Smart Facade Designs for Hospital Buildings
By Ikyatha Yerasala
Building facades are not just a significant aspect of design, but they also have a massive impact on the room temperature. Each material differs when it comes to heat entrapment and that thereby affects the overall cost. Ikyatha Yerasala writes more on choosing smart facades for hospital buildings.
A building facade, one of the most vital pieces of design, refers to the side, normally the front side of a building structure. A great opportunity for designers and architects to play around and display their design skills and artistic talent, a façade is more than just for show to the public.
A facade can refer to the vertical face of a building envelope, such as an external wall. A building may have more than one façade, such as the north façade, south façade etc. Although having an awe-inspiring look can attract people to the building, other factors to be considered when choosing a façade material includes durability, ease of installation and maintenance, cost, resistance to chemicals etc and more. In hospital buildings, facades are of significance mainly because they impact the temperature of the insides. Apart from the traditional materials, new materials are being experimented with, keeping in mind the requirement of the healthcare facility. Eco-friendly facades and sustainable options are great options when it comes to designing hospitals. “Technically speaking, the smart facade—or building envelope that adapts to environmental conditions—dates back to the first window. But the contemporary idea of the smart facade has only been around for a few short decades. Energy-producing algae face, Light Responsive Facades, Smog Eating facades, Operable skin facades are some of the eco-friendly facades that are gaining prominence. These facades become particularly important when there are health and well-being associated to it. So, it becomes imperative for healthcare and hospitals to choose a facade that is healing in nature and also enable them to connect with the nature,” says Juzer Kothari, Managing Director, Conserve Consultants Pvt Ltd, a specialist in healthcare sustainability.
IGBC Green Healthcare, which is specifically defined for healthcare-built environment, focuses on facades that are more energy efficient and eco-friendly in nature. Light power density should be reduced by 30 per cent of building facades reduce light pollution and restrictions on the materials to be used for their construction. “Green eco-friendly facades provide better air quality, noise damping and natural beauty. People love the vitality these living landscapes bring to the building they are in. They also support better acoustic buffering, biodiversity, thermal insulation and biophilic design. Recent studies have shown that they are imperative in the healing process. As sustainability consultants in healthcare, we understand the requirement of the council and also the occupants of the hospital environment, and their interaction with facades. In one of our hospital projects in Chennai, we have created eco-friendly facades, made of living plants, in the entire internal facade of the building. The ecosystem is powered by drip irrigations and the facade covers the length of the different levels in the hospitals, where occupants have access to fresh air and views, associated with quick healing,” adds Juzer.
Regulation of indoor environment
Design of appropriate building facade plays a very important role for healing in healthcare projects. The façade protects the people occupying the building and plays a major role in regulating the indoor environment. “Designing smart building envelopes translate into both tangible and intangible benefits. The tangible benefits can be, reduction in consumption of building materials, energy and operation and maintenance costs. The intangible benefits are better assistance in patient’s recovery and healing along with reduction in stress and improvement in the overall healthcare environment which can be achieved as an outcome of physical and visual connections to the natural environment along with thermal and acoustic comfort. Designing and material specifications of the building envelope play a major role in determining the amount of energy a building will use in its operation,” says Hiten Sethi, CEO and co-founder, Hiten Sethi Associates (HSA). The design of the building facade is governed by the performances expected out of it. “The basic performances expected out of a building facade providing thermal comfort, providing acoustic comfort against the external noise, enhancing indoor ambience by providing adequate task-based day lighting, protecting the indoors from wind and rain while maintaining adequate visual connectivity to outdoors, control of air infiltration, ease of maintenance and aesthetics,” adds Hiten.
Of course, the safety aspect is of utmost importance. Recently, the building's glass façade of Kamnagar Hospital in Mumbai posed a hindrance as it blocked air passage and firemen had to break the glasses on all the floors to evacuate those stranded inside. Also, climatology of the particular hospital site can help obtain a clearer picture before designing a building façade. Architect Umer Lateef gives a designer’s perspective on smart facades. “The science of site analysis gives a designer a clearer picture on how to approach the design to any given structure that is to be erected, by studying the climatology of the site one could obtain a clearer picture of the vital data that is to be considered for an efficient design. Orienting the design of a building correctly with respect to the sun’s path for a given site plays a vital role in the amount of heat the building receives. To further explain this, let’s consider a rectangular-shaped hospital that is to be oriented efficiently. The sun emits a lot more heat during the second half of the day as compared to the first half, hence the shorter side of the rectangular hospital should be facing East and West respectively, this would ensure the overall surface area that would receive more heat (the side facing West) is comparatively lesser since the longer sides of the rectangular building are not exposed to the West.”
Talking about some of the points worth considering when choosing façade material, Umer states, “Glass windows and other such openings on the west should be avoided as much as possible but in case it’s necessary to place a window then it should be provided with ideal shading elements like Chajjas. Preferably, the west facing side of the building should have a lawn to prevent heat from reflecting off the ground and hitting the surface off the building. The roof of the building should be insulated with insulating materials for eg Mangalore tiles that pack an air cavity between each tile which cuts the heat and prevents it from heating the building. Planting trees could act as a cheap and eco-friendly way of controlling the temperature of the structure and also adding to its aesthetics as good landscape.”
A facade of a hospital building is more than just show, it contributes to healing of the patients and has a great impact on their well-being too. To look at the impact of on a façade on the insides of the hospital, here’s a case study of NCI, Nagpur.
