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Children are particularly at high risk of health issues due to poor IAQ (Indoor Air Quality) Children breathe in a greater amount of air and breathe more rapidly than adults, and so potentially inhale more pollutants.
Whether at home or school the poor IAQ has an adverse impact on child health which leads to:
· Headaches
· Increased hyperactivity and poor focus
· Difficulties in memorizing
· Reduced cognitive performance
· Leads to poor sleeping habits
Understanding the concept of ventilation:
Ventilation is the process by which ‘Fresh’ air (normally outdoor air) is intentionally provided to a space and stale air is removed. This may be accomplished by either natural or mechanical means.
Case Study: Let us assume children go to bed by 9:30 PM and wake up by 5:30 AM, which is approximately eight hours of sleeping time and let us see how the air quality fluctuates under different circumstances.
Case 1 – Bedroom in Villa (without attached bathroom): In such cases there is no extraction of air and kids will be breathing same air for 8 hours which results in the decreased oxygen levels and increased carbon dioxide leading to the multiple health issues.
Case 2 – Bedroom in Villa (with attached bathroom + Extract Fan – intermittent working): In this case extract fan is switched ON only during the duration, while bathroom is in use. Once the person comes out of the bathroom, the extract fan is turned off. Even if they use bathroom daily once or twice, the fan is Switched ON for limited period. Therefore, in this case also oxygen levels will decrease and carbon dioxide levels will increase.
We need to understand the dynamics of the air circulation with the proper flow of fresh air and extract air. If we consider the mechanism of ACs, it simply controls the temperature, humidity and purity of air but it hardly has any role to play in Ventilation.
As we know extraction fans whether in Kitchen or bathroom work for limited time only and they do not have access to the all areas in a villa. And as far as supply of fresh air is considered we cannot rely on doors and windows. Also as all the spaces are airconditioned we ensure all rooms are closed, but not open to atmosphere.
So we need to devise a system where we have to supply fresh air to the villa without bringing in the atmospheric impurities and at the same time extract stale air.
Case 3 – Bedroom in Villa (with or without attached bathroom + Continuous Ventilation): In this case all rooms are provided with both fresh air and extract air via duct work which are connected to the fans that are working continuously.
When fresh air and extract air shall be provided continuously as per ASHRAE, can ensure indoor air quality. In this process the volume of extract air should be less than the volume of fresh air, so that the difference in the two will maintain positive pressure in the villa as a whole. However we need to check kitchen and bathrooms are negatively pressurized, to ensure cooking smell from kitchen and foul smell from bathrooms don't spread to other areas of the villa.
Therefore, owners of individual villas need to check the ventilation system of their homes, prior to finalizing HVAC Design. By installing continuous ventilation system, we can ensure Indoor air quality.
As Villa will be Air-conditioned and extracted air will be around 24 Deg C, which is nothing but energy, however, we can save energy by installing energy recovery ventilators (up to 1000CFM) or FAHU (above 1000CFM) with energy recovery options.
Here we discussed about effects of ventilation on children, however adults shall also face similar adverse effects and it shall have more adverse impact on elderly people above 60 years of age. Apparently you might not feel any respiratory issues but it slowly disrupts the human activities which in later stage can turn to be even more hazardous.
BTU Electromechanical Works LLC, operates from 2101, Latifa Tower, Sheikh Zayed road, Road, Dubai, UAE. We are HVAC Contractor for big projects and MEP Contractor for Fit out works. We are experienced in executing projects such as Villas, Supermarkets, Restaurants, Hotels, Community Malls, Logistic Centers & Fit Out works.
BTU Electromechanical Works LLC provides technical support such as Heat Load, Duct Sizing, Pipe Sizing, ESP Calculation, Pump Head Calculation and Complete HVAC System Design, to equipment suppliers, MEP Contractors and Clients.
Muneer Ahmed Shaik
B.E(Mech), MBA, PMP, LEED Green Associate I Co-Founder & Project Manger
BTU Electromechanical Works LLC I projects@btullc.com I www.btullc.com.