Are you having a dry air day at the office?

As human beings, we are not particularly aware of dry air and commonly fail to associate the discomfort or health problems we experience at work and home with low relative humidity. However, dry air does have significant adverse effects and common symptoms include headaches, dry throats, sore eyes and skin irritation, contact lens discomfort and greater susceptibility to respiratory infection.

One of the first noticeable effects of dry air is electrostatic shocks, which occur below a threshold of 40%RH and can rapidly become a nuisance. Above this level electrostatic shocks are eliminated although, where underfloor heating and certain types of floor covering are used, a higher 55%RH might be required to eradicate the problem.

Eyes are particularly susceptible to dry air as the thin layer of moisture on the cornea quickly evaporates. Contact lens wearers express discomfort that can increase by a factor of five as humidity drops from 45% to 20%, by which stage dust and dirt deposits on lenses increase causing greater irritation.  If the air is too dry the skin, scalp and hair also begin to suffer. With no exposure to moisture, skin develops rashes and rough patches, the scalp starts to flake and hair will become brittle.

The nose and throat act as a powerful humidifier for inhaled air and mucous helps protect against infection by trapping microbes and dust. They start to dry up in conditions below 55%RH, quickly resulting in nasal stuffiness, dry mouth and sore throat. Persistently low RH increases susceptibility to infections such as colds and coughs.

Humidity also affects our perception of smell. Odours described as acceptable at 50%RH become objectionable below 30%RH. Workplace smells can therefore be made more tolerable at the correct level of humidity.

People’s perception of warmth varies with RH and it is possible to reduce ambient temperature to provide a sensation of warmth when the humidity is at a comfortable level, so reducing heating costs.

There’s also a suggestion that dry air is linked with workplace stress. A survey commissioned by a mineral water manufacturer suggested that low levels of humidity in offices lead not only to low employee productivity but also to a higher level of stress. Whilst this has not been verified scientifically, there is some research evidence from Canada that dry air increases absenteeism.

Humidity Levels
Several professional bodies produce guidelines on appropriate humidity levels in office and commercial premises. CIBSE, BSRIA and BRE generally agree that the appropriate range of RH in an office environment should be around 50%RH, within a typical range of 40%RH-60%RH, a figure endorsed by HEVAC.

The Health and Safety Executive, in their Display Screen Equipment Regulations 1992, oblige employers to maintain a level of relative humidity that prevents discomfort and problems of sore eyes where people work at computer terminals for long periods, a situation which affects a high proportion of office staff.  However, a few dissenting voices, such as British Council for Offices (BCO), place little importance on humidity control and, with building budgets in mind, humidification is often ignored or considered retrospectively rather than as part of the original design of a building.

Causes
In the UK, low RH in the workplace occurs primarily in winter when heating systems are on. A typical office without a humidification system will experience relative humidity below 40% for about a third of the year.  Go further north and the problem is more extensive. Exceed the design specification of the building with more people, additional computer equipment and office machines, and the problem worsens as the indoor temperature rises.

A third of the year is a significant proportion and should not be ignored as employee welfare is an important issue. Commercially it makes sense, too: if people are comfortable, they’re more productive.

What to do?
Get a humidifier! See our extensive range for all domestic and commercial applications by clicking here.

If you require information on larger commercial or industrial systems, the Air & Water Centre's parent company is the UK's leading specialist in humidification - JS Humidifiers plc. They will solve your humidity problem.