What is IEQ? How IEQ Affect Employees' Productivity?
Employees spend most of their time in the indoor environment, thus the improvement of the indoor environment is required to be focused more than the outdoor environment. Some researchers pointed out that the Indoor Environmental Quality (IEQ) is typically unsatisfactory, with many occupants’ dissatisfaction and suffering from sick-building syndrome symptoms (a situation where the occupants of a building encounter critical health and comfort-related issues that directly correlate with the amount of time spent in the building). The symptoms of Sick Building Syndrome (SBS) include headache, itchy skin, cough, fatigue, nausea, etc. The recent studies also highlighted the critical impacts of the indoor thermal environment on occupants’ work performance. The purpose of writing this article is to share the areas of improvement that can be done on IEQ.
Indoor Environmental Quality (IEQ)
IEQ can be examined based on the 4 criteria, which are:
- acoustic quality
- lighting comfort
- indoor air quality
- thermal comfort
1. Acoustic Quality
Acoustic quality is defined as a state of satisfaction with acoustic conditions. Providing good acoustic surrounding can prevent the problems of occupants’ discomfort. The quality of the sound environment can be improved by studying several physical parameters, like the physical properties of sound and the structure of the building. The sound is generated based on the sound pressure level and audio frequency in a short and long time. The acoustic environment is contributed by the physical room properties, such as insulation, absorption and time.
In the office area, it is common that most of the employees encountered with echo issues while they were having conference meetings in the meeting room. Meeting rooms are constructed with hard surfaces material that will reflect sound waves lead to the increase of echo in the meeting room. The performance of wood partition wall in reducing the echo issue is good whereas the glass wall is the vice versa.
There are numerous methods that can be utilized in order to cope with echo issue in the meeting room, which include:
- Installation of fabric curtains. The curtains normally contain curve and soft surface, which allow them to make the room noticeably quieter
- Installation of perforated ceilings with sound absorptive insulation
- Installation of the acoustic wall panels
2. Lighting Comfort
Lighting comfort is defined as a subjective condition of visual well-being induced by the visual environment or surrounding. The physical properties of the visual environment that can be characterized and used to assess IEQ in an objective manner include luminance distribution, glare, light colour, rendering colour, flicker rate and amount of daylight.
In order to provide good lighting comfort level in the office area, these methods were used by most of the companies and proven their effectiveness, such as:
- Selection of lighting types according to the area and purpose
- Replacement of fluorescent lights with LEDs for cost-effectiveness
- Installation of roller blind to control natural lighting through the window. The ability of the roller blind, which can be rolled up or down easily, helps to give the room surrounding a modern appeal and indirectly solves the privacy issue
- Installation of tinted film to reduce Visible Light Transmission (VLT) that passes through the window
3. Indoor Air Quality
Indoor air quality can affects a person’s health, comfort, and ability to work. Poor indoor air quality can cause discomfort and health issues to employees, leading to higher absenteeism and lower work performance. Therefore, in 2010, the Industry Code of Practice on Indoor Air Quality 2010 (ICOP IAQ 2010) was introduced to ensure the compliance of the designated office workplaces through investigation from employees’ feedback and complaints.
The factors that contribute to the quality of indoor air are interior temperature, building design, layout, odours, maintenance and operation of building ventilation, air-conditioning system, moisture and humidity of indoor areas.
In order to maintain the good indoor air quality in the office area, the following practices can be utilized:
- Comply with office and building smoking policy
- Smoking in designated areas only
- Dispose of rubbish properly in appropriate dustbins that are emptied daily to prevent odours and biological contamination
- Conduct air conditioning cleaning and sanitizing regularly
4. Thermal Comfort
Thermal comfort is the condition of the mind which expresses satisfaction with the thermal environment. When thermal comfort level has reached over the comfort standard, an occupant will feel either too hot or too cold. In Malaysia, we can’t ignore the thermal comfort as Malaysia is a hot season country. Therefore, thermal comfort is usually placed as the primary scope of IEQ execution research.
Standard ISO 7730 is widely referred to when the analysis of thermal comfort parameters is conducted. In order to maintain good thermal comfort in the office area, we need to consider four physical variables, which are:
- Air temperature
- Radiant temperature
- Relative airspeed
- Air humidity
and two variables identified with individuals, which are:
- Metabolic heat
- Clothing insulation
Most of the Asian countries have typical average temperature of 22˚C to 31˚C. Many lab tests have been conducted to analyze the relationship between air temperature and occupants’ work performance. One of the studies successfully showed that the working performance will be reduced when the temperature reaches above 25˚C, while some other research studies highlighted that the human thermal comfort zone is between the temperatures from 22˚C to 27˚C, with relative humidity from 40% to 60%.
Installation of air-conditioning system appeared to be the most common approach to maintain the good thermal comfort level in the office area. However, some of the employees who sit near the window glass area are encountering with heat refraction from the sun, which will cause thermal discomfort. In order to cope with this issue, the installation of roller blinds and curtains appeared to be an effective way as well. Besides the sun protection, roller blind and curtain also can be utilized as temperature control. They keep the sunlight and heat away from entering into the building and control the temperature of the interior surrounding.
Adaptive Thermal Comfort and Personal Control
According to Zhang H. and other researchers, since thermal comfort plays a significant role in affecting occupants’ work performance, many studies signified that the occupants feel more comfortable and perform better when they are given with alternatives for controlling over their indoor climate, which mean that the occupants are more permissive of their thermal environment if they can control it.
Human body controls temperature with the environment through self-governing physiological thermos-regulatory activities. The speculation of thermal condition highlighted that the past thermal history of occupants will affect their thermal desire and inclinations. This adjustment is characterized as the enduring lessening of the human response to repeated surrounding stimulation can be both behavioral (clothing attire, windows, ventilators), and physiological (acclimatization), as highlighted by R. Hughes, S. Dhannu in 2008.
In addition, the differences in the perception of the thermal environment were identified among occupants in naturally ventilated, fully air-conditioned and mixed-mode (hybrid) buildings (M. Boji´c et. al., 2011). The studies showed that the indoor temperature in the naturally ventilated buildings regarded as most comfortable increased significantly in warmer climatic contexts, and decreased in colder climate zones. These investigations also highlighted that the indoor temperature observed in air-conditioned buildings differs from that observed in naturally ventilated buildings in a similar climatic context. The occupants of fully air-conditioned buildings are twice as sensitive to the changes in temperature as occupants in natural ventilation buildings. Occupants inside the air-conditioned buildings will mostly adjust less, and this will cause their thermal sensation to become more sensitive to changes in temperature (M. Chiogna et. al., 2012).
IEQ of a company is important to be continuously monitored to further improve the work productivity of employees. The occupants’ satisfaction is affected by not only indoor environmental parameters but also workspace and building features, control over the indoor environment, level of privacy, layout, size, personal workspace, and furniture of the office.
It is important to provide a standardized and systematic way to assess the occupants’ satisfaction with the indoor environment quality in order to collect enough data for analysis to solve the problems. Based on the study carried out by T. Leephakpreeda in 2005, the improvement of IEQ will indirectly help the employees to lessen the medical expense, take less the medical leaves and reduce the turnover of employees.
© 2020 Johnson Loh