DAYLIGHTING HOSPITAL PATIENT ROOMS INTERIORS

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					         I N T ERI OR S
         The importance of surface reflectivity
         Daylighting depends on both the light received directly from                To take advantage of available daylighting, electric lighting
         the sky and light reflected from interior surfaces. Patient                 should be designed and controlled either by dimming, or by
         rooms with high internal reflectivity will have more light at the           switching off completely. A light sensor and continuous or step
         back of the room and more even light distribution. Minimum                  dimmer can maintain ambient illumination levels at a constant
         reflectivities should be: ceiling, 90 percent; walls, 70 percent;           value, based on the amount of daylight in the space.
         floors, 40 percent; and furniture and equipment, 70 percent;
                                                                                     As sky conditions change, automatic, dimmable, indirect
         to allow daylight to reflect off these surfaces and penetrate
                                                                                     lighting luminaires make an unnoticeable transition from
         further into the room.
                                                                                     electric lighting to daylighting and back.

         Daylighting integration with electric lighting
                                                                                     Patient control of daylighting
         Task-ambient electric lighting design strategies work well with
                                                                                     The ability to manipulate the environment, including bedside
         daylighting because room ambient light levels, lower than task
                                                                                     control of lighting and window shades, contributes to a patient’s
         lighting requirements, are easy to meet with daylight. Ambient
                                                                                     psychological outlook, rate of healing, and quality of stay.3
         daylight should be supplemented with task electric lighting to
         increase lighting levels where specific tasks are performed.


         1                                                               2                                                                   3
             Ulrich, R.S., “How Design Impacts Wellness,” Healthcare         Devlin, A.S. and Arrneill, A., Health Care Environments and         Ulrich, p.23
             Forum Journal, September–October 1992, vol. 35, pp. 20-25       Patient Outcomes: A Review of the Literature,” Environment
                                                                             and Behavior, September 2003, vol. 35, num. 5, pp. 665-694




                                                                                                                                                                            DAY L IGHT I NG HOSPI TA L PAT I EN T ROOMS
                                                                                                                                                                                                       A Summary of a Joint Research Study



                                                                                                                                                                What is a daylit patient room?                                    Will daylighting save energy?
                                                                                                                                                                A daylit patient room uses light from the sky for daytime         When daylighting is used to reduce ambient electric lighting,
                                                                                                                                                                illumination, effectively reducing the need for electric light.   lighting energy savings during daylight hours can be as high
                                                                                                                                                                The amount of daylight that comes into a room depends             as 87 percent.
Legacy Salmon Creek Hospital                                                                                                                                    upon the area and location of the window and the amount
                                                                                                                                                                of the sky the window “sees.” The distribution of that            Can it reduce the mechanical system size and cost?
                                                                                                                                                                light is a function of the window’s shape and location in         Daylighting provides more illumination per watt than electric
         This is a brief summary of conclusions from Daylighing Patient              Funding for this document and for Daylighting Patient Rooms                the window wall and the proportions of the room, room             lighting and therefore less heat. When combined with a
         Rooms in Northwest Hospitals, a 2005 study jointly undertaken               in Northwest Hospitals was provided by the BetterBricks                    reflectivity, and obstructions within the space.                  task-ambient lighting strategy that only puts light where it is
         by the Energy Studies in Buildings Laboratory, Department                   program, the commercial buildings initiative of the Northwest                                                                                needed, daylighting results in significantly less heat gain in a
         of Architecture, University of Oregon (G.Z. Brown, Jeff                     Energy Efficiency Alliance. Supported by local electric utilities,         Does it cost anything to daylight a patient room?                 room than typical electric lighting alternatives, reducing the
         Kline, Gina Livingston, Brooks McDonald, Crawford Smith,                    BetterBricks advocates for changes to energy-related business              If the hospital construction budget includes adequate             cooling load and the size and cost of the HVAC system.
         Mark Wilkerson) and Zimmer Gunsul Frasca Architects LLP                     practices in Northwest buildings.                                          window area, shades, and electric lights, only a control to
         (Johanna Brickman, David Staczek).                                                                                                                     turn off the lights, when daylight is available, must be added    Can daylighting improve patient well-being?
                                                                                                                                                                (a short payback). The first cost of the patient room can be      A patient room providing good outdoor views and daylighting
                                                                                                                                                                reduced if the design of the room’s structural, mechanical,       can increase patient well-being: a psychological state resulting
                                                                                                                                                                and daylight systems are considered together to lower the         in reduced stress and anxiety, lower blood pressure, improved
                                                                                                                                                                floor-to-floor height, while increasing ceiling height and        post-operative recovery, reduced need for pain medication,
                 Energy Studies in Buildings Laboratory                                                                                                         improving daylighting.                                            and shorter hospital stays.1
                         University of Oregon
 DESIGN I NG T HE DAY L I T PAT I EN T ROOM                                                                                Daylight and view window differences
                                                                                                                           Daylight and view windows, in patient rooms, have different
                                                                                                                           and sometimes conflicting requirements, and the most
                                                                                                                           straightforward design resolution is to separate these two
                                                                                                                           windows and their functions.
  A Positioning the toilet room                                                        B
 Outboard toilet rooms, placed along the exterior wall, greatly                                                             D The daylight window provides ambient light.
 reduce daylighting potential. For maximum daylighting benefit,
                                                                                                                            E The view window, while also admitting light into the room,
 toilet rooms should be located between two adjacent patient
                                                                                                                           functions primarily as the patient’s view to the outside, relieving
 rooms, or placed inboard, adjacent to the interior corridor.
                                                                                                                           stress, promoting relaxation, and even preventing delirium.2

