HUMIDITY CONTROL HUMIDITY CONTROL
Taking control of humidity
Humidity control is one of the single most important elements of a healthy, comfortable working environment. But when a building lacks eff ective humidity control, it may be necessary to retrofi t a humidifi cation system in order to achieve those levels of comfort and wellbeing. John Barker of Humidity Solutions considers the options.
O
ver the last few years, there has been a renewed focus on the importance of good indoor air quality. It’s no wonder – with
all the studies revealing just how damaging poor air quality can be for the health and productivity of employees. But we’ve noticed that the focus is very much on avoiding the build-up of pollutants in the air (which is important), rather than on achieving the right levels of relative humidity needed for high indoor air quality. This means that, while many older buildings have been fi tted with fi ltration systems, they often don’t have any form of humidity control system. This might not sound like much of an issue, but it means that many buildings are now vulnerable to fl uctuations in RH, caused by anything from natural ventilation/leaky buildings and air conditioning, to the daily operation of a heating system. On the other hand, more modern, airtight buildings can suff er from an overreliance on mechanical ventilation systems, which means indoor air will only have the right RH level if the outdoor air has it. So in the UK, where it is often cold, the ventilation and heating will
remove what little water was in the air, leading to very low humidity levels (sometimes 20% or
lower). 38
All this means that the only way to achieve that comfortable level of relative humidity is by bringing in a humidifi er.
Health and wellbeing Maintenance and refurbishment are not only about energy effi ciency – they also support cost-eff ective building operation and occupant health and comfort. The acceptable RH range for a commercial workplace is between 40%- 60%, which suits both humans and machines working in the space. When the RH is on either side of this range, problems can start to occur. For example, if the RH is too high (above 60%), people start to feel hot, sweaty and out of proportion with the actual temperature. This leads to higher energy bills and very grumpy workers. But if the RH is too low, workers will start to feel cold and become more susceptible to infections – leading to rising levels in absenteeism and high energy bills due to increased heating use. Neither of these options are ideal, which is why it’s so important to keep your RH within that 20-point range.
In our experience, the most eff ective and energy-effi cient way to deal with low humidity (particularly when retrofi tting into an existing building) is to introduce a separate humidifi cation system that will inject water vapour directly into the space. This system is particularly eff ective for workplaces with low ceilings, where other solutions may struggle.
September 2019
As for choosing your solution – there are wwwwwseveral ways to achieving direct injection of moisture, so you need to choose your solution based on your individual needs. Luckily, there are several diff erent options available. These include atmospheric steam generators with fan boxes on top, or ultrasonic humidifi ers spread around the building perimeter. While both are eff ective, they are quite large and not very pretty to look at. Less intrusive options include using wetted media placed above the ceiling, but this would require extra ducting and diff users, so is quite disruptive to install.
One particular option is discreet, doesn’t take up fl oor space, and is easy to retrofi t into any building. It involves using a pressurised water system and multi-directional fan assisted nozzles, atomising water for easy absorption. The nozzles for this solution are around the same size as a CCTV camera, and only require a high-pressure ring main that follows cable routes and uses mechanical joints, making it simple to install and maintain, with no fi re certifi cation required.
Nozzles can be controlled in small groups
collectively in a zone with multiple zones possible from one central controller that maintains the water treatment plant and pumping station. The fan in each nozzle ensures the water is atomised and absorbed within 1.5 metres of the nozzle, enabling this system to be used in spaces with ceiling heights as low as 2.4m. The fact that cold water is used means there is no additional heating energy required for the humidifi er and
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