Acoustical Issues in Health Care
• HCAHPS (Hospital Consumer Assessment of Healthcare Provider & Systems) quarterly standardized assessment of total quality of care
• Patient satisfaction
For facilities that are required to comply with FGI-2010, immediate response is needed. Very few facilities comply with the acoustical requirements of FGI-2010, or even approach compliance.
Beginning in January 2011, The Joint Commission for Accreditation for Health Care Facilities announced that it will survey according to the requirements of FGI-2010, unless facilities show proof that another standard applies. If your facility is grandfathered to an older code or your state has not adopted FGI-2010, you should inform The Joint Commission so that you aren’t surveyed to the very strict provisions of FGI-2010.
The following sections summarize the new acoustical requirements of FGI-2010.
The standard requires, “Building façade sound isolation performance shall depend on the site classification and shall be as required to provide acceptable interior sound levels.”
Exterior noise is based on noise not produced by the health care facility and is divided into categories A, B, C, and D, where A is a quiet environment and D is an extremely loud environment.
Determination of which letter applies to your facility is very subjective. Table A.1.2.a attempts to define this, but a typical example of ambiguous requirements is that facilities are in category D if the distance from the nearest flight line is less than 1,000 ft. There is no mention of whether helicopter MedFlight paths are included in the definition of flight line. If they are, virtually all hospitals would be in category D, which requires a 50 dB exterior sound transmission class (STC) rating, and therefore, severely restricts the amount of glazing permitted. Even unglazed walls will probably not comply with this requirement, unless they include heavy masonry materials.
Double-pane glass has an STC of around 32. Thick laminated double-pane glass has an STC of only around 39.
Even if a facility doesn’t have MedFlight issues, if there is a reason to believe that the facility may not be in category A, one week of continuous monitoring is required and the monitoring methods must comply with ANSI/ASA Standard S 12.9.
There is a new requirement that facilities with helipads shall incorporate noise mitigation strategies to meet the acoustic requirements in the guidelines. The requirements being addressed are presumably the exterior noise intrusion into the building and the property line noise limits.
Noise produced on the facility property must not cause property line noise levels in excess of those listed in the appendix. These requirements are particularly difficult to comply with for air cooled chillers and emergency generators. With proper, and more expensive, design even emergency generators can be located very close to the property line. In some states, e.g., Illinois, state codes may be even stricter. Still, proper acoustical design can comply in virtually all cases. An example of this is the emergency generator shown in Figure 1. The picket fence is on the property line, and the property line noise levels comply with even the extremely strict requirements of Illinois Title 35.
SPEECH PRIVACY AND SPEECH INTELLIGIBILITY
Designs must comply with one of four “unintelligibility” standards. Basically, people in adjoining rooms should not be able to understand information spoken by a person in an adjoining room. These indices are quite complex, and the services of an acoustical expert are recommended.
There is a prescriptive requirement for normally occupied health care facilities to incorporate acoustic finishes that achieve average noise reduction coefficients (NRC) that comply with Table 1.2-1. NRC is a rating of the percentage of noise in the speech frequencies that is absorbed by materials. An NRC of 0.8 for a ceiling panel indicates that 80% of the sound striking it is absorbed.
For example, patient rooms must have surfaces that have an average NRC of at least 0.15. This is low compared to normal office design, but if a patient room uses gypsum board walls and ceiling and vinyl tile flooring, it will fail to comply with this requirement by a wide margin. The goal of this requirement is that there should be enough sound absorption that staff and patients can understand instructions without echoes causing confusion. There are several acoustical ceiling products that are cleanable and can make any normal room comply without the need for other absorptive surfaces. There is also at least one product available that can make walls absorb noise and still be very cleanable and paintable.
Another requirement that is intended to improve patient privacy is Table 1.2-3, which calls out minimum composite STC ratings for demising wall assemblies. For example, the demising wall between two patient rooms must have a STCc rating of at least 45. An example of a STC 45 wall is 3.5-in. metal studs filled with fiberglass, one layer of 5/8-in. gypsum board on one side of the studs, and two layers on the other side with a viscoelastic adhesive between them. This assumes a continuous wall with no openings, receptacles, medical gas outlets, or headwalls, which must be factored into the STC rating. One practical issue is that it is very difficult to comply with this requirement when a facility has back-to-back headwalls.
