For generations, barns were built according to local traditions that were shaped by agricultural practices, culture and climate. While agricultural techniques and culture have changed over time, the old lessons learned about local climate are just as important today as they ever were. By designing your hospital and barns to work with the land and the physical environment, you can reduce energy usage and operating costs, and provide healthier spaces for people and horses.
Begin by carefully orienting your buildings. Traditional barns are oriented with the long axis running east/west. This is the best orientation for maximizing passive solar design, which translates to a reduced cooling load and energy savings for conditioned space. The following rules of thumb may be adjusted slightly based on your local conditions:
• Place working areas and stalls on the south side, and support spaces on the north side.
• Use overhangs on the south to keep out the summer sun and let in the winter sun. Calculate the angle of the sun at noon in your location on the equinox and design the overhang to be just long enough to prevent solar gain on this day.
• Locate large openings on the south, high openings on the north, and reduce openings on the east and west, with the exception of doors at the ends of barn aisles.
Use the natural environment to assist in ventilating barns and indoor/outdoor treatment areas. Barn-associated recurrent airway obstructive disease (RAO) has long been recognized as a problem for horses that are housed in poorly ventilated barns. In a medical facility, it is even more important to maintain adequate air flow.
Study your site for natural wind direction and locate dirty zones, such as isolation barns and manure piles, downwind of cleaner functions.
Locate downwind buildings at least 1.5 building widths away from other buildings to prevent interference with natural site breezes and air flow.
Natural ventilation works like a chimney in a house. Hot air rises and creates a draft. Take advantage of the chimney effect by using continuous or cupola vents on the ridge line of the roof and provide openings low on the wall, such as at the perimeter stalls. Hot, soiled air rises, creating a draft for fresh air to enter.
Create enough height in the building to allow the chimney effect to work. A 6:12 or greater roof pitch is preferred. Cupolas should be large. Many pre-manufactured buildings have low roof pitches and small cupolas, and therefore do not ventilate properly.
Most places in North America experience westerly or southwesterly breezes. Locate large doors on both ends of the barn to capture these breezes and create cross-ventilation.
Design the roof peak with an exhaust fan system to supplement natural ventilation, which will be necessary at certain times of the day or year. Design the system to provide at least eight air changes per hour or 500 cubic feet per minute per horse, whichever is greater.
Show horse owners know that an artificial lighting system can disrupt a horse’s natural circadian rhythm, preventing his winter coat from growing. Natural daylight has the opposite effect; it keeps a horse better connected to the outdoors and encourages physiological well-being. In human medical facilities, natural daylighting has been proven to reduce patient recovery times and improve staff productivity.
Daylighting can also help you save money in lighting costs. Sunlight provides approximately 140 lumens of light for each watt of heat energy produced (EnergyStar.gov.), making it the most efficient lighting system available! In addition, typical office lighting systems cost 60 cents per square foot per year in utility costs (Lighting Research Center). You can save a lot of money by lighting with the sun.
Except in cold climates, avoid thick floor plans. Floor plans that are square in footprint are difficult to daylight. In pleasant climates, develop thinner or open plans, oriented on an east/west axis, that have a greater connection with the outdoors. These designs also work better for natural ventilation.
Reduce glare. Avoid conditions where direct sun can come through a window or skylight without being softened by a translucent glazing system.
Locate openings in ways that benefit your patients the most. If low openings are distracting or dangerous, place openings high in the wall. In staff areas or procedure rooms where horses are anesthetized, use lower openings.
A door is an opening as well. Design your hospital with rolling walls to open up the rooms in nice weather, taking take full advantage of daylight and fresh air.
Today’s green movement has allowed designers and building owners to re-evaluate local building traditions. Equine hospitals make excellent backdrops for traditional architecture and materials, and there is a lot to be gained by taking a regional approach.
If your locale has big daily temperature swings, use thermal mass to your advantage by building with masonry or concrete. These materials are cool in the morning, absorb heat during the day, and release heat at night, thereby moderating the indoor environment. Heavy mass materials work in extremely hot climates as well. In South Florida, for example, a concrete masonry building is cooler and rot-resistant.
Except in high latitudes, use light colored or reflective roofing to avoid excessive heat gain. Traditions such as reflective metal roofs in Texas have persisted because they are so effective.
Design deep porches in hot climates and incorporate breezeways to funnel moving air.
Use steep roofs in northern climates. The gambrel-roofed barn was developed partially because it was handy for storage, but also because it is very good at shedding snow.
Collect rainwater, if legal in your state, and use it for watering landscaping, cleaning the barn, etc.
Consider incorporating photovoltaic panels in the roof design in sunny climates. If your building already faces south, it is ideally set up for sunlight harvesting.
An equine hospital is an ideal building for climate-sensitive design. This is because it is by nature an indoor/outdoor environment. And, if you aren’t already convinced, think of the work you do every day. Most horses, and the people who work with them, prefer to be outside. Build to match your lifestyle and philosophy, and enjoy the benefits of a better, more sensible and more valuable structure.