diffi cult conditions, narrows the available maintenance windows. T ere is already an extensive amount of

research in the materials science fi eld for ultimate performance. Here, we will address the second major challenge; applying protective materials in situ. Climatic conditions are often the driving factor when considering an in-situ repair. T e weather will not only aff ect a technician’s ability to access the blades, but also the ability to apply the protective materials. Nearly all materials used in LEP will be

sensitive to damp surfaces, temperature and humidity. T ese elements are very diffi cult to control, especially for the duration of the repair. T erefore, a material that is less sensitive to these conditions is ideal for conducting repairs in situ. Temperature is a key factor with any application of a coating or tape system. T e temperature will aff ect the viscosity, working life (pot life) and eventual cure time. All manufacturers will give recommendations on minimum application temperatures. If used below these temperatures the product will be extremely diffi cult to handle and apply.

Belzona Polymerics manufactures and designs its materials specifi cally to overcome these issues and make application as easy as possible. T is is particularly true in the case of its newest system, Belzona 5721, which is designed to deliver eff ective in-situ leading edge protection.

INSIGHT FROM THE LAB Richard Collett, Belzona Polymerics’ chief R&D chemist, has been prominent in this latest development. He says, “From the outset, our aim was to develop a solution that provided excellent resistance to rain erosion and abrasion, whilst being easy to apply in situ. “Traditionally, the application

window available for wind turbine blade maintenance is narrow, requiring favourable weather conditions and adequate temperatures to carry out repairs. We wanted to be able to extend that application window further, providing more opportunities to carry out blade repair and protection. “Belzona 5721 helps to maximise

available maintenance windows in a number of ways. Firstly, it can be applied by brush as a single coat system. T is reduces downtime waiting for overcoating

A key challenge is conducting maintenance on turbines in the fi eld

Belzona materials can greatly increase the maintenance window

numerous layers and also makes it suitable for application from a platform or even rope access. What’s more, it cures without the requirement for external heat or UV, even at temperatures as low as 5⁰C. T is means it is touch dry in approximately 30-45 minutes – a major benefi t that minimises downtime.” T e benefi ts of using materials that can be applied at lower temperatures become apparent if we look at a UK case study. T e Hornsea off shore wind farm, which once fully constructed, will have a planned capacity of up to 6GW. Here, the average maximum monthly temperature at the nearest weather station in Bridlington varies throughout the year, ranging from less than 10°C to 20°C. Using this data as an estimate of expected temperatures when conducting blade maintenance, Belzona materials can increase the maintenance window of four to fi ve months of the year to approximately nine; an increase of 100%. T eoretically, in the case of Belzona 5721, maintenance could be conducted all year round. T is not only makes it easier to schedule O&M activities, but could also reduce costs as less equipment will be required to maintain climate controls during certain parts of the year.

It is not only the climatic conditions and parameters of a material that make it easier to apply. T ere is also the physical aspect to consider. T e easier it is for a technician to apply, the greater the likelihood that the system will perform as intended. Belzona LEP materials all have simple mixing ratios. Belzona 1221 and Belzona 5721 have volume mixing ratios of 1:1 and 1.75:1 respectively. T ese simple ratios make it easy for any applicator to ensure the correct mix is achieved. In addition to this, the materials also come in a variety of unit sizes, which means it is possible that part mixing may not even be required. Additionally, only a brush is necessary for application – there is no need for injection cartridges or specialist equipment.

DIG DEEPER THAN THE DATASHEETS In summary, wind power is an ever expanding and growing industry. One of the biggest drivers of cost is the operations and maintenance of the turbines once they are in the fi eld generating electricity. Leading edge erosion, caused by impact from rain droplets is one of the key issues facing the sector. T ere are a variety of polymeric coatings available for leading edge protection, however the issue of temperature is often overlooked. All materials have a recommended minimum application temperature, which often does not account for the low temperatures experienced in many wind farm installations. Materials such as those that Belzona Polymerics provides are designed for ease of application and eff ective curing at lower temperatures. T is not only gives a longer window of application but also makes it easier for the technician to apply in the fi eld, minimising application downtime considerably. 27

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