Painting below zero-the antarctic challenge

Extreme Construction. Session 5. Stream B Paper114.

Dr Linda Kestle and Colin GoochAUBEA Conference 2013

The Location – Scott Base Antarctica

Faculty of Technology and Built Environment

>>FACULTY OF TECHNOLOGY AND BUILT ENVIRONMENT

• The task set was to scrape down, prepare and repaint (3coat system) a selection of exterior timber windows at Scott Base, to very strict environmental protection rules/requirements. ‘Zero Harm’ was the catchphrase. No electric tools.

• Temps ranged from +1ºC to -17ºC when windchill was taken into account. Never painted at temps below -12ºC. Very low humidity averaging 19-35% so the atmosphere very dry. No rain, only snow precipitation. 24/7 daylight in December, January.

• The window sills were between 2.4m and 4.2m off ground level , so used a platformed mobile scaffold and/or stepladders.

The Maintenance Challenge

Kestle and Gooch

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The Site Context

Kestle and Gooch

Kestle and Gooch

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And within 10 mins Condition 2 hits

Kestle and Gooch

>>FACULTY OF TECHNOLOGY AND BUILT ENVIRONMENT

According to Resene Ezyspec and Masterspec (2010),

• Preparation and paint systems for exterior timber joinery are focussed on and assume an ambient temperature range of +10ºC and +35ºC, and should be a 3 coat solvent-borne enamel paint system with a super gloss finish.

• Avoid applying paint system to exterior timber joinery where any of the following conditions are present: snow, rain, fog or mist, and when RH exceeds 85%, or when temperatures are less than +3ºC, and to damp/wet surfaces.

Recommended Technical Painting Process specification(s)

Kestle and Gooch

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• All tasks undertaken at Scott Base demanded a zero harm effect on the external natural environment, and there was the constant risk and awareness of fire prevention

• For painting tasks zero harm meant extreme care when storing and handling paint /flammable products, NO scrapings, paint drips, were to land on the ground under any circumstances.

• Had to undertake the D4TR process before every potentially hazardous task. Safety ruled at all times.

The Hazards/Environmental Zero Harm

Kestle and Gooch

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Equipment and Materials:

Mobile scaffold platform and cage, dropcloths, duck tape, painter’s masking tape, tungsten tip and stanley blade scrapers, 60, 80,120 grit sandpaper, selleys rapidfilla, silaflex roofing/wall silicone sealant, paintbrushes, extra buckets, latex gloves, Kinco gloves (for handling scaffold). Scaffold chocks, and stepladders.

Workdays commenced 8.00 am concluded 5.30pm weather conditions permitting.

Optimally, mornings and early afternoons were spent setting up scaffolded working platform for zero harm, protecting/masking cladding and glazing, scraping and preparing previously painted timber joinery with handtools, and applying primer undercoat (Resene Quick Dry Acrylic Primer/Undercoat), and applying second topcoat enamel to windows that had been worked on the previous day, (Resene Super Gloss Enamel (int/ext).

Late afternoons usually involved a light sanding and filling of undercoated window(s), and judicious application of first topcoat enamel.

Equipment, materials and basic paint system process

Kestle and Gooch

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The state of the windows, and the typical process follows

Kestle and Gooch

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Examples of The finished job

Kestle and Gooch

>>FACULTY OF TECHNOLOGY AND BUILT ENVIRONMENT

According to Colin Gooch (Resene’s chief scientist),

• The success of (paint) film formation is critically dependent on the softness of the thermoplastic particle, which is dependent on the temperature at the time of film formation. Harder films are usually more serviceable than the softer acrylic films.

• If paints are applied below 10ºC, film formation will be impaired (reduced strength and increased porosity, and even cracking and powdering).

The scientific rationale in brief re paint film formation

Kestle and Gooch

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According to Colin Gooch,

• It was serendipity in part that using an off the shelf alkyd enamel paint system worked in the Antarctic, but low RH levels allowed the film formation to occur as if there was in fact an ambient temperature range present, as the film formed rather than as the film hardened.

• In addition, year round low temperatures retard chemical degradation of paint films so that the timber joinery surfaces remain resilient to fading, flaking and peeling for longer than expected periods.

So why did regular off the shelf paint work as if in an ambient temperature range?

Kestle and Gooch