BACKGROUND NOISE LEVELS
Another problematic requirement is, “Room noise levels shall fall within the sound level ranges shown for the chosen rating system in Table 1.2-2” and “Room noise levels shall be determined for the unoccupied room”.
For example, patient rooms are required to have dBA levels between 35 and 45. Note that this is an acceptable range and not a minimum noise level. This is a huge difference from other standards, in that building HVAC systems can fail for being too quiet. Ten dBA is not a wide range of background noise levels, so this is likely to force designers to add sound masking systems in order to comply.
Another example is operating rooms, which have a required background noise level of 40 to 50 dBA. This can be challenging with the current requirement for 20 ach of supply air and the potential for return air noise caused by VAV return devices that keep the operating rooms under positive pressure.
Vibration is addressed in FGI-2010, however the text states, “Vibration should not exceed levels in ANSI S2.71.” The use of the term “should” makes this non-mandatory text. There is also a requirement that rotating or vibrating equipment shall be considered for vibration isolating (but not that it must be isolated).
In addition, it is required that the types of isolators and their static deflections shall be as recommended in most current edition of the 2011 ASHRAE Handbook – HVAC Applications. In my opinion, this wording should be revised in subsequent editions of the FGI code since there are many times when an acoustical engineer’s knowledge of the situation and equipment indicates that variations from the ASHRAE recommendations are justified.
There is a new requirement that the structural floor shall be designed to control footfall vibration velocities within the limits in Table 1.2-5. This can require stiffer and somewhat more expensive floor structures. It seems unlikely to me that reviewers will routinely test for this; however, if complaints are received, they might ask facilities to show evidence of compliance.
NEONATAL INTENSIVE CARE UNIT (NICU)
There are several new requirements for NICU areas. The combination of continuous background sound and operation al sound in the NICU and associated adult sleeping areas shall not exceed an hourly average sound level (Leq) of 45 dBA or an hourly L10 of 50 dBA (average noise level in the 10% of the loudest hours), and the loudest sounds shall not exceed 65 dBA. NICU ceilings must have a noise reduction coefficient (NRC) of at least 0.95 over at least 80% of the ceiling area, or an average NRC of at least 0.85 over the entire ceiling area.
In addition, ceilings in infant rooms and adult sleeping areas must have a ceiling attenuation class (CAC) of at least 29. The combination of high NRC (sound absorption) and CAC (sound blocking) requires special ceiling tiles.
NICU fire alarms should (non-mandatory) be of the flashing light type with no audible signal. Alarm sound levels in other occupied areas must (mandatory) be adjustable. Telephones audible from the NICU should (non-mandatory) have adjustable announcing signals.
NICUs shall include provisions for both indirect lighting and high-intensity lighting. Light sources shall have color rendering index (CRI) of at least 80. Compliance with two other color quality standards is also required; however those indices are not often applied in the USA. In my opinion, this provision should be changed in future editions of the guidelines to require compliance with any one of these criteria.
Direct ambient lighting is not permitted in the NICU, and ambient lighting in adjacent areas shall be arranged to avoid direct line of sight from any infant to the fixture.
HOSPITAL CONSUMER ASSESSMENT OF HEALTH CARE PROVIDERS AND SYSTEMS (HCAHPS)
HCAHPS is a quarterly standardized assessment that is made by adult inpatients of their perception of the total quality of care provided by health care organizations. HCAHPS scores are publicly available at www.hospitalcompare.hhs.gov/. This permits consumers to compare the ratings of different health care providers, and it may become a powerful factor in determining which health care organization consumers choose to patronize.
There are eight criteria in the HCAHPS survey. Two of these are summaries of the other six. One of the six performance criteria is, “Patients who reported that the area around their room was “Always” quiet at night.” Studies have shown that this criterion is, on average, the lowest score received by health care organizations.
Some proposals for health care reform include varying the payment to health care organizations based on their HCAHPS scores.
We are advising our clients to have an audit performed by an acoustical consultant, even if compliance with FGI-2010 is not mandatory for them today. Based on the results of the audit, health care facilities will have an understanding of how much they would be affected if FGI-2010 were to be adopted by their authority having jurisdiction. Often, the most desirable modifications are those that affect noise in patient rooms and emergency rooms. This is because they can have an immediate effect on HCAHPS scores and patient satisfaction, while providing progress toward future FGI-2010 compliance. ES