                                                                                                                           The daylight window should be located with its head height as
                                                                                                                           high as possible in the wall and should extend the full width of
                                                                                                   D                       the room.
 Outboard                  Shared wall               Inboard
                                                                                                                           The view window should be sized and placed to allow views
                                                                                               E                           from the patient’s bed and, to reduce glare, should be shaded
                                                                                                           F               or of low visible light transmittance.
  B Room depth
                                                                                                       F                   There are two approaches to sizing the daylight window.
 The depth of the hospital room that
 can be usefully daylit is dependent on                                                                                    The first optimizes the size of the window for both daylighting
 the size and head height of the                                                                                           and thermal performance. The second sizes the window for
 daylight window. In our studies,                                                                                          maximum daylighting performance and uses shades,
                                                                                                                                                                                       F
 adequately daylit patient rooms, with                                                                                     light shelves and louvers to adjust its size, as needed, to
 inboard or shared toilets, ranged from                                                                                    maintain the best thermal performance, as conditions change.
                                                                                           A
 13 feet to 19 feet deep. Shallower
 rooms are most desirable, because                                                                                         Glazing specifications
 they facilitate more even daylight                                                                                        Daylight windows should, ideally, have low u-values, low
 distribution to the back of the room.                                                                                     solar heat gain coefficients (SHGC), and high visible light
                                                                                                                           transmission (VLT). Depending upon the climate and a room’s
  C Ceiling configuration and HVAC duct location                                                                           aperture control capabilities, either the R-value or SHGC
 Higher ceilings allow higher windows and deeper daylight                                              A                   may be relatively more important. Because they are not used
 penetration. An angled ceiling, sloping down from the                                                                     for daylighting, view windows can have a lower visual light
 bottom of the structure at the outboard wall to the nominal                                                               transmission and therefore, lower u-values and lower SHGC.
 ceiling height at the inboard wall (achieved by moving ducts
 away from the perimeter toward the corridor side of the room),                                                            The best window wall configurations
 will allow a higher window head height.                                                                                   In plan, an angled window wall can have a different orientation
                                                                                                                           than the rest of the building and potentially achieve better
 Typical hospital patient rooms place a supply duct along the building
                                                                                                                           daylighting performance. If the window wall is notched, or is
 perimeter to offset drafts from glazing. High performance glazing
                                                                                                                           designed with a corner window, the view window can have a
 allows the use of systems that can be located away from the exterior
                                                                                                                           different orientation than the daylight window.
 window, providing greater design flexibility for the integration of ceilings
 with daylight window head heights, within a given floor-to-floor height.




15’ 0”                             12’ 6”                       12’ 0”




   Flat ceiling; typical             Stepped ceiling; steel       Sloped ceiling;
   steel structure                   structure; upturned beam     concrete structure                           Angled window wall                       Notched window wall

				
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