The amount of water vapour in the air (expressed as Relative Humidity) is a critical issue for many industrial processes as well as human comfort and wellbeing.
High humidity levels are associated with the growth of mould and pathogens, which can seriously affect safety in the manufacture, storage and transport of food, and has serious implications for many industrial processes that require tightly controlled climatic conditions.
Specialists knowledge helps to deliver marine project
Watkins’ dedicated dehumidification team recently designed a bespoke ventilation and dehumidification solution to meet the requirements of a specialist maritime application.
A vessel in dry dock on an MOD site was undergoing a major refurbishment, and part of the work involved repairing and re-painting the hull, above and below the water-line.
Watkins Hire supplied a temporary package of dehumidifiers and ventilation equipment to create and maintain the required conditions for the repainting works to be undertaken.
The company’s specialists visited the site to assess the requirements, and recommended a tailored solution consisting of a combination of KwikVENT 1000, KwikVENT 8000 and KwikDRY 8000 units, with related ducting, mains electrical cabling and a distribution package.
The ventilation system comprised fans and ducting, which were used to remove paint fumes from the vessel and introduce fresh air to the areas needed for personnel working nearby.
The dehumidification plant successfully maintained the required Relative Humidity in the chambers within the vessel’s hull, allowing the critical paint application to be completed successfully.
All equipment provided for the project was supplied as new. Similar refurbishment projects are expected to be repeated on two further vessels during 2017.
Relative Humidity (RH) is defined as the amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature. People are sensitive to high humidity because our bodies depend on evaporative cooling (enabled by perspiration) to stay cool. In industry, humidity levels can be critical, with millions of pounds of production and stock at stake.
When RH increases, condensation can occur on surfaces, resulting in problems with mould, corrosion and other moisture-related issues. As well as leading to wood rot, this can present a serious safety hazard if emergency exits freeze up.
The good news is that, with the use of modern monitoring and humidity control systems, RH can be controlled to within very fine tolerances. Depending on the local climate and internal conditions, this may require humidification or dehumidification, or a combination of both to achieve the desired stable conditions.
There is a huge range of production and technical processes in factories, laboratories, hospitals, and other facilities that require specific RH levels to be maintained within specified tolerances.
In pharmaceutical manufacture, for example, RH can be critical to product safety and quality. The amount of moisture in the air affects powders and tablets, and their tendency to clump or crumble. Unacceptable moisture content levels can lead to an untimely and expensive shutdown in production.
The power industry takes humidity levels very seriously due to the risk of corrosion during planned or unplanned shutdowns. Dehumidified air is injected into areas around critical components such as turbines, boilers, and reactors to safeguard against damage. In some instances, low dew point air (-25°C) has to be delivered and maintained during such plant stoppages.
In data centres, RH levels may be carefully monitored and controlled in order to minimise the risk of static discharges, which can damage sensitive computer chips and related circuitry. The impact of uncontrolled static in sensitive facilities, perhaps involved in national defence or critical financial infrastructure, could be incalculable.
Even in the relative rough and tumble of the construction industry, humidity control plays a key role, due to the risk of mould growth that can despoil buildings, with the consequent effects on human health and rental value.
Once mould becomes established, the cost of remedial treatment can be high, and resultant delays in project completion can lead to retentions and penalties for overruns. In addition, controlling humidity and temperature may be required during climate-sensitive fit-outs, such as the installation of expensive timber.
In the marine and offshore sector, blast cleaning for tanks and ships and surface preparation for specialist coatings are sensitive to air-borne moisture. The integrity and longevity of treatments may depend on the stability of the environment in which the work is carried out. The life-span of costly coatings can be extended by ensuring specified temperature and humidity targets are maintained during application (see case study).
Food production is another obvious sector where temperature and humidity levels can be critical. In addition to the safety and hygiene issues, the productivity of specialist plant, such as spiral freezers, can be maximised through the introduction of low dew-point air, to minimise frost and ice build-up in cold store areas.
Over the years, my own company has provided humidity and temperature control solutions for all of these sectors, and many more diverse applications besides.
Our specialist humidity control team provides comprehensive support for building owners and industrial end users, based on access to one of the widest ranges of humidity control equipment, available for hire from our network across the UK and Ireland.
Equipment includes both refrigerant and desiccant-based dehumidifiers, capable of treating between100m3 to 8000m3 of air per hour, and removing between 29ltr/24hr (based on 60per cent RH at 20degC) and 71 litres/hr (based upon 80percent RH at 20°C).
As part of a strategic growth plan in this important and growing sector of environmental control, we recently invested in a new fleet of state-of-the-art desiccant dehumidifiers, based on the KwikDRY system.
Equipment is now hard at work across the country in factories, sports halls, industrial buildings, restoration projects following flood or water leakage, storage facilities, food processing, and floor laying on construction sites.