In July 1976, the American Legion convened at the Bellevue-Stratford Hotel in Philadelphia to celebrate the country's bicentennial. Within two days of the event's start, one veteran after another fell ill with pneumonia-like symptoms. Ultimately, 221 individuals were stricken, and 34 died.1
In January 1977, after months of investigation and speculation, the cause of the mysterious epidemic, which came to be known as Legionnaires' disease, was identified as a bacterium (Legionella pneumophila) growing in the hotel's cooling tower and introduced to the building via the nearby fresh-air intake.
The first recognized outbreak of Legionnaires' disease focused attention on indoor-air quality (IAQ), changing building standards forever. To engineers and designers, the challenge became one of providing a healthy indoor environment without sacrificing comfort or energy efficiency. How this challenge can be met in the highly competitive and ever-changing hotel industry is the subject of this article.
According to the International Hotel & Restaurant Association (www.ih-ra.com): “People spend 80 percent of their time inside buildings. While energy efficiency is critical to cutting costs and emissions, the indoor environment is the most fundamental element of service quality. Guests want a comfortable environment in order to be productive at meetings and enjoy their leisure time, be it in their rooms, in restaurants, or around establishment premises. At the same time, employees need to concentrate to work efficiently and creatively. To guarantee these expectations, a good indoor environment is essential.”
With the proliferation of the concepts of sustainability and “green,” travelers are making decisions based not only on price, but a hotel company's commitment to the health and well-being of its guests. They want an environment free of airborne pathogens that could result in discomfort, illness, or worse.
Recently, I stayed in a newly renovated guest room. From the moment I entered, I experienced a headache, nausea, and dizziness. The volatile organic compounds (VOCs) in and overwhelming odor of the carpet, vinyl wall covering, and adhesives likely were acting together to cause my discomfort, as within minutes of leaving the room, my symptoms diminished considerably.
When polled, the majority of hotel guests state that what is most important to them is a good night's sleep. Many factors affect a person's sleep, including the conditioned environment.
Typically, outside air is introduced to a guest room under the door separating the guest room from the corridor. The corridor is pressurized via a 100-percent-outdoor-air unit tempered to account for ambient conditions. Toilet exhaust fans with volumetric airflows between 35 and 50 cfm run continuously to keep the guest room at a slight negative pressure.
Following are questions that must be asked when commissioning or recommissioning such a system:
Are the toilet exhaust fans in proper working order?
Is the makeup-air unit adequately sized?
Is the makeup-air unit operating properly?
Is the outside air dehumidified enough to avoid mold growth?
Is the door separating the guest room from the corridor overcut to better accommodate airflow? If it is, noise issues may result.
The ducting of fresh air to individual guest rooms is costly and often “value-engineered” out of projects during design.
Ensuring that a hotel's indoor environment is one that will keep guests coming back is a never-ending job. From design to construction/renovation to operation, a hotel operator must be cognizant of issues associated with the indoor environment and address them proactively as well as reactively.
The U.S. Green Building Council's (USGBC's) Leadership in Energy and Environmental Design (LEED) Green Building Rating systems (www.usgbc.org) take a comprehensive approach to sustainable building design, construction, and operation, addressing total environment (e.g., thermal comfort, daylighting and views, productivity of workforce, ventilation, cleaning products). In a hotel, it is critical that not only air quality be addressed, but all other factors affecting the guest experience. Although no specific certification exists for hotels, the USGBC and American Hotel & Lodging Association (www.ahla.com) are working together to develop one.
Even if LEED certification is not sought, a number of design measures can go a long way toward ensuring better air quality:
An ultraviolet light
Specify proper dehumidification and pressurization. Consider desiccant dehumidification.
Specify sloped, corrosion-resistant drain pans.
Specify low-VOC materials (e.g., carpets, finishes, wall coverings).
Specify dedicated air-return ductwork.
Locate outdoor-air intakes upwind of and away from external equipment and discharge (cooling towers, kitchens, laundry rooms, lavatory exhausts).
Specify access doors and signs that simplify the inspection and cleaning of coils, drain pans, and humidifiers.
Specify cooling towers with drift eliminators.
Locate humidifiers and cooling coils so that moisture droplets do not accumulate on surfaces other than those intended.
Consider specifying high-efficiency filters that remove microorganisms greater than 2 µm.
Specify demand-based ventilation to ensure the proper amount of outside air is introduced to the building.
Implement a building-commissioning program.
Specify ultraviolet- (UV-) light systems to minimize mold growth.
Specify carpet displaying the Carpet and Rug Institute (www.carpet-rug.org) Green Label Plus Indoor Air Quality Carpet Testing Program seal.
Consider applying for LEED for New Construction, LEED for Commercial Interiors, or LEED for Core & Shell certification.
Clean or replace HVAC-system filters prior to occupancy.
If the building is occupied, isolate construction zones using airtight barriers and separate ventilation systems.
Consider flushing the building of air several days prior to occupancy, after furnishings and finishes are installed. Tests indicate that, with proper ventilation, carpet emissions dissipate within 48 to 72 hr.
Keep construction materials covered to avoid moisture buildup.
Consider applying for LEED for Existing Buildings certification.
Implement a preventive/predictive-maintenance plan for all HVAC equipment and IAQ, including a computerized maintenance-management system.
Install high-efficiency-particulate-air (HEPA) filters on all air-handling equipment.
Install HEPA filters on all vacuum cleaners.
Institute a retrocommissioning program, including an IAQ audit.
Maintain a proper supply of fresh air.
Maintain relative humidity in the 30-to-60-percent range.
Monitor systems, providing frequent cleaning and maintenance.
Consider using electronic air cleaners.
Educate management and housekeeping personnel on IAQ.
Use environmentally friendly cleaning supplies and chemicals.
Maintain the temperature of stored hot water at 140°F.
Employ filtration and UV lights in air-handling equipment.
Recommission or retrocommission equipment to ensure optimal performance.
The hospitality industry is ever-changing, posing challenges that affect the health and well-being of guests. With hotels operating around the clock, the hotel operator must take seriously his or her commitment to the quality of the indoor environment. No shortcuts should be taken when human life, not to mention the possibility of repeat patronage — the lifeblood of this highly competitive industry — is involved.
For past HPAC Engineering feature articles, visit www.hpac.com.
A member of HPAC Engineering's Editorial Advisory Board, John J. Lembo, LEED AP, formerly the senior director of energy for Starwood Hotels & Resorts Worldwide Inc., is vice president and managing director of The Ferreira Group, a firm specializing in building commissioning and facilities management.