With monitoring comes control
Dan Hopkins, Technical Manager at ebm-papst UK Ltd, discusses how a Building Management System can deliver a healthier outcome for occupants.
It is often quoted that in modern life we spend most of our time indoors, whether this is at home, at work, at leisure or whilst commuting, and this can add up to 90% our lives spent inside.
At work, whether this is in a commercial, industrial or retail environment, we could be spending most of our time at a designated work station or at several locations around the building. At home, our exponential rise in the use of the internet and sophisticated home entertainment devices, provides much greater choice to be indoors when we are at leisure.
Up until recently, we may not have given a second thought to the effect of these environments on our health, wellbeing, and cognitive ability. Previously, we may have attributed feelings of lethargy, tiredness, sore throats, dry skin, stinging eyes, and other irritating symptoms whilst we have been at work, to a phenomenon that has been referred to as ‘Sick building syndrome’.
Today we know more about the causes of these ailments, how the indoor environment can affect these symptoms, and the potential for the spread of bacteria and viruses.
As part of the UK Government commitment that the UK will reach net zero carbon emissions by 2050, the building regulations are periodically reviewed to deliver this goal. Approved Document L – Conservation of Fuel and Power (otherwise known as Part L) is a key component of this.
Regular revisions of Part L2 which relates specifically to non-residential properties, have mandated higher efficiency technical building systems. These systems include heating, ventilation, air conditioning, lighting, and domestic hot water systems. In addition to this, Part L2 also requires the building fabric to be constructed to an increased level of air tightness.
Increased air tightness reduces the infiltration of unconditioned air into the building and the loss of heating and cooling energy from the building to outside.
Contaminants build-up
Reducing the amount of air leakage minimises the loss of heating and cooling energy lost through the building fabric. However, this poses a risk of a build-up of contaminants. For this reason, Approved Document F – Ventilation (otherwise known as Part F), specifies a minimum ventilation rate per occupant, guidance on the maximum levels of indoor air pollutants, moisture control requirements and a ventilation rate for each installed printer and photocopier.
There is also guidance to install CO2 monitors, their calibration, installation position and concentration levels to indicate whether the ventilation strategy is effective in the light of Sars-CoV-2 transmission. Whilst the CO2 level provides an indication of the level of occupancy in a room and the potential concentration of bacterial and viral pollutants, it has limitations as an overall indicator of the presence of other potentially harmful contaminants that may be present.
Broadly speaking, the factors that affect indoor air quality can be considered in two categories: Cognitive factors, and contaminants that cause illness.
Cognitive factors include attributes such as ambient temperature, relative humidity (%RH), CO2 and Volatile organic chemical levels. The effects are usually short term whilst the occupant is exposed to unfavourable conditions, such as an environment that feels stale, stuffy or close. These effects will however be dissipated once the occupant removes themselves into a better environment.
At the extremes of acceptable temperature and humidity levels there are potential biological risks, such as mould growth, that can also affect the health of the occupant. In addition to these factors, strong odours (biological, or culinary in nature), can cause distraction and make the indoor space an unpleasant place to be.
Contaminants can influence the health of the occupant over the longer term and can be particulate, biological, gaseous, or vaporous in nature.
Particulates can come from organic sources (dust, mold spores, pollen, bacteria, wildfires, smoke and viruses) or inorganic sources (exhaust fumes, industrial processes, construction, or other combustion processes). Particulates are generally grouped by their particle size as follows: Coarse - PM10 (Particulate matter of 10µm diameter), Fine (PM1.0 to 2.5µm), and Ultra-fine – PM0.1 (particles of 0.1µm).
Gasses produced as a byproduct of combustion or industrial processes can also contaminate the indoor environment. Some of these contaminants are odour free, including carbon monoxide, nitrous oxide, sulphur dioxide and ozone.
Volatile organic chemicals (VOC’s) are vapours that can be produced in industrial plating or coating processes, curing of manufactured materials (Furniture, carpets, fixtures, and fittings), finishes such as paint and varnishes, or aspirated in aerosol form such as chemical cleaning agents.
Invisible presence
In addition to temperature and humidity, particulate matter, gases, vapours, and volatile organic chemicals cannot be seen by the naked eye and the occupant will be unaware of their presence and the consequential risk of damage to their health.
For this reason, the use of an indoor air quality monitor that can measure the content of the air we breathe can provide a means to both safeguard building occupants against exposure to harmful substances and enable delivery of an environment to maximise productivity.
IAQ monitors make the invisible visible, and the data that is gathered can be integrated into a wider building management control system to adjust ventilation levels. Monitoring the IAQ over time can also provide facilities management teams insight into whether maintenance (filter change or system cleaning), safety inspections or an investigation into unexpected air quality events are required.
In addition to this, an occupant’s experience can be optimised for productivity whilst at work, and better well-being when at leisure.
It is important the IAQ sensor used is of high quality, is calibrated and is capable of checking and adjustment for a drift in accuracy over time. Data should also be able to be gathered over time to allow for analysis of trends, unexpected temporary spikes in contaminants levels and indication that maintenance is required.
This will enable the building management system to determine the order of priority and the level of intervention required to maintain the indoor environment to the required indoor air quality levels. Standards and assessment schemes for IAQ, for example RESET, are already part of building sustainability standards and serve as a benchmark for the attainment of a healthy and productive indoor environment.
Essential role within building operation
Our need to conserve energy to deliver our net zero carbon commitment is leading to the requirement for buildings with greater airtightness. Greater air tightness increases the risk of a build-up of odourless contaminants, that cannot be seen, leading to an adverse effect on indoor air quality.
Indoor air quality has a direct effect on our cognitive ability, our productivity and well-being which is why monitoring is an essential part of the building owner and operators’ responsibility of a duty of care to their occupants.
With monitoring comes control, with control comes the ability to deliver and maintain a healthy indoor environment.
For these reasons, the competing requirements of approved documents L and F to deliver higher efficiency buildings with adequate indoor air quality, would benefit from the addition of IAQ monitoring and control systems. Indoor air quality sensors can provide the data required to minimise the consumption of energy whilst delivering the required amount of fresh, clean, indoor air to maintain a healthy and productive environment.
