grams)/400 microns dry

Hours per spray application @ 1000 micr ons wet

(approximately 1300 grams)/700 microns dry

The following figures also represent approximate drying times.

Note:

• This information is assuming good air movement and ventilation. If there is little or no air movement,
  re-coating times will be approximately twice the figure indicated above.
• Drying times are doubled at 5 C or at over 70% RH.
• No more than two coats by spray and four coats by brush/roller in any 24-hour period.
• Please ensure, however, that the previous coat(s) are fully dry in all areas before recoating.
• High humidity and low air movement or low steel temperatures can result in condensation on the
  steelwork causing prolonged drying times and possibly poor adhesion between Steelmaster 70WB and
  the primer.
• When end use is for dr y internal situations, there is no requirement for a topsealer. However, a
  topsealer may be considered for aesthetic reasons.
• Final drying time before application of the topsealer is a minimum of 36 hours. For best results, the
  topsealer should be applied within 14 days.

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Wet film thickness checks

Wet film reading should be taken regularly during application, using an aluminium or metal wet film

thickness comb. The readings should be regarded as a guide only to enable the applicator to establish a

technique for achievement of the r equired dry film thickness specification. During multi-coat operations,

wet film readings will prove unreliable when applying subsequent coats of Steelmaster 70WB.

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Dry film thickness checks

Take dry film thickness readings (DFTs) as soon as the coating is sufficiently hard to allow readings without

indenting the surface.

All DFT specifications are mean values, and the DFT of the primer must be deducted from the readings to

give the dry film thickness of the intumescent coating only.

Do not apply Topseal until all the readings are in accordance with the specified thickness.

Ensure that the Steelmaster 70WB is completely dry before applying Topseal (if required).

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Topsealer

Ensure that the Steelmaster 70WB is completely dry before applying Topsealer, and that the specified

intumescent DFT has been achieved . For most projcts, we recommend the use of Waterfine Top Sealer

(water based acrylic) at a DFT of 50 microns.

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Damage Repair

Any damaged areas should be abraded back to a sound surface. The abraded surface must be clean

and dry before re-applying (refer to the section entitled “Site Conditions During Application” ).

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Health and safety

Please observe the precautionary notices displayed on the container. Apply under well-ventilated

conditions. Do not breath or inhale spray mist/vapours. Avoid skin contact. Spillage on the skin should

immediately be removed with suitable cleanser, soap and water. Eyes should be well flushed with water

and medical attention sought immediately.

For detailed information on the health and safety information with precautions for use of this product,

please refer to the appropriate Material Safety Data Sheet.

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ISSUED 06 JANUARY 2005 BY JOTUN PAINTS

THIS DATA SHEET SUPERSEDES THOSE PREVIOUSLY ISSUED

Jotun is a World Wide company with factories, sales offices and stocks in more than 50 countries.

DISCLAIMER

The information in this data sheet is given to the best of our knowledge based on laboratory testing and

practical experience. However, as the product is often under conditions beyond our control, we can not

guarantee anything but the quality of the product itself. We reserve the right to change the given data

without notice.

DISTRIBUTOR:

TayFire (International) Ltd

Station Road

Errol

Perthshire

PH2 7SL

Tel:  +44 (0) 1821 641007

Fax: +44 (0) 1821 641008

E-mail: enquires@tayfire.co.uk