Sustainability in healthcare
Sustainable building is the one that consumes the least resources – both in construction and life cycle costs, says Siddharth Puri
Close your eyes and think of a green building, and the chances are that you will be thinking of a building that is actually green. A phallic glass tower with shrubbery on all floors or a tower with a vegetation on every floor. This is further reinforced by what comes up when we use ‘green building’ as a search string on google - it is simple enough experiment we can conduct in our homes. And this is also an illustration of the way that we – especially architects - are losing the battle to achieve sustainable design.
Environmental sustainability is by simple definition the maintenance of natural resources. This simply means that with a growing population, we have to consume less per capita and this includes our built environment. By further logical extension, a sustainable building is the one that consumes the least resources – both in construction and life cycle costs.
Going back to the ‘green towers’ (typified by image 1) that seems to be consumed by the public as an epitome of green design. The questions that seems to be never asked is what it does ‘cost to build’ and furthermore how many resources it consumes.
While there is validity in the idea of increasing the green foliage of an urban environment and I suspect with increased urbanisation and depleting resources, we will have no choice but to have vegetation grow vertically, but at the same time these buildings need to have a cost benefit analysis to determine whether the benefits of the increased green cover are worth the extra concrete, synthetic water proofing, steel, water and most importantly capital.
It is often easy to forget that capital is a resource too and capital is what we use to buy and consume resources. It is again a simple conclusion that a true metric of sustainability is to follow the money. A sustainable building in our opinion should simply consume less resources and this includes time material and most importantly capital both in terms of sunken cost and life cycle costs. A simple example is the Energy Performance Index (EPI). The lower the EPI, the lower the energy bills.
To prove that sustainability is not a costly complex exercise here we can look at two simple passive measures that help reduce costs and thus in our opinion are simply ‘greener’ –
1. Optimise the building size.
2. Optimise the envelope design
Optimise the building size
The premise is simple – the less we build, the less resources we consume. The job of the healthcare architect should start by asking an uncomfortable question: “What is the least we can build."
This is an incredibly counterintuitive approach that hits at the heart of the business of architecture and design. In the author’s experience, in healthcare architecture, we have more scope to do this than any other typology. By questioning operations, flows, footfalls and business plans, we can actually find ways to reduce the amount our clients need to build and this is something that we have personally done.
Coming back to the question of business of architecture – while it is another longer discussion that could fill a lot more pages, the solution lies somewhere in capitalising on the long-term value built. Both the architect and the client have to move away from the Rs/sq ft thinking and understand the true value – not just cost – of what is going to be built and more importantly what does not need to be built today and arrive at a consensus on what’s fair. Thinking on both sides needs to change to being heavily strategic.
However, one cannot deny the obvious challenges in a country that historically has never had a strategic culture and the advantages of building value is often lost in maintaining cash flows. That, too, however is a topic for another day.
Optimise the envelope design
Sustainability is and should be a key driver of every aspect of design and passive strategies that are easy to introduce are almost a natural extension of the process of designing. There are certain factors to be considered in order to strike a balance between aesthetics, thermal comfort and energy conservation/ lower carbon footprint. Conventional practices of hospital design, however, often times step away from these aspects due to concerns regarding initial costs and return on investment.
Careful design of the façade is one of those factors that can greatly reduce the energy consumption of a building. Important factors to consider: A) Access to daylight and views based on space programming. B) Incident solar radiation on the surface. C)Size of the fenestration (also dependent on orientation). D) Glazing percentage.
Use of natural light not only promotes a healthier environment but also helps in designing of artificial lighting which in turn reduces energy consumption. In the design of the façade of the multi-specialty hospital, (image 2) the first step is to map programme on the façade. The second step involves optimising the size of the opening needed along with the façade treatment required based on the orientation. For example –
1. The chemotherapy bays have been provided with large windows with louvres that not only prevent the solar gain from the summer sun and reduce solar gain but also give access to natural light.
2. In the patient rooms, full height windows have been provided that have been recessed to provide shade.
3. However, unlike the first two cases, for the OTs, prep recovery and the SICU the size of the openings have been reduced determined by the functionality of the space that does not require large windows.
Window performance greatly influences the thermal comfort of occupants. Hence for its design glazing percentages, size of opening, glazing properties such as U-value, SHGC and visual transmittance need to be kept in mind. The next step involves analysing the shading methodologies as we as do further refinement of the design in order to find the right balance between natural light and reducing solar insolation.
• ITERATION 1 :
- Windows - Ribbon windows
- Glazing percentage - 33%
- Shading - Unshaded
• ITERATION 2:
- Windows - Ribbon Windows
- Glazing percentage - 28%
- Shading - Unshaded
• ITERATION 3:
- Windows - Windows designed as per space programme.
- Glazing percentage - 28%
- Shading - Recessed windows and louvres
It can be seen from the images that as opposed to conventional use of ribbon windows with no shading in iteration 1 and 2, the openings in iteration 3 have been carefully designed, keeping in mind the orientation and the insolation radiation on the surface. The results clearly show the reduced insolation on the surface in iteration
3. On comparing iteration 2 and 3, keeping the glazing percentage the same, one can see that a simple step of recessing the smaller windows and using louvres for larger windows reduces the average insolation radiation on the surface.
A simple exercise like this can be easily introduced into the design process by using BIM and basic energy modelling tools easily available. We can run iterations and scenarios and arrive at optimised solutions that reduce construction cost and, at the same time, have a major impact on lifecycle costs.
Siddharth Puri is Director – Architecture, WardFour Designs.