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It is important that operating room designers and health care facility planners strive to limit their environmental impact. Several organizations offer health care-specific green design guidance for remodeling or new construction, including the U.S. Green Building Council Leadership in Energy and Environmental Design (LEED),115 Green Guide for Health Care,116 and the American National Standards Institute (ANSI)/American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)/American Society for Healthcare Engineering (ASHE) Standard 189.3-2021.117 Licensed inpatient health care facilities must follow the health care specific requirements. All other health care facilities have the option to pursue the health care compliance path.
For a new project or renovation to be LEED certified, it must accumulate a required number of points in the following six areas of green design and operation: sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, and innovation and design. A total of 110 points is available. Based on the degree of compliance, projects receive a LEED certificate rating of “certified” with 40-49 points, “silver” with 50-59 points, “gold” with 60-79 points, or “platinum” with 80 or more points. LEED certification is voluntary, but state and local governments may offer incentives when a facility meets a specified level of achievement. While there are other sustainability certification programs, LEED certification offers a clear example of how goals common to these sustainability programs can be achieved.
Performance in this area depends upon factors such as site selection; site development (protecting habitat, maximizing open space); alternative transportation (accessibility to public transportation, bicycle storage, parking capacity, and support for low-emission vehicles); storm water design; light pollution, and pollution during construction.
Water conservation is also assessed during certification. Much of the water use in health care facilities takes place behind the scenes. Sterilizers, food service, pure water systems, and cooling consume the vast majority of the water in many health care facilities. There are numerous technologies and strategies available to reduce water consumption associated with clinical and facility operations. Low-flow fixtures should be utilized in urinals, toilets, showers, and sinks. Design considerations should include the potential for safe water reclamation, infection control, and operative sterility.
Energy and atmosphere opportunities are based on several benchmarks including optimal energy efficiency, the use of onsite renewable energy, monitoring and tracking energy usage, and “green” power usage such as wind or solar power. The bulk of energy consumption in inpatient health care facilities is related to providing code-required air change rates and managing temperature and humidity levels. These requirements can be relaxed when spaces are unoccupied. The energy consumed by lighting can also be substantial. The use of natural lighting is encouraged, and when artificial lighting must be used, motion sensors can help conserve energy. Light emitting diode (LED) bulbs are now available for use in operating room surgical lighting. Substantial cost savings can be generated through energy conservation.118
Indoor environmental quality, including outdoor air delivery, is an essential component of green buildings. Optimization requires meeting ventilation standards and ensuring the use of low-fume materials (e.g., glues, paints, flooring systems, wood products). Factors such as temperature comfort, daylight, and views are also considered integral to the indoor environment.
Design and construction should encourage the use of eco-friendly materials. Certification requires, at a minimum, the storage/collection of recyclable materials. Additional certification points are given for building reuse (maintaining existing walls, roof, etc.), construction waste control, materials reuse, and for using recycled, regional, or quickly renewable materials. Health care waste and diversion are a special area of concern. Perioperative clinical care areas produce voluminous waste, generating more waste than other areas of a health care facility. Proper waste segregation can be improved by thoughtful operating room design that allows for sufficient space and separation of materials.
Finally, innovation in design awards credit is granted to projects that demonstrate quantifiable environmental benefit through new strategies and techniques not specifically addressed in the LEED rating system. Also, additional points are earned if the designer or architect is LEED accredited. Several examples of design that can promote more environmentally sustainable anesthesia include space considerations for waste segregation and waste anesthetic gas treatment. Waste anesthetic gas treatment space may be an area worthy of design innovation since all inhaled agents act as greenhouse gases and nitrous oxide depletes the ozone layer. Inhaled anesthetic reclamation systems under development may be helpful for reducing or neutralizing waste gases.
The setback of HVAC airflow change rates is one of the most cost-effective means of reducing energy consumption in a health care facility.118 Providing air flow as well as managing temperature and humidity within a hospital account for approximately half the energy and water consumption of a typical hospital. While a physical space is in use, facility ventilation code requires maintenance of specific airflow rates. However, when the space is unoccupied, the requirements are relaxed. The most impactful space to reduce airflow rates is the operating room. Most operating rooms provide between 12 and 30 air changes per hour (ACH) depending on the ventilation code in place and the cooling needs of the operating theatre, among other factors. The code minimum air change rates must be maintained during the delivery of operative care. The most common health care ventilation standard in the United States is ASHRAE 170 Standard for Healthcare Ventilation. Outside operative care, the air change rate may be reduced as prescribed in ASHRAE Standard 170 Healthcare Ventilation section 7.1.a.3 as long as pressure gradients between adjacent rooms are maintained. Typically, this results in setback air change rates between 5 and 10 per hour depending on the design of the HVAC system.
ASHRAE Standard 189.3-2017 Design, Construction, and Operation of Sustainable High-Performance Health Care Facilities limit setbacks to a minimum of 6 ACH for all operating rooms.
The implementation of air flow setbacks must be carefully planned. Some operating rooms are used exclusively for scheduled procedures, which makes implementing setbacks straightforward, such as nights and weekends. Facilities with unscheduled procedures require a more sophisticated approach. By interfacing the room scheduling system with the building automation system, the assignment of a clinical procedure triggers the necessary increase in ACH. A minimum of 20 minutes should be allowed for an operating room to get to a minimum of 20 ACH. When 20 minutes is still too long, an “on-deck” approach is taken, where one dedicated operating room is maintained at 20 ACH. If that room becomes occupied, then another operating room increases to 20 ACH in preparation for another potential emergency case. Operating room lights are easily set back; however, operating room temperature setbacks should be applied carefully. Temperature setbacks are appropriate for entirely scheduled operating rooms, but temperature setbacks are discouraged in operating rooms receiving unscheduled cases. For operating rooms, the air flow is the largest energy consumer so it should be the focus of energy savings efforts.
Nitrous oxide is a potent greenhouse gas and destructive to the ozone layer. Recent independent reports from the U.S., Australia, and U.K. note that large fractions (77-95%) of hospital N2O are lost before clinical use through leaking central pipeline systems.66,67,85,119 This has led to calls for abandoning nitrous oxide central piping in existing buildings and avoiding it in de novo construction. Substituting portable tanks and closing them between each use is feasible and dramatically reduces losses.66,67,84,119
Curated by: the ASA Committee on Environmental Health
Date of last update: January 29, 2024
