Hempaprime CUI 275

PRODUCT DATA SHEET

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Product characteristics

Recommended use
Hempaprime CUI 275 can be used across a wide temperature range where corrosion under insulation (CUI) typically occurs and where thermal cycling is present. It can be specified for operating temperatures from -196°C (-321°F) to 204°C (400°F), with sporadic allowance up to 275°C (527°F). The product significantly reduces the risk of cracking when applied at high DFTs compared to traditional epoxy phenolic coatings. It can be used in new construction and maintenance and repair, on carbon and stainless steels, and for both insulated and uninsulated service.

Service temperature:

• Maximum, dry exposure only (peak): 275°C [527°F].

Certificates / Approvals

• Meets requirements to ISO 12944 when used as part of a predefined paint system. C5-H, CX
• Meets the requirements of ISO 19277, when used as part of a predefined paint system. For categories CUI-1, CUI-2, CUI-3, CUI-1-Cryo, CUI-2-Cryo, CUI-3-Cryo
• Tested and assessed according to NACE TM0174; standard test method for evaluating protective coatings for immersion service. Resistance to Boiling Tap Water, Method B.
• Meets requirements to NORSOK M-501 when used as part of a predefined paint system. Edition 7, System 1D, 6C, 9.

Features

• Fast overcoating.
• Wide temperature resistance from cryogenic up to 275°C (527°F).
• Can be applied at temperatures down to -10°C (14°F).
• Can be spray applied on hot surfaces up to 204°C (400°F).
• Excellent crack resistance compared to traditional epoxy phenolic coatings.

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Product safety

Flash point
35°C [95°F]

VOC content mixed product

Legislation	Value
EU	305 g/L [2.55 lb/US gal]
US (coatings)	305 g/L [2.55 lb/US gal]
US (regulatory)	305 g/L [2.55 lb/US gal]
China	305 g/L [2.55 lb/US gal]

According to specific legislation, see details in the Explanatory Notes available at Hempel website, hempel.com or at your local Hempel website. VOC values may vary with shade, please consult the Safety Data Sheet, section 9.

Handling
Handle with care. Before and during use, observe safety labels on packaging and paint containers and follow all local and national safety regulations. Always consult Hempel’s Safety Data Sheet for this product along with the Product Data Sheet.

For professional use only.

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Product data

Product code
17530

Product components
Base 17539
Curing Agent 95072

Standard shade* / code
Aluminium grey 19690 **

Gloss
Semi-flat

Volume solids
66 ± 2%

Specific gravity
1.3 kg/L [11 lb/US gal]

Reference dry film thickness
150 micron [6.0 mils]

Aluminium shade / code
Aluminium red 19530 *

Gloss
Please consult Hempel’s Guideline on aluminium pigmented coatings.

Volume solids
65 ± 2%

Specific gravity
1.4 kg/L [11 lb/US gal]

Reference dry film thickness
150 micron [6.0 mils]

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Surface preparation

Cleanliness

• Remove oil, grease and other contaminants by suitable detergent cleaning.
• Remove salts, detergents and other contaminants by high pressure fresh water cleaning.
• Flash rust degree of maximum FR M (ISO 8501-4).

New build:

• Abrasive blasting to min. Sa 2½ (ISO 8501-1) / SP 10 (SSPC).
• Remove dust, blast media and loose materials.
• Water jetting to Wa 2½ (ISO 8501-4).

Maintenance and Repair

• Square up small damaged areas and treat them as one large combined area.
• Feather edges to sound surrounding coating.
• Remove dust, blast media and loose materials.
• Abrasive blasting to min. Sa 2½ (ISO 8501-1) / SP 10 (SSPC).
• Minor areas may be hand or power tool cleaned instead of abrasive blasting.
• Clean thoroughly by hand or power tool to St 2 (ISO 8501-1) / SP 2 (SSPC). Avoid polishing.
• Water jetting to Wa 2½ (ISO 8501-4).

Roughness

• Surface profile Medium (G) (ISO 8503-2).

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Application

Mixing ratio
Base 17539 : Curing Agent 95072 (3 : 1 by volume)
Stir well before use.

