Electrical Contracting News (ECN) November 2016 - Page 61

HVAC FEATURE this research presents compelling health imperatives for the management and improvement of indoor air quality in the workplace and beyond, there are further productivity and employee wellbeing benefits when office air quality is good. A 2005 report which examined the impact of office design on business performance, produced by CABE and the British Council for Offices (BCO), cited differences in productivity of 25 per cent between comfortable and uncomfortable staff, due to basics, such as air quality, temperature, overall comfort, noise and lighting. Clearly the problem is not just confined to either the office or the home: it is everywhere. Airtight buildings Modern, airtight buildings also present issues for indoor air quality. Although highly airtight buildings are energy efficient, they are often less well ventilated and prone to the accumulation of air pollutants. In recent years we have seen a rising demand for airtight energy efficient buildings, in response to growing concerns over climate change. However, simply increasing airtightness reduces ventilation levels, which may have an adverse impact on indoor air quality. Airtight buildings can also overheat. Excessively high workplace temperatures impact indoor air quality and reduce productivity. Hot rooms are linked to fatigue, irritability and headache. Chemicals are released from building materials faster when temperatures are higher, exposing occupants to higher pollutant levels. Unfortunately, it is not possible to solve indoor air quality problems by simply opening a window (if it is not fixed shut). Although 60 per cent of office workers say it is the first thing they do if they need ‘fresh air’, opening office windows can present further pollution risks by letting in outdoor toxins. Demanding change The latest demand ventilation systems, such as the Sentinel Totus 2 Demand Energy Recovery Ventilation system (D-ERV), integrate 90 per cent energy recovery into the ventilation system. The most practical way of managing indoor air quality is through continuous regulation, ideally using a modern demand ventilation system which automatically responds to the particular air quality needs of a space. Traditional fixed volume ventilation systems are either on or off, regardless of the conditions or the number of people in the room. Demand ventilation supplies or extracts air only when, and to the extent to which, it is required. This means continuous better air quality, as well as improved energy efficiency. Demand ventilation operates according to sophisticated control and sensory options that are designed to provide ventilation appropriate to the needs of the occupiers. Sensors determine the room’s air quality condition, adjusting the ventilation requirements automatically and managing the system’s ventilation rates accordingly. Information gathered by these sensors is used by the main unit to determine the optimal fan speed to deliver the right airflow to responding exactly to the room’s climatic needs. Sensors can be combined to generate a hierarchy of control for the ventilation system and its operation can be easily linked to a Building Management System f ܈[۝[[ۚ]ܚ[Y\]Z\Y \YܙKۛHH[\H]\›YYY[[]H\XX[H\Y H]\[X[[[][ۈ\[\X\H[[[\ [X[[\HXݙ\H[[][ۈ\[B QTK[Yܘ]HL\[[\BXݙ\H[H[[][ۈ\[K\œ\[H^XH[\HHHx&\\K[HZ\YܙH]\^]\Y]YK[H\[Z[Z\\ZX]YXHHYYXY[H]HX]^[\[\YY[HKB[\HXݙ\H\\ݙ[\B\M\[وHX][\HX[\\HH\Y QT\[\\H]Z[XH]L \[[[Y\\\ˈ[[\\]\\\HH]]X]X[[Y\\\\ٙZ\HHX]^[\[H[][[[\H[[˜H\\XHZ\Y \›Z[[Z\\[[\وݙ\X][ˈ\˜[HZ[[ZHY[YHق[HYH[]Z[XH[[XY[[\\]\H\[HH\Yۂۙ][ۜ\X[[[[]][[\H\\[XYY[YH\BX[]H[YXHH\ ]\Y܈BZ[[&\Z\ۙ][ۚ[[ YX[›ݙ\X][[[[Y\HۋXZ\ۙ][ۙYX\˂[YYBZ\YZ[[\B[\HYXY[ ^B\Hٝ[\[[[]Y[ۙBHX[][][ۂوZ\][˂\[]\H\Yܝš[[Y] ]\[[]YYK[B[\HYYXY[HX]Xݙ\Hق QT\[\[\\HZ\XB][]HZ[[[Y\B]Y[[Z[][HYY܈ZX]\˂H]\\[\[YHX]\œ][^[YH[\ۙ][ۜB\[H[ݚYHHX][˜XY]H\X[Yܝ܈\Y\˂\]H[܈Z\]X[]H][ٝ[Y[ݙ\YYHۘ\\[]܈Z\][ۋH]X[]HوHZ\[YHHZ[[[XH[[و\]\[ۙ\HHYH\YH܂Y[ۙ\\XZ[\܈[Y\X[][\ˈ]XKX\]ٙ\YH QT\[\ݚY\[YXY[[YX]H^H[\B\[܈[\ۛY[[XZ[X[B[X]KYX\\[ [œX[\X\[\ݙ\YHۈB[\ܝ[Hو[܈Z\]X[]HH\YH\œ]Z[\\[[KH[YB\܈\[\\ۜY\HZ\]X[]H[Z\Z[[˂ݙ[X\ M B MHP8$[ P^XK[ BL L ̌ M ML