Sustainability in Commercial Buildings

In recent years the real estate market has imposed new requirements on office buildings with regard to energy consumption and sustainability. Significantly, transaction details from estate and letting agents indicate that energy conscious sustainable office buildings have a higher rental and investment value than that of conventional office accommodation.

The extra investment costs are not always fully recovered, but sustainable buildings do have a distinct advantage with regard to their rentability. With renovation and development of older office buildings (on the better locations) more and more attention is being paid to strongly upgrading the general environmental impact of the buildings.

Factory and Warehouse Buildings
In the past, for factory and warehouse buildings, a sustainable concept was not common. The lower investment budgets and short rental periods (sometimes less than 3 years), coupled with a lower interest in the building image resulted in competition purely based on the rental price. This is now changing.

In 2010 in Tilburg, the first Breeam environmental certificate (see below) was awarded to a distribution center in the Netherlands. This set precedence for others. With the development of new factory and warehouse buildings more attention is being paid to running costs. The energy supply costs are increasing and the general increase in social responsibility for energy consumption has filtered through to all aspects of company life. There is awareness that buildings create 30-40% of all CO2 emissions. In addition, the governing authorities are legislating for lower energy consumption and limitation of the so-called “Carbon Footprint”.

Initiators
There are basically two parties who take the initiative in the implementation of sustainable actions that exceed the governmental regulations. On one side there are the building owners. Here there is an expectation that commercial real estate future (market) value and rentability shall be strongly influenced by its level of sustainability.

On the other side, there are the users and tenants who have self-interest in reducing their energy costs, and see it as socially responsible to implement sustainability. This would appear not to be a short-term hype but a serious consideration. There should be focus on rational targets and realistic actions with results (in e.g. energy consumption, flexibility, comfort and maintenance), together with investment with payback periods (also including possible subsidies such as the EIA and MIA). If considerations to go further than “quick wins” are made, the long term vision of developers, investors and tenants is the key issue.

Breeam
The total lifecycle of a building is considered in order to calculate a “weighted” sustainable building value. Developers and investors are more frequently insisting on an environmental certificate, recognizable as qualification of the sustainability of their buildings and to adhere to the requirements and wishes of tenants.

There are currently dozens of methods of calculating the “environmental score”. Breeam (Building Research Establishment Environmental Assessment Method) is becoming more and more the standard for The Netherlands. In this system the environmental impact is calculated on the basis of 9 categories (www.breeam.org).

Relevant Factors
It is important that the certification commences in the design phase. Sustainability begins already with the choice of location, for instance through evaluating and optimizing transport movements. In addition, the specific layout of the location is also important. Is intensive or double ground usage possible, for example by optimizing the logistic layout through compact storage systems or by multi-storey usage? How is the building orientated with regard to sun and wind – loading docks better downwind?

The quality of the building thermal insulation is important for energy conservation. A compact building form to limit transmission losses helps, as does the application of additional insulation (relatively cheap and efficient). With factory and warehouse buildings mainly the roof area and then the elevations are interesting. With distribution centers, the roof is easily 50% of the total building surfaces. An air lock at all intensively used entrances, together with provisions such as (inflatable) dock shelters and insulated dock levelers in warehouses greatly reduce energy losses through draught.

Lighting can also be made energy efficient by usage of controllable and dimmable LED armatures. Movement detection, time clocks and daylight detection can prevent unnecessary lighting usage. Movement detection in warehouses is possible if coupled to the WMS. Additionally, in working areas, the use of light and reflective colors (coating of the roof and wall cladding and coating of floors) is definitely advisable.

Low temperature heating is another possibility. The installation of pipework in the building floor construction of office buildings makes passive heating and cooling of the building mass possible. Under floor heating in warehouses is being used more and more, even in combination with watertight floors and induction systems. With floor heating the water temperature is much lower (30ºC) than with air heating (90ºC), also the air temperature with floor heating can be a few degrees Celsius lower than with air heating. Floor heating can therefore provide more comfort with less energy consumption.

Another advantage of floor heating over air heating is the reduction in dust displacement. With air heating the dust present in the room is displaced due to the higher velocity of air movement with the result that products present in a warehouse, over time, get covered with a layer of dust. The actual primary source of heat can be provided, for example, by geothermal storage in combination with heat pumps.

The energy requirement can also be reduced through heat recovery from ventilation air or from heat excesses in the building or from production processes. Energy creation by placement of solar panels or PV cells, together with installation of windmills to harness wind energy, is currently less interesting (often excessive payback periods) due to the high investment costs and lack of available specific subsidies.

For more information: 
Joost van Gilse
Director of the Architect and Engineering Consultant DENC
jvgilse@denc.nl
www.denc.com