Thinner
Hempel’s Thinner 08450

Cleaner
Hempel’s Tool Cleaner 99610

Pot life

Product temperature	20°C [68°F]	15°C [59°F]	30°C [86°F]
Pot life	2 hours	3 hours	1 hour
Pot life (spray)	2 hours	3 hours	1 hour
Pot life (brush)	2 hours	3 hours	1 hour

Application method

Tool	Thinning max vol.	Application parameters
Airless spray	5%	Nozzle pressure: 250 bar [3600 psi], Nozzle orifice: 0.017-0.025″
Brush/Roller	5%	Not Applicable.
Air spray	5%	Not Applicable.

Film thickness

	Low	High	Recommended
Dry film thickness	100 micron [4.0 mils]	225 micron [9.0 mils]	150 micron [6.0 mils]
Wet film thickness	153 micron [6.1 mils]	343 micron [14 mils]	229 micron [9.2 mils]
Theoretical spreading rate	6.6 m²/L [269 sq ft/US gal]	2.9 m²/L [118 sq ft/US gal]	4.4 m²/L [179 sq ft/US gal]

Application conditions

• To avoid condensation, apply on a clean and dry surface with a temperature that is at least 3°C [5°F] above the dew point.
• Surface temperature must be above -10°C [14°F] during application and curing.

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Drying and overcoating

Product compatibility

• Previous coat: Recommended product is: Hempel’s Galvosil 15700
• Subsequent coat: Recommended products are: Hempathane 55610, Hempel’s Silicone Acrylic 56940, Hempaxane Light 55030

Drying time

Surface temperature	-10°C [14°F]	0°C [32°F]	20°C [68°F]	40°C [104°F]
Surface dry hours	28	12	3½	2
Hard dry hours	35	14	4	2½
Dry to walk on hours	42	21	4½	3
Fully cured days	40	20	5	1½

Overcoating

Quality name	-10°C [14°F]	0°C [32°F]	20°C [68°F]	40°C [104°F]
Hempaprime CUI 275 Min	14 h	7 h	90 min	45 min
Hempaprime CUI 275 Max	90 d	90 d	60 d	30 d
Hempathane HS 55610 Min	27 h	14 h	3 h	90 min
Hempathane HS 55610 Max	90 d	90 d	28 d	14 d
Hempel’s Silicone Acrylic Min	14 h	7 h	90 min	45 min
Hempel’s Silicone Acrylic Max	90 d	90 d	60 d	30 d
Hempatherm IC 175 Min	54 h	27 h	6 h	3 h
Hempatherm IC 175 Max	Ext*	Ext*	Ext*	Ext*

Ext*: Depending on the actual exposure conditions, the coated surface is overcoatable for an extended period of time. Contact your local Hempel representative for advice.

Overcoating details

• Flash-coat technique is recommended when overcoating Galvosil qualities.
• If the maximum overcoating interval is exceeded, roughening of the surface is necessary to ensure intercoat adhesion.
• The surface must be clean before overcoating.
• Inorganic zinc silicates must be fully cured before overcoating.
• If the maximum overcoating interval between epoxy and topcoat is exceeded, apply an additional thin layer of the epoxy.

Other remarks

• The paint film must be dry and cured before insulating.

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Storage

Shelf life

Ambient temperature	25°C [77°F]
Base	36 months
Curing Agent	12 months

Shelf life from date of production, when stored in original, unopened containers. Thereafter, the product quality must be re-inspected. Storage at elevated temperatures may reduce shelf life. For advice, please consult Hempel.

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Carbon Footprint

Dry film thickness	1 µm	1 mil
GWP (Global Warming Potential)	10 g CO₂e/m²	0.052 lb CO₂e/ft²

The carbon footprint is for 1 square meter / square foot of surface area with a dry film thickness of 1 micron / mil.

The scope includes raw materials, in-bound transport to the Hempel factory, Hempel manufacturing processes, and any Volatile Organic Compounds emitted during and after the application of the product.

It is calculated based on the standard shade defined in this PDS. Values may vary with shade.

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References

Product Data Sheet – Hempaprime CUI 275
Issued by Hempel A/S – June 2025
Document Version: 4/4
Source: https://www.hempel.com

Technical Guidelines and Explanatory Notes
Last accessed: 28 May 2025
Reference link: https://www.hempel.com/service-and-support/technical-guidelines

Note: Always consult the latest version of the Product Data Sheet and associated documents directly from Hempel’s official website to ensure accuracy and compliance with the most current recommendations.