Envelope and Space Planning Introduction

On urban sites where optimal orientation and massing are difficult, the building envelope provides the greatest opportunity to conserve energy. In Santa Monica, the envelope should maximize daylight, natural ventilation and views to the exterior, and control solar heat gain and traffic noise. The building envelope may also be designed to integrate systems for collecting solar energy and rainwater.

Windows significantly affect building energy performance. The design of windows is critical in providing effective daylighting, solar control, ventilation, noise control and views to the exterior.

The most critical practices are EN1, EN2 and EN3, which control the entry of daylight and natural ventilation into a building, and their interior distribution. Addressing these issues early as a multi-disciplinary team offers the best opportunity to develop solutions that resolve these energy and environmental performance issues while reducing envelope and whole building costs.

Daylight offers the twin advantages of creating a high-quality work environment while reducing energy use for lighting. While building form establishes the daylighting potential of interior spaces, the distribution of windows and their light transmission characteristics determines the amount of daylight entering the building. Roof monitors and other forms of top-lighting, such as skylights and sawtooth roofs, are particularly applicable to Santa Monica because the majority of buildings are low-rise.

Effective solar control is an essential part of window design in Santa Monica. For commercial buildings with high internal electrical loads, such as offices or retail occupancies, reducing cooling loads and glare problems from windows, skylights and roof monitors is a very effective energy conservation strategy. For buildings and spaces with low internal electrical loads, passive solar heating by admitting sun when heat is required must be balanced with blocking midday summer sun. Solar control is best accomplished with high-performance glazing or exterior solar controls such as overhangs or awnings, rather than with internal blinds. The design issue is to control solar gain without compromising daylighting or exterior views.

Natural ventilation can reduce the energy required to cool buildings by reducing or eliminating the need for chillers, fans and pumps. The type and placement of operable windows or dedicated air inlets and outlets is critical in directing air into and out of the building so they provide both ventilation and cooling of interior surfaces.

Open windows that admit air into the building also admit exterior noise and pollutants. Natural ventilation relies on continuous air paths within ventilated spaces and can also conflict with acoustic requirements. Interior acoustic conditions can be improved by controlling excess internally generated noise at its source and minimizing noise from outdoors.

It is difficult to satisfy all of these performance requirements, many of which are conflicting. However, they can be resolved by designing different parts of the window for different need: for example, separating ventilation from daylighting by using dedicated vents or separating view from daylighting by using light shelves.

Interior space planning and finish materials significantly affect the distribution and effectiveness of daylighting, natural ventilation and passive solar gains. The design of the interior must ensure that light and air reach the largest area possible, requiring careful design of interior spaces and partitioning. The color and shape of interior surfaces has a major impact on the distribution and quality of daylight. Their design must be carefully coordinated with that of the windows and skylights.

Thermal mass can moderate indoor temperatures by dampening temperature swings. This minimizes the need for mechanical cooling and also stores solar heat to reduce winter heating needs. Moderate surrounding surface temperatures also contribute to the comfort of occupants. The amount and distribution of thermal mass and its exposure to sunlight and airflow dictates its effectiveness in moderating internal temperatures.

In addition to shaping building interiors to maximize the use of daylighting, ventilation and passive solar gains, other environmental strategies affect interior space planning. The Santa Monica Sustainable City Program has a proposed goal of diverting 70% of solid waste from the landfill by the year 2010.

Providing a recycling area is required by Santa Monica Municipal Code for multi-family and commercial buildings. Making the recycling area convenient, keeping it clean and well managed, and providing on-site education for users about waste separation and recycling can make the difference between minimal compliance with the law and a successful recycling effort.