Case Study
The National Cancer Institute (NCI)at Nagpur is proposed as a state of art 500-bedded - Oncology Centre, on a 23.5 acre site with a total built up area of 7,00,000 sq.ft:
Sustainable, climate-responsive design parameters
The climate of Nagpur can be divided into – summer, where temperatures rise beyond 45 degree celsius accompanied by dry winds making the climate scorching hot, the monsoon which is heavily dominated by south-westerly monsoon winds making it considerably wet and lastly, the winter, which brings in considerably cold weather.
The vast climatic variation with scorching summers, wet rainy seasons and chilling winters made the process of designing a climate-responsive building a challenging yet exciting one. HSA has used the principal of reducing the energy requirements through an Integrated Design Approach and further enhanced the process by using clean renewable energy to the maximum extent in order to fulfill the energy requirements of the hospital. Special emphasis has been laid on the building façade in order to reduce the energy requirement for heating, cooling and lighting.
The façade of the building was required to keep the heat of the sun out in summers and encourage the penetration of its warmth in the indoors during winters. Study of sun path diagrams have been used to design elements like sun shades, deeper recesses & fenestrations in terms of aluminum louvers which have been used to optimize the lux levels and indoor temperatures. The façade features are composed with less of glass and more of mass on the exterior to reduce heat penetration. The façade also protects the people occupying the building and plays a major role in regulating indoor environment.
Designing a smart building envelope translated to various benefits. The tangible benefits are reduction in consumption of building materials and energy, reduction in operation and maintenance costs. The intangible benefits are better assistance in patient’s recovery and healing along with reduction in stress and improvement in the overall health care environment which will be achieved as an outcome of physical and visual connections to the natural environment along with thermal and acoustic comfort. The overall elevation has been designed such that it makes the building look approachable, yet create a sense of security for patients.
HSA’s solutions
The bold and confident character of the structure has been achieved by creating symmetry in the elevation which imparts the image of the healing center with confidence. Functionality has lead the way and evolved into aesthetics. The features of the façade are composed with less of glass and more of mass on the exterior to reduce the heat penetration in to the building. The glass to wall ratio is maintained at 22%. Glazing equivalent of 24 mm thk DGU reflected glass shall be used
The curtain walls are designed as semi-unitised glazing in diamond shape grid, straight grid, semi-unitised glazing with horizontal fins and semi-unitised glazing with vertical metal fins.
In this system, the vertical mullions and horizontal transoms are installed on MS/SS/Aluminum brackets which are anchored to the columns/slabs. Cut to size glass is structurally glazed to the Aluminum sub frame by structural sealant. The sub frame with the glass is installed on the Grid work. In the above system 50% of the work is done at site.
There is no aluminum member visible from outside, only the grooves running horizontally & vertically shall be seen. The glass is held with the help of structural sealant and the application of structural sealant is the critical operation as this is the sealant which holds the glass to the frame for life. For the installation of this system scaffolding from outside for installation needs to be erected. The glazing at main entrance point is designed as the fixed spider glazing system.
The spider system offers the most practical solutions to glass assembly. To fix the glass up at the edges of the facade, one or two arms-accessories can be used. In special applications, the number of arms might be more than two and the sheet of glass can be fixed by one arm at each corner. The used accessories can be mounted against metal frames or against glass fins and tension rods are used to pull these accessories together. The glass railing is designed as Al.’U’ Channel system.
The façade of NCI is also designed based on wind analysis.
The basic wind speed in Nagpur is around 44 m / sec. The risk coefficient to be considered for façade design i.e. K1 = 1 .The structure is identified as Category – 3 i.e. the structure located in terrain with closely spaced obstructions upto 10m height and falls under Building class – C i.e. structure having length greater than 50 m . The topography of the site is general plain ground and has K3 = 1. Wind pressure for full height of building is 1.5 KPa and wind pressure upto 10m height from the ground level is 1 KPa. All the above factors are taken in to consideration during designing of the façade and selection of the building material for the same.
Elevation features arrived at as a response to the Sun path diagram at Nagpur.
Shadow of building during summer solstice i.e. 21st June
Sunrays penetration in East elevation during Spring equinox i.e. 21st March
The elevation of the building on east and west is designed as an inclined surface with the roof overhang extending beyond the façade and has horizontal fins on the vertical façade designed such that it obstructs most of the sun rays coming inside the structure from 10 am to 12 noon and 2 pm to 5 pm thereby reducing the heating of the space in summer due to direct radiation.
The longer side of the building is oriented towards south.
The south façade is designed as the longer side of the building with a straight vertical façade and has horizontal fins on the vertical surface designed such that they allow the penetration of the direct sunrays inside the building such that it helps in warming up the internal spaces during the chilled winter days.
Use of these design strategies for façade help in reducing the cooling and heating load on HVAC systems there by reducing the energy consumption of the structure.
Fire requirements
The openable vent of minimum 2.5% of the floor area shall be provided as per fire requirements. And shall also be integrated with automatic smoke detection system. An opening to the glass façade of minimum width 1.5m and height 1.5m shall be provided at every floor at a level of 1.2 from flooring facing compulsory open space as well as on road side. Minimum one such opening shall be provided at the interval of every 15m. Material used for cladding shall be noncombustible and shall not emit toxic gasses and it shall be eco-friendly.
Materials used
The curtain walls are designed as semiunitised glazing in diamond shape grid, straight grid, semiunitised glazing with horizontal fins and semiunitised glazing with vertical metal fins.
The glazing at main entrance point is designed as the fixed spider glazing system.
The glass railing is designed as Aluminum ’U’ Channel system.